Guidance for Industry
Sterile Drug Products Produced
by
Aseptic Processing — Current
Good Manufacturing Practice
This guidance represents the Food
and Drug Administration's (FDA's) current thinking on this topic. It does not
create or confer any rights for or on any person and does not operate to bind
FDA or the public. You can use an alternative approach if the approach
satisfies the requirements of the applicable statutes and regulations. If you
want to discuss an alternative approach, contact the FDA staff responsible for
implementing this guidance. If you cannot identify the appropriate FDA staff,
call the appropriate number listed on the title page of this guidance.
This guidance is
intended to help manufacturers meet the requirements in the Agency's current
good manufacturing practice (CGMP) regulations (2l CFR parts 210 and 211) when
manufacturing sterile drug and biological products using aseptic processing.
This guidance replaces the 1987 Industry Guideline on Sterile Drug Products
Produced by Aseptic Processing (Aseptic Processing Guideline). This revision
updates and clarifies the 1987 guidance.
For sterile drug
products subject to a new or abbreviated drug application (NDA or ANDA) or a
biologic license application (BLA), this guidance document should be read in
conjunction with the guidance on the content of sterile drug applications
entitled Guideline for the Submission of Documentation for Sterilization
Process Validation in Applications for Human and Veterinary Drug Products
(Submission Guidance). The Submission Guidance describes the types of
information and data that should be included in drug applications to
demonstrate the efficacy of a manufacturer's sterilization process. This
guidance compliments the Submission Guidance by describing procedures and
practices that will help enable a sterile drug manufacturing facility to meet
CGMP requirements relating, for example, to facility design, equipment
suitability, process validation, and quality control.
FDA's guidance documents, including this guidance, do not
establish legally enforceable responsibilities. Instead, guidances describe
the Agency's current thinking on a topic and should be viewed only as
recommendations, unless specific regulatory or statutory requirements are
cited. The use of the word should in Agency guidances means that something
is suggested or recommended, but not required.
The text boxes included in this guidance include
specific sections of parts 210 and 211 of the Code of Federal Regulations
(CFR), which address current good manufacturing practice for drugs. The intent
of including these quotes in the text boxes is to aid the reader by providing a
portion of an applicable regulation being addressed in the guidance. The
quotes included in the text boxes are not intended to be exhaustive. Readers
of this document should reference the complete CFR to ensure that they have
complied, in full, with all relevant sections of the regulations.
This section describes
briefly both the regulatory and technical reasons why the Agency is developing
this guidance document.
This guidance pertains
to current good manufacturing practice (CGMP) regulations (21 CFR parts 210 and
211) when manufacturing sterile drug and biological products using aseptic
processing. Although the focus of this guidance is on CGMPs in 21 CFR 210 and
211, supplementary requirements for biological products are in 21 CFR 600-680.
For biological products regulated under 21 CFR parts 600 through 680, §§
210.2(a) and 211.1(b) provide that where it is impossible to comply with the
applicable regulations in both parts 600 through 680 and parts 210 and 211, the
regulation specifically applicable to the drug product in question shall
supercede the more general regulations.
There are basic
differences between the production of sterile drug products using aseptic
processing and production using terminal sterilization.
Terminal sterilization
usually involves filling and sealing product containers under high-quality
environmental conditions. Products are filled and sealed in this type of
environment to minimize the microbial and particulate content of the in-process
product and to help ensure that the subsequent sterilization process is
successful. In most cases, the product, container, and closure have low
bioburden, but they are not sterile. The product in its final container is then
subjected to a sterilization process such as heat or irradiation.
In an aseptic process,
the drug product, container, and closure are first subjected to sterilization
methods separately, as appropriate, and then brought together. Because there is no process to sterilize the
product in its final container, it is critical that containers be filled and
sealed in an extremely high-quality environment. Aseptic processing involves
more variables than terminal sterilization. Before aseptic assembly into a final product, the
individual parts of the final product are generally subjected to various
sterilization processes. For example, glass containers are subjected to dry heat;
rubber closures are subjected to moist heat; and liquid dosage forms are
subjected to filtration. Each of
these manufacturing processes requires validation and control. Each process
could introduce an error that ultimately could lead to the distribution of a
contaminated product. Any manual or mechanical manipulation of the sterilized
drug, components, containers, or closures prior to or during aseptic assembly
poses the risk of contamination and thus necessitates careful control. A
terminally sterilized drug product, on the other hand, undergoes final
sterilization in a sealed container, thus limiting the possibility of error.
Sterile drug manufacturers should have a keen awareness of
the public health implications of distributing a nonsterile product. Poor CGMP
conditions at a manufacturing facility can ultimately pose a life-threatening
health risk to a patient.
This guidance document
discusses selected issues and does not address all aspects of aseptic
processing. For example, the guidance addresses primarily finished drug
product CGMP issues while only limited information is provided regarding
upstream bulk processing steps. This guidance updates the 1987 Aseptic
Processing Guideline primarily with respect to personnel qualification,
cleanroom design, process design, quality control, environmental monitoring,
and review of production records. The use of isolators for aseptic processing
is also discussed.
Although this guidance
document discusses CGMP issues relating to the sterilization of components,
containers, and closures, terminal sterilization of drug products is not
addressed. It is a well-accepted principle that sterile drugs should be
manufactured using aseptic processing only when terminal sterilization is not
feasible. However, some final packaging may afford some unique and
substantial advantage (e.g., some dual-chamber syringes) that would not be
possible if terminal sterilization were employed. In such cases, a
manufacturer can explore the option of adding adjunct processing steps to
increase the level of sterility assurance.
A list of references
that may be of value to the reader is included at the conclusion of this
document.
21 CFR 211.42(b) states, in part, that “The
flow of components, drug product containers, closures, labeling, in-process
materials, and drug products through the building or buildings shall be
designed to prevent contamination.”
21 CFR 211.42(c) states, in
part, that “Operations
shall be performed within specifically defined areas of adequate size. There
shall be separate or defined areas or such other control systems for the
firm’s operations as are necessary to prevent contamination or mixups during
the course of the following procedures: * * * (10) Aseptic processing, which
includes as appropriate: (i) Floors, walls, and ceilings of smooth, hard
surfaces that are easily cleanable; (ii) Temperature and humidity controls;
(iii) An air supply filtered through high-efficiency particulate air filters
under positive pressure, regardless of whether flow is laminar or nonlaminar;
(iv) A system for monitoring environmental conditions; (v) A system for
cleaning and disinfecting the room and equipment to produce aseptic
conditions; (vi) A system for maintaining any equipment used to control the
aseptic conditions.”
21 CFR 211.46(c) states, in
part, that “Air
filtration systems, including prefilters and particulate matter air filters,
shall be used when appropriate on air supplies to production areas * * *.”
21 CFR 211.63 states that “Equipment used in the
manufacture, processing, packing, or holding of a drug product shall be of
appropriate design, adequate size, and suitably located to facilitate
operations for its intended use and for its cleaning and maintenance.”
21 CFR 211.65(a) states that
“Equipment shall
be constructed so that surfaces that contact components, in-process
materials, or drug products shall not be reactive, additive, or absorptive so
as to alter the safety, identity, strength, quality, or purity of the drug
product beyond the official or other established requirements.”
21 CFR 211.67(a) states that
“Equipment and
utensils shall be cleaned, maintained, and sanitized at appropriate intervals
to prevent malfunctions or contamination that would alter the safety,
identity, strength, quality, or purity of the drug product beyond the
official or other established requirements.”
21 CFR 211.113(b) states that
“Appropriate
written procedures, designed to prevent microbiological contamination of drug
products purporting to be sterile, shall be established and followed. Such
procedures shall include validation of any sterilization process.”
|
As provided for in the
regulations, separate or defined areas of operation in an aseptic processing
facility should be appropriately controlled to attain different degrees of air
quality depending on the nature of the operation. Design of a given area
involves satisfying microbiological and particle criteria as defined by the
equipment, components, and products exposed, as well as the operational
activities conducted in the area.
Clean area control
parameters should be supported by microbiological and particle data obtained
during qualification studies. Initial cleanroom qualification includes, in
part, an assessment of air quality under as-built, static conditions. It is
important for area qualification and classification to place most emphasis on
data generated under dynamic conditions (i.e., with personnel present,
equipment in place, and operations ongoing). An adequate aseptic processing
facility monitoring program also will assess conformance with specified clean
area classifications under dynamic conditions on a routine basis.
The following table
summarizes clean area air classifications and recommended action levels of
microbiological quality (Ref. 1).
TABLE
1- Air Classificationsa
Clean Area Classification
(0.5 um particles/ft3)
|
ISO
Designationb
|
> 0.5 mm particles/m3
|
Microbiological Active Air Action Levelsc
(cfu/m3 )
|
Microbiological Settling Plates Action Levelsc,d
(diam. 90mm; cfu/4 hours)
|
100
|
5
|
3,520
|
1e
|
1e
|
1000
|
6
|
35,200
|
7
|
3
|
10,000
|
7
|
352,000
|
10
|
5
|
100,000
|
8
|
3,520,000
|
100
|
50
|
a-
All
classifications based on data measured in the vicinity of exposed
materials/articles during periods of activity.
b-
ISO 14644-1 designations
provide uniform particle concentration values for cleanrooms in multiple
industries. An ISO 5 particle concentration is equal to Class 100 and
approximately equals EU Grade A.
c- Values represent recommended
levels of environmental quality. You may find it appropriate to establish
alternate microbiological action levels due to the nature of the operation or method of
analysis.
d-
The additional use
of settling plates is optional.
e-
Samples from
Class 100 (ISO 5) environments should normally yield no microbiological
contaminants.
Two clean areas are of
particular importance to sterile drug product quality: the critical area and
the supporting clean areas associated with it.
A. Critical Area – Class 100 (ISO 5)
A critical area is one
in which the sterilized drug product, containers, and closures are exposed to
environmental conditions that must be designed to maintain product sterility (§
211.42(c)(10)). Activities conducted in such areas include manipulations
(e.g., aseptic connections, sterile ingredient additions) of sterile materials
prior to and during filling and closing operations.
This area is critical
because an exposed product is vulnerable to contamination and will not be
subsequently sterilized in its immediate container. To maintain product
sterility, it is essential that the environment in which aseptic operations
(e.g., equipment setup, filling) are conducted be controlled and maintained at
an appropriate quality. One aspect of environmental quality is the particle
content of the air. Particles are significant because they can enter a product
as an extraneous contaminant, and can also contaminate it biologically by
acting as a vehicle for microorganisms (Ref. 2). Appropriately designed air
handling systems minimize particle content of a critical area.
Air in the immediate
proximity of exposed sterilized containers/closures and filling/closing
operations would be of appropriate particle quality when it has a
per-cubic-meter particle count of no more than 3520 in a size range of 0.5 mm and
larger when counted at representative locations normally not more than 1 foot
away from the work site, within the airflow, and during filling/closing
operations. This level of air cleanliness is also known as Class 100 (ISO
5).
We recommend that
measurements to confirm air cleanliness in critical areas be taken at sites
where there is most potential risk to the exposed sterilized product,
containers, and closures. The particle counting probe should be placed in an
orientation demonstrated to obtain a meaningful sample. Regular monitoring
should be performed during each production shift. We recommend conducting
nonviable particle monitoring with a remote counting system. These systems are
capable of collecting more comprehensive data and are generally less invasive
than portable particle counters. See Section X.E. for additional guidance on
particle monitoring.
Some operations can
generate high levels of product (e.g., powder) particles that, by their nature,
do not pose a risk of product contamination. It may not, in these cases, be
feasible to measure air quality within the one-foot distance and still
differentiate background levels of particles from air contaminants. In these
instances, air can be sampled in a manner that, to the extent possible,
characterizes the true level of extrinsic particle contamination to which the
product is exposed. Initial qualification of the area under dynamic conditions
without the actual filling function provides some baseline information on the
non-product particle generation of the operation.
HEPA-filtered air should be supplied in critical areas at a
velocity sufficient to sweep particles away from the filling/closing area and
maintain unidirectional airflow during operations. The velocity parameters
established for each processing line should be justified and appropriate to
maintain unidirectional
airflow and air quality under dynamic conditions within the critical area (Ref.
3).
Proper design and
control prevents turbulence and stagnant air in the critical area. Once
relevant parameters are established, it is crucial that airflow patterns be
evaluated for turbulence or eddy currents that can act as a channel or
reservoir for air contaminants (e.g., from an adjoining lower classified
area). In situ air pattern analysis should be conducted at the critical
area to demonstrate unidirectional airflow and sweeping action over and away
from the product under dynamic conditions. The studies should be well
documented with written conclusions, and include evaluation of the impact of
aseptic manipulations (e.g., interventions) and equipment design. Videotape or
other recording mechanisms have been found to be useful aides in assessing
airflow initially as well as facilitating evaluation of subsequent equipment
configuration changes. It is important to note that even successfully
qualified systems can be compromised by poor operational, maintenance, or
personnel practices.
Air
monitoring samples of critical areas should normally yield no microbiological contaminants.
We recommend affording appropriate investigative attention to contamination
occurrences in this environment.
Supporting clean areas
can have various classifications and functions. Many support areas function as
zones in which nonsterile components, formulated products, in-process
materials, equipment, and container/closures are prepared, held, or
transferred. These environments are soundly designed when they minimize the
level of particle contaminants in the final product and control the
microbiological content (bioburden) of articles and components that are
subsequently sterilized.
The nature of the
activities conducted in a supporting clean area determines its classification.
FDA recommends that the area immediately adjacent to the aseptic processing
line meet, at a minimum, Class 10,000 (ISO 7) standards (see Table 1) under
dynamic conditions. Manufacturers can also classify this area as Class 1,000
(ISO 6) or maintain the entire aseptic filling room at Class 100 (ISO 5). An
area classified at a Class 100,000 (ISO 8) air cleanliness level is appropriate
for less critical activities (e.g., equipment cleaning).
An essential part of
contamination prevention is the adequate separation of areas of operation. To
maintain air quality, it is important to achieve a proper airflow from areas of
higher cleanliness to adjacent less clean areas. It is vital for rooms of higher air cleanliness
to have a substantial positive
pressure differential relative to adjacent rooms of lower air cleanliness. For
example, a positive pressure differential of at least 10-15 Pascals (Pa) should be maintained between adjacent rooms of
differing classification (with doors closed). When doors are open, outward airflow should be sufficient to
minimize ingress of contamination, and it is critical that the time a door can
remain ajar be strictly controlled (Ref. 4).
In some cases, the
aseptic processing room and adjacent cleanrooms have the same classification.
Maintaining a pressure differential (with doors closed) between the aseptic
processing room and these adjacent rooms can provide beneficial separation. In
any facility designed with an unclassified room adjacent to the aseptic
processing room, a substantial overpressure (e.g., at least 12.5 Pa) from the
aseptic processing room should be maintained at all times to prevent contamination. If this pressure differential drops below the
minimum limit, it is important that the environmental quality of the aseptic
processing room be restored and confirmed.
The Agency recommends
that pressure differentials between cleanrooms be monitored continuously
throughout each shift and frequently recorded. All alarms should be documented
and deviations from established limits should be investigated.
Air change rate is
another important cleanroom design parameter. For Class 100,000 (ISO 8)
supporting rooms, airflow sufficient to achieve at least 20 air changes per
hour is typically acceptable. Significantly higher air change rates are
normally needed for Class 10,000 and Class 100 areas.
A suitable facility
monitoring system will rapidly detect atypical changes that can compromise the
facility’s environment. An effective system facilitates restoration of
operating conditions to established, qualified levels before reaching action
levels. For example, pressure differential specifications should enable prompt
detection (i.e., alarms) of an emerging low pressure problem to preclude
ingress of unclassified air into a classified room.
A compressed gas should
be of appropriate purity (e.g., free from oil) and its microbiological and
particle quality after filtration should be equal to or better than that of the
air in the environment into which the gas is introduced. Compressed gases such
as air, nitrogen, and carbon dioxide are often used in cleanrooms and are
frequently employed in purging or overlaying.
Membrane filters can be
used to filter a compressed gas to meet an appropriate high-quality standard.
These filters are often used to produce a sterile compressed gas to conduct
operations involving sterile materials, such as components and equipment. For
example, we recommend that sterile membrane filters be used for autoclave air lines,
lyophilizer vacuum breaks, and tanks containing sterilized materials.
Sterilized holding tanks and any contained liquids should be held under
positive pressure or appropriately sealed to prevent microbial contamination.
Safeguards should be in place to prevent a pressure change that can result in
contamination due to back flow of nonsterile air or liquid.
Gas filters (including
vent filters) should be dry. Condensate on a gas filter can cause blockage
during use or allow for the growth of microorganisms. Use of hydrophobic
filters, as well as application of heat to these filters where appropriate,
prevents problematic moisture residues. We recommend that filters that serve
as sterile boundaries or supply sterile gases that can affect product be integrity
tested upon installation and periodically thereafter (e.g., end of use).
Integrity tests are also recommended after activities that may damage the
filter. Integrity test failures should be investigated, and filters should be
replaced at appropriate, defined intervals.
HEPA filter integrity
should be maintained to ensure aseptic conditions. Leak testing should be
performed at installation to detect integrity breaches around the sealing
gaskets, through the frames, or through various points on the filter media.
Thereafter, leak tests should be performed at suitable time intervals for HEPA
filters in the aseptic processing facility. For example, such testing should
be performed twice a year for the aseptic processing room. Additional testing
may be appropriate when air quality is found to be unacceptable, facility
renovations might be the cause of disturbances to ceiling or wall structures,
or as part of an investigation into a media fill or drug product sterility
failure. Among the filters that should be leak tested are those installed in
dry heat depyrogenation tunnels and ovens commonly used to depyrogenate glass
vials. Where justified, alternate methods can be used to test HEPA filters in
the hot zones of these tunnels and ovens.
Any aerosol used for
challenging a HEPA filter should meet specifications for critical
physicochemical attributes such as viscosity. Dioctylphthalate (DOP) and
poly-alpha-olefin (PAO) are examples of appropriate leak testing aerosols.
Some aerosols are problematic because they pose the risk of microbial
contamination of the environment being tested. Accordingly, the evaluation of
any alternative aerosol involves ensuring it does not promote microbial growth.
There is a major
difference between filter leak testing and efficiency testing. An
efficiency test is a general test used to determine the rating of the filter. An intact HEPA filter should be capable of
retaining at least 99.97 percent of particulates greater than 0.3 mm in
diameter.
The purpose of
performing regularly scheduled leak tests, on the other hand, is to detect
leaks from the filter media, filter frame, or seal. The challenge involves use
of a polydispersed aerosol usually composed of particles with a light-scattering
mean droplet diameter in the submicron size range, including a sufficient number of particles at
approximately 0.3 mm. Performing a leak test without introducing a
sufficient upstream challenge of particles of known size upstream of the filter
is ineffective for detecting leaks. It is important to introduce an aerosol
upstream of the filter in a concentration that is appropriate for the accuracy
of the aerosol photometer. The leak test should be done in place, and the
filter face scanned on the downstream side with an appropriate photometer
probe, at a sampling rate of at least one cubic foot per minute. The
downstream leakage measured by the probe should then be calculated as a percent
of the upstream challenge. An appropriate scan should be conducted on the
entire filter face and frame, at a position about one to two inches from the
face of the filter. This comprehensive scanning of HEPA filters should be
fully documented.
A single probe reading
equivalent to 0.01 percent of the upstream challenge would be considered as
indicative of a significant leak and calls for replacement of the HEPA filter
or, when appropriate, repair in a limited area. A subsequent confirmatory
retest should be performed in the area of any repair.
HEPA filter leak
testing alone is insufficient to monitor filter performance. It is important
to conduct periodic monitoring of filter attributes such as uniformity of
velocity across the filter (and relative to adjacent filters). Variations in
velocity can cause turbulence that increases the possibility of contamination.
Velocities of unidirectional air should be measured 6 inches from the filter
face and at a defined distance proximal to the work surface for HEPA filters in
the critical area. Velocity monitoring at suitable intervals can provide
useful data on the critical area in which aseptic processing is performed. The
measurements should correlate to the velocity range established at the time of
in situ air pattern analysis studies. HEPA filters should be replaced when
nonuniformity of air velocity across an area of the filter is detected or
airflow patterns may be adversely affected.
Although contractors
often provide these services, drug manufacturers are responsible for ensuring
that equipment specifications, test methods, and acceptance criteria are
defined, and that these essential certification activities are conducted
satisfactorily.
Note: The design
concepts discussed within this section are not intended to be exhaustive.
Other appropriate technologies that achieve increased sterility assurance are
also encouraged.
Aseptic
processes are designed to minimize exposure of sterile articles to the
potential contamination hazards of the manufacturing operation. Limiting the
duration of exposure of sterile product elements, providing the highest
possible environmental control, optimizing process flow, and designing
equipment to
prevent entrainment of lower quality air into the Class 100 (ISO 5) clean area are essential to achieving high
assurance of sterility (Ref. 4).
Both personnel and
material flow should be optimized to prevent unnecessary activities that could
increase the potential for introducing contaminants to exposed product,
container-closures, or the surrounding environment. The layout of equipment
should provide for ergonomics that optimize comfort and movement of operators.
The number of personnel in an aseptic processing room should be minimized. The
flow of personnel should be designed to limit the frequency with which entries
and exits are made to and from an aseptic processing room and, most
significant, its critical area. Regarding the latter, the number of transfers
into the critical area of a traditional cleanroom, or an isolator, should be
minimized. To prevent changes in air currents that introduce lower quality
air, movement adjacent to the critical area should be appropriately restricted.
Any intervention or
stoppage during an aseptic process can increase the risk of contamination. The
design of equipment used in aseptic processing should limit the number and
complexity of aseptic interventions by personnel. For example, personnel
intervention can be reduced by integrating an on-line weight check device, thus
eliminating a repeated manual activity within the critical area. Rather than
performing an aseptic connection, sterilizing the preassembled connection using
sterilize-in-place (SIP) technology also can eliminate a significant aseptic
manipulation. Automation of other process steps, including the use of technologies
such as robotics, can further reduce risk to the product.
Products should be
transferred under appropriate cleanroom conditions. For example,
lyophilization processes include transfer of aseptically filled product in
partially sealed containers. To prevent contamination, a partially closed
sterile product should be transferred only in critical areas. Facility design should ensure that the area
between a filling line and the lyophilizer provide for Class 100 (ISO 5)
protection. Transport and loading procedures should afford the same protection.
The sterile drug
product and its container-closures should be protected by equipment of suitable
design. Carefully designed curtains and rigid plastic shields are among the
barriers that can be used in appropriate locations to achieve segregation of
the aseptic processing line. Use of an isolator system further enhances
product protection (see Appendix 1).
Due to the
interdependence of the various rooms that make up an aseptic processing
facility, it is essential to carefully define and control the dynamic
interactions permitted between cleanrooms. Use of a double-door or integrated
sterilizer helps ensure direct product flow, often from a lower to a higher
classified area. Airlocks and interlocking doors will facilitate better
control of air balance throughout the aseptic processing facility. Airlocks
should be installed between the aseptic manufacturing area entrance and the
adjoining unclassified area. Other interfaces such as personnel transitions or
material staging areas are appropriate locations for air locks. It is critical
to adequately control material (e.g., in-process supplies, equipment, utensils)
as it transfers from lesser to higher classified clean areas to prevent the
influx of contaminants. For example, written procedures should address how
materials are to be introduced into the aseptic processing room to ensure that
room conditions remain uncompromised. In this regard, materials should be
disinfected according to appropriate procedures or, when used in critical
areas, rendered sterile by a suitable method.
If stoppered vials exit an aseptic processing zone or room
prior to capping, appropriate assurances should be in place to safeguard the
product, such as local protection until completion of the crimping step. Use
of devices for on-line detection of improperly seated stoppers can provide
additional assurance.
Cleanrooms are normally
designed as functional units with specific purposes. The materials of
construction of cleanrooms ensure ease of cleaning and sanitizing. Examples of
adequate design features include seamless and rounded floor to wall junctions
as well as readily accessible corners. Floors, walls, and ceilings should be
constructed of smooth, hard surfaces that can be easily cleaned. Ceilings and
associated HEPA filter banks should be designed to protect sterile materials
from contamination. Cleanrooms also should not contain unnecessary equipment,
fixtures, or materials.
Processing equipment
and systems should be equipped with sanitary fittings and valves. With rare
exceptions, drains are considered inappropriate for classified areas of the
aseptic processing facility other than Class 100,000 (ISO 8) areas. It is
essential that any drain installed in an aseptic processing facility be of
suitable design.
Equipment should be
appropriately designed (§ 211.63) to facilitate ease of sterilization. It is
also important to ensure ease of installation to facilitate aseptic setup. The
effect of equipment design on the cleanroom environment should be addressed.
Horizontal surfaces or ledges that accumulate particles should be avoided.
Equipment should not obstruct airflow and, in critical areas, its design should
not disturb unidirectional airflow.
Deviation or change
control systems should address atypical conditions posed by shutdown of air
handling systems or other utilities, and the impact of construction activities
on facility control. Written procedures should address returning a facility to
operating conditions following a shutdown.
21 CFR 211.22(a) states
that “There shall be a quality control unit that shall have the
responsibility and authority to approve or reject all components, drug
product containers, closures, in-process materials, packaging material,
labeling, and drug products, and the authority to review production records
to assure that no errors have occurred or, if errors have occurred, that they
have been fully investigated. The quality control unit shall be responsible
for approving or rejecting drug products manufactured, processed, packed, or
held under contract by another company.”
21 CFR 211.22(c) states that
“The quality control unit shall have
the responsibility for approving or rejecting all procedures or
specifications impacting on the identity, strength, quality, and purity of
the drug product.”
21
CFR 211.25(a) states that “Each person engaged in the manufacture, processing,
packing, or holding of a drug product shall have education, training, and
experience, or any combination thereof, to enable that person to perform the
assigned functions. Training shall be in the particular operations that the
employee performs and in current good manufacturing practice (including the current
good manufacturing practice regulations in this chapter and written
procedures required by these regulations) as they relate to the employee's
functions. Training in current good manufacturing practice shall be conducted
by qualified individuals on a continuing basis and with sufficient frequency
to assure that employees remain familiar with CGMP requirements applicable to
them.”
21
CFR 211.25(b) states that “Each person responsible for supervising the
manufacture, processing, packing, or holding of a drug product shall have the
education, training, and experience, or any combination thereof, to perform
assigned functions in such a manner as to provide assurance that the drug
product has the safety, identity, strength, quality, and purity that it purports
or is represented to possess.”
21
CFR 211.25(c) states that “There shall be an adequate number of qualified personnel to perform and supervise the
manufacture, processing, packing, or holding of each drug product.”
21
CFR 211.28(a) states that “Personnel engaged in the manufacture, processing, packing, or holding of a drug
product shall wear clean clothing appropriate for the
duties they perform. Protective apparel, such as head, face, hand, and arm
coverings, shall be worn as necessary to protect drug products from
contamination.”
21
CFR 211.28(b) states that “Personnel shall practice good sanitation and health
habits.”
21
CFR 211.28(c) states that “Only
personnel authorized by supervisory personnel shall enter those areas of the
buildings and facilities designated as limited‑access areas.”
21 CFR 211.28(d) states that
“Any person
shown at any time (either by medical examination or supervisory observation)
to have an apparent illness or open lesions that may adversely affect the
safety or quality of drug products shall be excluded from direct contact with
components, drug product containers, closures, in-process materials, and drug
products until the condition is corrected or determined by competent medical
personnel not to jeopardize the safety or quality of drug products. All
personnel shall be instructed to report to supervisory personnel any health
conditions that may have an adverse effect on drug products.”
21 CFR 211.42(c) states, in part, that “Operations
shall be performed within specifically defined areas of adequate size. There
shall be separate or defined areas or such other control systems for the
firm’s operations as are necessary to prevent contamination or mixups during
the course of the following procedures: * * * (10) Aseptic processing, which
includes as appropriate: * * * (iv) A system for monitoring environmental
conditions * * *.”
21
CFR 211.113(b) states that “Appropriate written procedures, designed to prevent
microbiological contamination of drug products purporting to be sterile,
shall be established and followed. Such procedures shall include validation
of any sterilization process.”
|
A well-designed, maintained, and operated aseptic process minimizes
personnel intervention. As operator activities increase in an aseptic
processing operation, the risk to finished product sterility also increases. To
ensure maintenance of product sterility, it is critical for operators involved
in aseptic activities to use aseptic technique at all times.
Appropriate training should be conducted before an
individual is permitted to enter the aseptic manufacturing area. Fundamental training topics should include
aseptic technique, cleanroom behavior, microbiology, hygiene, gowning, patient
safety hazards posed by a nonsterile drug product, and the specific written
procedures covering aseptic manufacturing area operations. After initial
training, personnel should participate regularly in an ongoing training
program. Supervisory personnel should routinely evaluate each operator’s
conformance to written procedures during actual operations. Similarly, the
quality control unit should provide regular oversight of adherence to
established, written procedures and aseptic technique during manufacturing
operations.
Some of the techniques
aimed at maintaining sterility of sterile items and surfaces include:
·
Contact sterile materials
only with sterile instruments
Sterile
instruments should always be used in the handling of sterilized materials.
Between uses, sterile instruments should be held under Class 100 (ISO 5)
conditions and maintained in a manner that prevents contamination (e.g., placed
in sterilized containers). Instruments should be replaced as necessary
throughout an operation.
After
initial gowning, sterile gloves should be regularly sanitized or changed, as
appropriate, to minimize the risk of contamination. Personnel should not
directly contact sterile products, containers, closures, or critical surfaces
with any part of their gown or gloves.
·
Move slowly and
deliberately
Rapid
movements can create unacceptable turbulence in a critical area. Such
movements disrupt the unidirectional airflow, presenting a challenge beyond
intended cleanroom design and control parameters. The principle of slow, careful
movement should be followed throughout the cleanroom.
·
Keep the entire body out of
the path of unidirectional airflow
Unidirectional
airflow design is used to protect sterile equipment surfaces,
container-closures, and product. Disruption of the path of unidirectional flow
air in the critical area can pose a risk to product sterility.
·
Approach a necessary
manipulation in a manner that does not compromise sterility of the product
To
maintain sterility of nearby sterile materials, a proper aseptic manipulation
should be approached from the side and not above the product (in vertical
unidirectional flow operations). Also, operators should refrain from speaking when in direct
proximity to the critical area.
·
Maintain Proper Gown Control
Prior
to and throughout aseptic operations, an operator should not engage in any
activity that poses an unreasonable contamination risk to the gown.
Only personnel who are
qualified and appropriately gowned should be permitted access to the aseptic
manufacturing area. The gown should provide a barrier between the body and
exposed sterilized materials and prevent contamination from particles generated
by, and microorganisms shed from, the body. The Agency recommends gowns that
are sterilized and nonshedding, and cover the skin and hair (face-masks, hoods,
beard/moustache covers, protective goggles, and elastic gloves are examples of
common elements of gowns). Written procedures should detail the methods used
to don each gown component in an aseptic manner. An adequate barrier should be
created by the overlapping of gown components (e.g., gloves overlapping
sleeves). If an element of a gown is found to be torn or defective, it should
be changed immediately. Gloves should be sanitized frequently.
There should be an
established program to regularly assess or audit conformance of personnel to
relevant aseptic manufacturing requirements. An aseptic gowning qualification
program should assess the ability of a cleanroom operator to maintain the
quality of the gown after performance of gowning procedures. We recommend that
this assessment include microbiological surface sampling of several locations
on a gown (e.g., glove fingers, facemask, forearm, chest). Sampling sites
should be justified. Following an initial assessment of gowning, periodic
requalification will provide for the monitoring of various gowning locations
over a suitable period to ensure consistent acceptability of aseptic gowning
techniques. Annual requalification is normally sufficient for those automated
operations where personnel involvement is minimized and monitoring data
indicate environmental control. For any aseptic processing operation, if
adverse conditions occur, additional or more frequent requalification could be
indicated.
To protect exposed
sterilized product, personnel should to maintain gown quality and strictly
adhere to appropriate aseptic techniques. Written procedures should adequately
address circumstances under which personnel should be retrained, requalified,
or reassigned to other areas.
The basic principles of training, aseptic technique, and personnel
qualification in aseptic manufacturing also are applicable to those performing
aseptic sampling and microbiological laboratory analyses. Processes and
systems cannot be considered to be in control and reproducible if the validity
of data produced by the laboratory is in question.
Personnel can
significantly affect the quality of the environment in which the sterile
product is processed. A vigilant and responsive personnel monitoring program
should be established. Monitoring should be accomplished by obtaining surface
samples of each operator's gloves on a daily basis, or in association with each
lot. This sampling should be accompanied by an appropriate sampling frequency
for other strategically selected locations of the gown (Ref. 5). The quality
control unit should establish a more comprehensive monitoring program for
operators involved in operations which are especially labor intensive (i.e.,
those requiring repeated or complex aseptic manipulations).
Asepsis is fundamental
to an aseptic processing operation. An ongoing goal for manufacturing
personnel in the aseptic processing room is to maintain contamination-free gloves
and gowns throughout operations. Sanitizing gloves just prior to sampling is
inappropriate because it can prevent recovery of microorganisms that were
present during an aseptic manipulation. When operators exceed established
levels or show an adverse trend, an investigation should be conducted
promptly. Follow-up actions can include increased sampling, increased
observation, retraining, gowning requalification, and in certain instances,
reassignment of the individual to operations outside of the aseptic
manufacturing area. Microbiological trending systems, and assessment of the
impact of atypical trends, are discussed in more detail under Section X.
Laboratory Controls.
21
CFR 210.3(b)(3) states that “Component means any ingredient intended for use in the
manufacture of a drug product, including those that may not appear in such
drug product.”
21
CFR 211.80(a) states that “There shall be written procedures describing in
sufficient detail the receipt, identification, storage, handling, sampling,
testing, and approval or rejection of components and drug product containers
and closures; such written procedures shall be followed.”
21
CFR 211.80(b) states that “Components and drug product containers and closures
shall at all times be handled and stored in a manner to prevent
contamination.”
21
CFR 211.84(d) states, in part, that “Samples shall be examined and tested
as follows: * * * (6) Each
lot of a component, drug product container, or closure that is liable to
microbiological contamination that is objectionable in view of its intended
use shall be subjected to microbiological tests before use.”
21
CFR 211.94(c) states that “Drug product containers and closures shall be clean
and, where indicated by the nature of the drug, sterilized and processed to
remove pyrogenic properties to assure that they are suitable for their
intended use.”
21
CFR 211.94(d) states that “Standards or specifications, methods of testing,
and, where indicated, methods of cleaning, sterilizing, and processing to
remove pyrogenic properties shall be written and followed for drug product
containers and closures.”
21
CFR 211.113(b) states that “Appropriate written procedures, designed to prevent
microbiological contamination of drug products purporting to be sterile,
shall be established and followed. Such procedures shall include validation
of any sterilization process.”
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A drug product produced
by aseptic processing can become contaminated through the use of one or more
components that are contaminated with microorganisms or endotoxins. Examples
of components include active ingredients, Water for Injection (WFI), and other
excipients. It is important to characterize the microbial content (e.g.,
bioburden, endotoxin) of each component that could be contaminated and
establish appropriate acceptance limits.
Endotoxin load data are
significant because parenteral products are intended to be nonpyrogenic. There
should be written procedures and appropriate specifications for acceptance or
rejection of each lot of components that might contain endotoxins. Any
components failing to meet defined endotoxin limits should be rejected.
In aseptic processing,
each component is individually sterilized or several components are combined,
with the resulting mixture sterilized. Knowledge of bioburden is important in
assessing whether a sterilization process is adequate. Several methods can be
suitable for sterilizing components (see relevant discussion in Section IX). A
widely used method is filtration of a solution formed by dissolving the
component(s) in a solvent such as Water For Injection, USP. The solution is
passed through a sterilizing membrane or cartridge filter. Filter
sterilization is used where the component is soluble and is likely to be
adversely affected by heat. A variation of this method includes subjecting the
filtered solution to aseptic crystallization and precipitation (or
lyophilization) of the component as a sterile powder. However, this method involves
more handling and manipulation and therefore has a higher potential for
contamination during processing.
Dry heat sterilization
is a suitable method for components that are heat stable and insoluble.
However, conducting carefully designed heat penetration and distribution
studies is of particular significance for powder sterilization because of the
insulating effects of the powder.
Irradiation can be used
to sterilize some components. Studies should be conducted to demonstrate that
the process is appropriate for the component.
Containers and closures
should be rendered sterile and, for parenteral drug products, nonpyrogenic.
The process used will depend primarily on the nature of the container and/or closure
materials. The validation study for such a process should be adequate to
demonstrate its ability to render materials sterile and non-pyrogenic. Written
procedures should specify the frequency of revalidation of these processes as
well as time limits for holding sterile, depyrogenated containers and closures.
Pre-sterilization
preparation of glass containers usually involves a series of wash and rinse
cycles. These cycles serve an important role in removing foreign matter. We
recommend use of rinse water of high purity so as not to contaminate
containers. For parenteral products, final rinse water should meet the
specifications of WFI, USP.
The adequacy of the
depyrogenation process can be assessed by spiking containers and closures with
known quantities of endotoxin, followed by measuring endotoxin content after
depyrogenation. The challenge studies can generally be performed by directly
applying a reconstituted endotoxin solution onto the surfaces being tested.
The endotoxin solution should then be allowed to air dry. Positive controls
should be used to measure the percentage of endotoxin recovery by the test
method. Validation study data should demonstrate that the process reduces the
endotoxin content by at least 99.9 percent (3 logs) (see Section VII).
Subjecting glass
containers to dry heat generally accomplishes both sterilization and
depyrogenation. Validation of dry heat sterilization and depyrogenation should
include appropriate heat distribution and penetration studies as well as the
use of worst-case process cycles, container characteristics (e.g., mass), and
specific loading configurations to represent actual production runs. See
Section IX.C. Plastic containers used for parenteral products also should be
non-pyrogenic. Where applicable, multiple WFI rinses can be effective in
removing pyrogens from these containers.
Plastic containers can
be sterilized with an appropriate gas, irradiation, or other suitable means.
For gases such as Ethylene Oxide (EtO), certain issues should receive
attention. For example, the parameters and limits of the EtO sterilization
cycle (e.g., temperature, pressure, humidity, gas concentration, exposure time,
degassing, aeration, and determination of residuals) should be specified and
monitored closely. EtO is an effective surface sterilant and is also used to
penetrate certain
packages with porous overwrapping. Biological
indicators are of special importance in demonstrating the effectiveness of EtO
and other gas sterilization processes. We recommend that these methods be carefully controlled
and validated to evaluate whether consistent penetration of the sterilant can
be achieved and to minimize residuals. Residuals from EtO processes typically
include ethylene oxide as well as its byproducts,
and should be within specified limits.
Rubber closures (e.g.,
stoppers and syringe plungers) can be cleaned by multiple cycles of washing and
rinsing prior to final steam or irradiation sterilization. At minimum, the
initial rinses for the washing process should employ at least Purified Water,
USP, of minimal endotoxin content, followed by final rinse(s) with WFI for
parenteral products. Normally, depyrogenation can be achieved by multiple
rinses of hot WFI. The time between washing, drying (where appropriate), and
sterilizing should be minimized because residual moisture on the stoppers can
support microbial growth and the generation of endotoxins. Because rubber is a
poor conductor of heat, extra attention is indicated in the validation of
processes that use heat with respect to its penetration into the rubber stopper
load (See Section IX.C). Validation data from the washing procedure should
demonstrate successful endotoxin removal from rubber materials.
A potential source of
contamination is the siliconization of rubber stoppers. Silicone used in the
preparation of rubber stoppers should meet appropriate quality control criteria
and not have an adverse effect on the safety, quality, or purity of the drug
product.
Contract facilities
that perform sterilization and/or depyrogenation of containers and closures are
subject to the same CGMP requirements as those established for in-house
processing. The finished dosage form manufacturer should review and assess the
contractor's validation protocol and final validation report. In accord with
211.84(d)(3), a manufacturer who establishes the reliability of the supplier’s
test results at appropriate intervals may accept containers or closures based
on visual identification and Certificate of Analysis review.
A container closure
system that permits penetration of microorganisms is unsuitable for a sterile
product. Any damaged or defective units should be detected, and removed,
during inspection of the final sealed product. Safeguards should be
implemented to strictly preclude shipment of product that may lack container
closure integrity and lead to nonsterility. Equipment suitability problems or
incoming container or closure deficiencies can cause loss of container closure
system integrity. For example, failure to detect vials fractured by faulty
machinery as well as by mishandling of bulk finished stock has led to drug
recalls. If damage that is not readily detected leads to loss of container
closure integrity, improved procedures should be rapidly implemented to prevent
and detect such defects.
Functional defects in
delivery devices (e.g., syringe device defects, delivery volume) can also
result in product quality problems and should be monitored by appropriate
in-process testing.
Any defects or results
outside the specifications established for in-process and final inspection are
to be investigated in accord with § 211.192.
21 CFR 211.63 states that “Equipment used in the manufacture,
processing, packing, or holding of a drug product shall be of appropriate
design, adequate size, and suitably located to facilitate operations for its
intended use and for its cleaning and maintenance.”
21 CFR 211.65(a) states that “Equipment shall be
constructed so that surfaces that contact components, in-process materials,
or drug products shall not be reactive, additive, or absorptive so as to
alter the safety, identity, strength, quality, or purity of the drug product
beyond the official or other established requirements.”
21 CFR 211.67(a) states that
“Equipment and
utensils shall be cleaned, maintained, and sanitized at appropriate intervals
to prevent malfunctions or contamination that would alter the safety,
identify, strength, quality, or purity of the drug product beyond the
official or other established requirements.”
21 CFR 211.94(c) states that
“Drug product
containers and closures shall be clean and, where indicated by the nature of
the drug, sterilized and processed to remove pyrogenic properties to assure
that they are suitable for their intended use.”
21 CFR 211.167(a) states that
“For each batch
of drug product purporting to be sterile and/or pyrogen‑free, there
shall be appropriate laboratory testing to determine conformance to such
requirements. The test procedures shall be in writing and shall be
followed.”
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Endotoxin contamination
of an injectable product can occur as a result of poor CGMP controls. Certain
patient populations (e.g., neonates), those receiving other injections
concomitantly, or those administered a parenteral in atypically large volumes
or doses can be at greater risk for pyrogenic reaction than anticipated by the
established limits based on body weight of a normal healthy adult (Ref. 6, 7).
Such clinical concerns reinforce the importance of exercising appropriate CGMP
controls to prevent generation of endotoxins. Drug product components,
containers, closures, storage time limitations, and manufacturing equipment are
among the areas to address in establishing endotoxin control.
Adequate cleaning,
drying, and storage of equipment will control bioburden and prevent
contribution of endotoxin load. Equipment should be designed to be easily
assembled and disassembled, cleaned, sanitized, and/or sterilized. If adequate
procedures are not employed, endotoxins can be contributed by both upstream and
downstream processing equipment.
Sterilizing-grade
filters and moist heat sterilization have not been shown to be effective in
removing endotoxin. Endotoxin on equipment surfaces can be inactivated by
high-temperature dry heat, or removed from equipment surfaces by cleaning
procedures. Some clean-in-place procedures employ initial rinses with
appropriate high purity water and/or a cleaning agent (e.g., acid, base,
surfactant), followed by final rinses with heated WFI. Equipment should be
dried following cleaning, unless the equipment proceeds immediately to the
sterilization step.
21 CFR 211.111 states
that “When appropriate, time limits for
the completion of each phase of production shall be established to assure the
quality of the drug product. Deviation from established time limits may be
acceptable if such deviation does not compromise the quality of the drug
product. Such deviation shall be justified and documented.”
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When appropriate, time
limits must be established for each phase of aseptic processing
(§ 211.111). Time
limits should include, for example, the period between the start of bulk
product compounding and its sterilization, filtration processes, product
exposure while on the processing line, and storage of sterilized equipment,
containers and closures. The time limits established for the various
production phases should be supported by data. Bioburden and endotoxin load
should be assessed when establishing time limits for stages such as the
formulation processing stage.
The total time for
product filtration should be limited to an established maximum to prevent
microorganisms from penetrating the filter. Such a time limit should also
prevent a significant increase in upstream bioburden and endotoxin load.
Because they can provide a substrate for microbial attachment, maximum use
times for those filters used upstream for solution clarification or particle removal
should also be established and justified.
21
CFR 211.63, 211.65, and 211.67 address, respectively, “Equipment design,
size, and location,” “Equipment construction,” and “Equipment cleaning and
maintenance.”
21
CFR 211.84(c) states, in part, that “Samples shall be collected in
accordance with the following procedures: * * * (3) Sterile equipment and aseptic
sampling techniques shall be used when necessary.”
21
CFR 211.100(a) states, in part, that “There shall be written procedures for
production and process control designed to assure that the drug products have
the identity, strength, quality, and purity they purport or are represented
to possess. Such procedures shall include all requirements in this subpart *
* *.”
21
CFR 211.113(b) states that “Appropriate written procedures, designed to prevent
microbiological contamination of drug products purporting to be sterile,
shall be established and followed. Such procedures shall include validation
of any sterilization process.”
|
This section primarily
discusses routine qualification and validation study recommendations. Change
control procedures are addressed only briefly, but are an important part of the
quality systems established by a firm. A change in facility, equipment,
process, or test method should be evaluated through the written change control
program, triggering an evaluation of the need for revalidation or
requalification.
To ensure the sterility
of products purporting to be sterile, sterilization, aseptic filling and
closing operations must be adequately validated (§ 211.113). The goal of even
the most effective sterilization processes can be defeated if the sterilized
elements of a product (the drug formulation, the container, and the closure)
are brought together under conditions that contaminate any of those elements.
An aseptic processing
operation should be validated using a microbiological growth medium in place of
the product. This process simulation, also known as a media fill, normally
includes exposing the microbiological growth medium to product contact surfaces
of equipment, container closure systems, critical environments, and process
manipulations to closely simulate the same exposure that the product itself
will undergo. The sealed containers filled with the medium are then incubated
to detect microbial contamination. Results are then interpreted to assess the
potential for a unit of drug product to become contaminated during actual operations
(e.g., start-up, sterile ingredient additions, aseptic connections, filling,
closing). Environmental monitoring data from the process simulation can also
provide useful information for the processing line evaluation.
A media fill program
should incorporate the contamination risk factors that occur on a production
line, and accurately assesses the state of process control. Media fill studies
should closely simulate aseptic manufacturing operations incorporating, as
appropriate, worst-case activities and conditions that provide a challenge to
aseptic operations. FDA recommends that the media fill program address
applicable issues such as:
·
Factors associated with the
longest permitted run on the processing line that can pose contamination risk
(e.g., operator fatigue)
·
Representative number, type,
and complexity of normal interventions that occur with each run, as well as
nonroutine interventions and events (e.g., maintenance, stoppages, equipment
adjustments)
·
Lyophilization, when
applicable
·
Aseptic assembly of
equipment (e.g., at start-up, during processing)
·
Number of personnel and
their activities
·
Representative number of
aseptic additions (e.g., charging containers and closures as well as sterile
ingredients) or transfers
·
Shift changes, breaks, and
gown changes (when applicable)
·
Type of aseptic equipment
disconnections/connections
·
Aseptic sample collections
·
Line speed and configuration
·
Weight checks
·
Container closure systems
(e.g., sizes, type, compatibility with equipment)
·
Specific provisions in
written procedures relating to aseptic processing (e.g., conditions permitted
before line clearance is mandated)
A written batch record,
documenting production conditions and simulated activities, should be prepared
for each media fill run. The same vigilance should be observed in both media
fill and routine production runs. The firm’s rationale for the conditions and
activities simulated during the media fill should be clearly defined. Media
fills should not be used to justify practices that pose unnecessary
contamination risks.
When a processing line
is initially qualified, individual media fills should be repeated enough times
to ensure that results are consistent and meaningful. This approach is
important because a single run can be inconclusive, while multiple runs with
divergent results signal a process that is not in control. We recommend that
at least three consecutive separate successful runs be performed during initial line qualification.
Subsequently, routine semi-annual qualification conducted for each processing
line will evaluate the state of control of the aseptic process. Activities and interventions representative of
each shift, and shift changeover, should be incorporated into the design of the
semi-annual qualification program. For example, the evaluation of a production
shift should address its unique time-related and operational features. All personnel who are authorized to enter the
aseptic processing room during manufacturing, including technicians and
maintenance personnel, should participate in a media fill at least once a
year. Participation should be consistent with the nature of each operator’s
duties during routine production.
Each change to a
product or line change should be evaluated using a written change control
system. Any changes or events that have the potential to affect the ability of
the aseptic process to exclude contamination from the sterilized product should
be assessed through additional media fills. For example, facility and
equipment modifications, line configuration changes, significant changes in
personnel, anomalies in environmental testing results, container closure system
changes, extended shutdowns, or end product sterility testing showing
contaminated products may be cause for revalidation of the system.
When data from a media
fill indicate the process may not be in control, an investigation should be
conducted to determine the origin of the contamination and the scope of the
problem. Once corrections are instituted, process simulation run(s) should be
performed to confirm that deficiencies have been corrected and the process has
returned to a state of control. When an investigation fails to reach
well-supported, substantive conclusions as to the cause of the media fill
failure, three consecutive successful runs in tandem with increased scrutiny of
the production process may be warranted.
The duration of aseptic
processing operations is a major consideration in media fill design. Although
the most accurate simulation model would be the full batch size and duration
because it most closely simulates the actual production operations, other
appropriate models can be justified. The duration of the media fill run should
be determined by the time it takes to incorporate manipulations and
interventions, as well as appropriate consideration of the duration of the
actual aseptic processing operation. Interventions that commonly occur
should be routinely simulated, while those occurring rarely can be simulated
periodically.
While conventional
manufacturing lines are usually automated, operated at relatively high speeds,
and designed to limit operator intervention, some processes still include
considerable operator involvement. When aseptic processing employs manual
filling or closing, or extensive manual manipulations, the duration of the
process simulation should generally be no less than the length of the actual
manufacturing process to best simulate contamination risks posed by operators.
For lyophilization
operations, FDA recommends that unsealed containers be exposed to partial
evacuation of the chamber in a manner that simulates the process. Vials should
not be frozen, and precautions should be taken that ensure that the medium
remains in an aerobic state to avoid potentially inhibiting the growth of
microorganisms.
The simulation run
sizes should be adequate to mimic commercial production conditions and
accurately assess the potential for commercial batch contamination. The number
of units filled during the process simulation should be based on contamination
risk for a given process and sufficient to accurately simulate activities that
are representative of the manufacturing process. A generally acceptable
starting point for run size is in the range of 5,000 to 10,000 units. For
operations with production sizes under 5,000, the number of media filled units
should at least equal the maximum batch size made on the processing line (Ref.
8).
When
the possibility of contamination is higher based on the process design (e.g.,
manually intensive filling lines), a larger number of units,
generally at or approaching the full production batch size, should be used. In contrast, a process conducted in an isolator
(see Appendix 1) can have a low risk of contamination because of the lack of
direct human intervention and can be simulated with a lower number of units as
a proportion of
the overall operation.
Media fill size is an
especially important consideration because some batches are produced over multiple shifts or yield
an unusually large number of units. These factors should be carefully
evaluated when designing the simulation to adequately encompass conditions and
any potential risks associated with the larger operation.
The media fill program
should adequately address the range of line speeds employed during production.
Each media fill
run should evaluate a single line speed, and the speed chosen should be
justified. For example, use of high line speed is often most appropriate in
the evaluation of manufacturing processes characterized by frequent
interventions or a significant degree of manual manipulation. Use of slow line
speed is generally appropriate for evaluating manufacturing processes with
prolonged exposure of the sterile drug product and containers/closures in the
aseptic area.
Media fills should be
adequately representative of the conditions under which actual manufacturing
operations are conducted. An inaccurate assessment (making the process appear
cleaner than it actually is) can result from conducting a media fill under
extraordinary air particulate and microbial quality, or under production
controls and precautions taken in preparation for the media fill. To the
extent standard operating procedures permit stressful conditions (e.g., maximum
number of personnel present and elevated activity level), it is important that
media fills include analogous challenges to support the validity of these
studies. Stressful conditions do not include artificially created
environmental extremes, such as reconfiguration of HVAC systems to operate at
worst-case limits.
In general, a
microbiological growth medium, such as soybean casein digest medium, should be
used. Use of anaerobic growth media (e.g., fluid thioglycollate medium) should
be considered in special circumstances. The media selected should be
demonstrated to promote growth of gram-positive and gram-negative bacteria, and
yeast and mold (e.g., USP indicator organisms). The QC laboratory should
determine if USP indicator organisms sufficiently represent production-related
isolates. Environmental monitoring and sterility test isolates can be
substituted (as appropriate) or added to the growth promotion challenge.
Growth promotion units should be inoculated with a <100 CFU challenge. If the growth
promotion testing fails, the origin of any contamination found during the
simulation should nonetheless be investigated and the media fill promptly
repeated.
The production process
should be accurately simulated using media and conditions that optimize
detection of any microbiological contamination. Each unit should be filled
with an appropriate quantity and type of microbial growth medium to contact the
inner container closure surfaces (when the unit is inverted or thoroughly
swirled) and permit visual detection of microbial growth.
Some drug manufacturers
have expressed concern over the possible contamination of the facility and
equipment with nutrient media during media fill runs. However, if the medium
is handled properly and is promptly followed by the cleaning, sanitizing, and,
where necessary, sterilization of equipment, subsequently processed products
are not likely to be compromised.
Media units should be
incubated under conditions adequate to detect microorganisms that might
otherwise be difficult to culture.
Incubation conditions should be established in accord with the following
general guidelines:
- Incubation
temperature should be suitable for recovery of bioburden and environmental
isolates and should at no time be outside the range of 20-35oC. Incubation
temperature should be maintained within +2.5oC of the
target temperature.
- Incubation time should not be less than 14 days. If two
temperatures are used for the incubation of the media filled units, the
units should be incubated for at least 7 days at each temperature
(starting with the lower temperature).
Each
media-filled unit should be examined for contamination by personnel with
appropriate education, training, and experience in inspecting media fill units
for microbiological contamination. If QC personnel do not perform the
inspection, there should be QC unit oversight throughout any such examination.
All suspect units identified during the examination should be brought to the
immediate attention of the QC microbiologist. To allow for visual detection of
microbial growth, we recommend substituting clear containers (with otherwise
identical physical properties) for amber or other opaque containers. If
appropriate, other methods can also be considered to ensure visual detection.
When a firm performs a
final product inspection of units immediately following the media fill run, all
integral units should proceed to incubation. Units found to have defects not
related to integrity (e.g., cosmetic defect) should be incubated; units that
lack integrity should be rejected. Erroneously rejected units should be
returned promptly for incubation with the media fill lot.
After incubation is
underway, any unit found to be damaged should be included in the data for the
media fill run, because the units can be representative of drug product
released to the market. Any decision to exclude such incubated units (i.e.,
non-integral) from the final run tally should be fully justified and the
deviation explained in the media fill report. If a correlation emerges between
difficult to detect damage and microbial contamination, a thorough
investigation should be conducted to determine its cause (see Section VI.B).
Written
procedures regarding aseptic interventions should be clear and specific (e.g.,
intervention type; quantity of units removed), providing for consistent
production practices and assessment of these practices during media fills. If
written procedures and batch documentation are adequate to describe an
associated clearance, the
intervention units removed during media fills do not need to be incubated. Where procedures lack specificity, there would be
insufficient justification for exclusion of units removed during an
intervention from incubation. For example,
if a production procedure requires removal of 10 units after an intervention at the
stoppering station infeed, batch records (i.e., for production and media fills)
should clearly document conformance with this procedure. In no case should
more units be removed during a media fill intervention than would be cleared
during a production run.
The
ability of a media fill run to detect potential contamination from a given
simulated activity should not be compromised by a large-scale line clearance.
We recommend incorporating appropriate study provisions to avoid and address a
large line clearance that results in the removal of a unit possibly
contaminated during an unrelated event or intervention.
Appropriate
criteria should be established for yield and accountability
(reconciliation of filled units). Media fill record reconciliation documentation
should include a full accounting and description of units rejected from a
batch.
The process simulation
run should be observed by the QC Unit, and contaminated units should be
reconcilable with the approximate time and the activity being simulated during
the media fill. Video recording of a media fill may serve as a useful aide in
identifying personnel practices that could negatively affect the aseptic
process.
Any
contaminated unit should be considered objectionable and investigated. The microorganisms should be identified to
species level. The investigation should survey the possible causes of
contamination. In addition, any failure investigation should assess the impact
on commercial drugs produced on the line since the last media fill.
Whenever
contamination exists in a media fill run, it should be considered indicative of
a potential sterility assurance problem, regardless of run size. The number of
contaminated units should not be expected to increase in a directly
proportional manner with the number of vials in the media fill run. Test
results should reliably and reproducibly show that the units produced by an
aseptic processing operation are sterile. Modern aseptic processing operations
in suitably designed facilities have demonstrated a capability of meeting
contamination levels approaching zero (Ref. 8, 9) and should normally yield no
media fill contamination. Recommended criteria for assessing state of aseptic
line control are as follows:
·
When filling
fewer than 5000 units, no contaminated units should be detected.
-- One (1) contaminated unit is considered cause for
revalidation, following an investigation.
·
When
filling from 5,000 to 10,000 units:
-- One (1) contaminated unit should result in an investigation,
including consideration of a repeat media fill.
-- Two (2) contaminated units are considered cause for
revalidation, following investigation.
·
When
filling more than 10,000 units:
-- One (1) contaminated unit should result in an investigation.
-- Two (2) contaminated units are considered cause for
revalidation, following investigation.
For any run size, intermittent incidents of microbial
contamination in media filled runs can be indicative of a persistent low-level
contamination problem that should be investigated. Accordingly, recurring
incidents of contaminated units in media fills for an individual line,
regardless of acceptance criteria, would be a signal of an adverse trend on the
aseptic processing line that should lead to problem identification, correction,
and revalidation.
A firm's use of media fill acceptance criteria allowing
infrequent contamination does not mean that a distributed lot of drug product
purporting to be sterile may contain a nonsterile unit. The purpose of an
aseptic process is to prevent any contamination. A manufacturer is fully
liable for the shipment of any nonsterile unit, an act that is prohibited under
the FD&C Act (Section 301(a) 21 U.S.C. 331(a)). FDA also recognizes that
there might be some scientific and technical limitations on how precisely and
accurately process simulations can characterize a system of controls intended
to exclude contamination.
As with any process
validation run, it is important to note that invalidation of a media
fill run should be a rare occurrence. A media fill run should be aborted only
under circumstances in which written procedures require commercial lots to be
equally handled. Supporting documentation and justification should be provided
in such cases.
Filtration is a common
method of sterilizing drug product solutions. A sterilizing grade filter
should be validated to reproducibly remove viable microorganisms from the
process stream, producing a sterile effluent. Currently, such filters usually have a rated
pore size of 0.2 mm or smaller. Use of redundant sterilizing filters should be
considered in many cases. Whatever filter or combination of filters is used,
validation should include microbiological challenges to simulate worst-case
production conditions for the material to be filtered and integrity test
results of the filters used for the study. Product bioburden should be
evaluated when selecting a suitable challenge microorganism to assess which
microorganism represents the worst-case challenge to the filter. The microorganism
Brevundimonas diminuta (ATCC 19146) when properly grown, harvested and
used, is a common challenge microorganism for 0.2 mm rated
filters because of its small size (0.3 mm
mean diameter). The manufacturing process
controls should be designed to minimize the bioburden of the unfiltered
product. Bioburden of unsterilized bulk solutions should be determined to
trend the characteristics of potentially contaminating organisms.
In certain cases, when
justified as equivalent or better than use of B. diminuta, it may be
appropriate to conduct bacterial retention studies with a bioburden isolate.
The number of microorganisms in the challenge is important because a filter can
contain a number of pores larger than the nominal rating, which has the
potential to allow passage of microorganisms. The probability of such passage
is considered to increase as the number of organisms (bioburden) in the
material to be filtered increases. A challenge concentration of at least 107
organisms per cm2 of effective filtration area should
generally be used, resulting in no passage of the challenge microorganism. The
challenge concentration used for validation is intended to provide a margin of
safety well beyond what would be expected in production.
Direct inoculation into
the drug formulation is the preferred method because it provides an assessment
of the effect of drug product on the filter matrix and on the challenge
organism. However, directly inoculating B. diminuta into products with
inherent bactericidal activity against this microbe, or into oil-based
formulations, can lead to erroneous conclusions. When sufficiently justified,
the effects of the product formulation on the membrane's integrity can be
assessed using an appropriate alternate method. For example, a drug product
could be filtered in a manner in which the worst-case combination of process
specifications and conditions are simulated. This step could be followed by
filtration of the challenge organism for a significant period of time, under
the same conditions, using an appropriately modified product (e.g., lacking an
antimicrobial preservative or other antimicrobial component) as the vehicle.
Any divergence from a simulation using the actual product and conditions of
processing should be justified.
Factors that can affect
filter performance generally include (1) viscosity and surface tension of the
material to be filtered, (2) pH, (3) compatibility of the material or
formulation components with the filter itself, (4) pressures, (5) flow rates,
(6) maximum use time, (7) temperature, (8) osmolality, (9) and the effects of
hydraulic shock. When designing the validation protocol, it is important to
address the effect of the extremes of processing factors on the filter
capability to produce sterile effluent. Filter validation should be conducted
using the worst-case conditions, such as maximum filter use time and pressure
(Ref. 12). Filter validation experiments, including microbial
challenges, need not be conducted in the actual manufacturing areas. However,
it is essential that laboratory experiments simulate actual production
conditions. The specific type of filter membrane used in commercial production
should be evaluated in filter validation studies. There are advantages to
using production filters in these bacterial retention validation studies. When
the more complex filter validation tests go beyond the capabilities of the
filter user, tests are often conducted by outside laboratories or by filter
manufacturers. However, it is the responsibility of the filter user to review
the validation data on the efficacy of the filter in producing a sterile
effluent. The data should be applicable to the user's products and conditions
of use because filter performance may differ significantly for various
conditions and products.
After a filtration
process is properly validated for a given product, process, and filter, it is
important to ensure that identical filters (e.g., of identical polymer
construction and pore size rating) are used in production runs. Sterilizing
filters should be routinely discarded after processing of a single lot.
However, in those instances when repeated use can be justified, the sterile
filter validation should incorporate the maximum number of lots to be
processed. Integrity testing of the filter(s) can be performed prior to
processing, and should be routinely performed post-use. It is important that
integrity testing be conducted after filtration to detect any filter leaks or
perforations that might have occurred during the filtration. Forward flow
and bubble point tests, when appropriately employed, are two integrity
tests that can be used. A production filter’s integrity test specification
should be consistent with data generated during bacterial retention validation
studies.
Equipment surfaces that
contact sterilized drug product or its sterilized containers or closures must
be sterile so as not to alter purity of the drug (211.67 and 211.113). Where
reasonable contamination potential exists, surfaces that are in the vicinity of
the sterile product should also be rendered free of viable organisms. It is as
important in aseptic processing to validate the processes used to sterilize such critical equipment as it
is to validate processes used to sterilize the drug product and its container
and closure. Moist heat and dry heat sterilization, the most widely used, are
the primary processes discussed in this document. However, many of the heat
sterilization principles discussed in this guidance are also applicable to
other sterilization methods.
Sterility of aseptic
processing equipment should normally be maintained by sterilization between
each batch. Following sterilization, transportation and
assembly of equipment, containers, and closures should be performed with strict
adherence to aseptic methods in a manner that protects and sustains the
product's sterile state.
Validation studies
should be conducted to demonstrate the efficacy of the sterilization cycle.
Requalification studies should also be performed on a periodic basis. The
specific load configurations, as well as biological indicator and temperature
sensor locations, should be documented in validation records. Batch production
records should subsequently document adherence to the validated load patterns.
It is important to
remove air from the autoclave chamber as part of a steam sterilization cycle.
The insulating properties of air interfere with the ability of steam to
transfer its energy to the load, achieving lower lethality than associated with
saturated steam. It also should be noted that the resistance of microorganisms
can vary widely depending on the material to be sterilized. For this reason,
careful consideration should be given during sterilization validation to the
nature or type of material chosen as the carrier of the biological indicator to
ensure an appropriately representative study.
Potentially difficult
to reach locations within the sterilizer load or equipment train (for SIP
applications) should be evaluated. For example, filter installations in piping
can cause a substantial pressure differential across the filter, resulting in a
significant temperature drop on the downstream side. We recommend placing
biological indicators at appropriate downstream locations of the filter.
Empty chamber studies evaluate numerous locations throughout
a sterilizing unit (e.g., steam autoclave, dry heat oven) or equipment train
(e.g., large tanks, immobile piping) to confirm uniformity of conditions (e.g.,
temperature, pressure). These uniformity or mapping studies should be
conducted with calibrated measurement devices.
Heat penetration
studies should be performed using the established sterilizer loads. Validation
of the sterilization process with a loaded chamber demonstrates the effects of
loading on thermal input to the items being sterilized and may identify
difficult to heat or penetrate items where there could be insufficient
lethality to attain sterility. The placement of biological indicators at
numerous positions in the load, including the most difficult to sterilize places,
is a direct means of confirming the efficacy of any sterilization procedure.
In general, the biological indicator should be placed adjacent to the
temperature sensor so as to assess the correlation between microbial lethality
and predicted lethality based on thermal input. When determining which
articles are difficult to sterilize, special attention should be given to the
sterilization of filters, filling manifolds, and pumps. Some other examples
include certain locations of tightly wrapped or densely packed supplies,
securely fastened load articles, lengthy tubing, the sterile filter apparatus,
hydrophobic filters, and stopper load.
Ultimately, cycle
specifications for such sterilization methods should be based on the delivery
of adequate lethality to the slowest to heat locations. A sterility assurance
level of 10-6 or better should be demonstrated for a sterilization
process. For more information, please also refer to the FDA guidance entitled Guideline
for the Submission of Documentation for Sterilization Process Validation in
Applications for Human and Veterinary Drug Products.
The sterilizer
validation program should continue to focus on the load areas identified as
most difficult to penetrate or heat. The suitability of the sterilizer should be
established by qualification, maintenance, change control, and periodic
verification of the cycle, including biological challenges. Change control
procedures should adequately address issues such as a load configuration change
or a modification of a sterilizer.
For
both validation and routine process control, the reliability of the data
generated by sterilization cycle monitoring devices should be considered to be
of the utmost importance. Devices that measure cycle parameters should be
routinely calibrated. Written procedures should be established to ensure that
these devices are maintained in a calibrated state. For example, we recommend
that procedures address the following:
·
Temperature and pressure
monitoring devices for heat sterilization should be calibrated at suitable
intervals. The sensing devices used for validation studies should be
calibrated before and after validation runs.
·
Devices used to monitor
dwell time in the sterilizer should be periodically calibrated.
·
The microbial count of a
biological indicator should be confirmed. Biological indicators should be
stored under appropriate conditions.
·
If the reliability of a
vendor’s Certificate of Analysis is established through an appropriate
qualification program, the D-value of a biological indicator (e.g., spore
strips, glass ampuls) can be accepted in lieu of confirmatory testing of each
lot. However, a determination of resistance (D-value) should be performed for
any biological indicator inoculated onto a substrate, or used in a way that is
other than described by the vendor. D-value determinations can be conducted by
an independent laboratory.
·
Where applicable,
instruments used to determine the purity of steam should be calibrated.
·
For dry heat depyrogenation
tunnels, devices (e.g. sensors and transmitters) used to measure belt speed
should be routinely calibrated. Bacterial endotoxin challenges should be
appropriately prepared and measured by the laboratory.
To ensure robust process control, equipment should be
properly designed with attention to features such as accessibility to
sterilant, piping slope, and proper condensate removal (as applicable).
Equipment control should be ensured through placement of measuring devices at those
control points that are most likely to rapidly detect unexpected process
variability. Where manual manipulations of valves are required for sterilizer
or SIP operations, these steps should be documented in manufacturing procedures
and batch records. Sterilizing equipment should be properly maintained to
allow for consistent, satisfactory function. Routine evaluation of sterilizer
performance-indicating attributes, such as equilibrium (come up) time is
important in assuring that the unit continues to operate as per the validated
conditions.
21 CFR 211.22(b) states
that “Adequate laboratory facilities for the testing and approval (or
rejection) of components, drug product containers, closures, packaging
materials, in-process materials, and drug products shall be available to the
quality control unit.”
21 CFR 211.22(c) states that
“The quality control unit shall have
the responsibility for approving or rejecting all procedures or
specifications impacting on the identity, strength, quality, and purity of
the drug product.”
21
CFR 211.42(c) states, in part, that “Operations shall be performed
within specifically defined areas of adequate size. There shall be separate or
defined areas or such other control systems for the firm’s operations as are
necessary to prevent contamination or mixups during the course of the
following procedures: * * * (10) Aseptic processing, which includes as
appropriate: * * * (iv) A system for monitoring environmental conditions; * *
*.”
21
CFR 211.56(b) states that “There shall be written procedures assigning
responsibility for sanitation and describing in sufficient detail the
cleaning schedules, methods, equipment, and materials to be used in cleaning
the buildings and facilities; such written procedures shall be followed.”
21
CFR 211.56(c) states, in part, that “There shall be written procedures for use of suitable
rodenticides, insecticides, fungicides, fumigating agents, and cleaning and
sanitizing agents. Such written procedures shall be designed to prevent the
contamination of equipment, components, drug product containers, closures,
packaging, labeling materials, or drug products and shall be followed * * *.”
21 CFR 211.110(a) states, in
part, that “To
assure batch uniformity and integrity of drug products, written procedures
shall be established and followed that describe the in-process controls, and
tests, or examinations to be conducted on appropriate samples of in-process
materials of each batch. Such control procedures shall be established to
monitor the output and to validate the performance of those manufacturing
processes that may be responsible for causing variability in the
characteristics of in-process material and the drug product * * *.”
21 CFR 211.113(b) states that
“Appropriate
written procedures, designed to prevent microbiological contamination of drug
products purporting to be sterile, shall be established and followed. Such
procedures shall include validation of any sterilization process.”
21
CFR 211.160(b) states that “Laboratory controls shall include the establishment
of scientifically sound and appropriate specifications, standards, sampling
plans, and test procedures designed to assure that components, drug product
containers, closures, in‑process materials, labeling, and drug products
conform to appropriate standards of identity, strength, quality, and purity.
Laboratory controls shall include: (1) Determination of conformance to
appropriate written specifications for the acceptance of each lot within each
shipment of components, drug product containers, closures, and labeling used
in the manufacture, processing, packing, or holding of drug products. The
specifications shall include a description of the sampling and testing
procedures used. Samples shall be representative and adequately identified.
Such procedures shall also require appropriate retesting of any component,
drug product container, or closure that is subject to deterioration. (2)
Determination of conformance to written specifications and a description of
sampling and testing procedures for in-process materials. Such samples shall
be representative and properly identified. (3) Determination of conformance
to written descriptions of sampling procedures and appropriate specifications
for drug products. Such samples shall be representative and properly
identified. (4) The calibration of instruments, apparatus, gauges, and
recording devices at suitable intervals in accordance with an established
written program containing specific directions, schedules, limits for
accuracy and precision, and provisions for remedial action in the event
accuracy and/or precision limits are not met. Instruments, apparatus,
gauges, and recording devices not meeting established specifications shall
not be used.”
21
CFR 211.165(e) states that “The accuracy, sensitivity, specificity, and
reproducibility of test methods employed by the firm shall be established and
documented. Such validation and documentation may be accomplished in
accordance with § 211.194(a)(2).”
21 CFR 211.192
states,
in part, that “All
drug product production and control records, including those for packaging
and labeling, shall be reviewed and approved by the quality control unit to
determine compliance with all established, approved written procedures before
a batch is released or distributed * * *.”
|
In aseptic processing,
one of the most important laboratory controls is the environmental monitoring
program. This program provides meaningful information on the quality of the
aseptic processing environment (e.g., when a given batch is being manufactured)
as well as environmental trends of ancillary clean areas. Environmental
monitoring should promptly identify potential routes of contamination, allowing
for implementation of corrections before product contamination occurs (211.42
and 211.113).
Evaluating the quality
of air and surfaces in the cleanroom environment should start with a
well-defined written program and scientifically sound methods. The monitoring
program should cover all production shifts and include air, floors, walls, and
equipment surfaces, including the critical surfaces that come in contact with
the product, container, and closures. Written procedures should include a list
of locations to be sampled. Sample timing, frequency, and location should be
carefully selected based upon their relationship to the operation performed.
Samples should be taken throughout the classified areas of the aseptic
processing facility (e.g., aseptic corridors, gowning rooms) using
scientifically sound sampling procedures. Sample sizes should be sufficient to
optimize detection of environmental contaminants at levels that might be
expected in a given clean area.
It is important that
locations posing the most microbiological risk to the product be a key part of
the program. It is especially important to monitor the microbiological quality
of the critical area to determine whether or not aseptic conditions are
maintained during filling and closing activities. Air and surface samples
should be taken at the locations where significant activity or product exposure
occurs during production. Critical surfaces that come in contact with the
sterile product should remain sterile throughout an operation. When
identifying critical sites to be sampled, consideration should be given to the
points of contamination risk in a process, including factors such as difficulty
of setup, length of processing time, and impact of interventions. Critical
surface sampling should be performed at the conclusion of the aseptic
processing operation to avoid direct contact with sterile surfaces during
processing. Detection of microbial contamination on a critical site would not
necessarily result in batch rejection. The contaminated critical site sample
should prompt an investigation of operational information and data that
includes an awareness of the potential for a low incidence of false positives.
Environmental monitoring methods
do not always recover microorganisms present in the sampled area. In
particular, low-level contamination can be particularly difficult to detect.
Because false negatives can occur, consecutive growth results are only one type
of adverse trend. Increased incidence of
contamination over a given period is an equal or more significant trend to be
tracked. In the absence of any
adverse trend, a single result above an action level should trigger an
evaluation and a determination about whether remedial measures may be
appropriate. In all room classes, remedial measures should be taken in
response to unfavorable trends.
All environmental
monitoring locations should be described in SOPs with sufficient detail to
allow for reproducible sampling of a given location surveyed. Written SOPs
should also address elements such as (1) frequency of sampling, (2) when the
samples are taken (i.e., during or at the conclusion of operations), (3)
duration of sampling, (4) sample size (e.g., surface area, air volume), (5)
specific sampling equipment and techniques, (6) alert and action levels, and
(7) appropriate response to deviations from alert or action levels.
Microbiological
monitoring levels should be established based on the relationship of the
sampled location to the operation. The levels should be based on the need to
maintain adequate microbiological control throughout the entire sterile
manufacturing facility. One should also consider environmental monitoring data
from historical databases, media fills, cleanroom qualification, and
sanitization studies, in developing monitoring levels. Data from similar
operations can also be helpful in setting action and alert levels, especially
for a new operation.
Environmental
monitoring data will provide information on the quality of the manufacturing
environment. Each individual sample result should be evaluated for its
significance by comparison to the alert or action levels. Averaging of results
can mask unacceptable localized conditions. A result at the alert level urges
attention to the approaching action conditions. A result at the action level
should prompt a more thorough investigation. Written procedures should be
established, detailing data review frequency and actions to be taken. The
quality control unit should provide routine oversight of near-term (e.g.,
daily, weekly, monthly, quarterly) and long-term trends in environmental and
personnel monitoring data.
Trend reports should
include data generated by location, shift, room, operator, or other
parameters. The quality control unit should be responsible for producing
specialized data reports (e.g., a search on a particular isolate over a year
period) with the goal of investigating results beyond established levels and
identifying any appropriate follow-up actions. Significant changes in
microbial flora should be considered in the review of the ongoing environmental
monitoring data.
Written procedures
should define the system whereby the most responsible managers are regularly
informed and updated on trends and investigations.
The suitability,
efficacy, and limitations of disinfecting agents and procedures should be
assessed. The effectiveness of these disinfectants and procedures should be
measured by their ability to ensure that potential contaminants are adequately
removed from surfaces.
To prevent introduction
of contamination, disinfectants should be sterile, appropriately handled in
suitable (e.g., sterile) containers and used for no longer than the predefined period
specified by written procedures. Routinely used disinfectants should be
effective against the normal microbial vegetative flora recovered from the
facility. Many common disinfectants are ineffective against spores. For
example, 70 percent isopropyl alcohol is ineffective against Bacillus spp.
spores. Therefore, a sound disinfectant program also includes a sporicidal
agent, used according to a written schedule and when environmental data suggest
the presence of sporeforming organisms.
Disinfection procedures
should be described in sufficient detail (e.g., preparation, work sequence,
contact time) to enable reproducibility. Once the procedures are established,
their adequacy should be evaluated using a routine environmental monitoring
program. If indicated, microorganisms associated with adverse trends can be
investigated as to their sensitivity to the disinfectants employed in the
cleanroom in which the organisms were isolated.
Acceptable methods for
monitoring the microbiological quality of the environment include:
a. Surface Monitoring
Environmental
monitoring involves sampling various surfaces for microbiological quality. For
example, product contact surfaces, floors, walls, and equipment should be
tested on a regular basis. Touch plates, swabs, and contact plates can be used
for such tests.
b. Active Air Monitoring
Assessing
microbial quality of air should involve the use of active devices
including but not limited to impaction, centrifugal, and membrane (or gelatin)
samplers. Each device has certain advantages and disadvantages, although all
allow testing of the number of organisms per volume of air sampled. We
recommend that such devices be used during each production shift to evaluate
aseptic processing areas at carefully chosen locations. Manufacturers should
be aware of a device's air monitoring capabilities, and the air sampler should
be evaluated for its suitability for use in an aseptic environment based on
collection efficiency, cleanability, ability to be sterilized, and disruption
of unidirectional airflow. Because devices vary, the user should assess
the overall suitability of a monitoring device before it is placed into
service. Manufacturers should ensure that such devices are calibrated and used
according to appropriate procedures.
c. Passive Air Monitoring (Settling Plates)
Another
method is the use of passive air samplers, such as settling plates (petri
dishes containing nutrient growth medium exposed to the environment). Because
only microorganisms that settle onto the agar surface are detected, settling
plates can be used as qualitative, or semi-quantitative, air monitors. Their
value in critical areas will be enhanced by ensuring that plates are positioned
in locations posing the greatest risk of product contamination. As part of
methods validation, the quality control laboratory should evaluate what media
exposure conditions optimize recovery of low levels of environmental isolates.
Exposure conditions should preclude desiccation (e.g., caused by lengthy
sampling periods and/or high airflows), which inhibits recovery of
microorganisms. The data generated by passive air sampling can be useful when
considered in combination with results from other types of air samples.
Characterization of
recovered microorganisms provides vital information for the environmental
monitoring program. Environmental isolates often correlate with the
contaminants found in a media fill or product sterility testing failure, and
the overall environmental picture provides valuable information for an
investigation. Monitoring critical and immediately surrounding clean areas as
well as personnel should include routine identification of microorganisms to
the species (or, where appropriate, genus) level. In some cases, environmental
trending data have revealed migration of microorganisms into the aseptic
processing room from either uncontrolled or lesser controlled areas.
Establishing an adequate program for differentiating microorganisms in the
lesser-controlled environments, such as Class 100,000 (ISO 8), can often be
instrumental in detecting such trends. At minimum, the program should require
species (or, where
appropriate, genus) identification
of microorganisms in these ancillary environments at frequent intervals to
establish a valid, current database of contaminants present in the facility
during processing (and to demonstrate that cleaning and sanitization procedures
continue to be effective).
Genotypic methods have
been shown to be more accurate and precise than traditional biochemical and
phenotypic techniques. These methods are especially valuable for
investigations into failures (e.g., sterility test; media fill contamination).
However, appropriate biochemical and phenotypic methods can be used for the
routine identification of isolates.
The goal of
microbiological monitoring is to reproducibly detect microorganisms for
purposes of monitoring the state of environmental control. Consistent methods
will yield a database that allows for sound data comparisons and
interpretations. The microbiological culture media used in environmental
monitoring should be validated as capable of detecting fungi (i.e., yeasts and
molds) as well as bacteria and incubated at appropriate conditions of time and
temperature. Total aerobic bacterial count can be obtained by incubating at 30
to 35oC for 48 to 72 hours. Total combined yeast and mold count can
generally be obtained by incubating at 20 to 25oC for 5 to 7 days.
Incoming lots of
environmental monitoring media should be tested for their ability to reliably
recover microorganisms. Growth promotion testing should be performed on all
lots of prepared media. Where appropriate, inactivating agents should be used
to prevent inhibition of growth by cleanroom disinfectants or product residuals
(e.g., antibiotics).
Manufacturing process
controls should be designed to minimize the bioburden in the unfiltered
product. In addition to increasing the challenge to the sterilizing filter,
bioburden can contribute impurities (e.g., endotoxin) to, and lead to
degradation of, the drug product. A prefiltration bioburden limit should be
established.
Other suitable
microbiological test methods (e.g., rapid test methods) can be considered for
environmental monitoring, in-process control testing, and finished product
release testing after it is demonstrated that the methods are equivalent or
better than traditional methods (e.g.,USP).
Routine particle
monitoring is useful in rapidly detecting significant deviations in air
cleanliness from qualified processing norms (e.g., clean area classification).
A result outside the established classification level at a given location
should be investigated as to its cause. The extent of investigation should be
consistent with the severity of the excursion and include an evaluation
of trending data. Appropriate corrective action should be implemented, as
necessary, to prevent future deviations.
See Section IV.A for
additional guidance on particle monitoring.
21 CFR 210.3(b)(21) states that
“Representative
sample means
a sample that consists of a number of units that are drawn based on rational
criteria such as random sampling and intended to assure that the sample
accurately portrays the material being sampled.”
21 CFR 211.110(a) states, in
part, that “To
assure batch uniformity and integrity of drug products, written procedures
shall be established and followed that describe the in-process controls, and
tests, or examinations to be conducted on appropriate samples of in-process
materials of each batch. Such control procedures shall be established to
monitor the output and to validate the performance of those manufacturing
processes that may be responsible for causing variability in the
characteristics of in-process material and the drug product.”
21 CFR 211.160(b) states that
“Laboratory
controls shall include the establishment of scientifically sound and
appropriate specifications, standards, sampling plans, and test procedures
designed to assure that components, drug product containers, closures, in‑process
materials, labeling, and drug products conform to appropriate standards of
identity, strength, quality, and purity. Laboratory controls shall include:
(1) Determination of conformance to appropriate written specifications for
the acceptance of each lot within each shipment of components, drug product
containers, closures, and labeling used in the manufacture, processing,
packing, or holding of drug products. The specifications shall include a
description of the sampling and testing procedures used. Samples shall be
representative and adequately identified. Such procedures shall also require
appropriate retesting of any component, drug product container, or closure
that is subject to deterioration. (2) Determination of conformance to
written specifications and a description of sampling and testing procedures
for in-process materials. Such samples shall be representative and properly
identified. (3) Determination of conformance to written descriptions of
sampling procedures and appropriate specifications for drug products. Such
samples shall be representative and properly identified. (4) The calibration
of instruments, apparatus, gauges, and recording devices at suitable
intervals in accordance with an established written program containing
specific directions, schedules, limits for accuracy and precision, and
provisions for remedial action in the event accuracy and/or precision limits
are not met. Instruments, apparatus, gauges, and recording devices not
meeting established specifications shall not be used.”
21 CFR 211.165(a) states, in
part, that “For
each batch of drug product, there shall be appropriate laboratory
determination of satisfactory conformance to final specifications for the
drug product, including the identity and strength of each active ingredient,
prior to release * * *.”
21 CFR 211.165(e) states that
“The accuracy,
sensitivity, specificity, and reproducibility of test methods employed by the
firm shall be established and documented. Such validation and documentation
may be accomplished in accordance with § 211.194(a)(2).”
21 CFR 211.167(a) states that
“For each batch
of drug product purporting to be sterile and/or pyrogen‑free, there
shall be appropriate laboratory testing to determine conformance to such
requirements. The test procedures shall be in writing and shall be
followed.”
21 CFR 211.180(e) states, in
part, that “Written
records required by this part shall be maintained so that data therein can be
used for evaluating, at least annually, the
quality standards of each drug product to determine the need for changes in
drug product specifications or manufacturing or control procedures * * *.”
21 CFR 211.192 states that “All drug product production
and control records, including those for packaging and labeling, shall be
reviewed and approved by the quality control unit to determine compliance
with all established, approved written procedures before a batch is released
or distributed. Any unexplained discrepancy (including a percentage of
theoretical yield exceeding the maximum or minimum percentages established in
master production and control records) or the failure of a batch or any of
its components to meet any of its specifications shall be thoroughly
investigated, whether or not the batch has already been distributed. The
investigation shall extend to other batches of the same drug product and
other drug products that may have been associated with the specific failure
or discrepancy. A written record of the investigation shall be made and
shall include the conclusions and followup.”
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Certain aspects of
sterility testing are of particular importance, including control of the
testing environment, understanding the test limitations, and investigating
manufacturing systems following a positive test.
The testing laboratory
environment should employ facilities and controls comparable to those used for
aseptic filling operations. Poor or deficient sterility test facilities or
controls can result in test failure. If production facilities and controls are
significantly better than those for sterility testing, the danger exists of
mistakenly attributing a positive sterility test result to a faulty laboratory
even when the product tested could have, in fact, been nonsterile. Therefore,
a manufacturing deficiency may go undetected. The use of isolators for
sterility testing minimizes the chance of a false positive test result.
Sterility testing
methods are required to be accurate and reproducible, in accordance with
211.194 and 211.165. USP <71> “Sterility Tests” is the principal
source used for sterility testing methods, including information on test
procedures and media.
As a part of methods
validation, appropriate microbiological challenge testing will demonstrate
reproducibility of the method to reliably recover representative microorganisms. If growth is
inhibited, modifications (e.g., increased dilution, additional membrane filter
washes, addition of inactivating agents) to the test method should be
implemented to optimize recovery. Ultimately, methods validation studies should
demonstrate that the method does not provide an opportunity for false
negatives.
It is essential that the media used to perform sterility
testing be rendered sterile and demonstrated as growth promoting. Personnel performing sterility testing should be
qualified and trained for the task. A written program should be in place to
maintain updated training of personnel and confirm acceptable sterility testing
practices.
Sterility tests are
limited in their ability to detect contamination because of the small sample
size typically used. For example, as described by USP, statistical evaluations
indicate that the sterility test sampling plan "only enables the detection
of contamination in a lot in which 10% of the units are contaminated about nine
times out of ten in making the test" (Ref. 13). To further illustrate, if
a 10,000-unit lot with a 0.1 percent contamination level was sterility tested
using 20 units, there is a 98 percent chance that the batch would pass the test.
It is important that
the samples represent the entire batch and processing conditions. Samples
should be taken:
·
at the beginning, middle,
and end of the aseptic processing operation
·
in conjunction with
processing interventions or excursions
Because of the limited
sensitivity of the test, any positive result is considered a serious CGMP issue
that should be thoroughly investigated.
Care should be taken in
the performance of the sterility test to preclude any activity that allows for
possible sample contamination. When microbial growth is observed, the lot
should be considered nonsterile and an investigation conducted. An initial
positive test would be invalid only in an instance in which microbial growth
can be unequivocally ascribed to laboratory error.
Only
if conclusive and documented evidence clearly shows that the contamination
occurred as part of testing should a new test be performed. When available evidence is inconclusive,
batches should be rejected as not conforming to sterility requirements.
After considering all
relevant factors concerning the manufacture of the product and testing of the
samples, the comprehensive written investigation should include specific
conclusions and identify corrective actions. The investigation's persuasive
evidence of the origin of the contamination should be based on at least the
following:
1.
Identification
(speciation) of the organism in the sterility test
Sterility test isolates
should be identified to the species level. Microbiological monitoring data
should be reviewed to determine if the organism is also found in laboratory and
production environments, personnel, or product bioburden. Advanced identification methods (e.g., nucleic-acid
based) are valuable for investigational purposes. When comparing results from
environmental monitoring and sterility positives, both identifications should
be performed using the same methodology.
2.
Record of laboratory
tests and deviations
Review of laboratory
deviation and investigation findings can help to eliminate or implicate the
laboratory as the source of contamination. For example, if the organism is
seldom found in the laboratory environment, product contamination is more
likely than laboratory error. If the organism is found in laboratory and
production environments, it can still indicate product contamination.
The proper handling of
deviations is an essential aspect of laboratory control. When a deviation
occurs during sterility testing, it should be documented, investigated, and
remedied. If any deviation is considered to have compromised the integrity of
the sterility test, the test should be invalidated immediately without
incubation.
A sterility positive result
can be viewed as indicative of production or laboratory problems, and the
entire manufacturing process should be comprehensively investigated since such
problems often can extend beyond a single batch. To more accurately monitor
potential contamination sources, we recommend keeping separate trends by
appropriate categories such as product, container type, filling line, sampling,
and testing personnel. Where the degree of sterility test sample manipulation
is similar for a terminally sterilized product and an aseptically processed
product, a higher rate of initial sterility failures for the latter should be
taken as indicative of aseptic processing production problems.
Microbial monitoring of the
aseptic area of the laboratory and personnel can also reveal trends that are
informative. Upward trends in the microbial load in the aseptic area of the
laboratory should be promptly investigated as to cause, and corrected. In some
instances, such trends can appear to be more indicative of laboratory error as
a possible source of a sterility test failure.
Where a laboratory has
a good track record with respect to errors, this history can lower suspicion of
the lab as a source of contamination since chances are higher that the
contamination arose from production. However, the converse is not true.
Specifically, where a laboratory has a poor track record, firms should not
assume that the contamination is automatically more attributable to the
laboratory and consequently overlook a genuine production problem.
Accordingly, it is essential that all sterility positives be thoroughly
investigated.
3.
Monitoring of
production area environment
Trend analysis of
microorganisms in the critical and immediately adjacent areas is especially
helpful in determining the source of contamination in a sterility failure investigation.
Consideration of environmental microbial data should not be limited to results
of monitoring the production environment for the lot, day, or shift associated
with the suspect lot. For example, results showing little or no recovery of
microorganisms can be misleading, especially when preceded or followed by a
finding of an adverse trend or atypically high microbial counts. It is
therefore important to look at both short- and long-term environmental trend
analyses.
4.
Monitoring Personnel
The review of data and
associated trends from daily monitoring of personnel can provide important
information indicating a route of contamination. The adequacy of personnel
practices and training also merit significant review and consideration.
5.
Product Presterilization
Bioburden
We recommend review of
trends in product bioburden and consideration of whether adverse bioburden
trends have occurred.
6.
Production record
review
Complete batch and
production control records should be reviewed to detect any signs of failures
or anomalies that could have a bearing on product sterility. For example, the
investigation should include elements such as:
- Events that could
have impacted on the critical zone
- Batch and trending
data that indicate whether utility and/or support systems are functioning
properly. For instance, records of air quality monitoring for filling
lines could show a time at which there was improper air balance or an
unusually high particle count.
- Whether construction
or maintenance activities could have had an adverse impact
7.
Manufacturing history
The manufacturing
history of a product or similar products should be reviewed as part of the
investigation. Past deviations, problems, or changes (e.g., process,
components, equipment) are among the factors that can provide an indication of
the origin of the problem.
21 CFR 211.100(a) states that “There shall be written
procedures for production and process control designed to assure that the
drug products have the identity, strength, quality, and purity they purport
or are represented to possess. Such procedures shall include all
requirements in this subpart. These written procedures, including any
changes, shall be drafted, reviewed, and approved by the appropriate
organizational units and reviewed and approved by the quality control unit.”
21 CFR 211.100(b) states that “Written production and
process control procedures shall be followed in the execution of the various
production and process control functions and shall be documented at the time
of performance. Any deviation from the written procedures shall be recorded
and justified.”
21
CFR 211.186 and 211.188 address, respectively, "Master production and
control records" and "Batch production and control records."
21 CFR 211.192 states that “All drug product production and control
records, including those for packaging and labeling, shall be reviewed and
approved by the quality control unit to determine compliance with all
established, approved written procedures before a batch is released or
distributed. Any unexplained discrepancy (including a percentage of
theoretical yield exceeding the maximum or minimum percentages established in
master production and control records) or the failure of a batch or any of
its components to meet any of its specifications shall be thoroughly
investigated, whether or not the batch has already been distributed. The
investigation shall extend to other batches of the same drug product and
other drug products that may have been associated with the specific failure
or discrepancy. A written record of the investigation shall be made and
shall include the conclusions and followup.”
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Manufacturers should
build process and environmental control activities into their aseptic
processing operation. It is critical that these activities be maintained and
strictly implemented on a daily basis. The requirement for review of all batch
records and data for conformance with written procedures, operating parameters,
and product specifications prior to arriving at the final release decision for
an aseptically processed product calls for an overall review of process and
system performance for that given cycle of manufacture. All in-process and
laboratory control results must be included with the batch record documentation
in accordance with section 211.188. Review of environmental and personnel
monitoring data, as well as other data relating to acceptability of output from
support systems (e.g., HEPA / HVAC, WFI, steam generator) and proper
functioning of equipment (e.g., batch alarms report; integrity of various
filters) are considered essential elements of the batch release decision.
While interventions
and/or stoppages are normally recorded in the batch record, the manner of
documenting these occurrences varies. In particular, line stoppages and any
unplanned interventions should be sufficiently documented in batch records with
the associated time and duration of the event. In addition to lengthened dwell
time of sterile product elements in the critical area, an extensive
intervention can increase contamination risk. Sterility failures have often
been attributed to atypical or extensive interventions that have occurred as a
response to an undesirable event during the aseptic process. Written
procedures describing the need for line clearances in the event of certain
interventions, such as machine adjustments and any repairs, should be
established. Such interventions should be documented with more detail than
minor events. Interventions that result in substantial activity near exposed
product or container closures or that last beyond a reasonable exposure time
should, where appropriate, result in a local or full line clearance.
Any disruption in power
supply, however momentary, that could affect product quality is a manufacturing
deviation and must be included in batch records (211.100, 211.192).
Aseptic processing
using isolation systems separates the external cleanroom environment from the
aseptic processing line and minimizes its exposure to personnel. A
well-designed positive pressure isolator, supported by adequate procedures for
its maintenance, monitoring, and control, offers tangible advantages over
traditional aseptic processing, including fewer opportunities for microbial
contamination during processing. However, users should remain vigilant to
potential sources of operational risk. Manufacturers should also be aware of
the need to establish new procedures addressing issues unique to isolators.
A. Maintenance
1. General
Maintenance of isolator
systems differs in some significant respects from the traditional, non-isolated
aseptic processing operations. Although no isolator forms an absolute seal,
very high integrity can be achieved in a well-designed unit. However, a leak
in certain components of the system can constitute a significant breach of
integrity. The integrity of gloves, half-suits, and seams should receive daily
attention and be addressed by a comprehensive preventative maintenance
program. Replacement frequencies should be established in written procedures
that ensure parts will be changed before they breakdown or degrade. Transfer
systems, gaskets, and seals are among the other parts that should be covered by
the maintenance program.
2. Glove Integrity
A faulty glove or
sleeve (gauntlet) assembly represents a route of contamination and a critical
breach of isolator integrity. A preventative maintenance program should be
established. The choice of durable glove materials, coupled with a
well-justified replacement frequency, are key aspects of good manufacturing
practice to be addressed. With every use, gloves should be visually evaluated
for any macroscopic physical defect. Physical integrity tests should also be
performed routinely. A breach in glove integrity can be of serious
consequence. The monitoring and maintenance program should identify and
eliminate any glove lacking integrity and minimize the possibility of placing a
sterile product at risk.
Due to the potential
for microbial migration through microscopic holes in gloves and the lack of a
highly sensitive glove integrity test, we recommend affording attention to the
sanitary quality of the inner surface of the installed glove and to integrating
the use of a second pair of thin gloves.
B. Design
1. Airflow
There are two types of
aseptic processing isolators: open and closed. Closed isolators
employ connections with auxiliary equipment for material transfer. Open isolators
have openings to the surrounding environment that are carefully engineered to
segregate the inner isolator environment from the surrounding room via
overpressure.
Turbulent flow can be
acceptable within closed isolators, which are normally compact in size and do
not house processing lines. Other aseptic processing isolators employ
unidirectional airflow that sweeps over and away from exposed sterile
materials, avoiding any turbulence or stagnant airflow in the area of exposed
sterilized materials, product, and container closures. In most sound designs,
air showers over the critical area once and then is systematically exhausted
from the enclosure. The air handling system should be capable of maintaining
the requisite environmental conditions within the isolator.
2. Materials of Construction
As in any aseptic
processing design, suitable materials should be chosen based on durability, as
well as ease of cleaning and decontamination. For example, rigid wall
construction incorporating stainless steel and glass materials is widely used.
3. Pressure Differential
Isolators that include
an open portal should be designed to ensure complete physical separation from
the external environment. A positive air pressure differential adequate to
achieve this separation should be employed and supported by qualification
studies. Positive air pressure differentials from the isolator to the
surrounding environment have largely ranged from approximately 17.5 to 50
Pascals. The appropriate minimum pressure differential
established by a firm will depend on the system’s design and, when applicable,
its exit port. Air balance between the isolator and other direct interfaces
(e.g., dry heat tunnel) should also be qualified.
The positive pressure
differential should be coupled with an appropriately designed opening to the
external environment to prevent potential ingress of surrounding room air by
induction. Induction can result from local turbulent flow causing air swirls
or pressure waves that might push extraneous particles into the isolator.
Local Class 100 (ISO 5) protection at an opening is an example of a design
provision that can provide a further barrier to the external environment.
4. Clean Area Classifications
The interior of the
isolator should meet Class 100 (ISO 5) standards. The classification of the
environment surrounding the isolator should be based on the design of its
interfaces (e.g., transfer ports), as well as the number of transfers into and
out of the isolator. A Class 100,000 (ISO 8) background is commonly used based
on consideration of isolator design and manufacturing situations. An aseptic
processing isolator should not be located in an unclassified room.
C. Transfer of Materials/Supplies
The ability to maintain
integrity of a decontaminated isolator can be affected impacted by the design
of transfer ports. Various adaptations, of differing capabilities, allow for
the transfer of supplies into and out of the isolator.
Multiple material
transfers are generally made during the processing of a batch. Frequently,
transfers are performed via direct interface with manufacturing equipment.
Properly maintained and operated rapid transfer ports (RTPs) are an effective
transfer mechanism for aseptic transfer of materials into and out of
isolators. Some transfer ports might have
significant limitations, including marginal decontaminating capability (e.g.,
ultraviolet) or a design that has the potential to compromise isolation by
allowing ingress of air from the surrounding room. In the latter case,
localized HEPA-filtered unidirectional airflow cover in the area of such a port
should be implemented. Isolators often include a mousehole or other
exit port through which product is discharged, opening the isolator to the
outside environment. Sufficient overpressure should be supplied and monitored
on a continuous basis at this location to ensure that isolation is maintained.
D. Decontamination
1. Surface Exposure
Decontamination
procedures should ensure full exposure of all isolator surfaces to the chemical
agent. The capability of a decontaminant to penetrate obstructed or covered
surfaces is limited. For example, to facilitate contact with the
decontaminant, the glove apparatus should be fully extended with glove fingers
separated during the decontamination cycle. It is also important to clean the
interior of the isolator per appropriate procedures to allow for a robust
decontamination process.
2. Efficacy
The
decontamination method should render the inner surfaces of the isolator free of
viable microorganisms. Multiple available vaporized agents are suitable for
achieving decontamination. Process development and validation studies should
include a thorough determination of cycle capability. The characteristics of
these agents generally preclude the reliable use of statistical methods (e.g.,
fraction negative) to determine process lethality (Ref. 13). An appropriate,
quantified Biological Indicator (BI) challenge should be placed on various
materials and in many locations throughout the isolator,
including difficult to reach areas. Cycles should be developed with an
appropriate margin of extra kill to provide confidence in robustness of the
decontamination processes. Normally, a four- to six-log reduction can be justified
depending on the application. The specific BI spore titer used and the
selection of BI placement sites should be justified. For example,
demonstration of a four-log reduction should be sufficient for controlled,
very low bioburden materials introduced into a transfer isolator, including
wrapped sterile supplies that are briefly exposed to the surrounding cleanroom
environment.
The uniform
distribution of a defined concentration of decontaminating agent should also be evaluated as part of
these studies (Ref. 14). Chemical indicators may also be useful as a
qualitative tool to show that the decontaminating agent reached a given
location.
3. Frequency
The design of the
interior and content of an isolator should provide for its frequent
decontamination. When an isolator is used for multiple days between
decontamination cycles, the frequency adopted should be justified. This
frequency, established during validation studies, should be reevaluated and
increased if production data indicate deterioration of the microbiological
quality of the isolator environment.
A breach of isolator
integrity should normally lead to a decontamination cycle. Integrity can be
affected by power failures, valve failure, inadequate overpressure, holes in
gloves and seams, or other leaks. Breaches of integrity should be
investigated. If it is determined that the environment may have been
compromised, any product potentially impacted by the breach should be rejected.
E. Filling Line Sterilization
To ensure sterility of
product contact surfaces from the start of each operation, the entire path of
the sterile processing stream should be sterilized. In addition, aseptic
processing equipment or ancillary supplies to be used within the isolator
should be chosen based on their ability to withstand steam sterilization (or
equivalent method). It is expected that materials that permit heat
sterilization (e.g., SIP) will be rendered sterile by such methods. Where
decontamination methods are used to render certain product contact surfaces
free of viable organisms, a minimum of a six-log reduction should be
demonstrated using a suitable biological indicator.
F. Environmental Monitoring
An environmental
monitoring program should be established that routinely ensures acceptable microbiological
quality of air, surfaces, and gloves (or half-suits) as well as particle
levels, within the isolator. Nutrient media should be cleaned off of surfaces
following a contact plate sample. Air quality should be monitored periodically
during each shift. For example, we recommend monitoring the exit port for
particles to detect any unusual results. Media used for environmental
monitoring should not be exposed to decontamination cycle residues, as recovery
of microorganisms would be inhibited.
G. Personnel
Although cleanroom
apparel considerations are generally reduced in an isolator operation, the
contamination risk contributed by manual factors can not be overlooked.
Isolation processes generally include periodic or even frequent use of one or more
gloves for aseptic manipulations and handling of material transfers into and
out of the isolator. One should be aware that locations on gloves, sleeves, or
half suits can be among the more difficult to reach places during
decontamination, and glove integrity defects might not be promptly detected.
Traditional aseptic processing vigilance remains critical, with an
understanding that contaminated isolator gloves can lead to product
nonsterility. Accordingly, meticulous aseptic technique standards must be
observed (211.113), including appropriate use of sterile tools for
manipulations.
Blow-fill-seal (BFS)
technology is an automated process by which containers are formed, filled, and
sealed in a continuous operation. This manufacturing technology includes
economies in container closure processing and reduced human intervention and is
often used for filling and packaging ophthalmics, respiratory care products,
and, less frequently, injectables. This appendix discusses some of the
critical control points of this technology. Except where otherwise noted
below, the aseptic processing standards discussed elsewhere in this document
should apply to blow-fill-seal technology.
A. Equipment Design and Air Quality
Most BFS machines
operate using the following steps.
·
Heat a plastic polymer resin
·
Extrude it to form a parison
(a tubular form of the hot resin)
·
Cut the parison with a
high-temperature knife
·
Move the parison under the
blow-fill needle (mandrel)
·
Inflate it to the shape of
the mold walls
·
Fill the formed container
with the liquid product
·
Remove the mandrel
·
Seal
Throughout this
operation, sterile-air is used, for example, to form the parison and inflate it
prior to filling. In most operations, the three steps with the greatest
potential for exposure to particle contamination and/or surrounding air are
those in which (1) the parison is cut, (2) the parison is moved under the
blow-fill mandrel, and (3) the mandrel is removed (just prior to sealing).
BFS machinery and its
surrounding barriers should be designed to prevent the potential for extraneous
contamination. As with any aseptic processing operation, it is critical that
product contact surfaces be sterile. A validated steam-in-place cycle, or
equivalent process, should be used to sterilize the equipment path through
which the product is conveyed. In addition, any other surface that represents a potential contamination risk to the
sterile product should be sterile.
The classified
environment surrounding BFS machinery should generally meet Class 100,000 (ISO
8), or better, standards, depending on the design of the BFS machinery and the
surrounding room. HEPA-filtered or sterile air provided by membrane filters
should be used during the steps when sterile products or materials are exposed
(e.g., parison formation, container molding or filling steps). Air in the
critical area should meet Class 100 (ISO 5) microbiological standards during
operations. A well-designed BFS system should also normally achieve Class 100
(ISO 5) airborne particle levels. Only personnel who have been qualified and
appropriately gowned should enter the classified environment surrounding the
BFS machinery. Refer to Section V of this document for guidance on personnel
training, qualification, and monitoring.
BFS equipment design
typically calls for use of specialized measures to reduce particle levels that
can contaminate the exposed product. In contrast to nonpharmaceutical
applications using BFS machinery, control of air quality (i.e., particles) is
critical for sterile drug product manufacture. Particles generated during the
plastic extrusion, cutting, and sealing processes should be controlled.
Provisions for carefully controlled airflow can protect the product by forcing
generated particles outward while preventing any ingress from the adjacent
environment. Furthermore, equipment designs that separate the filling zone
from the surrounding environment provide additional product protection.
Barriers, pressure vacuums, microenvironments, and appropriately directed high
velocities of sterile air have been found useful in preventing contamination
(Ref. 15). Smoke studies and multi-location particle data can provide valuable
information when performing qualification studies to assess whether proper
particle control dynamics have been achieved throughout the critical area.
In addition to suitable
design, it is important to establish an adequate preventative maintenance
program. For example, because of its potential to contaminate the sterile drug
product, the integrity of the cooling, heating and other utility systems
associated with the BFS machine should be maintained and routinely monitored.
B. Validation/Qualification
Advantages of BFS
processing are known to include rapid container closure processing and
minimized aseptic interventions. However, only a properly functioning process
can realize these advantages. We recommend affording special attention to
setup, troubleshooting of equipment, and related aseptic personnel procedures.
Equipment sterilization, media fills, polymer extrusion/sterilization,
product-plastic compatibility, forming and sealing integrity, and unit weight
variation are among the key issues to address in validation and qualification
studies.
Data gathered during
such studies should ensure that BFS containers are sterile and, if used for
parenteral drugs, nonpyrogenic. This can generally be achieved by validating
that time temperature conditions of the extrusion process are effective against
endotoxin or spore challenges in the polymeric material.
The choice of
appropriate polymer material for a BFS operation includes assessing if a
material is pharmaceutical grade, safe, pure, and passes appropriate criteria
(Ref. 17) for plastics. Polymer suppliers should be qualified and monitored
for raw material quality.
C. Batch Monitoring and Control
Various in-process
control parameters (e.g., container weight variation, fill weight, leakers, air
pressure) provide information to monitor and facilitate ongoing process
control. It is essential to monitor the microbial air quality. Samples
should be taken according to a comprehensive sampling plan that provides data
representative of the entire filling operation. Continuous monitoring of
particles can provide valuable data relative to the control of a blow-fill-seal
operation.
Container closure
defects can be a major problem in control of a BFS operation. It is critical
that the operation be designed and set-up to uniformly manufacture integral
units. As a final measure, the inspection of each unit of a batch should
include a reliable, sensitive, final product examination that is capable of
identifying defective units (e.g., leakers). Significant defects due to
heat or mechanical problems, such as wall thickness, container or closure
interface deficiencies, poorly formed closures, or other deviations should be
investigated in accordance with §§ 211.100 and 211.192.
The
purpose of this appendix is to supplement the guidance provided in this
document with information on products regulated by CBER or CDER that are
subject to aseptic processing at points early in the manufacturing process, or
that require aseptic processing through the entire manufacturing process
because it is impossible to sterile filter the final drug product. The scope
of this appendix includes aseptic processing activities that take place prior
to the filling and sealing of the finished drug product. Special considerations
include those for:
A. Aseptic processing from early manufacturing steps
Some
products undergo aseptic processing at some or all manufacturing steps
preceding the final product closing step. With other products, there is a point
in the process after which they can no longer be rendered sterile by
filtration. In such cases, the product would be handled aseptically at all
steps subsequent to sterile filtration. In other instances, the final drug
product cannot be sterile-filtered and, therefore, each component in the
formulation would be rendered sterile and mixed aseptically. For example,
products containing aluminum adjuvant are formulated aseptically because once
they are alum adsorbed, they cannot be sterile-filtered.
When
a product is processed aseptically from the early stages, the product and all
components or other additions are rendered sterile prior to entering the
manufacturing process. It is critical that all transfers, transports, and
storage stages be carefully controlled at each step of the process to maintain
sterility of the product. In some cases, bulk drug substances or products
should be tested for sterility.
Procedures
(e.g., aseptic connection) that expose a product or product contact surfaces
should be performed under unidirectional airflow in a Class 100 (ISO 5)
environment. The environment of the room surrounding the Class 100 (ISO
5) environment should be Class 10,000 (ISO
7) or better. Microbiological and airborne particle monitoring should be
performed during operations. Microbial surface monitoring should be performed
at the end of operations, but prior to cleaning. Personnel monitoring should
be performed in association with operations.
Process
simulation studies covering the steps preceding filling and sealing should be
designed to incorporate all conditions, product manipulations, and
interventions that could impact on the sterility of the product. The process
simulation, from the early process steps, should demonstrate that process
controls are adequate to protect the product during manufacturing. These
studies should incorporate all product manipulations, additions, and procedures
involving exposure of product contact surfaces to the environment. The studies
should include worst-case conditions such as maximum duration of open
operations and maximum number of participating operators. However, the process
simulations do not need to mimic total manufacturing time if the manipulations
that occur during manufacturing are adequately represented.
It
is also important that process simulations incorporate storage of sterile bulk
drug substances or product and transport to other manufacturing areas. For
instance, there should be assurance of bulk vessel integrity for specified
holding times. The transport of sterile bulk tanks or other containers should
be simulated as part of the media fill. Please refer to Section IX.A for more
guidance on media simulation studies. Process simulation studies for the
formulation stage should be performed at least twice per year.
B. Aseptic processing of cellular therapy products
and cell-derived products
Cellular
therapy and some cell-derived products (e.g., lysates, semi-purified extracts)
represent a subset of the products that cannot be filter-sterilized and
therefore undergo aseptic manipulations throughout the manufacturing process.
Where possible, closed systems should be used during manufacturing. Cellular
therapy products often have short processing times at each manufacturing stage,
particularly between the harvest, formulation of the final product, and product
release. These products are frequently released from the manufacturing
facility and administered to patients before final product sterility testing
results are available. In situations where results of final sterility testing
are not available before the product is administered, additional controls and
testing should be considered. For example, additional sterility tests can be
performed at intermediate stages of manufacture, such as after the last
manipulation of the product prior to harvest. Other tests that may indicate
microbial contamination, such as microscopic examination, Gram stain (or other
bacterial and fungal stain), and endotoxin testing should be performed and meet
acceptance criteria prior to product release.
1.
ISO 14644-1: Cleanrooms and
Associated Controlled Environments, Classification of Air Cleanliness.
2. NASA
Standard for Cleanroom and Work Stations for Microbially Controlled
Environment, Publication NHB 5340.2 (August l967).
3. Technical Order 00‑25‑203,
Contamination Control of Aerospace Facilities, U.S. Air Force, December l,
l972.
4. Ljungqvist,
B., and Reinmuller, B., Cleanroom Design: Minimizing Contamination Through
Proper Design; Interpharm Press, 1997.
5.
Lord, A. and J. W. Levchuk,
"Personnel Issues in Aseptic Processing," Biopharm, 1989.
6.
Morbidity and Mortality
Weekly Report, "Clinical Sepsis and Death in a Newborn Nursery Associated
with Contaminated Medications" – Brazil, 1996, Centers for Disease Control and
Prevention, July, 1998; 47(29);610-2.
7.
Grandics, Peter, “Pyrogens
in Parenteral Pharmaceuticals,” Pharmaceutical Technology, April 2000.
8.
Recommendations of PQRI
Aseptic Processing Working Group, Product Quality Research Institute; March,
2003.
9.
Technical Report No. 36,
“Current Practices in the Validation of Aseptic Processing," Parenteral
Drug Association, Inc., 2002.
10.
Leahy, T. J. and M. J.
Sullivan, “Validation of Bacterial ‑ Retention Capabilities of Membrane
Filters," Pharmaceutical Technology, Nov., l978.
11.
Pall, D. B. and E. A.
Kirnbauer, et al., "Particulate Retention by Bacteria Retentive Membrane
Filters," Pall Corporation Colloids and Surfaces, l (l980) 235‑256,
Elsevier Scientific Publishing Company, Amsterdam.
12.
Technical Report No. 26,
"Sterilizing Filtration of Liquids," Parenteral Drug Association,
Inc., 1998.
13.
Sigwarth, V. and A. Stark,
“Effect of Carrier Materials on the Resistance of Spores of Bacillus
stearothermophilus to Gaseous Hydrogen Peroxide,” PDA Journal of
Pharmaceutical Science and Technology, Vol. 57, No. 1, January/February 2003.
14.
Isolators used for Aseptic
Processing and Sterility Testing, Pharmaceutical Inspection Convention
Cooperation Scheme (PIC/S); June, 2002.
15.
Price, J., “Blow-Fill-Seal
Technology: Part I, A Design for Particulate Control,” Pharmaceutical
Technology, February, 1998.
16.
United States Pharmacopoeia
Some relevant FDA
guidance documents include:
§
Guidance for the Submission of Documentation for Sterilization
Process Validation in Applications for Human and Veterinary Drug Products
§
Guideline for Validation of Limulus Amebocyte Lysate Test as an
End Product Endotoxin Test for Human and Animal Parenteral Drugs, Biological
Products, and Medical Devices
§
Guide to Inspections of Lyophilization of Parenterals
§
Guide to Inspections of High
Purity Water Systems
§
Guide To Inspections of
Microbiological Pharmaceutical Quality Control Laboratories
§
Guide To Inspections of
Sterile Drug Substance Manufacturers
§
Pyrogens: Still a Danger;
(Inspection Technical Guide)
§
Bacterial Endotoxins/Pyrogens;
(Inspection Technical Guide)
§
Heat Exchangers to Avoid
Contamination; (Inspection Technical Guide)
§
Compliance Program Guidance
Manual 7356.002 A, Sterile Drug Process Inspections
§
ICH Q5A, Guidance on Viral
Safety Evaluation of Biotechnology Products Derived from Cell Lines of
Human or Animal Origin
§
See also the draft guidance
Container and Closure Integrity Testing in Lieu of Sterility Testing as a
Component of the Stability Protocol for Sterile Products, which was issued in
1998. Once final, it will represent the Agency's thinking on this topic.
Air lock- A small room with interlocked doors,
constructed to maintain air pressure control between adjoining rooms (generally
with different air cleanliness standards). The intent of an aseptic processing
airlock is to preclude ingress of particulate matter and microorganism
contamination from a lesser controlled area.
Alert Level- An established microbial or airborne particle
level giving early warning of potential drift from normal operating conditions
and triggers appropriate scrutiny and follow-up to address the potential
problem. Alert levels are always lower than action levels.
Action Level- An established microbial or airborne particle
level that, when exceeded, should trigger appropriate investigation and
corrective action based on the investigation.
Aseptic
Manufacturing Area- The
classified part of a facility that includes the aseptic processing room and
ancillary cleanrooms. For purposes of this document, this term is synonymous
with “aseptic processing facility” as used in the segregated segment context.
Aseptic Processing
Facility- A building, or
segregated segment of it, containing cleanrooms in which air supply, materials,
and equipment are regulated to control microbial and particle contamination.
Aseptic Processing Room-
A room in which one or more aseptic activities or processes is performed.
Asepsis- A state of control attained by using an
aseptic work area and performing activities in a manner that precludes
microbiological contamination of the exposed sterile product.
Bioburden- The total number of microorganisms associated
with a specific item prior to sterilization.
Barrier- A physical partition that affords aseptic
processing area (ISO 5) protection by partially separating it from the
surrounding area.
Biological
Indicator (BI)-
A population of microorganisms inoculated onto a suitable medium (e.g.,
solution, container or closure) and
placed within appropriate sterilizer load locations to determine the
sterilization cycle efficacy of a physical or chemical process. The challenge
microorganism is selected based upon its resistance to the given process.
Incoming lot D-value and microbiological count define the quality of the BI.
Clean Area- An area with defined particle and
microbiological cleanliness standards.
Cleanroom- A room
designed, maintained, and controlled to prevent particle and microbiological
contamination of drug products. Such a room is assigned and
reproducibly meets an appropriate air cleanliness classification.
Component- Any ingredient intended for use in the
manufacture of a drug product, including those that may not appear in the final
drug product.
Colony Forming Unit
(CFU)- A microbiological term
that describes the formation of a single macroscopic colony after the
introduction of one or more microorganisms to microbiological growth media.
One colony forming unit is expressed as 1 CFU.
Critical Area ‑ An area designed to maintain sterility
of sterile materials. Sterilized product, containers, closures, and equipment
may be exposed in critical areas.
Clean Zone- See Clean Area.
Critical surfaces- Surfaces that may come into contact with or
directly affect a sterilized product or its containers or closures. Critical
surfaces are rendered sterile prior to the start of the manufacturing
operation, and sterility is maintained throughout processing.
Decontamination- A process that eliminates viable bioburden via
use of sporicidal chemical agents.
Disinfection- Process by which surface bioburden is reduced
to a safe level or eliminated. Some disinfection agents are effective only
against vegetative microbes, while others possess additional capability to
effectively kill bacterial and fungal spores.
Depyrogenation- A process used to destroy or remove pyrogens
(e.g., endotoxin).
D value- The time (in minutes) of exposure at a given
temperature that causes a one-log or 90 percent reduction in the population of
a specific microorganism.
Dynamic- Conditions relating to clean area
classification under conditions of normal production.
Endotoxin- A pyrogenic product (e.g., lipopolysaccharide)
present in the bacterial cell wall. Endotoxin can lead to reactions in
patients receiving injections ranging from fever to death.
Gowning
Qualification- A program that
establishes, both initially and on a periodic basis, the capability of an
individual to don the complete sterile gown in an aseptic manner.
HEPA filter- High efficiency particulate air filter with minimum
0.3 mm particle retaining efficiency of 99.97 percent.
HVAC- Heating, ventilation, and air conditioning.
Intervention- An aseptic manipulation or activity that
occurs at the critical area.
Isolator- A
decontaminated unit, supplied with Class 100 (ISO 5) or higher air quality,
that provides uncompromised, continuous isolation of its interior from the
external environment (e.g., surrounding cleanroom air and personnel). There
are two major types of isolators:
Closed isolator systems exclude
external contamination from the isolator’s interior by accomplishing material
transfer via aseptic connection to auxiliary equipment, rather than use of
openings to the surrounding environment. Closed systems remain sealed
throughout operations.
Open
isolator systems are designed to allow for the continuous or
semi-continuous ingress and/or egress of materials during operations through
one or more openings. Openings are engineered (e.g., using continuous
overpressure) to exclude the entry of external contamination into the isolator.
Laminar flow- An airflow moving in a single direction and in
parallel layers at constant velocity from the beginning to the end of a
straight line vector.
Operator- Any individual participating in the aseptic
processing operation, including line set-up, filler, maintenance, or other
personnel associated with aseptic line activities.
Overkill
sterilization process- A
process that is sufficient to provide at least a 12 log reduction of
microorganisms having a minimum D value of 1 minute.
Pyrogen- A substance that induces a febrile reaction in
a patient.
Sterile Product- For purposes of this guidance, sterile
product refers to one or more of the elements exposed to aseptic conditions
and ultimately making up the sterile finished drug product. These elements
include the containers, closures, and components of the finished drug product.
Sterilizing grade
filter- A filter that, when
appropriately validated, will remove all microorganisms from a fluid stream,
producing a sterile effluent.
Quality Control Unit- An organizational element with
authority and responsibility as defined by 211.22.
Unidirectional flow- An airflow moving in a single direction, in a
robust and uniform manner, and at sufficient speed to reproducibly sweep
particles away from the critical processing or testing area.
Terminal
sterilization- The application
of a lethal agent to sealed, finished drug products for the purpose of
achieving a predetermined sterility assurance level (SAL) of usually less than
10-6 (i.e., a probability of a nonsterile unit of greater than one
in a million).
ULPA filter- Ultra-low penetration air filter with minimum
0.3 mm particle retaining efficiency of 99.999 percent.
Validation- Establishing documented evidence that provides
a high degree of assurance that a specific process will consistently produce a
product meeting its predetermined specifications and quality attributes.
Worst case- A set of conditions encompassing upper and
lower processing limits and circumstances, including those within standard
operating procedures, that pose the greatest chance of process or product
failure (when compared to ideal conditions). Such conditions do not
necessarily induce product or process failure.