[Code of Federal Regulations]
[Title 40, Volume 23]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR160.113]

[Page 160]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 160_GOOD LABORATORY PRACTICE STANDARDS--Table of Contents
 
            Subpart F_Test, Control, and Reference Substances
 
Sec. 160.113  Mixtures of substances with carriers.

    (a) For each test, control, or reference substance that is mixed 
with a carrier, tests by appropriate analytical methods shall be 
conducted:
    (1) To determine the uniformity of the mixture and to determine, 
periodically, the concentration of the test, control, or reference 
substance in the mixture.
    (2) When relevant to the conduct of the study, to determine the 
solubility of each test, control, or reference substance in the mixture 
by the testing facility or the sponsor before the experimental start 
date.
    (3) To determine the stability of the test, control, or reference 
substance in the mixture before the experimental start date or 
concomitantly according to written standard operating procedures, which 
provide for periodic analysis of each batch.
    (b) Where any of the components of the test, control, or reference 
substance carrier mixture has an expiration date, that date shall be 
clearly shown on the container. If more than one component has an 
expiration date, the earliest date shall be shown.
    (c) If a vehicle is used to facilitate the mixing of a test 
substance with a carrier, assurance shall be provided that the vehicle 
does not interfere with the integrity of the test.