W.H.Doub1, A.M.Wokovich1, J.C.Black1, W.P.Adams2, 1DPA, OPS, CDER, FDA, St. Louis, MO, 2OPS, CDER, FDA, Rockville, MD
Several configurations of the Andersen Cascade Impactor (ACI) were evaluated to assess its utility to provide sufficient precision for the measurement of “fines” in aqueous nasal sprays when used for in vitro bioequivalence (BE) studies. Deposition of nasal inhalation pharmaceuticals were assessed with the full (8–stage), standard (ACI28.3) and 90 lpm (ACI90/28.3) configurations, both at a flowrate of 28.3 lpm. These results were compared to those obtained using the ACI28.3 and ACI90/28.3 configurations employing only three stages (top two and final plus filter). Additionally, three different spherical induction chambers (1L, 2L, and 5L) were examined both with and without the Andersen preseparator.
Early experiments showed the 1L chamber to be too small for use with aqueous nasal sprays and it was eliminated from all subsequent comparisons. Using either remaining chamber, the ACI90/28.3 configuration allows as much as 40% more drug to be collected in the CI, although absolute amounts are very small (0.5-1%) with both configurations. A dramatic increase in the measurement precision is observed when the 2L chamber is used. The use of the 3–stage ACI configurations yields additional improvement in the precision of the measurement of “fines”, particularly with the 2L chamber.
This work was presented at AAPS 2002.