DRUG-RELEASE TEST TO ASSESS QUALITY OF TOPICAL FORMULATIONS IN JAPANESE MARKET

Three release test methods-watch glass method, rotating dialyses cell method, and disk assembly method (DA)-were assessed for use in a quali ty control procedure for four different semisolid topical formulations containing indomethacin (IDM). Although minor modification in the met hods to optimize the release rate was necessary for each formulation, DA proved superior to the other two methods and thus was used to asses s the quality of topical formulations on the Japanese market. First, D A was used for a storage test of hydrophilic ointments and cataplasms; difference in the release profiles of IDM from these formulations sho wed changes with time, which suggests the usefulness of DA for checkin g lot-to-lot uniformity. Second, dermal patch and rape as transdermal delivery systems containing nitroglycerin or isosorbide dinitrate were investigated. Since different sizes and shapes of these products are available, various assemblies of DA were required to Pt individual pro ducts. Different release patterns were obtained among the products for both drugs. These results suggest that DA is a simple, reproducible, and more useful quantitative release test for quality control of topic al formulations.