NEW IMPROVED PADDLE METHOD FOR DETERMINING THE IN-VITRO DRUG-RELEASE PROFILES OF TRANSDERMAL DELIVERY SYSTEMS

A new improved paddle method for determining the in vitro drug release profiles from transdermal delivery systems has been developed. This m ethod/procedure employs a convex screen patch holder which is placed a t the bottom of a dissolution vessel so as to hold the transdermal del ivery systems in position between the apex of a convex screen and the bottom of a dissolution vessel. The release profiles of nitroglycerin (GTN) from five marketed products, each with two different sizes, were determined using this new method and compared with those obtained usi ng the Cygnus' and the FDA's sandwich patch holders. The results stron gly indicate that the new method is reproducible and applicable for in vitro characterization of all brands of marketed transdermal delivery systems and the convex screen patch holder is a more versatile and an even simpler tool for use than the sandwich patch holders.