CONTROLLED-RELEASE COEVAPORATES OF DIPYRIDAMOLE PREPARED WITH ACRYLICPOLYMERS

The objective of this study was to obtain controlled-release dosage fo rms of dipyridamole chosen as a model drug practically insoluble above pH 5. The coevaporates were prepared by the solvent method using ente ric and insoluble acrylic polymers as well as their mixtures in differ ent proportions. The in vitro dissolution test results were determined by the USP XXII paddle method at different pH values during a period of 8 h. These results showed that the progressive pa-dependent release of dipyridamole could only be achieved by blending enteric and insolu ble polymers. To overcome the difficulty in maintaining sink condition s with the paddle method, the dissolution profiles of some of the form ulations were investigated using the open flow-through cell method.