STUDIES ON DISSOLUTION TESTS FOR SOFT GELATIN CAPSULES .4. DISSOLUTION TEST OF NIFEDIPINE SOFT GELATIN CONTAINING WATER-SOLUBLE VEHICLES BY THE ROTATING DIALYSIS CELL METHOD

The dissolution of oval soft gelatin capsules containing 5 mg of nifedipine dissolved in a water soluble vehicle was evaluated by the rotating dialysis cell (RDC) method and the paddle (PD) method as described in the Japanese Pharmacopoeia (JP) XI. The dissolution pattern of nifedipine obtained by the PD method was linear, and almost 100% of the content was dissolved within 7 to 10 min. The dissolution pattern obtained by the RDC method corresponded to the absorption pattern vs. time curve obtained by the oral administration test in humans. When the RDC method was performed with the cell containing a buffered solution coupled with n-octanol as the dissolution medium, the in vitro dissolution pattern best simulated the in vivo absorption pattern.