Captopril floating and/or bioadhesive tablets: design and release kinetics.

Two viscosity grades of hydroxypropylmethylcellulose (HPMC 4000 and 15,000 cps) and Carbopol 934P were used to prepare captopril floating tablets. In vitro dissolution was carried out in simulated gastric fluid (enzyme free) at 37 degrees C +/- 0.1 degree C using the USP apparatus 2 basket method. Compared to conventional tablets, release of captopril from these floating tablets was apparently prolonged; as a result, a 24-hr controlled-release dosage form for captopril was achieved. Drug release best fit both the Higuchi model and the Korsmeyer and Peppas equation, followed by first-order kinetics. While tablet hardness and stirring rate had no or little effect on the release kinetics, tablets hardness was found to be a determining factor with regard to the buoyancy of the tablets.