STUDIES ON THE CONTROLLED-RELEASE PELLETS OF NIFEDIPINE

Controlled-release pellets of nifedipine have been prepared and evaluated by in vitro and in vivo (in dogs and human bodies) tests in the study. The pellet-released drug fitted to a first-order process (K=0.23 h^-1) as wall as Higuchi's function (K=37.05h^1/2).After administration the concentration of these pellets was more steady than that of sustained-release pellets reported in dogs. It was also found to be steady in human. The concentration reached 20 ng/ml in about 10 minutes and stayed between 20～70ng/ml within from 10 minutes to 15 hours. The bioavailability of the controlled-release pellets is a little higher than that of the conventional pellets.The pharmacokinetic character of nifedipine has primarily been explored in this article,and corresponds with a two-compartment model (t_1/2β=3.5h).