Dissolution characteristics of nicardipine hydrochloride microcapsules from hard gelatin capsules and tablets

Nicardipine hydrochloride microcapsules prepared by using ethylcellulose as coating material were put into hard gelatin capsules and were comparessed into tablets to investigate the effect of direct tableting agent on the release of nicardipine hydrochloride. Dissolution tests were studied in simulated gastric medium without enzyme using the USP XXII rotating basket method. In vitro release was evaluated by zero order, first order, RRSBW, Hixson-Crowell, Higuchi and Hopfenberg kinetic models. The release of nicardipine hydrochloride was found to be governed by the core: wall ratio, microcapsule particle size and the kind of direct tabletting agent. Release from hard gelatin capsules and tabletted microcapsules were significantly more prolonged than the respective batches of the microcapsules, but release of tabletted microcapsules was found to be low degree for drug. Therefore, direct tabletting agents such as lactose, lactose fast flo and avicel pH 101 were added to the tablets to increase the release rate of drug. It was concluded that avicel pH 101 could be used to increase dissolution rates from tabletted microcapsules. The multiple regression technique was assumed for the analysis of experimental data. Three-dimensional response-surface graphs for percentage of nicardipine hydrochloride released as a function of percentage of drug content and dissolution time were generated