Design and evaluation of microcapsules of diltiazem hydrochloride.

: Diltiazem Hydrochloride (DTZ.HCl), a potent calcium channel blocker was microencapsulated by emulsion/solvent evaporation technique using non-aqueous solution of Ethylcellulose (EC) polymer to achieve its release from microcapsules at a slower rate. At the optimal conditions of process variables such as stirring speed, temperature of the medium, drug-polymer ratio, maximum encapsulation efficiency was obtained and the microcapsules produced were free flowing, discrete and spherical as evident from Scanning Electron Microscopy. The in vitro release experiments were carried out in the simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.2 phosphate buffer) using USP XXII apparatus II. The data obtained from the dissolution profiles were compared in the light of different kinetic models and the regression coefficients were compared.