The purpose of the present study was to develop an optimized gastroretentive drug delivery system of Diltiazem HCl Hollow microspheres by the optimization technique. The Diltiazem HCl microspheres were prepared by non aqueous emulsion solvent evaporation method using different grades of Eudragit (Eudragit RS 100 and Eudragit RL 100) in combination. Response Surface Analysis data was obtained using Software STAT-EASE, design expert, 7.0, Trial Version. A 32 factorial design was employed in formulating the GRDDS with Stirring speed(X1) and polymer concentration (X2) as independent variables and Two dependent variables were particle size and Drug entrapment. The main effect and interaction terms were quantitatively evaluated using a mathematical model. Regression analysis and numerical optimization were performed to identify the best formulation. The result of analysis of variance test for both effects indicated that the test is significant. The best batch exhibited a high entrapment efficiency and particle size.
