Effects of selected formulation parameters on the entrapment of diclofenac sodium in ethyl cellulose microspheres

Abstract

Computer optimization technique was employed to investigate the key variables affecting the preparation of diclofenac sodium microspheres. The amount of dichloromethane and stabilizer such as sodium alginate or pectin were used as independent variables, while drug content and microsphere diameter were selected as dependent variables for deciding the optimum formulation conditions. A 3 2 full factorial design was employed and second-order regression models were developed for the responses. The results of analysis of variance test, for drug content in microspheres, indicated that the test is significant and the contribution of amount of stabilizer was found to be higher in magnitude than that of dichloromethane. The diameter of the microspheres showed poor correlation with the selected independent variables. All the batches yielded microspheres with excellent topographical characteristics. Contour graphs are presented to visualize the impact of independent variables on the drug content in the microspheres.