Application of Central Composite Design for the Development and Evaluation of Chitosan-based Colon Targeted Microspheres and in vitro Characterization

Abstract

pH-sensitive colon targeted microspheres loaded with dicyclomine hydrochloride were prepared using both emulsion crosslinking and solvent evaporation techniques to retard the release of dicyclomine in the upper gastrointestinal tract and to deliver it directly to colon. Several factors were used to evaluate the product, Eudragit RS100-coated chitosan-based microspheres, such as production yield, entrapment efficiency, and cumulative drug release. Three factorial central composite design was applied to examine the effect of the independent variables, concentrations of chitosan, Tween 80, and Eudragit RS100 on the physicochemical properties of the microspheres. Design-Expert software was used to design fifteen formulations during this study and the quadratic model was best fitted with the response data. In vitro dissolution studies proved that the release of dicyclomine hydrochloride from the microspheres fits Korsmeyer-Peppas model. F1, F10 and F12 exhibited best patterns of dicyclomine hydrochloride release with negligible drug release at pH 1.2, and maximum drug release at pH 7.4, indicating their ability to target the colon.