Abstract

The aim of this study was design and development of colon-specific delivery system of satranidazole based on pectin microbeads formed by cross-linking with calcium chloride. Satranidazole loaded calcium-pectinate microbeads were prepared by ionotropic gelation method. Application of response surface methodology was used to study the effect of pectin concentration, calcium chloride concentration and stirring speed on drug release and encapsulation efficiency. Particle size of the calcium-pectinate microbeads was determined by particle size analyzer. The SEM was used to characterize the surface of these microbeads. In vitro drug-release studies were performed in conditions simulating stomach-to-colon transit in the presence and absence of rat cecal contents. The in vitro drug release studies exhibited low drug release at gastric pH, however continuous release of drug was observed from the formulation at colonic pH. Further, the release of drug from formulation was found to be higher in the presence of rat cecal contents, indicating the effect of colonic enzymes on the calcium pectinate microbeads. The significance of differences was evaluated by analysis of variance (ANOVA). Differences were considered statistically significant at P < 0.05. Thus, by experiment design important parameters affecting formulation characteristics of satranidazole loaded calcium-pectinate microbeads can be identified for colon specific delivery.

Keywords: Response surface methodology, calcium-pectinate microbeads, cross-linking, satranidazole, colon specific delivery, pectin, rat cecal contents, drug release kinetics, mechanism of drug release, Design of experiment, Box-Behnken's design, simulated gastro intestinal fluid, ionotropic gelation method, analysis of variance, Amoebiasis, colonic microflora