Modified Chitosan Cross-linked Starch Polymers for Oral Insulin Delivery

A chitosan, with citric acid cross-linked CMS grafted with methacrylic acid and poly(ethyleneglycol monomethyl ether methacrylate), was prepared for oral delivery of insulin. Increases in chitosan content increased the bioadhesivity. The equilibrium swelling and in vitro release profiles in enzyme-free simulated gastric (SGF) and intestinal fluids (SIF) by the insulin entrapped gels were established. Increasing the chitosan content in the copolymer enhanced the hydrolysis in the SIF. In all cases, the biological activity of insulin was retained. The antimicrobial activity of hydrogels was examined against a Staphylococcus aureus. Based on these results, new designs to improve insulin release behavior are being carried out.