Abstract
We reviewed the effectiveness of chitosan capsules for colon-specific delivery of insulin. The release of drug from the chitosan capsules was markedly increased in the presence of rat cecal contents, although no release from the capsules was observed in an artificial gastric juice and an artificial intestinal juice. The results of swelling and elongation tests using the chitosan film strongly suggested that chitosan capsules were degraded by the microorganisms in rat cecal contents. The intestinal absorption of insulin following oral administration of chitosan capsules containing insulin with or without additives was investigated by an in vivo rat absorption experiment. A marked decrease in plasma glucose level was observed following administration of the capsules containing 20 IU insulin and Na-glycocholate as compared with the capsules containing insulin only. These results suggested that chitosan capsule could be a useful carrier for colon-specific delivery of peptides including insulin.
