Advances in the colon-targeted chitosan based multiunit drug delivery systems for the treatment of inflammatory bowel disease

Chitosan is the polymer of choice for delivery of the active moieties to the colon due to its cationic nature that enables strong mucosal attachment. Chitosan is explored for formulations such as pellets, beads, microspheres, nanoparticles and drug-polymer conjugates for colon targeting of various therapeutic agents in inflammatory bowel disease (IBD). The major challenge in the colonic delivery of drugs in IBD is altered physiological pH, which can be addressed via chitosan containing multiparticulate drug delivery systems owing to their biodegradability in the colon. Its ionic interaction with anionic polymers forms gastro-resistant multi-unit systems that ensures safe delivery of payloads to the colon. In contrast to commercial grade gastro-resistant polymers, chitosan has GRAS (generally regarded as safe) status that ensures safety for long-term therapy in case of chronic diseases such as IBD. Here, we review in detail essential properties of chitosan and chitosan based multiunit formulations for treatment/mitigation of IBD.