Functional chitosan carriers for oral colon-specific drug delivery

Abstract

Chitosan is a polysaccharide consisting of D-glucosamine and N-acetyl-D-glucosamine units linked by β-(1, 4) linkages. It is derived via deacetylation of chitin. Chitosan is a cationic polymer which is biodegradable, biocompatible, nontoxic, and mildly allergenic. It is characterized by antitumor, antimicrobial, and antioxidant activities which render a widespread research interest for pharmaceutical and biomedical applications. Used as a matrix and/or coat material, chitosan can protect drugs from chemical and enzymatic degradation with reference to oral delivery. Chitosan binds strongly to mucus and exhibits mucosal permeationenhancing property that promotes drug absorption through intestinal epithelial cells. Oral colon-specific delivery systems have been explored for targeted drug administration for the treatment of colon cancer, ulcerative colitis, Crohn’s disease, diverticulitis, irritable bowel syndrome, Hirschsprung’s disease, antibiotic-associated colitis, and other colon diseases. This chapter gives an overview of relevant physicochemical and biological properties of chitosan and its derivatives and innovative formulations with respect to their use as oral colonspecific drug delivery systems.