Why Chitosan? From properties to perspective of mucosal drug delivery

Non-parenteral drug delivery routes primarily remove the local pain at the injection site. The drugs administered through the oral route encounter the process of hepatic first pass metabolism. Among the alternative delivery routes, mucosal route is being investigated as the most preferred route. Different mucosal routes include the gastrointestinal tract (oral), vagina, buccal cavity and nasal cavity. Novel formulations are being developed using natural and synthetic polymers that could increase the residence time of the drug at mucosal surface in order to facilitate permeation and reduce (or bypass) the first pass metabolism. For recombinant drugs, the formulations are accompanied by enzyme inhibitors and penetration enhancers. Buccal cavity (buccal and sublingual mucosa) has smaller surface area than the gastrointestinal tract but the drugs can easily escape the first pass metabolism. Chitosan is the most applied natural polymer while synthetic polymers include Carbopol and Eudragit. Chitosan has inherent properties of mucoadhesion and penetration enhancement apart from biodegradability and efflux pump inhibition. This review hoards the important research purview of chitosan as a compatible drug carrier macromolecule for mucosal delivery on single platform.