Drug delivery applications of chitin and chitosan: a review

Polymers are used in drug delivery devices for drug encapsulation and release. Natural polymers often have advantages such as biocompatibility, biodegradability and biologically recognizable moieties which support cellular activities, compared to synthetic polymers. Chitosan, a naturally occurring polysaccharide obtained from chitin, has recently drawn attention because chitosan is non-toxic, biocompatible, biodegradable, stable and sterilizable. The additional qualities of chitosan are the release rate of drug, easy modification, cross-linking ability with other polymers, antimicrobial properties, gel forming ability, bioadhesion, immunostimulation, activation of macrophages and gas permeability. Here, I review applications of chitosan in drug delivery. The properties of chitin and chitosan, and the mechanisms of drug release are also presented.