Chitosan and Its Derivatives as Promising Drug Delivery Carriers

Chitosan, a natural based polymer obtained by alkaline deacetylation ofchitin, is non-toxic, biocompatible, and biodegradable. These propertiesmake chitosan a good candidate for the development of conventional andnovel drug delivery systems. Recently, there has been a growing interest inthe chemical modification of chitosan in order to improve its solubility andwiden its applications. Chemical modification of chitosan is useful for theassociation of bioactive molecules to the polymer and controlling the drugrelease profile. Chemical modification will introduce desired properties andenlarge the field of the potential applications of chitosan with the choice ofvarious types of side chains. In this monograph, recent studies on the varioustypes of chitosan microspheres are discussed from the viewpoint of drugdelivery applications. Moreover, different types of chitosan derivatives developedas controlled drug delivery carriers and their preparation methods arediscussed in detail. The modifications discussed here include amphiphilicchitosan derivatives, N-(aminoalkyl) chitosan, carboxymethyl chitosan, thiolatedchitosans, phosphorylated chitosan, etc. Special emphasis has beengiven to the development of chitosan-based polyelectrolyte complexes, graftcopolymerized chitosan and chitosan-based stimuli-responsive hydrogelsas drug delivery carriers. The reviewed studies lead to the conclusion thatchitosan derivatives are promising materials for the controlled delivery ofvarious types of therapeutic agents.