Chitosan as a responsive biopolymer in drug delivery

Abstract Chitosan (deacetylated chitin) is a promising naturally derived biopolysaccharide, which is widely used in numerous biomedical and pharmaceutical applications due to its beneficial properties like solubility, biodegradability, biocompatibility, etc. Since past few decades, it has been used as excipient in the formulations of different drug delivery dosage forms. Owing to its cationic nature, and presence of primary amino groups in its structure, which are mainly responsible for mucoadhesion, transfection, in situ gelation, efflux pump inhibition, etc. It also possesses stimuli-responsive (such as pH, temperature, ionic strength, magnetic, etc.) properties. These responsive properties of chitosan make it an advanced biopolymer to be widely employed in the formulation of many smart polymeric systems for delivery of numerous drugs. The current chapter addresses various responsive drug delivery systems formulated using chitosan and its derivatives.