Thiolated-Chitosan: A Novel Mucoadhesive Polymer for Better-Targeted Drug Delivery

Abstract Mucoadhesion is a complex process that involves interaction (chemical and physical) between the mucin epithelial layer and polymers with mucoadhesive potential. Mucoadhesive polymers help in achieving drug delivery by adhering to mucous membranes in different parts of the body (like intestinal mucosa, oral mucosa, gastric mucosa, etc.) and provide an opportunity to attain an adequate concentration of the loaded drug at the desired site of action. In this context, thiolated chitosan is one of the most extensively utilized and favored mucoadhesive polymers, which is obtained via immobilization of thiol group on the polymeric chain of chitosan. The structural properties of chitosan uniquely allow the modification of its innate architect to sulfhydryl bearing derivatives. Upon thiol modification, the mucoadhesive, cohesive, and in situ gelling features of chitosan gets significantly improved. These modifications further augment the permeation enhancement capabilities of native chitosan and make it more suitable for vivid pharmaceutical and biomedical applications. This chapter expounds the state-of-the-art information on characteristics and methods of preparation, and a crosstalk discussion on the application of mucoadhesive thiolated chitosan as an effective delivery module is also covered in this chapter.