The Chemistry of Chitin and Chitosan Justifying their Nanomedical Utilities

Abstract

Chitin and chitosan are among the most commonly used natural polymers in nanomedicine because they display very attractive characteristics for drug delivery and have proven very effective when formulated in nanoparticle forms. Properties such as the cationic character and the solubility of chitosan in aqueous medium have been reported as determinants of the success of this polysaccharide. However, its most attractive property relies on its ability to adhere to mucosal surfaces, leading to prolonged residence time at drug absorption sites and enabling higher drug permeation. This is because chitin and chitosan are able to interact with anionic agents and form water-soluble barriers which participate in drug release. The wide nanomedical applications of chitin and chitosan are due not only to their excellent biocompatibility, biodegradability, non-toxicity, ordourless nature and economic efficiency but also due to their distinct chemical structure with high percentage of primary amino groups and acetamido groups in chitosan and chitin respectively, for easy binding to bio-molecules such as DNAs and proteins. This review highlights the properties and modifications of chitin and chitosan which are responsible for the wide range of applications of these materials, particularly in nanomedicine for drug delivery and gene therapy, thereby encouraging more research into the exploration of their properties and modifications for improved applications.