Chitosan is a biopolymer with a wide range of biomedical applications, including wound healing, tissue engineering and tissue repair, and local delivery of cells, drugs, proteins, genes, and other therapeutics. Currently, nasal drug delivery technology using chitosan to speed the absorption of the API shows great potential, with several applications in clinical trials. Non-viral gene delivery systems using chitosan as a carrier are also the subject of intense research activity.

Chitosan chemistry

Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit; D) and N-acetyl-D-glucosamine (acetylated unit; A).

Chitosan is produced commercially by deacetylation of chitin, which is the structural element in the exoskeleton of crustaceans (crabs, shrimps, etc.). The degree of deacetylation (%DA) can be determined by NMR spectroscopy. Variation in the %DA can lead to varying functionality of chitosans in different applications.

PROTASAN UP Chitosan Chloride and Chitosan Glutamate Salts are readily soluble in water. The viscosity of a chitosan solution primarily depends on the average molecular weight of the polymer, which can be determined by size exclusion chromatography combined with light scattering detection. The amino group in chitosan has a pKa value of ~6.5, while the charge density is dependent upon the solution pH and the degree of chitosan deacetylation. As a positively charged biopolymer, chitosan is bioadhesive and readily binds to negatively charged surfaces such as mucosal membranes. Chitosan enhances the transport of polar drugs across epithelial surfaces, and is biocompatible and biodegradable.