100 страниц. 2012 год. LAP Lambert Academic Publishing There is growing interest in developing chemical and biochemical processes to obtain and modify biopolymers, and to other useful technical properties for their applications in different fields. The latest and most interesting example is chitin, it is mainly used for production of chitosan by a deacetylation reaction usually obtained in alkaline medium. Chitosan exhibits several favorable properties, such as biodegradability and biocompatibility. It also has mucoadhesive properties due to its positive charges at neutral pH that enable an ionic interaction with the negative charges of sialic acid residues of the mucus. Numerous studies have demonstrated that chitosan and its derivatives are effective and safe absorption enhancers to improve mucosal (nasal, peroral) delivery of hydrophilic macromolecules, such as peptides, proteins, and heparins. Chitosan has been developed for a variety of biomedical applications including wound dressings and drug delivery systems.