Chitosan: A Novel Functional Excipient Used in Mucoadhesive Formulation
Polymers have been used as a main tool to control the drug release rate from the formulations. Extensive applications of polymers in drug delivery have been realized because polymers offer unique properties which so far have not been attained by any other materials. Chitosan is a cationic natural polysaccharide which is derived from the chitin of crustaceans, with crabs and shrimp-shell wastes as its principal source. Its properties include extent of deacetylation and the average molecular weight of polymer as well as low toxicity and good bioavailability make it a novel excipient in pharmaceutical formulation as a relatively new development. Together with chitin, chitosan is well thought-out the second most abundant polysaccharide subsequent to cellulose. But in contrast to cellulose, the application of Chitosan in pharmaceutical field is a pretty new development. Recently there are so many mucoadhesive formulation were prepared and evaluated within different dosage forms such as ophthalmic, nasal sublingual, buccal, periodontal, gastrointestinal, colon specific, vaginal, transdermal as well as gene carrier which is based on the application of chitosan and its derivatives. Chitosan is biocompatible and show the activities such as antimicrobial and antifungal activities, which makes it a favourable option for biomedical applications. It has been proven to be useful in tissue growth, in tissue repair and accelerating wound-healing and bone regeneration. Microcrystalline chitosan (MCCh) is a highly crystalline grade of chitosan base may be particularly valuable as an excipient. Mucoadhesive tendency of chitosan might also depend on its crystallinity. Efficient gel formation by MCCh could result in substantial mucoadhesion, at least as far as “adhesion by hydration” is concerned. The objective of this review is to summarized the application and formulation based on the chitosan and its derivatives and also to elaborate the importance of chitosan in pharmaceutical field.