Current state of the potential use of chitosan as pharmaceutical excipient

One of the most fashionable polymers with potential in pharmaceutical research is chitosan. Chitosan comprises a series of natural biodegradable polysaccharides that differ in their degree of deacetylation, molecular weight, viscosity and, consequently, pKa. Structurally, the presence of a number of amino groups turns this polymer chemically reactive with anionic systems, and this feature is mainly responsible for the numerous applications found until now. One application is its use as an excipient in the pharmaceutical industry. The use as excipient includes binding, disintegrating and tablet coating, ultimately related with the production of controlledrelease solid dosage forms. This polymer has also been investigated as a potential adjuvant for swellable controlled drug delivery systems. Owing to its mucoadhesive properties via the oral route as well as its absorption-enhancing effects, it has been explored by a number of researchers. Also, owing to its release and adhesive properties, chitosan films have been developed as wound dressings, oral mucoadhesive and water-resistant adhesives. This chapter will discuss the properties that turn chitosan into excipient for use in the pharmaceutical industry, and also the related research made until now concerning this objective.