Chitosan and trimethyl chitosan (TMC) as drug absorption enhancers: Moving forward toward clinical acceptance

This chapter focuses on the main aspects of the absorption enhancing properties of chitosan and trimethyl chitosan (TMC), properties of relevant in vitro absorption enhancement models, and synthetic strategies of TMC. It discusses in vivo testing in terms of regulatory status for the possible acceptance of chitosan and TMC as drug absorption enhancers. Biotechnological drugs are usually relatively large and hydrophilic, rendering the paracellular pathway the optimal absorption route in noninvasive drug delivery. Chitosan is generally considered to have good biocompatibility and biodegradability which is imperative for its potential in pharmaceutical applications. The regulatory status of chitosan depends on its intended use in either food or pharmaceutical formulations. An important factor when determining the extent of biological activity and safety of chitosan and TMC is to assure that the polymer under investigation contains truly limited amount of impurities that could otherwise interfere with biological tests.