Chitosan and its derivatives as intraocular penetration enhancers

An overview of literature information on the research on chitosan and its derivatives as promoters of intraocular penetration of topically administered drugs is presented. The main objective of this research has been increasing the intraocular bioavailability of drugs administered via eye drops. This has been pursued using cornea-permeabilizing water-soluble chitosan and derivatives, e.g. N-trimethylchitosan or quaternary ammonium-chitosan conjugates, which have enhanced the intraocular bioavailability of hydrophilic and lipophilic drugs administered to rabbits via eye drops, in situ gelling systems, or liposomes. Also the potential of chitosan-based formulations has been confirmed by proving their safety to ocular structures. The results illustrated in this overview have indicated chitosan as a biomaterial on which to build to innovate ophthalmic formulations.