Chitosan-Based Ocular Drug Delivery Systems

Chitosan is widely used in ocular drug delivery systems due to its biocompatibility, biodegradability, and favorable physicochemical characteristics. Chitosan-based ocular drug delivery systems are widely reported to improve the bioavailability at the anterior/posterior pole of the eye due to its mucoadhesive property that helps to increase efficacy of existing ocular drugs, affords stimuli responsive/targeted-based delivery regimen, enhances the corneal permeability, and improves the accumulation of drugs in the corneal/conjunctival epithelia for an extended period of time. This review summarizes the major ocular diseases affecting the eye, ocular delivery systems, novel ocular drug delivery systems, intraocular drug transport barriers, and ocular transporters. The utilization of chitosan toward the ocular drug delivery systems such as stimuli responsive systems, targeted delivery systems, and gene-based delivery systems is also discussed.