Chitosan and its role in ocular therapeutics.

From the past few decades, tremendous awareness has been laid on the use of natural polymers in ocular drug delivery. Chitosan, a modified natural carbohydrate polymer, has number of applications in the field of ophthalmics and attracted a great deal of attention of scientific community, academicians and environmentalists due to its unique features. Chitosan has been explored for the delivery of drugs, genes, biotechnological products, proteins and peptides to the target site within ocular tissues. Chitosan being a polycationic in nature interacts with the polyanionic surface of ocular mucosa through hydrogen bonding / ionic interactions and enhance the mucoadhesive effect of formulation. Sustained and controlled ocular delivery can be achieved with chitosan based formulations like chitosan gels, inserts, chitosan coated liposome/niosome and chitosan nanoparticles. This review discussed various aspects related to chitosan and chitosan based formulations particularly developed for ocular therapeutics. The fate and toxicological consideration related to chitosan, resulting with its interaction to ocular tissues, has also been summed up in addition.