Despite numerous scientific efforts, efficient ocular drug delivery remains a challenge for
Pharmaceutical scientists. Most ocular diseases are treated by topical drug application in the form of solutions, suspensions and ointment. These conventional dosage forms suffer from the problems of poor ocular bioavailability, because of various anatomical and pathophysiological barriers prevailing in the Eye. This review provides an insight into the various constraints associated with ocular drug delivery, summarizes recent findings and applications of various nanoparticulate systems like microemulsions, Nan suspensions, nanoparticles, liposomes, niosomes, dendrimers and cyclodextrins in the field of
Ocular drug delivery and also depicts how the various upcoming of nanotechnology like
nanodiagnostics, nanoimaging and nanomedicine can be utilized to explore the frontiers of ocular drugdelivery and therapy.Significance.:Much of the published data suggests that in the case of ophthalmic drug delivery, an appropriate particle size and a narrow size range, ensuring low irritation, adequate bioavailability and compatibility with ocular tissues, should be sought for every suspended drugThough the delivery of drugs to the anterior segment of the eye is achieved mainly through topical delivery, very little of the topically applied drug reaches the posterior segment of the eye. This necessitates the administration of some drugs, such as antiglaucomadrugs, corticosteroids and certain antibiotics by the systemic route. However, a very small fraction of the dose reaches the ocular tissues, following systemic administration. The doses required to give a therapeutic effect via this route, however, can lead to considerable side effects. Depending on their particle charge, surface properties and relative hydrophobic, nanoparticles can be designed to be successfully used in overcoming retinal barriers. In addition to these points, encapsulation of drugs in nanospheres, liposomes, and so on, can also provide protection for the drug and hence prolong exposure of the drug by controlled release. Nanotechnology-based drug delivery is also very efficient in crossing membrane barriers, such as the blood retinal barrier in the eye.