Expanding Arsenal against Ocular Diseases through Nanoemulsion: Success So Far and the Road Ahead.

The eye is a most delicate organ protected by several complex biological barriers that are static and dynamic. The presence of these ocular barriers retards drug absorption from topically applied dosage forms at the conjunctival sac. The efficient topical delivery of the drug into the globe is more difficult to achieve and there is a need to develop a topical formulation that may reduce the use of injections and increase patient compliance with decreased frequency of administration. In the advancements of research in nanotechnology, nanoemulsions can be used as biocompatible carriers to deliver the drug to the ocular cavity. The lipophilic globules can increase the solubility of hydrophobic cargos which provides increased permeation ability and ocular bioavailability which can sustain drug release and corneal retention. Because of their small size, these formulations do not cause blurring of vision. Nanoemulsions (NEs) over the past decade have been used to treat several ocular diseases in the anterior eye segment. This review summarizes the economic burden, pathology of ocular diseases, formulation considerations for ocular formulations, and recent advances of these NEs as effective carriers for ocular drug delivery highlighting their performance in pre-clinical studies.