Nanocarriers Based Ocular Therapeutics: Updates, Challenges and Future Prospectives.

Background: Ocular disorders mainly affect patient's eyesight and quality of life. Formulation scientists encounter a hurdle in drug distribution to ocular tissues. Anatomical barriers (static and dynamic) and physiological barriers, such as nasolacrimal drainage system, blinking action of eye, and metabolic barriers and efflux pumps, are the principal obstacles to medication delivery to the posterior and anterior parts. Over the last twenty years, ophthalmic research has evolved rapidly for the development of innovative, safe, and patient friendly formulations and drug delivery devices or techniques that may get over these obstacles and sustain drug levels in tissues.

Methods: Literature from the past ten years has been collected using various search engines, such as ScienceDirect, J-Gate, Google Scholar, Pubmed, Sci-Hub, etc., and research data have been compiled according to various novel carrier systems.

Results: Nanocarriers have been shown to be helpful in overcoming the drawbacks of traditional ocular dosing forms. Modification of standard topical solutions by both permeability and viscosity imparters has resulted in breakthroughs in anterior segment medication delivery. Various nanocarriers, including liposomes, implants, dendrimers, nanosuspensions, nanoparticles, solid lipid nanocarriers, niosomes and proniosomes have been studied for enhanced penetration and the successful targeted drug administration to various ocular locations.

Conclusion: Recently developed nanocarriers for ocular delivery have proved to be cost-effective, efficacious, safe, and sustained-release carriers, which can be incorporated in suitable dosage forms. In this review, the authors have discussed various challenges in ocular drug administration. Various research reports on advancements in ocular drug delivery based on modified drug delivery carriers have been analyzed and included. Additionally, marketed formulations and patent literature on ocular drug delivery have been added as a part to support the review content.