A Paradigm Shift in Ocular Drug Delivery to Posterior Segment: Review on Current Drug Delivery Approaches

Objectives: Owing to the increasing number of patients suffering from posterior eye disorders, efficient medicine delivery to the posterior segment is now in great demand in the clinical services. With unmet medical requirements, the posterior eye segment is an important therapeutic target. So, physicians should be informed of new indications and current strategies of drug delivery when new technologies enter the market. Summary: The most common causes of vision impairment in developed nations are abnormalities of the posterior eye tissues. Poor drug distribution to lesions in patient's eyes is a key barrier to ocular disease therapy. The existence of barriers, such as the corneal barrier, aqueous barrier, and inner and outer blood-retinal barriers, severely limits medication accessibility in these locations. Because of its anatomical peculiarities, the posterior portion is particularly difficult to access for medications. The use of several new strategies for drug delivery is therefore a viable option for enhanced therapy of ocular disorders since recent advances in ocular drug delivery systems research have brought fresh insights into drug development. Conclusion: This article provides an overview of several aspects of ocular medication administration to the posterior region, with a focus on nano carrier-based approaches, suprachoroidal drug delivery system and ophthalmic devices, including the structure of the eye, its barriers, delivery routes, and the present status of drugs/devices.