Review On Ocular in Situ Gels Using Natural Polymers: A Promising Approach for Sustained Ocular Drug Delivery

Ocular drug delivery remains a significant challenge due to the anatomical and physiological barriers present in the eye. Traditional ocular dosage forms such as eye drops often suffer from issues of poor bioavailability and rapid drug clearance. In recent years, ocular in situ gels, formed by natural polymers, have emerged as a promising strategy for sustained drug delivery to the eye. This review provides an overview of the advantages, formulation strategies, and potential of ocular in situ gels, focusing on natural polymers. These gels are designed to undergo a sol-to-gel transition in response to physiological conditions, offering controlled and prolonged release of therapeutic agents. The use of natural polymers, such as alginate, gellan gum, pectin, chitosan, and xanthan gum, has gained significant attention due to their biocompatibility, biodegradability, and low toxicity profiles. The review discusses various factors influencing the formulation of ocular in situ gels, including polymer selection, gelation mechanisms, and the effect of additives. Moreover, we explore the in vivo performance, advantages, and challenges in the clinical translation of these formulations..