Microspheres in Ocular Coils: A Novel Approach in an Intraocular Drug Delivery System

Microsphere technology is a revolutionary ocular drug delivery technology, mitigating the constraints of conventional drug delivery methods, including rapid tear turnover, anatomical barriers, limited dose flexibility, systemic side effects and poor bioavailability. These microspheres, when integrated with ocular coils, can diminish systemic adverse effects and elevate patient compliance by enabling the release of drugs in a controlled and sustained manner. These carriers are made up of biodegradable and biocompatible polymers. They can encapsulate both hydrophilic and lipophilic drugs, providing localised treatment for chronic ocular diseases involving glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, dry eye syndrome, uveitis, etc. Distinct fabrication methods are utilised for hydrophilic and lipophilic drugs based on their properties. This review mainly provides a comprehensive overview of microspheres classification, various polymers used in the preparation of microspheres, encapsulation techniques, release mechanisms, evaluation parameters, various merits and demerits and ocular coils while also highlighting persistent challenges such as biocompatibility, drug loading efficiency and scalability. This technology is not only confined to minimising the side effects but also has a major function of delivering an accurate treatment. The future of ocular drug delivery is bright, with microspheres expected to improve the patient's condition as material science and the regulatory environment advance.