A COMPREHENSIVE INSIGHT ON OCULAR DRUG DELIVERY SYSTEM

The eye is the most distinctive organ in the human body. Various drug delivery methods are utilised to deliver drugs into the eyes, however because of the drawbacks of conventional systems, researchers are looking for novel approaches to improve contact time, bioavailability, and residence length, as well as minimise patient pain and dosage frequency. 90% of currently available ophthalmic formulations are in conventional dose forms. The ideal ophthalmic drug delivery system must be able to continue drug release for a lengthy period of time while remaining in close contact to the front of the eye. Due to its unique structure and physiology, including multiple types of barriers such as distinct layers of cornea, sclera, and retina, blood aqueous and blood–retinal barriers, choroidal and conjunctival blood flow, and so on, ocular drug delivery has been a big issue for scientists. These obstacles make delivering a single medicine or a dose form to the posterior portion of the eye difficult. To resolve these concerns, novel dosage forms like nanoparticles, liposomes, and microemulsions etc. have been designed. In this review, information on various ocular drug delivery systems, such as eye ointments, gels, and the use of viscosity enhancers, prodrugs, penetration enhancers, microparticles, liposomes, niosomes, ocular inserts, implants, intravitreal injections, nanoparticles, nanosuspension, microemulsion, dendrimers, iontophoresis, and periocular injections is illustrated.  Barriers to drug penetration, routes of ocular drug administration, and ways to increase ocular bioavailability were the focus of this review.

Keywords: Ocular absorption, Ocular bioavailability, Nanoparticles, Microemulsion