Ocular Delivery: Innovations in Ocular Inserts, Contact Lenses, and Microneedles

Ocular drug delivery systems are essential for treating various eye conditions. Ocular conventional drug delivery techniques, such as eye drops (topical administration), often face challenges, like rapid drainage and low bioavailability. To overcome these challenges, scientists have developed ocular inserts with sustained delivery systems. Biocompatible materials, such as hydrogels, polymers, and biodegradable nanoparticles, have been investigated for insert manufacturing. These materials provide controlled release, improved retention time in the outer surface of the eye, and enhanced penetration of active pharmaceutical ingredients passing through the corneal barrier. Innovations in contact lens technology have made it possible to develop drug-loaded lenses that can deliver drugs in a sustained manner directly to the ocular surface by enhancing drug retention time and therapeutic efficacy. Microneedle-based ocular delivery, a relatively new methodology, has made progress by open-hollow and biodegradable microneedles that permit minimally invasive penetration to the sclera or cornea. Microneedle-based ocular delivery provides high bioavailability with prolonged release of drugs. The introduction of smart polymers, nanotechnology, and 3D printing with these systems has enhanced accuracy, patient comfort, and therapeutic efficacy. Together, these advances represent an evolution from current topical ocular treatment options to long-acting, patient-comfort ocular therapies with high efficacy and accuracy.