Advancements in materials and fabrication techniques for microneedle ocular patch: a comprehensive review

Abstract With the increasing prevalence of ocular diseases, there is an urgent need to look beyond conventional formulations, such as eye drops, ointments, and intravitreal injections, to treat various ocular diseases. Understanding the limitations of conventional treatments and the challenges faced by ophthalmologists is crucial, and the use of a novel microneedle (MN) ocular/scleral patch could be an ideal drug delivery method. The current emphasis is on the application of these emerging MN techniques to deliver the drug close to the target area as possible using a minimally invasive approach for treating ocular diseases. This review outlines recent advancements in ophthalmic drug delivery using MNs, covering their classification, materials, mechanisms, fabrication techniques, applications, safety considerations, and future prospects. Despite significant research in formulation studies and animal models, the clinical efficacy and safety of MNs in ophthalmology require further investigation. This review further discusses the ongoing research and clinical trials on MN drug delivery systems for various ophthalmic diseases. This review also addresses the current challenges, such as ideal polymer, composition, the sterilization of MNs, and the lack of prospective clinical trials, while emphasizing the current utility and ongoing research to fully harness the benefits of MN-based ocular drug delivery systems to treat ocular diseases. Graphical abstract