Engineered Mucoadhesive and Mucopenetrating Biomaterials for Ocular Drug Delivery

Eye diseases including dry eye disease are rapidly increasing in the modern era, especially among the younger generation. Topical formulations administered via the ocular surface are the most common treatment for ocular diseases. Rapid tear clearance, blinking, and anatomical barriers like ocular mucosal barrier continue to make effective drug delivery to the eye extremely difficult. Patient adherence is further compromised by the low bioavailability and frequent dosing of traditional topical formulations, such as eye drops. Mucoadhesive biomaterials have emerged as a promising strategy to enhance residence time on the ocular surface, improve drug absorption, enable controlled release, and potentially reduce side effects. In this review article, we discuss the fundamental principles of ocular mucosal mucoadhesion and explore a wide range of engineered mucoadhesive systems, from biopolymer to synthetic polymer‐based designs, including the strategies that integrate both mucoadhesive and mucopenetrating properties to enhance nanoparticle retention on the ocular surface for prolonged periods. From a materials perspective, we cover synthetic polymers, lipids, hydrogels, biopolymers, and related systems, and we highlight recent advances in mucus‐mimetic materials that hold promise for the development of next‐generation ocular drug delivery platforms.