Advancing Ocular Medication Delivery with Nano-Engineered Solutions: A Comprehensive Review of Innovations, Obstacles, and Clinical Impact.

Recent advancements in ocular drug delivery have led to the introduction of a range of nanotechnology-based systems, such as polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, inorganic nanoparticles, niosomes, liposomes, nanosuspensions, dendrimers, nanoemulsions, and microemulsions. These systems enhance drug retention, penetration, bioavailability, and targeted delivery, promising prolonged drug release, and improved patient compliance. However, their interactions with biological systems pose potential toxicity risks, necessitating a careful evaluation of nanoparticle size, shape, surface charge, and coating. Traditional ocular drug delivery methods, like topical applications and injections, face challenges due to anatomical and physiological barriers, leading to frequent dosing and systemic toxicity risks. Nanocarriers offer solutions by improving drug permeation and targeted delivery, yet translating these innovations from research to clinical practice involves overcoming hurdles related to manufacturing scale-up, quality control, regulatory approval, and cost-effectiveness. The quality by design (QbD) framework provides a systematic approach to optimize nanocarrier formulation and process design, ensuring safety and efficacy. Assessing the safety of nanocarriers through in vivo and in vitro studies is crucial for their clinical application. This review explores the use of various nanomedicines in ocular drug delivery, highlighting the current state of ocular medication delivery and considering critical aspects such as scaling up and clinical applications.