Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte St., Kansas City, Missouri 64108-2718, USA.
AAPS J. 2010 Sep;12(3):348-60. doi: 10.1208/s12248-010-9183-3. Epub 2010 May 1.
Ocular drug delivery has been a major challenge to pharmacologists and drug delivery scientists due to its unique anatomy and physiology. Static barriers (different layers of cornea, sclera, and retina including blood aqueous and blood-retinal barriers), dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution), and efflux pumps in conjunction pose a significant challenge for delivery of a drug alone or in a dosage form, especially to the posterior segment. Identification of influx transporters on various ocular tissues and designing a transporter-targeted delivery of a parent drug has gathered momentum in recent years. Parallelly, colloidal dosage forms such as nanoparticles, nanomicelles, liposomes, and microemulsions have been widely explored to overcome various static and dynamic barriers. Novel drug delivery strategies such as bioadhesive gels and fibrin sealant-based approaches were developed to sustain drug levels at the target site. Designing noninvasive sustained drug delivery systems and exploring the feasibility of topical application to deliver drugs to the posterior segment may drastically improve drug delivery in the years to come. Current developments in the field of ophthalmic drug delivery promise a significant improvement in overcoming the challenges posed by various anterior and posterior segment diseases.
由于眼部独特的解剖结构和生理特性，眼部药物递送一直是药理学家和药物递送科学家面临的重大挑战。静态屏障（包括角膜、巩膜和视网膜的不同层以及血房水和血视网膜屏障）、动态屏障（脉络膜和结膜血流、淋巴清除和泪液稀释）以及外排泵的联合作用，使得药物单独或制成剂型进行递送极具挑战性，特别是递送到后段。近年来，人们越来越关注鉴定各种眼部组织中的内流转运体，并设计针对转运体的母体药物靶向递送。同时，胶体剂型，如纳米粒、纳米胶束、脂质体和微乳液，也被广泛探索以克服各种静态和动态屏障。新型药物递送策略，如生物黏附凝胶和纤维蛋白密封剂为基础的方法，被开发用于维持靶部位的药物浓度。设计非侵入性的持续药物递送系统并探索将药物经皮递送至后段的可行性，可能会在未来几年内极大地改善药物递送。目前在眼部药物递送领域的发展有望显著改善各种前、后段疾病带来的挑战。
