Contact lenses as drug controlled release systems: a narrative review

ABSTRACT Topically applied therapy is the most common way to treat ocular diseases, however given the anatomical and physiological constraints of the eye, frequent dosing is required with possible repercussions in terms of patient compliance. Beyond refractive error correction, contact lenses (CLs) have, in the last few decades emerged as a potential ophthalmic drug controlled release system (DCRS). Extensive research is underway to understand how to best modify CLs to increase residence time and bioavailability of drugs within therapeutic levels on the ocular surface.These devices may simultaneously correct ametropia and have a role in managing ophthalmic disorders that can hinder CL wear such as dry eye, glaucoma, ocular allergy and cornea infection and injury. In this narrative review the authors explain how the ocular surface structures determine drug diffusion in the eye and summarize the strategies to enhance drug residence time and bioavailability. They synthesize findings and clinical applications of drug soaked CLs as DCRS combined with delivery diffusion barriers, incorporation of functional monomers, ion related controlled release, molecular imprinting, nanoparticles and layering. The authors draw conclusions about the impact of these novel ophthalmic agents delivery systems in improving drug transport in the target tissue and patient compliance, in reducing systemic absorption and undesired side effects, and discuss future perspectives.

摘要 局部给药疗法是眼部疾病的主流治疗手段，但受眼部解剖与生理结构限制，需频繁给药，这可能对患者依从性造成不利影响。除用于矫正屈光不正外，隐形眼镜（Contact Lenses，CLs）在近数十年间已发展为一类潜在的眼科药物控释系统（Drug Controlled Release System，DCRS）。当前学界正开展大量研究，以优化隐形眼镜的改性方案，从而延长药物在眼表的驻留时间，并提升药物在治疗浓度范围内的生物利用度。这类装置可同时实现屈光不正矫正，还可用于管理可妨碍隐形眼镜佩戴的眼部病症，如干眼症、青光眼、眼部过敏、角膜感染与损伤。在本篇叙述性综述中，作者阐明了眼表结构对眼部药物扩散过程的调控机制，并总结了提升药物驻留时间与生物利用度的相关策略。作者整合了载药隐形眼镜作为药物控释系统的研究成果与临床应用场景，这类系统结合了递送扩散屏障构建、功能单体掺入、离子关联控释、分子印迹技术、纳米颗粒负载与分层修饰等技术手段。作者就这类新型眼科给药系统在改善靶组织药物递送效率与患者依从性、降低全身吸收与不良副作用方面的作用得出了结论，并探讨了未来研究展望。