Sarmout Malake, Xiao Yutang, Hu Xiao, Rakhmetova Aiym, Koole Leo H
Innovative Engineering Laboratory for Ocular Drug Delivery, Eye Hospital of Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China.
Heliyon. 2023 Jun 5;9(6):e16916. doi: 10.1016/j.heliyon.2023.e16916. eCollection 2023 Jun.
Soft contact lenses are increasingly being explored as a vehicle for controlled delivery of ophthalmic drugs. However, traditional methods of drug-loading by soaking have limitations such as burst delivery and the release of drugs at the front side of the lens, leading to poor drug efficacy and systemic side effects. This study introduces a new methodology, termed asymmetric drug loading, whereby the ophthalmic drug 'Rebamipide' is attached to and released from the post-lens (=cornea-contacting) surface exclusively. The methodology involves using polymeric microparticles that carry a lipophilic crystalline ophthalmic drug at their surface. These drug-loaded microparticles first transfer the drug to the concave surface of the contact lens, and when worn, the drug is transferred again, now from the lens to the cornea. This is achieved through the diffusion of the drug from one hydrophobic microenvironment (the silicone moieties of the contact lens polymer network) to another hydrophobic microenvironment (the corneal epithelium) over a short pathway. The second drug transfer was observed and studied in experiments using an porcine eye model. The results show that the drug amount that was absorbed by the cornea after applying the rebamipide-loaded contact lenses is approximately 3× (10.7 ± 3.1 μg) as much as the amount of rebamipide that gets transferred after the instillation of one eye drop (1% solution (). The new drug-loading method offers a practical and reproducible means of delivering ophthalmic drugs to the cornea through soft contact lenses. The drug payloads achieved are comparable to dosages used during eye drop therapy.
软性隐形眼镜正越来越多地被探索作为眼科药物控释的载体。然而，传统的浸泡载药方法存在局限性，如药物突发释放以及在镜片前表面释药，导致药物疗效不佳和全身副作用。本研究引入了一种新方法，称为不对称载药，即眼科药物“瑞巴派特”仅附着于镜片后表面（即与角膜接触的表面）并从该表面释放。该方法涉及使用在其表面携带亲脂性结晶眼科药物的聚合物微粒。这些载药微粒首先将药物转移到隐形眼镜的凹面，佩戴时，药物再次转移，这次是从镜片转移到角膜。这是通过药物在短路径上从一个疏水微环境（隐形眼镜聚合物网络的硅氧烷部分）扩散到另一个疏水微环境（角膜上皮）来实现的。在使用猪眼模型的实验中观察并研究了第二次药物转移。结果表明，佩戴载有瑞巴派特的隐形眼镜后角膜吸收的药量约为滴入一滴眼药水（1%溶液）后转移的瑞巴派特药量的3倍（10.7±3.1μg）。这种新的载药方法提供了一种通过软性隐形眼镜将眼科药物递送至角膜的实用且可重复的手段。实现的药物载量与眼药水治疗期间使用的剂量相当。
