Department of Polymer Science and Engineering, Polymeric Nano-Materials Laboratory, Kyungpook National University, Daegu 41566, South Korea.
Optical Convergence Technology Center, Daegu Catholic University, Gyeongsan-si, Gyeongbuk 38430, Korea.
ACS Appl Bio Mater. 2023 Dec 18;6(12):5372-5384. doi: 10.1021/acsabm.3c00637. Epub 2023 Nov 15.
Drug-releasing contact lenses are emerging therapeutic systems for treating ocular diseases. However, their applicability is limited by the burst release of drugs during lens wear and premature drug leakage during packaging, rendering the precise control of release duration or dose difficult. Here, we introduce a pH-sensitive contact lens exhibiting on-demand drug release only during lens wear and negligible premature drug leakage during packaging and transportation, which is accomplished by incorporating drug-loaded mesoporous silica nanoparticles (MSNs) coated with a pH-sensitive polymer into the contact lens. The compositionally optimized pH-sensitive polymer has a lower critical solution temperature (LCST) at >45 °C at pH 7.4, whereas its LCST decreases to <35 °C under acidic conditions (pH ∼ 6.5). Consequently, the MSN-incorporated contact lens sustainably releases the loaded drugs only in the acidic state at 35 °C, which corresponds to lens-wear conditions, through the MSN pores that open because of the shrinkage of polymer chains. Conversely, negligible drug leakage is observed from the contact lens under low-temperature or neutral-pH conditions corresponding to packaging and transportation. Furthermore, compared with the plain contact lens, the pH-sensitive contact lens exhibits good biocompatibility and unchanged bulk characteristics, such as optical (transmittance in the visible-light region), mechanical (elastic modulus and tensile strength), and physical (surface roughness, oxygen permeability, and water content) properties. These findings suggest that the pH-sensitive contact lens can be potentially applied in ocular disease treatment.
释药隐形眼镜是一种新兴的治疗眼部疾病的治疗系统。然而，其适用性受到在镜片佩戴期间药物突释和包装过程中药物过早泄漏的限制，从而难以精确控制释放持续时间或剂量。在这里，我们介绍了一种 pH 敏感隐形眼镜，它仅在镜片佩戴期间按需释放药物，并且在包装和运输过程中药物过早泄漏可以忽略不计，这是通过将载药介孔硅纳米粒子（MSNs）包被 pH 敏感聚合物来实现的。组成优化的 pH 敏感聚合物在 pH 7.4 时具有 >45°C 的较低临界溶液温度（LCST），而在酸性条件（pH ∼ 6.5）下其 LCST 降低至 <35°C。因此，载药的 MSN 隐形眼镜仅在 35°C 的酸性条件下通过聚合物链收缩导致 MSN 孔打开的情况下可持续释放负载药物，这与镜片佩戴条件相对应。相反，在对应于包装和运输的低温或中性 pH 条件下，从隐形眼镜中观察到可忽略不计的药物泄漏。此外，与普通隐形眼镜相比，pH 敏感隐形眼镜具有良好的生物相容性和不变的体相特性，例如光学（可见光区域的透光率）、机械（弹性模量和拉伸强度）和物理（表面粗糙度、氧气透过率和含水量）特性。这些发现表明，pH 敏感隐形眼镜可潜在应用于眼部疾病的治疗。
