环孢素A壳聚糖纳米粒修饰人工晶状体表面的实验研究

Experimental study on surface modification of intraocular lens by cyclosporine A-loaded chitosan nanoparticle

背景 白内障囊外摘出术后发生后囊膜混浊（PCO）是影响患者术后视力的主要原因,目前探讨药物的局部应用来预防PCO已成为研究的热点. 目的 采用离子交联法制备环孢素A壳聚糖纳米粒（CyA-CS-NP）,观察其体外释放性能及修饰聚甲基丙烯酸甲酯（PMMA）人工晶状体（IOL）边缘的可行性.方法 制备壳聚糖纳米粒（CS-NP）和CyA-CS-NP,用透射电子显微镜观察纳米粒的形态学特征,用高效液相色谱仪（HPLC）观察纳米粒的形态学特征、载药率、包载率及体外释药性能,并测定CyA-CS-NP修饰后IOL表面CyA的含量.CyA-CS-NP修饰经等离子处理PMMA IOL边缘,并用扫描电子显微镜观察IOL的表面特征.用X射线光电子能谱仪（XPS）检测单纯等离子体处理过的IOL和CyA-CS-NP修饰过的IOL边缘,分析并比较两种修饰方法处理的IOL表面的元素组成及化学键类型改变；用后焦距法和分光光度计分别测定IOL的屈光度和波长360～ 490 nm内的透光率,并参照ISO/CD 11979-2进行有效分辨率测试,检测IOL的光学性能；参照国际标准ISO/CD 11979-3测定IOL襻抗疲劳度测试. 结果 CS-NP和CyA-CS-NP呈单分散性、形状规则的类球形,粒径分别为（158±18）nm和（219±29） nm.CyA-CS-NP的平均包载率为64.2％,平均载药率为7.6％.体外缓释实验表明,第1天的快速释放阶段释药量达46.6％,此后为缓释阶段,在第12天时释药量达到77.7％.修饰后的IOL边缘存在CyA-CS-NP涂层,XPS检测显示IOL边缘存在CyA-CS-NP的特定元素及官能团,而等离子体处理的IOL未出现类似元素及官能团.3枚IOL表面负载CyA的平均质量为171.88 μg,修饰后的IOL屈光度、分辨率和透光率分别为（16.64±0.23）D、（90.28±0.25）％及（73.57±0.62）％,与修饰前的（16.62±0.29）D、（90.28±0.21）％及（73.61±0.60）％相比差异均无统计学意义（t=0.381、0.078、2.291,均P＞0.05）.IOL襻符合国际标准. 结论 与修饰前相比,经CyA-CS-NP边缘修饰的IOL光学性能和襻抗疲劳强度均无明显变化,符合国际标准,满足IOL的临床使用要求,可能成为眼内缓释给药的理想途径.

Background Posterior capsular opacification （PCO） following cataract extracapsular extraction is a major cause of the reduction of visual acuity.Topical administration of eye drops is a research hotspot for the prevention of PCO.Objective This study was to evaluate the release of cyclosporine A-loaded chitosan nanoparticles （CyA-CS-NP） by ionic gelation in vitro and its feasibility of modification of the surface of polymethylmethacrylate intraocular lens （PMMA IOL） with CyA-CS-NP.Methods The CS-NP and CyA-CS-NP were prepared by ionic gelation of CS with sodium tripolyphosphate.The characteristics of CS-NP,such as the appearance and mean size,and drug entrapment efficient （EE）,loading capacity （LC）,and the drug release were studied ; the CyA content on the IOL surface was detected by high performance liquid chromatography （HPLC）.The IOL surface modified with CyA-CS-NP was observed by scanning electron microscope and X-ray photoelectron spectroscopy technique （XPS）,the changes of elements and chemical bond types between simple plasma processed IOL and CyA-CS-NP modified IOL were analyzed.The transmittance at the wavelength of 360-490 nm and refraction of IOL were detected using back focal length method and spectrophotometer,and the effective resolution of IOL was evaluated according to the instruction of ISO/CD 11979-2.Loops anti fatigue test of IOL referred to the criteria of ISO/CD 11979-3.Results The CS-NP and CyA-CS-NP showed monodisperse,uniform appearance similar to spherical shape with a mean size of （158±18） nm and （219±29） nm,respectively.The CyA-CS-NP had high CyA association efficiency and loading capacity （64.2% and 7.6%）.In vitro release study revealed a fast release on the first day followed by a increased drug release during an 11-day following up.The sustained release was approximately 46.6% at day 1 and 77.7% at day 12,respectively.The surface of IOLs with cling film was smooth without CS-NP;while the edge of IOLs appeared a layer of CyA-CS-NP after modification.XPS analysis displayed some elements such as phosphonium,CNH2 and O =CN that appeared on the modified surface,indicating that CyA-CS-NP existed on the surface of IOLs edge.The mean quality of CyA on three IOLs surface after modification was 171.88 μg.The diopter,distinguishing ability and transmittance of modified IOL were （16.64±0.23） D,（90.28 ± 0.25） % and （73.57 ±0.62） %,and those of unmodified IOL were （16.62±0.29） D,（90.28±0.21） %,（73.61±0.60）%,without significant differences between them （t =0.381,0.078,2.291,all at P 〉 0.05）.The antifatigue ability of loops complied with the criteria of ISO/CD 11979-3.Conclusions The optical property and antifatigue ability of loops of the edge-modified IOLs by CyA-CS-NP reach the normal standard and meet the requirement of clinic application.The edge-modified IOLs by CyA-CS-NP can be a delivery system for intraocular drug release.