普朗尼克/甘草酸二钾-纳米柔性脂质体促进视网膜药物吸收及其机制研究

Retinal drug delivery has become an increasingly important field of research, especially when treating retinal disorders such as age related macular degeneration, diabetic retinopathy, and inherited retinal generations. These diseases are the leading causes of vision loss in the world which require repeated long-term administration of therapeutic agents. New drugs for the medication of the retinal disorders have emerged, but now the rate limiting steps in the development of treatments for retinal disorders is new approaches to deliver these agents to the tissues of the back of the eye. Currently, the intravitreal route is widely used to deliver therapeutic entities to the retina. However, frequent administration of drugs via this route can lead to retinal detachment, endophthalmitis and increased intraocular pressure. Our preliminary experiments found that nanoliposome modified with dipotassium glycyrrhizinate (named as nanoflexosomes) could significantly improve intraocular drug penetrating and retinal drug absorption; Several efflux transporters such as P-glycoprotein(P-gp), multidrug resistance-associated proteins(MRPs), lung resistance protein(LRP), and breast cancer resistant protein (BCRP) had been revealed in ocular tissues. Based on these findings, dipotassium glycyrrhizinate and pluronic double modified nanoflexosomes will be designed to study its efficacy in improving retinal drug absorption. The mechanism of the dipotassium glycyrrhizinate modification supplying nanoflexosomes with higher ability of penetrating into/through ocualr barriers, and pluronic modification supplying with reversing efflux transporters will also be investigated. Ranibizumab, one kind of anti-VEGF agents approved for the treatment of age related macular degeneration when intravitreally injected, will be used as model drug to ascertain that dipotassium glycyrrhizinate and pluronic double modified nanoflexosomes would markedly improve retinal drug absorption, and its clinical value will be evaluated objectively. This study would provide us with new ideas and theories of novel noninvasive retinal drug delivery system.

糖尿病视网膜病变等一些严重视网膜相关疾病，需长期药物治疗，但目前临床主要以玻璃体腔注射等途径进行药物治疗，存在给药风险且患者依从性差，影响长期药物治疗效果。本课题组前期研究发现①甘草酸二钾修饰型纳米脂质体（纳米柔性脂质体）滴眼后具有促药物有效吸收到达视网膜组织的作用；②角膜、视网膜等眼组织表达大量具有外排药物作用的转运蛋白。因此，本课题设计普朗尼克/甘草酸二钾双重修饰纳米脂质体，考察其滴眼后促进药物有效吸收至视网膜的能力，探讨普朗尼克修饰赋予纳米柔性脂质体逆转外排泵作用、甘草酸二钾修饰赋予纳米柔性脂质体穿透眼部屏障的作用机制，以及两者协同作用机制；构建视网膜新生血管性疾病动物模型，选用VEGF单克隆抗体药物雷珠单抗为代表药物，确证普朗尼克/甘草酸二钾-纳米柔性脂质体促进雷珠单抗视网膜组织的吸收作用及其疗效，评价其临床意义，为视网膜等眼后节疾病临床中"非创伤性"给药治疗提供新思路和理论依据。

本项目主要通过研究纳米柔性脂质体等纳米药物促进眼局部给药后药物有效吸收至视网膜等眼内组织，并结合眼部外排转运蛋白的调控，提高眼部创新性药物治疗效果的实验研究，为视网膜等眼后节疾病临床中“非创伤性”给药治疗提供新思路和理论依据。在项目实施过程中，外排转运蛋白方面，我们基于眼部外排转运蛋白研究较为分散，研究结果亦出入较大，甚至报道的研究结果互相矛盾等研究现状，在纳米药物递送系统眼部给药方面，立足于高效且高稳定性（符合滴眼液的要求）这一眼科纳米创新药物科学问题，经过4年的研究，取得了相应的研究进展：1首次系统全面地研究了外排转运蛋白在人眼部各组织的表达和分布，并证实了在人角膜、结膜、虹膜-睫状体、脉络膜-视网膜等组织中表达有多种外排转运蛋白；2基于创新药物治疗研究需要立足于眼“病”，本项目以糖尿病性视网膜病变为目标治疗疾病，首次研究外排转运蛋白在糖尿病模型小鼠眼组织中表达与功能变化，为其调控提供基础，结果显示在糖尿病病理状态下，外排转运蛋白表达显著下降，甚至是血-视网膜内屏障外排转运蛋白表达和功能下降是糖尿病病理状态下视网膜生理功能下降甚至发生糖尿病视网膜病变的一个重要因素，因此，基于疾病病理状态下的外排转运蛋白调控研究更有临床意义；3首次研究了纳米柔性脂质体作为眼部药物递送系统，并从细胞水平和动物水平对其促进眼部药物吸收及其机制进行了研究，揭示纳米柔性脂质体与常规脂质体吸收差异及其吸收机制差异；4首次发现药用辅料Soluplus可构建稳定的纳米胶束滴眼液，提高难溶性药物的溶解度，促进眼部药物吸收，并进行了一系列研究，先后以环孢素A、姜黄素、香豆素-6为模型药物，研究Soluplus纳米胶束促进眼部药物吸收及其机制，初步构建了Soluplus纳米胶束眼用制剂技术平台；5本课题组首次提出“鼻腔黏膜-三叉神经节-角膜神经通路”，即药物经鼻腔给药后，可主要由鼻黏膜中广泛分布的三叉神经吸收后转运至三叉神经节，进一步递送至角膜神经末梢、视网膜等眼部组织，且药物递送效果优于眼表给药，并通过对给药后药物分布的定量测定及结合神经示踪技术，进一步确证上述通路的存在，为糖尿病性眼部并发症的创新治疗（以鼻治眼）提供理论依据。通过本课题资助研究，已发表SCI收录期刊论文7篇，在投稿SCI收录期刊论文2篇，在国内外专业学术会议发言10次，获授权发明专利1项，申请发明专利3项（实质审查阶段）。