眼用维生素A棕榈酸酯阳离子脂质体-原位凝胶的研制及体外释药研究

目的：以维生素A棕榈酸酯（VAP）为模型，制备眼用阳离子脂质体-原位凝胶系统，并对其体外释药行为进行考察。方法：采用薄膜分散法制备VAP脂质体，根据胶凝温度筛选泊洛沙姆407的最佳处方浓度，采用无膜溶出模型对该制剂的体外释放行为进行考察。结果：透射电镜显示VAP脂质体-原位凝胶（VAPL—ISG）粒径分布均匀，经N-三甲基壳聚糖（TMC）包衣后Zeta电位〉40mV，泊洛沙姆407的最佳浓度为25％，VAPL—ISG中药物释放和凝胶溶蚀均呈现良好的零级释放特征。结论：VAPL—ISG具有阳离子脂质体和原位凝胶的优势，延缓了药物释放，为下一步研究其延长角膜滞留时间打下基础。

Studies on the Preparation of Ocular Vitamin A Palmitate Cationic Liposome-in situ Gel System and the Drug Release in Vitro

Objective： To prepare a ocular cationic liposome-in situ gel system with vitamin A palmitate （VAP）as a model drug, and investigate the drug release profile in vitro. Method： VAP liposome was prepared by the film dispersion method. The optimal concentration of poloxamer 407 was selected according to the gelation temperature. A novel membraneless model was used to study the drug release in vitro. Result： Images of TEM showed that VAPL-ISG was uniformly distributed. The Zeta potentials were above 40 mV, after TMC coating. The best concentration of poloxamer 407 in the formulation was 25%. Both the drug release in vitro and gel dissolution profile of VAPL-ISG exhibited the characteristics of zero order kinetics. Conclusion ： VAPL-ISG obtaines the advantages of both cationic liposome and in situ gel system, and can delay the drug release in vitro, which provides the base of the further study in the cornea residence time promotion in vivo.