熊果酸脂质体的制备及体外释放特性考察

目的:制备熊果酸脂质体,优化熊果酸脂质体的处方工艺,并研究其理化性质及体外释放特性。方法:采用摇瓶法考察熊果酸在不同pH介质中的油水分配系数;采用薄膜-超声法制备熊果酸脂质体,以包封率为指标,通过正交试验优选熊果酸脂质体的处方工艺。采用透射电镜观察其形态,激光粒度测定仪测定其粒径和zeta电位,动态透析法考察其体外释放的特性。结果:熊果酸油水分配系数lgPo/w随pH增大而降低,且均>0.5,说明熊果酸具有较好的亲脂性。优选的处方工艺为载药量6 mg,磷脂-胆固醇2∶1,PBS摩尔浓度0.01 mol.L-1,超声时间3 min。制备的熊果酸脂质体透射电镜下呈球形或椭圆球形,平均粒径(223.7±68.4)nm,zeta电位-20.63 mv,包封率(89.85±1.66)%,48 h体外累计释放率>80%,体外释放符合一级动力学模型。结论:制备的熊果酸脂质体包封率高,体外释放性能良好,具有缓释特性。

Preparation and in vitro Release Behavior Investigation of Ursolic Acid Liposome

Objective: To prepare ursolic acid liposome,optimize formulation of ursolic acid liposome and investigate its physicochemical properties and in vitro release behavior. Method: Oil-water partition coefficient of ursolic acid in a series of phosphate buffer solutions of different pH by shake flask method;Ursolic acid liposome were prepared by film-ultrasonic dispersion method,with entrapment efficiency as index,formulation of ursolic acid liposome was optimized by orthogonal test.Morphology was examined by transmission electron microscope,particle size and zeta potential were determined by laser particle sizer/zeta potential system,in vitro release behavior of ursolic acid liposome was studied by dynamic dialysis. Result: Oil-water partition coefficients of ursolic acid lgP_O/W decreased with increasing of pH,and they were >0.5,it suggested that ursolic acid had good lipophilic.Optimized formulation was:drug loading of 6 mg,phospholipid-cholesterol 2: 1,the molar concentration of PBS 0.01 mol· L^-1,ultrasonic time 3 min.These prepared ursolic acid liposome were spherical or elliptical sphere under transmission electron,the mean particle size was (223.7±68.4) nm,zeta potential was -20.63 mv,entrapment efficiency was (89.85±1.66)%,in vitro release behavior fitted the first order kinetic model,in vitro cumulative release rate was >80% in 48 h. Conclusion: Prepared ursolic acid liposome had high entrapment efficiency and good in vitro release property with sustained release characteristics.