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目的制备褪黑素脂质体并考察其理化性质。方法采用薄膜分散法制备褪黑素脂质体,在单因素考察基础上,采用均匀试验设计优化最佳处方和工艺;透射电镜下观察外观形态,激光散射测定Zeta电势和粒度分布,低温高速离心法分离脂质体与未包封的药物,UV法测定包封率与载药量,膜动态透析法探讨其体外释药特性。结果均匀试验设计优化的最佳处方为药脂比1∶25,磷脂和胆固醇比10∶1,温度40℃,最佳处方制备的脂质体为封闭的多层囊状或多层圆球体,大小均匀,平均粒径为(5.542±0.04)μm,Zeta电势为-31.68mV,包封率为(77.23±2.51)%,载药量为(3.60±0.29)%。体外释放可延长至72h,释放特性符合双相动力学方程(rα=0.9886和rβ=0.9874)。结论采用薄膜分散法制备的褪黑素脂质体,包封率较高,体外释药有明显的缓释效果。
Objective To prepare melatonin liposomes and investigate its physicochemical properties. Methods Melatonin liposomes were prepared by thin film dispersion method. Based on the single factor test, the best prescription and technology were optimized by uniform design. The appearance morphology was observed under transmission electron microscope. Zeta potential and particle size distribution were determined by laser light scattering. The liposomes and non-encapsulated drugs were separated by liposomes. The entrapment efficiency and drug loading were measured by UV and the in vitro release characteristics were investigated by membrane dynamic dialysis. Results The optimal prescription for the optimization of experimental design was liposome with ratio of lipid to lipid 1:25, ratio of phospholipid to cholesterol 10: 1 and temperature 40 ℃. The liposomes prepared by best prescription were closed multilamellar or multilayered spheroids, The average size was (5.542 ± 0.04) μm, the Zeta potential was -31.68mV, the entrapment efficiency was (77.23 ± 2.51)% and the drug loading was (3.60 ± 0.29)%. In vitro release can be extended to 72h, the release characteristics in line with biphasic kinetic equation (rα = 0.9886 and rβ = 0.9874). Conclusion Melatonin liposomes prepared by the method of film dispersion have higher entrapment efficiency and obvious release effect in vitro.