盐酸洛拉曲克长循环脂质体制备及其抑瘤特性研究

Preparation of long-circulating nolatrexed dihydrochloride liposomes and its antitumor activity

目的研制具有缓释作用的盐酸洛拉曲克长循环脂质体(LCL-NLTX)并考察其理化特性以及在体内的抗瘤效应。方法用两亲性聚乙二醇-二硬脂酰磷脂酰乙醇胺(PEG-DSPE)对脂质体膜进行修饰,以薄膜挤压-硫酸铵梯度法制备LCL-NLTX;体内抑瘤试验用H22小鼠肝癌细胞接种于昆明小鼠皮下采用动物移植性肿瘤实验法,考察盐酸洛拉曲克长循环脂质体(NLCL)、LCL-NLTX和游离盐酸洛拉曲克给药后对实体瘤的瘤重抑制率及肿瘤体积变化。结果制备的盐酸洛拉曲克隐形脂质体包封率达68%左右,粒径109nm。体内抑瘤试验显示LCL-NLTX、NLCL均具有抗肿瘤效应;LCL-NLTX较游离盐酸洛拉曲克及盐酸洛拉曲克普通脂质体短时间内抑瘤性较差,而长时间则显较强的抑瘤性,其瘤重抑制率为41.86%。结论新制备的LCL-NLTX在体内显示了其较好的缓释效应,可以弥补盐酸洛拉曲克在体内半衰期比较短的缺点。

Objective To prepare long-circulating liposome （LCL） for sustained release of nolatrexed dihydrochloride and evaluate the effect of this preparation against the growth of hepatocarcinoma cells in mice. Methods The long-circulating nolatrexed dihydrocldoride liposome was prepared by film dispersion-extrusion combined with ammonium sulphate gradient method. Amphipathic polyethylene glycol-distearoyl phosphatidylethanolamine （PEG-DSPE） was added to modify the property of the liposome membrane. The drug entrapment efficiency of the nolatrexed dihydrochloride-containing liposome was determined using UV detector with Sephadex GS0. Electron microscopy and laser particle analyzer were employed to determine the size of the nolatrexed dihydrochloride liposome. For in vivo evaluation of the effect of the liposomal preparation, H22 mouse hepatoma carcinoma cells were transplanted subcutaneouly in mice in the axillary region of the fight hind limb to induce growth of solid tumors, which were evaluated for tumor weight inhibition rate and tumor volume changes after administration of the LCL preparations. Results The mean diameter of the long-circulating nolatrexed dihydrochloride liposomes was 109 rim, with an entrapment efficiency of 68.5%. In vivo antitumor experiment showed that both the common liposomal and LCL preparations of nolatrexed dihydrochloride produced antitumor effect in vivo, and the latter had weaker antitumor effect than free and common liposomal preparation of nolatrexed dihydrochloride, but in the long term, the I.CL preparation showed stronger antitumor effect with a tumor weight inhibition rate of 41.68%. Conclusion LCL allows sustained release ofnolatrexed dihydrochloride in vivo, and may effectively lengthen the relatively short half life of this drug after administration.