共载紫草素和盐酸阿霉素pH敏感脂质体的制备及理化性质评价

Preparation and physicochemical property evaluation of shikonin and doxorubicin hydrochloride coencapsulated pH-sensitive liposomes

目的采用正交试验优化紫草素和盐酸阿霉素pH敏感脂质体(SHK/DOX-pHSL)的制备工艺并进行评价。方法采用薄膜分散法-硫酸铵梯度法制备共载紫草素和盐酸阿霉素pH敏感脂质体。采用正交试验优化SHK/DOX-pHSL的最佳处方和制备工艺,通过凝胶柱色谱法测定包封率,并通过激光粒度仪和透射电镜测定脂质体的粒径、Zeta电位和形态特征进行表征,应用透析袋恒温法进行体外释药行为研究。结果正交试验获得SHK/DOX-pHSL最佳处方为:孵育温度为50℃,药脂比(盐酸阿霉素/脂材)为1︰20,硫酸铵溶液pH值为8.5;在最佳制备工艺下,脂质体中紫草素和盐酸阿霉素的包封率分别为(44.10±0.36)%和(91.00±1.00)%,平均粒径为143.40 nm,PDI为0.243,Zeta电位为-41.34 mV;透射电子显微镜观察结果显示,脂质体的外观形态呈现圆形或类圆形且均匀分散;在稳定性试验中紫草素和盐酸阿霉素的RSD值分别为0.64%和0.28%,表明在72 h内制剂稳定性好;体外释放试验表明,DOX-Free释放呈突释,SHK/DOX-pHSL在pH为5.0和7.4两种条件下释放曲线明显不同,在酸性环境即pH值为5.0条件下的释放速度较快,在pH为7.4的条件下释放速度较慢。结论本实验采用薄膜分散法-硫酸铵梯度法所制得的共载紫草素和盐酸阿霉素pH敏感脂质体成功制备,所得的脂质体具有较高的包封率、均匀的粒度分布、良好的稳定性和较高的pH值敏感性,因此具有很好的应用前景。

Objective To optimize and evaluate he preparation process of shikonin and adriamycin hydrochloride pH-sensitive liposomes(SHK/DOX-pHSL)by orthogonal test.Methods pH-sensitive liposomes coencapsulated with shikonin and adriamycin hydrochloride were prepared by film dispersion method and ammonium sulfate gradient method.The optimal formulation and preparation process of SHK/DOX-pHSL were optimized by orthogonal test.The gel column chromatography was used to determine the encapsulation rate,laser particle size analyzer and transmission electron microscopy were used to determine the particle size,zeta potential and morphological characteristics of the liposomes,in vitro drug release behaviour was studied by dialysis bag thermostatic method.Results The optimal formulation of SHK/DOX-pHSL was obtained by orthogonal test as follows:incubation temperature was 50℃,drug/lipid ratio was 1:20,pH value of ammonium sulfate solution was 8.5.In the optimal preparation conditions,the encapsulation efficiencies of shikonin and adriamycin hydrochloride in liposomes were(44.10±0.36)%and(91.00±1.00)%,respectively,with an average particle size of 143.40 nm,PDI of 0.243 and Zeta potential of-41.34 mV.The results of transmission electron microscopy showed that the appearance of liposomes was round or quasi-round and uniformly dispersed.In the stability test,the RSD values of shikonin and adriamycin hydrochloride were 0.64%and 0.28%,respectively,indicating that the preparation had good stability within 72 h.The in vitro release test showed that DOX-Free presents sudden release,the release curves of SHK/DOX-pHSL were significantly different at pH 5.0 and 7.4.The release rate was faster at pH 5.0 in acidic environment and slower at the condition of pH 7.4.Conclusions In this study,shikonin-adriamycin hydrochloride pH-sensitive liposomes are successfully prepared by thin-film dispersion method-ammonium sulfate gradient method.The liposomes presents high encapsulation efficiency,uniform particle size distribution,good stability,and obvious pH sensitivity,which has good application prospects.