cRGD介导的pH敏感性紫杉醇羧甲基壳聚糖-软脂酸胶束  

pH-sensitive micelles loaded paclitaxel using carboxymethyl chitosan-palmitic acid mediated by cRGD

作　　者：李继昭[1] 袁志强[1] 闫萌[1] 李明旺[1] 张学农[1] 

机构地区：[1]苏州大学药学院,江苏苏州215123

出　　处：《药学学报》2016年第4期642-649,共8页Acta Pharmaceutica Sinica

基　　金：国家自然科学基金资助项目(81571788;81273463);国家大学生创新实践课题资助项目(201310285098X)

摘　　要：合成cRGD-羧甲基壳聚糖-软脂酸(cRGD-CMCh-PA)载体,以紫杉醇(paclitaxel,PTX)为模型药物,薄膜分散法制备pH敏感性载紫杉醇-cRGD-羧甲基壳聚糖-软脂酸胶束(PTX-cRGD-CMCh-PA),采用FT-IR、~1H NMR对相关产物结构进行表征,并对胶束粒径、电位和形态进行测定;透析法考察载药胶束在pH 5.3和7.4的磷酸缓冲盐溶液(phosphate buffered saline,PBS)中体外释药行为。采用MTT法考察了细胞毒性,共聚焦显微镜及活细胞工作站动态观察胶束的细胞动态摄取过程;近红外小动物活体成像技术探索胶束的肿瘤靶向性。结果显示:合成的cRGD-CMCh-PA羧甲基化程度为45.0%,软脂酸接枝率为15.0%;载药胶束包封率和载药量分别为99.67%和28.5%,粒径为(162.9±1.5)nm。pH 7.4 PBS条件下PTX释放缓慢,释药遵循Higuchi方程;pH 5.3 PBS中2 h内出现突释现象,呈现pH敏感特性。PTX-CMCh-PA的IC50为2.077μg·mL^(-1),PTX-cRGD-CMCh-PA的IC50为0.876μg·mL^(-1);共聚焦显微镜和活细胞工作站均显示肿瘤细胞对PTX-cRGD-CMCh-PA摄取率更为显著,近红外小动物活体成像技术显示其对肿瘤具有更高的靶向性。本实验中合成的cRGD-CMCh-PA胶束具有pH敏感释药特点和良好的肿瘤靶向性,是一种具有开发潜力的新型药物载体。cRGD-carboxymethyl chitosan-palmitic acid（cRGD-CMCh-PA） was synthesized and a pH- sensitive paclitaxel-loaded cRGD-CMCh-PA micelles（PTX-cRGD-CMCh-PA） was prepared with the film dispersion method; related substances were characterized by FT-IR and ~1H NMR. PTX-cRGD-CMCh-PA micelles were studied with the particle size distribution, zeta potential, morphology and release behavior in vitro was investigated by the method of equilibrium dialysis. In vitro cytotoxicity of different formulations on A549 cells was tested by MTT assay. The uptake process of micelles was explored using confocal microscopy and a live cell station was used to observe the dynamic phagocytosis. The subcutaneous and orthotropic tumor models were built to study the distribution of Di R-labeled micelles by near-infrared fluorescence（NIR） imaging system. The FT-IR spectra and ~~1H NMR spectra confirmed the successful conjugation of cRGD-CMCh-PA polymer and the degree of carboxymethyl and the palmitic acid grafted on chitosan were 45.0% and 15.0%. PTX-cRGD-CMCh-PA micelles were prepared with particle size of（162.9 ± 1.5） nm, zeta potential of ＋26.3 m V and encapsulation efficiency and the drug loading of 99.67% and 28.5%, respectively. The micelles released slowly in pH 7.4 whose release curves were accorded with the Higuchi equation; they had an initial burst effect in second hours and showed a pH sensitive release behavior in pH 5.3. The IC_（50） of PXT-CMCh-PA and PTX-cRGD-CMCh-PA were 2.077 μg·mL^（-1） and 0.876 μg·mL^（-1）, respectively. The cells uptake process of micelles in A549 cells revealed that the micelles were mainly co-located with lysosome and PTX-cRGD-CMCh- PA showed much better targeting effect. The NIR fluorescence imaging results showed that the micelles had a good targeting effect on both subcutaneous and orthotropic tumors. In this study, a novel copolymer cRGD- CMCh-PA was synthesized with a sustained and pH-dependent drug release activity which would potentially become a new carrier for hydroph

关 键 词：RGD 壳聚糖 软脂酸 药物递送 紫杉醇 

分 类 号：R943[医药卫生—药剂学]