具有活性羧基末端的长循环脂质体的制备和分布  

STUDY ON PREPARATION AND BIODISTRIBUTION OF PEG IMMUNOLIPOSOMES WITH ACTIVE CARBOXYLIC TERMINALS

作　　者：张宇锋[1] 谢蜀生[1] 侯新朴[1] 高翔 张朔 陈祖舜[2] 

机构地区：[1]北京医科大学药学院,北京100083 [2]清华大学智能技术与系统国家实验室,北京100084

出　　处：《药学学报》2000年第11期854-859,共6页Acta Pharmaceutica Sinica

基　　金：国家自然科学基金!(39770 879) ;清华大学智能技术与系统国家实验室开放课题

摘　　要：目的　研究长循环免疫脂质体 (immunoliposomes,IML)的制备方法 ,体外靶细胞杀伤活性和在小鼠体内的组织分布。方法　合成和纯化了 1个带末端羧基的磷脂酰乙醇胺 (PE)的聚乙二醇衍生物 (DPPE PEG30 0 0 COOH) ,掺入脂质体中制成长循环脂质体 ;通过羧基活泼酯化 ,将膀胱癌单克隆抗体BDI 1或小鼠IgG共价连接到该脂质体表面制成免疫脂质体 ,体外肿瘤细胞杀伤实验检测载阿霉素免疫脂质体 (ADM BDI 1 IML)特异杀伤靶细胞的能力。用同位素氚示踪法测量免疫脂质体在小鼠的组织分布。结果　抗体在脂质体上的结合率可达 30 %。体外肿瘤细胞杀伤实验证明载阿霉素免疫脂质体有选择性杀伤靶细胞人膀胱癌细胞EJ的能力。和普通脂质体相比 ,免疫脂质体在血中的滞留时间明显延长 ,并减少了在肝、脾的聚集。结论　长循环免疫脂质体在血中有较长的滞留时间 ,在体外有特异寻靶活性 ,载阿霉素免疫脂质体有选择性杀伤靶细胞的活性 。AIM In order to accumulate into its target specifically, the immunoliposomes must possess two characteristics: specific target efficiency to its target cells and prolonged circulation in blood. A new type of polyethylene glycol (PEG) immunoliposomes carrying monoclonal antibodies at the distal end of PEG chains should be developed. METHODS A dipalmitoylphosphatidylethanolamine (DPPE) derivative of PEG with carboxyl group (DPPE PEG 3000 COOH) was newly synthesized. Small unilamellar liposomes were prepared from egg phosphatidyl choline and cholesterol (5∶4, mol/mol) containing 6 mol% DPPE PEG 3000 COOH using reverse phase evaporation method followed with bath sonication. Monoclonal antibody of human bladder cancer cell (BDI 1), which is highly specific to human bladder cancer cell, was conjugated to PEG liposomes as well as mouse IgG at the distal end of polyethylene glycol chain. Doxorubicin was entrapped into these immunoliposomes by remote (NH 4) 2SO 4 gradient loading method. The specific targeting efficiency of these immnoliposomes was tested by cytotoxicity test in vitro , enzyme linked immune sorbent assay (ELISA) and indirect fluorescent immunoassay. Its biodistribution was carried out in mice. RESULTS The specific targeting efficiency of BDI 1 immunoliposomes (BDI 1 IML)to EJ cells has been demonstrated, in contrast to the non specific human colon carcinoma cells (LOVO). PEG liposomes linked with mouse IgG (mouse IgG immunoliposomes, IgG IML) displayed lower reticulo endothelial systems (RES) uptake and longer circulation time than liposomes without PEG after intravenous injection. CONCLUSION The long circulation of these PEG immunoliposomes in vivo , combined with its specific targeting efficiency demonstrated in vitro , guarantees the positive targeting efficiency of these immunoliposomes to its target carcinoma in vivo .

关 键 词：单克隆抗体 长循环脂质体 活性羧基末端 

分 类 号：R944.9[医药卫生—药剂学]