聚乙二醇POPA磷脂衍生物构建的酶敏脂质体

以磷酰胺键将聚乙二醇高分子MePEG2000-NH₂与磷脂POPA连接在一起, 合成聚乙二醇磷脂衍生物, 以聚乙二醇磷脂衍生物为主要膜材构建酸敏脂质体。采用荧光分析法系统研究了聚乙二醇磷脂衍生物脂质体在酸性条件下对荧光染料的释药特性。以聚乙二醇磷脂衍生物构建的酸敏脂质体，在pH 6.5～7.5时稳定，其稳定性与制备脂质体的磷脂种类及胆固醇含量密切相关，在pH 5.0时发生显著的荧光泄漏，泄漏率与环境酸性的强度及处于酸性的时间呈正相关。聚乙二醇磷脂衍生物构建的脂质体具有开发成酸敏释药脂质体的前景。

Acid-sensitive liposomes prepared with poly(ethylene glycol)- POPA derivatives

The poly(ethylene glycol)-lipid derivatives were synthesized for constructing pH-sensitive     liposomes.  The polyethylene glycol polymer MePEG2000-NH₂ and phospholipids POPA were connected by phosphorus-amide linkage.  The poly(ethylene glycol)-lipid derivatives acidic sensitive liposomes were prepared.  Factor effects on polymer insertion into liposomes were evaluated and the pH-sensitivity of the polymer      associated liposomes were studied by calcein release assay.  The poly(ethylene glycol)-lipid derivatives acidic sensitive liposomes were prepared successfully by the extruding linkage device.  The liposomes constructing by poly(ethylene glycol)-lipid derivatives was stable at pH 6.5−7.5, the stability was closely related to phospholipid types and cholesterol content of the preparation of liposomes.  At pH 5.0 occurred when divulging fluorescence occurred obviously, the leakage rate and the strength was with a positive correlation between time of in the  acidic environment and intensity of acid.  The acidic sensitive liposomes prepared by poly(ethylene glycol)- lipid derivatives were developed as a potential pH sensitive delivery system.