For the purpose of obtaining liposomes with long circulation time in blood, we synthesized 1-O-palmityl-D-glucuronic acid (PGlcUA) and incorporated it into the liposomal membranes. The clearance of the PGlcUA-liposomes composed of dipalmitoylphosphatidylcholine (DPPC), choleterol, and PGlcUA (40 : 40 : 20 as a molar ratio) from blood and their tissue distribution were compared with those of dipalmitoylphosphatidylglycerol (DPPG)-liposomes (DPPC/cholesterol/DPPG=40 : 40 : 20). When [3H]inulin-loaded PGlcUA-liposomes and DPPG-liposomes were intravenously injected into rats, the half-life of the PGlcUA-liposomes in the blood appeared to be 1.7-fold longer than that of DPPG-liposomes. Radioactivities present in plasma and various tissues were measured 22h after administration of these liposomes, and radioactivity remaining in the plasma was 2.5-fold greater when PGlcUA-liposomes were injected. The distribution pattern of [3H]inulin in PGlcUA-liposomes was similar to that in DPPG-liposomes. The radioactivity recovered in urine was 25% lower in rats treated with PGlcUA-liposomes than in those treated wit DPPG-liposomes. Since both PGlcUA-and DPPG-liposomes exhibited similar size distribution and ζ-potential, glucuronic acid, rather than negative charge, on the liposomal surface appears to endow liposomes with a longer circulation time in the bloodstream.
为了获得在血液中循环时间较长的脂质体,我们合成了 1-O-棕榈酰-
D-葡萄糖醛酸(
PGlcUA),并将其加入脂质体膜中。我们比较了由
二棕榈酰
磷脂酰
胆碱(
DPPC)、
胆固醇和
PGlcUA(摩尔比为 40 : 40 : 20)组成的
PGlcUA 脂质体与
二棕榈酰
磷脂酰
甘油(
DPPG)脂质体(
DPPC/
胆固醇/
DPG=40 : 40 : 20)在血液中的清除率及其组织分布情况。给大鼠静脉注射[3H]
菊粉负载的
PGlcUA 脂质体和
DPPG 脂质体时,
PGlcUA 脂质体在血液中的半衰期似乎比
DPPG 脂质体长 1.7 倍。注射这些脂质体 22 小时后,测量了血浆和各种组织中的放射性活度,结果显示,注射
PGlcUA 脂质体后,血浆中残留的放射性活度是
DPPG 脂质体的 2.5 倍。
PGlcUA 脂质体中[3H]
菊粉的分布模式与
DPPG 脂质体相似。接受
PGlcUA 脂质体治疗的大鼠尿液中回收的放射性比接受
DPPG 脂质体治疗的大鼠低 25%。由于
PGlcUA 和
DPPG 脂质体的大小分布和ζ电位相似,脂质体表面的
葡萄糖醛酸而不是负电荷似乎使脂质体在血液中的循环时间更长。