Palmitoyl amino acids and palmitoyl glutathione were synthesized. Liposome-like vesicles based on these compounds were prepared and their barrier functions were examined. These vesicles showed encapsulation efficiencies for aqueous solute comparable to that of conventional phosphatidylcholine liposomes (PC-liposomes). They were also stable in fresh rat plasma at 37°C. The biological behavior (blood clearance, urinary excretion and tissue distribution) of the vesicles based on palmitoyl serine (PSer-liposomes) or palmitoyl glutathione (PGSH-liposomes) was examined after intravenous injection in rats. The synthetic liposomes were cleared very rapidly from the blood compared with PC-liposomes. PSer-Liposomes showed a large amount of urinary excretion of aqueous marker ([3H] inulin), suggesting that the mechanisms of vesicle degradation in vivo and in vitro are different. These synthetic liposomes showed low affinity to the spleen and high affinity to the liver in the tissue distribution study, and thus they may be expected to be a useful drug carrier which is targetable to the liver. A suppressing effect of PGSH-liposomes on the increase of plasma glutamate oxaloacetate transaminase (GOT) induced by a high dose of acetaminophen in mice was observed, and transport of glutathione into the liver cells apparently occurred. The suppressing effect was greater than that of free glutathione or PC-liposomes containing free glutathione. However, the effect was not observed in the case of PGSH-liposomes without phosphatidylcholine, which appears to have an important role in the liposome-cell interaction.
合成了棕榈酰
氨基酸和棕榈酰
谷胱甘肽。基于这些化合物的脂质体样囊泡被制备出来,并检测了它们的屏障功能。这些囊泡对
水溶性溶质的包封效率与传统
磷脂酰
胆碱脂质体(PC-脂质体)相当。它们在37°C的新鲜大鼠血浆中也表现稳定。基于棕榈酰
丝氨酸(PSer-脂质体)或棕榈酰
谷胱甘肽(
PGSH-脂质体)的囊泡在大鼠静脉注射后的
生物行为(血液清除、尿液排泄和组织分布)被研究。合成脂质体相比PC-脂质体从血液中清除得非常迅速。PSer-脂质体显示出大量的
水溶性标记物([3H]
菊粉)的尿液排泄,表明囊泡在体内和体外的降解机制是不同的。这些合成脂质体在组织分布研究中对脾脏的亲和力低,而对肝脏的亲和力高,因此它们可能成为肝脏靶向的有用药物载体。观察到
PGSH-脂质体对小鼠因高剂量
扑热息痛引起的血浆谷
氨酸
草酰乙酸转
氨酶(GOT)升高的抑制作用,并且明显发生了
谷胱甘肽向肝细胞的转运。抑制效果大于游离
谷胱甘肽或含有游离
谷胱甘肽的PC-脂质体。然而,在没有
磷脂酰
胆碱的
PGSH-脂质体中并未观察到这种效果,这表明
磷脂酰
胆碱在脂质体-细胞相互作用中起着重要作用。