Characterization of a lipophilic prodrug of 5-fluorouracil with a cholesterol promoiety and its application to liposomes.
作者:MITSURU HASHIDA、KIMIHIKO SATO、YOSHINOBU TAKAKURA、HITOSHI SEZAKI
DOI:10.1248/cpb.36.3186
日期:——
A lipophilic prodrug of 5-fluorouracil (FU) with a cholesterol promoiety, cholesteryl-5-(5-fluorouracilcarbamoyl)capronate (ChFU), was synthesized and its physicochemical and biological properties were studied in comparison with those of octadecylcarbamoyl FU (C18FU) having the same linkage structure. ChFU and C18FU showed enhanced lipophilicity and almost complete incorporation into liposomes while incorporation of FU was very small. In neutral and alkaline media, FU was rapidly regenerated from ChFU with a half-life of about 14 min and C18FU showed a similar rapid conversion. The conversion of ChFU to FU was suppressed by the incorporation into liposomes and the regenerated FU was released from liposomes with a half-life of about 1 h. The release of FU from the liposomal formulation of C18FU was much slower than that of ChFU. The liposomal formulation of ChFU showed almost the same in vivo antitumor activity against P388 leukemia as that of FU solution with less side effects. The liposomal formulation of C18FU exhibited superior in vivo antitumor effect to those of ChFU and free FU. The mode of incorporation of these lipophilic FU prodrugs into liposomes seemed to affect the conversion kinetics of the prodrugs and their subsequent pharmacological efficacy.
研究人员合成了一种带有胆固醇原基的 5-氟尿嘧啶(FU)亲脂性原药--胆固醇基-5-(5-氟尿嘧啶氨基甲酰基)己酸酯(ChFU),并将其理化性质和生物学性质与具有相同连接结构的十八烷基氨基甲酰基 FU(C18FU)进行了比较。ChFU 和 C18FU 具有更强的亲脂性,几乎能完全掺入脂质体,而 FU 的掺入量非常小。在中性和碱性介质中,FU 能迅速从 ChFU 中再生,半衰期约为 14 分钟,C18FU 也表现出类似的快速转化。将 ChFU 加入脂质体后,ChFU 向 FU 的转化受到抑制,再生的 FU 从脂质体中释放出来,半衰期约为 1 小时。ChFU 脂质体制剂对 P388 白血病的体内抗肿瘤活性与 FU 溶液几乎相同,但副作用较小。C18FU 脂质体制剂的体内抗肿瘤效果优于 ChFU 和游离 FU。将这些亲脂 FU 原药纳入脂质体的方式似乎会影响原药的转化动力学及其后续药效。