Prodrugs of purine and pyrimidine analogues for the intestinal di/tri-peptide transporter PepT1: affinity for hPepT1 in Caco-2 cells, drug release in aqueous media and in vitro metabolism.
Prodrugs of purine and pyrimidine analogues for the intestinal di/tri-peptide transporter PepT1: affinity for hPepT1 in Caco-2 cells, drug release in aqueous media and in vitro metabolism.
复制标题
肠道二肽/三肽转运蛋白 PepT1 的嘌呤和嘧啶类似物的前药：Caco-2 细胞中 hPepT1 的亲和力、水介质中的药物释放和体外代谢。
DOI：
10.1016/s0168-3659(02)00413-3
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
B. Steffansen
中科院分区：
文献类型：
--
作者：
A. E. Thomsen;G. Friedrichsen;Arne Hagsten Sørensen;R. Andersen;C. Nielsen;B. Brodin;M. Begtrup;S. Frokjaer;B. Steffansen
提高嘌呤和嘧啶类似物（如无环鸟苷）的口服生物利用度的一般给药方法可能是将这些化合物可逆地连接到稳定的二肽前片段，这些二肽前片段与人类肠道二/三肽转运体hPepT1有亲和力。本研究合成了阿昔洛韦和1-（2-羟乙基）胸腺嘧啶的新型前药l-Glu-Sar和d-Glu-Ala酯，并测定了它们在Caco-2细胞中对hPepT1的亲和力。此外，研究了前药在各种水和生物介质中的降解情况，并与前药valaciclovir的相应水解进行了比较。亲和力研究表明，l-Glu-Sar前药对hPepT1具有高亲和力（Ki ~ 0.2-0.3 mM），而d-Glu-Ala前药的亲和力较差（Ki ~ 50 mM）。前药d-Glu[1-（2-羟乙基）胸腺嘧啶]- ala和l-Glu[无环鸟苷]- sar分别在pH高于4.5和5.5时表现出特异性的碱催化降解。这意味着pH ~ 7.4 （t1/2 ~ 3.5和5.5 h）下的降解速率比上小肠pH ~ 6.0时快约25倍。在10%的猪肠道匀浆和80%的人血浆中，l-Glu-Sar前药的半衰期大约在45 - 90分钟之间，表明酶催化降解有限。相比之下，valaciclovir在10%的猪肠道匀浆中进行广泛的酶催化水解（t1/2 ~ 1 min）。综上所述，l-Glu-Sar可能作为嘌呤和嘧啶类似物的前片段，其中母体化合物的释放主要由特定碱催化水解控制。无环鸟苷在相应的pH 7.4下被定量释放，而1-（2-羟乙基）连接的胸腺嘧啶被释放，而不是母体化合物胸腺嘧啶。
A general drug delivery approach for increasing oral bioavailability of purine and pyrimidine analogues such as acyclovir may be to link these compounds reversibly to stabilized dipeptide pro-moieties with affinity for the human intestinal di/tri-peptide transporter, hPepT1. In the present study, novel l-Glu-Sar and d-Glu-Ala ester prodrugs of acyclovir and 1-(2-hydroxyethyl)-linked thymine were synthesized and their affinities for hPepT1 in Caco-2 cells were determined. Furthermore, the degradation of the prodrugs was investigated in various aqueous and biological media and compared to the corresponding hydrolysis of the prodrug valaciclovir. Affinity studies showed that the l-Glu-Sar prodrugs had high affinity for hPepT1 (Ki∼0.2–0.3 mM), whereas the d-Glu-Ala prodrugs had poor affinity (Ki∼50 mM). The pH-rate profiles of the prodrugs d-Glu[1-(2-hydroxyethyl)thymine]-Ala and l-Glu[acyclovir]-Sar showed specific base catalyzed degradation at pH above 4.5 and 5.5, respectively. This implicates that the degradation rates at pH∼7.4 (t1/2∼3.5 and 5.5 h) are approximately 25 times faster than at upper small intestinal pH∼6.0. In 10% porcine intestinal homogenate and 80% human plasma the half-lives of the l-Glu-Sar prodrugs were approximately between 45 and 90 min indicating a limited enzyme catalyzed degradation. In contrast, valaciclovir underwent extensive enzyme catalyzed hydrolysis in 10% porcine intestinal homogenate (t1/2∼1 min). In conclusion, l-Glu-Sar may potentially function as pro-moiety for purine and pyrimidine analogues, where release of parent compound primarily is controlled by a specific base catalyzed hydrolysis. Acyclovir is quantitatively released at the relevant pH 7.4, whereas the 1-(2-hydroxyethyl)-linked thymine is released instead of the parent compound thymine.