Effects of the Ester Moiety on Stereoselective Hydrolysis of Several Propranolol Prodrugs in Rat Tissues.
作者:Koichi TAKAHASHI、Satoko TAMAGAWA、Hitomi SAKANO、Toyoshi KATAGI、Nobuyasu MIZUNO
DOI:10.1248/bpb.18.1401
日期:——
stereoselective hydrolysis of the succinate ester was observed only in intestine homogenate, but the S/R ratio was almost 1 in plasma, liver and intestine homogenates. No interconversion between (R)- and (S)-isomer was observed during the hydrolysis of any of the ester prodrugs. These results indicate that hydrolysis of ester-type prodrugs of propranolol occurs stereoselectively in rat tissues, and that
在磷酸盐缓冲液(pH 7.4),大鼠血浆和大鼠组织匀浆中研究了普萘洛尔,O-乙酰基,O-丙酰基,O-丁酰基,O-新戊酰基和琥珀酰基酯的几种酯型前药水解的立体化学特征。在磷酸盐缓冲液中,在(R)-和(S)-普萘洛尔的酯之间的水解速率没有观察到差异。酯部分对在磷酸盐缓冲液中的水解速率的影响按以下顺序:乙酸盐>丙酸酯>丁酸酯>琥珀酸酯>新戊酸酯。在大鼠血浆和组织匀浆中,酯的水解被加速,并且观察到立体选择性水解。在血浆中,除了琥珀酸酯以外,(R)-异构体的水解比(S)-异构体的水解快。另一方面,在肝脏和肠的匀浆中,(S)-异构体的水解速度比(R)-异构体快,除了肝脏匀浆中的琥珀酸酯和新戊酸酯。而且,水解速率的比率(S / R)随前药的类型而变化。随着酯的烷基链长度的增加,肝脏中的S / R比值趋于统一,而肠的匀浆度却几乎保持恒定。对于新戊酸酯,在血浆和肠匀浆中观察到立体选择性水解,而在肝匀浆中未观