Kinetic Studies of the Hydrolysis and Lactonization of Camptothecin and Its Derivatives, CPT-11 and SN-38, in Aqueous Solution.
作者:Katsuya AKIMOTO、Akiko KAWAI、Kazumi OHYA
DOI:10.1248/cpb.42.2135
日期:——
The effect of pH and temperature on the reaction rate of the hydrolysis and lactonization of camptothecin and its derivatives, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (CPT-11) and 7-ethyl-10-hydroxycamptothecin (SN-38), in aqueous solution was studied by high-performance liquid chromatography or two-wavelength spectrophotometry. Hydrolysis and lactonization of each compound progressed according to pH-and temperature-dependent pseudo-first-order kinetics. The ratio of the lactone form of each compound to its hydroxy-acid form was determined mainly by the pH of the solution and was not influenced by temperature. Half-lives of the lactone and hydroxy-acid forms of CPT-11 at 37°C and pH 7.4 were 13.7 min and 4.25 h, respectively.
pH值和温度对喜树碱及其衍生物,即7-乙基-10-[4-(1-哌啶) -1-哌啶]羰氧基喜树碱(CPT-11)和7-乙基-10-羟基喜树碱(SN-38)在水溶液中的水解和内酯化反应速率的影响,是通过高效液相色谱法或双波长分光光度法进行研究的。每种化合物的水解和内酯化过程均遵循依赖于pH值和温度的伪一级动力学。每种化合物的内酯形式与其羟酸形式的比例主要由溶液的pH值决定,且不受温度的影响。CPT-11的内酯形式和羟酸形式在37°C和pH 7.4条件下的半衰期分别为13.7分钟和4.25小时。