The behavior of 1,4-benzodiazepine drugs in acidic media. V. Kinetics of hydrolysis of flutazolam and haloxazolam in aqueous solution.
作者:TOMONARI KUWAYAMA、YUKIHISA KURONO、TSUYUKO MURAMATSU、TAMOTSU YASHIRO、KEN IKEDA
DOI:10.1248/cpb.34.320
日期:——
The hydrolysis of flutazolam and haloxazolam was investigated kinetically. The cleavage reaction of the diazepinone nucleus of flutazolam was reversible, and the ring-cleaved form was in equilibrium with the ring-closed form in aqueous solution. On the other hand, the cleavage reaction of haloxazolam was irreversible. It was concluded that the 2-hydroxyethyl substituent attached to the amide nitrogen atom of flutazolam is responsible for the reversible character of the hydrolytic cleavage of the diazepinone nucleus. The hydrolysis mechanism was elucidated on the basis of the pH-rate profile. To compare the effects of substituents on the hydrolysis, the rate constants of oxazolam and cloxazolam in acidic solution were also determined.
对氟噻氯氮卓和哈洛噻氯氮卓的水解反应进行了动力学研究。氟噻氯氮卓在水溶液中具有可逆的二氮杂萘核裂解反应,开放环的形式与闭环形式达到平衡。另一方面,哈洛噻氯氮卓的裂解反应是不可逆的。结论是,氟噻氯氮卓上连接在酰胺氮原子上的2-羟基乙基取代基是其二氮杂萘核水解裂解可逆特性的关键。水解机制是基于pH-反应速率曲线进行阐明的。为了比较取代基对水解的影响,还测定了在酸性溶液中氧噻氯氮卓和氯噻氯氮卓的速率常数。