硝苯地平形成硝基自由基阴离子：一种电化学方法。

A nitro radical anion formation from nifedipine: an electrochemical approach.

作者信息

Squella J A, Solabarrieta C, Nuñez-Vergara L J

机构信息

Laboratorio de Electroquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago.

出版信息

Chem Biol Interact. 1993 Dec;89(2-3):197-205. doi: 10.1016/0009-2797(93)90009-n.

DOI:10.1016/0009-2797(93)90009-n

PMID:8269547

Abstract

The cyclic voltammetric behaviour of nifedipine was studied. The addition of three aprotic solvents to nifedipine in an aqueous citrate buffer system was examined. Qualitatively they result in separation of the initial irreversible 4 electron reduction into two stages, the NO2/RNO2.- and RNO2.-, 4H/RNHOH, H2O couples, respectively. Particular attention was directed to the 1-electron RNO2/RNO2.- couple as measured by the cyclic voltammetric mode in mixed media. Analysis of the cyclic voltammetric response as a function of scan rate and non-aqueous solvent content yields information on the stability of the radical anion. The chemical forward reaction of the radical anion follows a second order kinetics with a stability constant of 1.1 x 10(-3) l mol-1 s-1 and a half-life time of 0.09 s for 1 mM of nifedipine in aqueous citrate buffer, pH 7.4/DMF; 50:50.

摘要

研究了硝苯地平的循环伏安行为。考察了在柠檬酸盐水溶液缓冲体系中向硝苯地平添加三种非质子溶剂的情况。定性地说，它们导致最初不可逆的4电子还原分离为两个阶段，分别是NO₂/RNO₂⁻和RNO₂⁻、4H/RNHOH、H₂O电对。特别关注在混合介质中通过循环伏安模式测量的1电子RNO₂/RNO₂⁻电对。分析循环伏安响应随扫描速率和非水溶剂含量的变化，可得到有关自由基阴离子稳定性的信息。自由基阴离子的化学正向反应遵循二级动力学，在pH 7.4的柠檬酸盐水溶液缓冲液/DMF（50:50）中，1 mM硝苯地平的稳定性常数为1.1×10⁻³ l·mol⁻¹·s⁻¹，半衰期为0.09 s。