Identification of nifedipine metabolites and their determination by gas chromatography.
作者:SHUJI KONDO、AKIRA KUCHIKI、KEIICHI YAMAMOTO、KOICHI AKIMOTO、KOUICHI TAKAHASHI、NORIO AWATA、ISAO SUGIMOTO
DOI:10.1248/cpb.28.1
日期:——
The urinary metabolites of nifedipine in a dog were isolated and identified by chromatographic and spectrometric techniques. A new major metabolite, 2, 6-dimethyl-4-(2-nitrophenyl)-5-methoxycarbonylpyridine-3-carboxylic acid (M-I), was found in both dog and human urine. A highly sensitive and specific method is described for the determination of nifedipine, M-I, and a previously reported metabolite. The method for analysis of nifedipine is based on the oxidation of nifedipine to its pyridine analog, benzene extraction, and determination by electron-capture gas chromatography. The method for analysis of the metabolites is based on ethyl acetate extraction of the acidified specimen, derivatization of M-I to its methyl ester, and determination by electron-capture gas chromatography. Quantitative determination was possible down to 5 ng/ml of nifedipine using 1 ml samples of biological specimens. This method was used to measure plasma levels of nifedipine and its metabolites in dogs, and urinary excretion by humans after oral administration of a nifedipine preparation. It was found that nifedipine was absorbed, metabolized, and excreted rapidly, and that the main metabolite was M-I.
通过色谱和光谱技术分离并鉴定了狗体内硝苯地平的尿代谢物。在狗和人的尿液中都发现了一种新的主要代谢物,2, 6-二甲基-4-(2-硝基苯基)-5-甲氧基羰基吡啶-3-羧酸 (M-I)。描述了一种高度灵敏且特异的方法来测定硝苯地平、M-I 和先前报道的代谢物。硝苯地平的分析方法基于硝苯地平氧化成吡啶类似物、苯萃取、电子捕获气相色谱测定。代谢物的分析方法基于酸化样品的乙酸乙酯萃取、M-I衍生为其甲酯,并通过电子捕获气相色谱法测定。使用 1 ml 生物标本样品可以定量测定低至 5 ng/ml 的硝苯地平。该方法用于测量狗体内硝苯地平及其代谢物的血浆水平以及人类口服硝苯地平制剂后的尿排泄量。结果发现硝苯地平吸收、代谢和排泄迅速,主要代谢产物为M-I。