代谢
乙氧苄碘唑(Etridiazole),即5-乙氧基-3-三氯甲基硫代-1,2,4-二唑,被口服给予大鼠和志愿者。合成了乙氧苄碘唑的两个代谢物:5-乙氧基-1,2,4-硫代二唑-3-羧酸(ET-CA)和N-乙酰-S-(5-乙氧基-1,2,4-硫代二唑-3-基甲基)-L-半胱氨酸(ET-MA)。开发了一种选择性和灵敏的分析程序,用于测定尿液中乙氧苄碘唑、羧酸ET-CA和巯基尿酸ET-MA的含量。应用氮选择性检测的气相色谱(GC-NPD)检测乙氧苄碘唑的检测限为36微克/升尿液(变异系数CV=15.4%,样本数n=3)。应用硫选择性检测的气相色谱(GC-FPD)检测ET-CA的检测限为100微克/升尿液(变异系数CV=9.8%,样本数n=3)。在大鼠口服乙氧苄碘唑后的尿液中,ET-CA和ET-MA被识别为乙氧苄碘唑的代谢物,而在口服乙氧苄碘唑的人的尿液中,仅识别出ET-CA。在大鼠中,未代谢的乙氧苄碘唑的排泄量不到给药剂量的0.1%。然而,ET-CA在大鼠中占给药剂量的22±9%,在人类中占13±6%。ET-MA似乎是乙氧苄碘唑的一个次要尿液代谢物。建议将ET-CA作为生物监测乙氧苄碘唑的可能生物标志物。
Etridiazole, 5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole, was orally administered to rats and human volunteers. Two metabolites of etridiazole were synthesized: 5-ethoxy-1,2,4-thiadiazole-3-carboxylic acid (ET-CA) and N-acetyl-S-(5-ethoxy-1,2,4-thiadiazol-3-yl-methyl)-L-cysteine (ET-MA). Selective and sensitive analytical procedures to determine etridiazole, the carboxylic acid ET-CA and the mercapturic acid ET-MA in urine were developed. The detection limit of etridiazole, applying GC with nitrogen selective detection (GC-NPD), was 36 micrograms/l urine (CV = 15.4%, n = 3). The detection limit of ET-CA, applying GC with sulphur selective detection (GC-FPD), was 100 micrograms/l urine (CV = 9.8%, n = 3). In urine of rats orally treated with etridiazole, ET-CA and ET-MA were identified as metabolites of etridiazole, whereas in urine of humans given oral etridiazole, only ET-CA was identified. Unmetabolized etridiazole was excreted for less than 0.1% of the administered dose in rats. ET-CA, however, accounted for 22 +/- 9% of the administered dose of etridiazole in rats and for 13 +/- 6% in humans. ET-MA appeared to be a minor urinary metabolite of etridiazole. ET-CA is proposed as a possible biomarker for the biological monitoring of etridiazole.
来源:Hazardous Substances Data Bank (HSDB)