二甲硝咪唑在动物组织中代谢的残留标志物研究

Study on the marker residue for the metabolites of DMZ in animal tissue by HPLC-ESI-MS

目的研究二甲硝咪唑(DMZ)在动物组织中代谢残留情况,探索可能存在的残留物形式,寻找药物使用的残留标志物。方法选择12只肉鸡以含有DMZ浓度为267 mg/L的饮水饲养,连续给药8 d,在最后一次给药的12 h后宰杀,收集可食肌肉组织样品,同时作空白对照。利用生物酶解、化学水解、溶剂提取处理技术,高效液相色谱-电喷雾-质谱(HPLC-ESI-MS)手段分析残留物组成及结构。结果染毒组织样品在保留时间7.52、8.37和11.11 min出现色谱峰,经标准加入及离子碎片质谱分析证明,残留物包括主要游离羟基化代谢物2-羟甲基-1-甲基-5硝基咪唑(DMZ-OH,m/z 158,8.37 min),其浓度为3 139μg/kg;部分原型药物DMZ(m/z 142,11.11 min),浓度为1 392μg/kg;少量的去甲基化游离代谢物2-甲基-5硝基咪唑(m/z 128,7.52 min)。结论药物的主要代谢物为DMZ-OH,可以作为检测DMZ滥用的残留标志物。

Objective To identify the marker residue of DMZ in the animal tissue and explore the possible existence of parent drug and its metabolites. Methods DMZ was administered to twelve maram goldline chickens in their drinking water at a dosage of 267 mg/L for 8 days. Twelve hours after the last dose, muscles from killed animals were collected and homogenized. Blank controls were set up. Samples were hydrolyzed by enzymes and chemicals to release residues and then extracted, and analyzed by HPLC- ESI-MS. Results Three peaks were found by comparing the incurred tissue to the blank control, with the retention time at 7.52, 8.37 and 11.11 min respectively. The result of LC-MS confirmed that residues included major hydroxylated free metabolite DMZ-OH （ m/z 158, RT 8. 37 min） with the concentrations of 3 139 g/kg, some of the free parent drug DMZ （ m/z 142, RT 11.11 min） with the concentrations of 1 392 g/kg and a minor demethylated free metabolite 2-methy-5-nitroimidazole （ m/z 128, RT 7.52 min ） in the incurred chicken muscles. Conclusion DMZ-OH was the major metabolite for DMZ and a marker residue for the use of DMZ.