庆大霉素在羊体内代谢和残留消除规律研究

Study on Metabolism and Depletion of Gentamicin in Sheep

为研究庆大霉素在羊体内代谢和残留消除规律,以4 mg/kg肌肉注射硫酸庆大霉素注射液,每日2次,代谢研究连续注射2.5 d,残留消除研究连续注射3 d。按动物试验要求采集肌肉、肝脏、肾脏、脂肪、血液、尿液和粪便,UPLC-MS/MS法测定样品中庆大霉素的残留量。结果显示,庆大霉素在羊体内1 h可到血药峰浓度,尿液中的排泄总量占注射总量的80%左右,粪便中不足0.1%;在肝脏、肾脏、尿液中原型药总量占注射总量90%以上,证明庆大霉素在羊体内不代谢,原型药随尿液排出体外;庆大霉素在肾脏中残留浓度最高且消除时间长,确定肾脏是庆大霉素在羊体内的靶组织,庆大霉素原型药为残留标示物。研究结果可为庆大霉素的安全使用以及正确制订其在羊组织中的最高残留限量标准提供科学依据和建议。

This study was aimed to explore the metabolism and elimination of gentamicin in sheep.Gentamicin were injected twice a day with a quantity of 4 mg per kilogram body weight(BW).The continuous injection was lasted for 2.5 days for metabolism study,and for 3 days for elimination study.The samples of muscle,liver,kidney,fat,blood,urine and stool were collected according to the requirement of animal experiment.The residues of gentamicin in different tissues were detected using UPLC-MS/MS.The results showed that the concentration of gentamicin in blood reached peak after one hour of injection.Approximately eighty percent of totally injected gentamacin was excreted via urine,and less than 0.1 percent was excreted via stools.More than 90%of gentamicin existed as prototype form in liver,kidney and urine,when comparing with the totally injected amount,exhibiting that gentamicin was not metabolized in sheep,and the drug was excreted as its original form via urine.Kidney is the highest with gentamicin residual concentration,and with longest elimination time,exhibiting that kidney is the target organ for gentamicin residue analysis in sheep.Our work can give further evidence for rational usage of gentamicin in sheep,and also provide basic data for establishing MRLs in sheep tissues.