恩诺沙星及其代谢物环丙沙星在牛蛙体内的残留消除规律研究

Study on the residue elimination law of Enrofloxacin and its metabolite Ciprofloxacin in Bullfrogs(Lithobates catesbeiana)

为研究恩诺沙星及其代谢产物环丙沙星在牛蛙(Lithobates catesbeiana)体内药代动力学及分布,明确恩诺沙星在牛蛙体内的最大残留限量及休药期。本实验进行牛蛙单次口灌10%恩诺沙星粉混悬液(20 mg/kg·bw),在0.5、1、2、4、8、12、24、48、96、192、336、480 h分组织取样检测实验。研究显示:恩诺沙星和环丙沙星在牛蛙血液中的达峰时间(T_(max))相同为1 h,峰浓度(C_(max))分别为26.592μg/mL、2.256μg/mL;恩诺沙星在牛蛙肌肉、肝脏、肾脏、脑中的T_(max)均为8 h,C_(max)分别为10.21、13.84、17.52、3.95 mg/kg;环丙沙星在牛蛙肌肉、肝脏、肾脏的T_(max)分别为12、8、12 h,C_(max)分别为1.362、20.46、4.07 mg/kg,在脑中未检测出环丙沙星。结果表明:恩诺沙星在牛蛙体内吸收迅速,21.90%~40.35%恩诺沙星转化为环丙沙星,与鱼类和甲壳类生物相比,环丙沙星在牛蛙体内更易消除;恩诺沙星在牛蛙体内的最大残留限量MRL为108.22μg/kg;单剂量10%恩诺沙星粉(20 mg/kg bw)适用于治疗由于嗜水气单胞菌(MIC:0.1μg/mL)患病牛蛙;牛蛙在室温为25℃左右的饲养环境下,建议休药期不低于514.24 h(22 d)。

The purpose of this experiment is to study the pharmacokinetics and distribution of Enrofloxacin and its metabolite Ciprofloxacin in Lithobates catesbeiana,and to determine the Maximum Residue Limit of Enrofloxacin in L.catesbeiana and its drug withdrawal period.L.catesbeiana were given a single oral infusion of 10%Enrofloxacin powder suspension(20 mg/kg·bw),and samples were taken at 0.5,1,2,4,8,12,24,48,96,192,336 and 480 h.The T_(max)of Enrofloxacin and Ciprofloxacin in blood was the same as 1 h,and the C_(max)was 26.59,2.26 mg/kg,respectively;The T_(max)of Enrofloxacin in muscle,liver,kidney and brain was the same as 8 h,and the C_(max)was 10.21,13.84,17.52 and 3.95 mg/kg,respectively.The T_(max)of Ciprofloxacin in muscle,liver,and kidney were 12,8,and 12 h,respectively,and the C_(max)was 1.36,20.46 and 4.07 mg/kg,respectively.No Ciprofloxacin was detected in the brain.The results showed that Enrofloxacin was rapidly absorbed in L.catesbeiana,with 21.90%~40.35%being converted into Ciprofloxacin,and compared to fish and crustaceans,Ciprofloxacin is more easily eliminated in L.catesbeiana;The MRL of Enrofloxacin in L.catesbeiana is 108.22μg/kg;A single dose of 10%Enrofloxacin powder(20 mg/kg bw)is suitable for treating of L.catesbeiana infected with Aeromonas hydrophila(MIC:0.1μg/mL).L.catesbeiana are recommended to rest for no less than 514.24 hours(22 days)at a room temperature of around 25℃.