氟苯尼考及其代谢物在淡水小龙虾中残留消除规律的研究

本试验建立了小龙虾组织中氟苯尼考(FF)和氟苯尼考胺(FFA)残留的高效液相色谱检测方法,并采用连续6 d药浴(水温25℃)的方式,研究淡水小龙虾肌肉和肝胰脏中FF及其主要代谢物FFA代谢动力学和消除规律。检测方法是以PBS(pH 6.0)和乙酸乙酯-氨水(体积比为98∶2)作为提取溶剂,采用XTerra@RP18(5μm,4.6 mm×250 mm)反向色谱柱,利用乙腈-磷酸二氢钠缓冲液(体积比为3∶7)为流动相,流速0.8 mL.min-1,紫外检测波长224 nm。在添加20～500μg.kg-1标样时,该方法的回收率大于70%,变异系数低于7.92%。FF和FFA的检出限分别为20μg.kg-1和10μg.kg-1。残留消除试验结果表明:在药浴FF 6 d后,在组织中两种药物均检出,说明其代谢物也有出现。停药后168 h,肌肉中检测不到FFA;停药后336 h,肝胰脏中检测不到FFA残留,肌肉和肝胰脏中均检测不到FF残留。两种药物在肝胰脏的消除速率都慢于肌肉,FF的消除速率均略慢于FF和FFA总量在组织中的消除速率,肝胰脏中的FFA浓度远高于肌肉中的。FF和FFA两种药物残留总量在淡水小龙虾肌肉和肝胰脏的消除曲线方程分别是y=505.06e-0.012 9x和y=775.71e-0.010 0x、y=690.78e-0.013 5x和y=1 778.7e-0.011 1x,消除半衰期(t1/2)分别为51.33 h和62.43 h,在肌肉和肝胰脏中降至100μg.kg-1的理论时间分别为5.94 d和10.8 d。考虑到温度为影响药物代谢和残留的最主要环境因素,建议FF在小龙虾体内的休药期为270℃.d。

Residues and elimination of florfenicol and its metabolite florfenicol amine in the freshwater crayfish

A HPLC method was developed to determine the residues of florfenicol(FF)and florfenicol amine(FFA)in crawfish tissues and using a continuous six-day dipping administration to study the pharmacokinetics and elimination rules of florfenicol and its main metabolite florfenicol amine in the muscle and hepatopancreas of freshwater crayfish.The detection method was based on PBS(pH 6.0)and ethyl acetate-ammonium hydroxide(valume ratio 98∶2)as the extraction solvents,reversed-phase column of XTerra@RP18(5 μm,4.6 mm×250 mm)as the analysis column,using acetonitrile-sodum dihydrogen phosphate solution(volume ratio 3∶7)as the mobile phase,the flow rate 0.8 mL·min-1,and 224 nm as the ultraviolet detection wavelength.At spiked level 20-500 μg·kg-1,the method recoveries were greater than 70%,and RSD was less than 7.92%.The detection limits of florfenicol and florfenicol amine were 20 μg·kg-1 and 10 μg·kg-1,repectively.The results of residues elimination showed that two drugs had been detected after dipping FF 6 d,which indicated its metanolite had appeared.Florfenicol amine had neither been detected in muscle 168 h after discontinuation,and nor been detected in hepatopancreas 336 h after discontinuation.No florfenicol could be detected in muscle and hepatopancreas 336 h after discontinuation.The elimination rates of these two drugs in hepatopancreas were slower than their elimination rate in muscle.The elimination rate of florfenicol was slightly slower than the toal elimination rate of florfenicol and florfenicol amine in tissues.The concentration of florfenicol amine in hepatopancreas was much higher than its concentration in muscle.The eliminate equations of the amount of florfenicol and florfenicol amine in muscle and hepatopancreas were y=505.06e-0.012 9x and y=775.71e-0.010 0x,y=690.78e-0.013 5x and y=1 778.7e-0.011 1x,the elimination half-lives(t1/2)were 51.33 h and 62.43 h,respectively.The time in theory when the concentration was reduced to 100 μg·kg-1 in muscle and hepatopancreas were respectively 5.94 d and 10.8 d.The water temperature in this experiment was 25 ℃.Taking into account that temperature was the main factor influencing the metabolism of antibacterials,so we suggested the withdrawal time of florfenicol for crawfish be 270 ℃·d.