中文摘要：

采用反相高效液相色谱法（RP-HLPC），研究了（25±1）℃水温条件下单次经口灌注20mg·kg-1双氟沙星（DIF）后，DIF在异育银鲫体内的药代动力学特征及其代谢产物沙拉沙星（SAR）的残留规律。结果表明：DIF在血液及各组织中的药时数据均符合二室开放模型。血液和各组织中均出现重吸收峰现象，肝脏组织达峰浓度最大。其中DIF在血液、肝脏、肾脏、肌肉中吸收半衰期（T1/2a）分别为0．144、0．274、0．137和8．636h；消除半衰期（7＂1脚）分别为18．322、26．013、33．066和52．504h；总体清除率（CL）分别为0．082、0．068、0．077和0．058L·h·kg-2；药时曲线下面积（Auc）分别为243．244／ag·mL·h-2和294．857、258．587、344．630μg·g·h-2；表观分布容积（Vd）分别为0．676、0．220、0．226和1．258L·kg-1，血浆蛋白结合率为52．39％～64．10％。组织中均可检测到DIF的代谢产物SAR，其中血液中检测到的时间迟于其它组织；根据肌肉组织的DIF和SAR最大残留限量为100和30μg·kg-1，建议DIF休药期为18d以上。

英文摘要：

Pharmacokinetics of difloxacin （DIF） and tissue distribution of its metaboiite were estimated with a single dose of 20 mg kg-1 body weight after oral administration in Carassais auratus gibebio at （25.0± 1. 0） ℃ by reversed phase high performance liquid chromatography（RP-HPLC）. The results showed that the kinetic profiles o{ DIF and SAR could described by a two-compartment open model. DIF had reuptake phenomena in plasma and tissues, and the largest concentration appeared in liver. The dis- tribution half-time （T1/2o）, elimination half-time （T1/2β）, body clearance （CL/F）, area under the concen- tration-time curve（AUC） and apparent volume of distribution （Vd/F） of DIF were 0. 144 h. 18. 322 h. O. 082 L. h kg2 .243. 244 μg mL h-2 and O. 676 1 kg1 in plasma, O. 2741 h,26. 0131 h.O. 068 L h kg-2 . 294. 857 μg g h-2 and 0. 2199 1 kg 1 in liver,0. 137 h.33. 066 h.0. 077 L h kg-2 .258. 587 μg g h-1and 0. 226 1 kg-1 in kidney, 8. 636 h.52. 504 h.0. 058 L h kg 2.344. 63μg g h-2 and 1. 258 1 kg-1 in muscle. DIF was 52. 39%-64. 10% bound to plasma protein. SAR, the metabolite of DIF, can be de- tected in the tissues mentioned above, but the time of SAR appeared in plasma lagged behind those of oth- er tissuesrs. According to the maximum residue limit of DIF and SAR in edible tissues, which were 100 and 30μg kg-1 in E. sinensis, the commended withdrawal time of DIF in Carassais auratus gibebio was 18 days at least.