单次投喂乳酸诺氟沙星在鳜鱼体内的代谢消除规律

Pharmacokinetics and Removal of Norfloxacin Lactate in Mandarin Fish Siniperca chuatsi at Single-doseage

水温(28±2)℃时,按20mg/kg的剂量给平均体质量(500±10)g的鳜鱼单次口服乳酸诺氟沙星,服药后0.5、1、2、3、4、6、8、12、24、48、72、96h,分别测定鳜鱼血浆、肌肉、肝脏和肾脏中的药物含量,采用非房室模型分析药物在鳜鱼体内的代谢消除规律。结果显示,乳酸诺氟沙星在鳜鱼血浆、肌肉、肝脏、肾脏中的达峰时间分别为4.333、6、3、5h,达峰质量浓度分别为3.625、2.39、33.089、19.375mg/L,各组织中肝脏吸收的药物含量最高,其次是肾脏、血浆和肌肉;乳酸诺氟沙星在鳜鱼血浆、肌肉、肝脏、肾脏中的消除半衰期分别为42.589、131.652、16.830、30.558h,药物在肝脏中消除速度最快,而在肌肉中消除最慢。以肌肉中药物残留限量为50μg/kg计,建议单次投喂乳酸诺氟沙星的休药期不低于24d。

The drug concentrations in plasma, muscle, liver, and kidney were detected in mandarin fish Siniperca chuatsi orally administrated by norfloxacin lactate at a single dose of 20 mg/kg body weight at （28±2） ℃ 0.5, 1, 2, 3, 4, 6, 8, 12, 24, 48, 72 and 96 h after oral administration by high performance liquid chromatography （HPLC） method in order to study the metabolism and elimination of norfloxacin lactate. The results showed that the peaking time （tmax） of the drug was 4. 333 h in plasma, 6 h in muscle, 3 h in liver and 5 h in kidney, and that the corresponding maximal drug concentration （Cmax）3. 625 mg/L in plasma, 2.39 mg/L in muscle, 33. 089 mg/L in liver and 19. 375 mg/L in kidney, with the maximal ab- sorption of the drug in liver, and followed by in kidney, plasma and muscle. The elimination half-life （tl/2） of norfloxacin lactate was 42. 589 h in plasma, 131. 652 h in muscle, 16. 830 h in liver and 30. 558 h in kidney, the most rapid elimination of norfloxacin lactate in liver and the slowest in muscle. It is recom- mended that the withdrawal time be more than 24 d under this experiment condition according to the maxi- mum residue limit （MRL） of 50 ug/kg in muscle.