Plasma pharmacokinetics (PK) and tissue disposition of enrofloxacin (EFX) was studied in rainbow trout (Oncorhynchus mykiss) after a single oral administration of 10 mg/kg, and by immersion baths of 20 ppm during 2.5 h and 100 ppm during 0.5 h, at water temperature of 16.3 ± 0.3 °C.

Concentrations of EFX in plasma and tissues (skin, muscle, liver, kidney and gut) were determined using high performance liquid chromatography (HPLC) with fluorescence detection.

Pharmacokinetic parameters were analyzed with a non-compartmental model. After oral administration, t½β, AUC and AUC_tissues/AUC_plasma ratio were 42.98 h, 21.80μg-h/ml and ≤ 18.63, respectively.

After immersion baths of 20 ppm during 2.5 h and 100 ppm during 0.5 h, the t½β, AUC and AUC_tissues/AUC_plasma were 42.77 and 44.67, 9.83 and 12.83 μg-h/ml and ≤ 9.81 and ≤ 7.13, respectively.

Therefore, oral (10 mg/kg) and bath administration in rainbow trout can provide AUC/MIC of ≥125 and Cmax/MIC of ≥10 to treat diseases caused by susceptible bacteria with MIC ≤ 0.04 μg/ml. This information can be helpful for the right use of EFX in rainbow trout. Also, this is the first study that determines the antibiotic tissue disposition in rainbow trout by using different administration routes.

在单剂量口服10 mg / kg的虹鳟鱼（Oncorhynchus mykiss）中并通过在2.5 h内浸泡20 ppm的水浴和在0.5 h内浸泡100 ppm的水浴研究了恩诺沙星（EFX）的血浆药代动力学（PK）和组织分布，在水温16.3±0.3°C时。

使用具有荧光检测功能的高效液相色谱（HPLC）测定血浆和组织（皮肤，肌肉，肝脏，肾脏和肠道）中EFX的浓度。

用非房室模型分析药代动力学参数。口服后，t1 / 2β，AUC和AUC_组织/ AUC_血浆比分别为42.98h，21.80μg-h/ ml和≤18.63。

在2.5小时内20 ppm的浸浴和0.5小时内100 ppm的浸浴之后，t1 / 2β，AUC和AUC_组织/ AUC_血浆分别为42.77和44.67、9.83和12.83μg -h/ ml，分别≤9.81和≤7.13 。

因此，在虹鳟鱼中口服（10 mg / kg）和洗澡可以提供≥125的AUC / MIC和≥10的Cmax / MIC，以治疗由MIC≤0.04μg/ ml的易感细菌引起的疾病。此信息有助于在虹鳟鱼中正确使用EFX。此外，这是第一项通过使用不同的给药途径确定虹鳟鱼中抗生素组织配置的研究。