To date, the pharmacokinetics of fluoroquinolones in estuarine crocodiles (Crocodylus porosus) have been reported for enrofloxacin but not for marbofloxacin (MBF), which is a broad-spectrum antibiotic used only in veterinary medicine. This study investigated the pharmacokinetics of MBF after intramuscular administration at two difference dosages (2 and 4 mg/kg body weight) in estuarine crocodiles and estimated pharmacokinetic/pharmacodynamic (PK/PD) surrogate parameters for the optimization of dosage regimens. Ten treated estuarine crocodiles were divided into two groups (n = 5) using a randomization procedure according to a parallel study design. Blood samples were collected at assigned times up to 168 h. MBF plasma samples were cleaned up using liquid–liquid extraction and analyzed using a validated high-performance liquid chromatography method with fluorescence detection. A non-compartment approach was used to fit the plasma concentration of MBF vs time curve for each crocodile. The plasma concentrations of MBF were quantifiable for up to 168 h in both groups. The elimination half-life values of MBF were long (33.99 and 39.28 h for 2 and 4 mg/kg, respectively) with no significant differences between the groups. The average plasma protein binding of MBF was 30.85%. According to the surrogated PK/PD parameter (AUC_0–24-to-MIC ratio >100–125), the 2 and 4 mg/kg dosing rates should be effective for bacteria with MIC values lower than 0.125 μg/mL and 0.35 μg/mL, respectively.

中文翻译：

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河口鳄鱼（Crocodylus porosus）肌肉注射后马波沙星的药代动力学分布

迄今为止，氟喹诺酮类药物在河口鳄鱼（Crocodylus porosus）中的药代动力学已报道为恩诺沙星，但尚未报道马波沙星（MBF），后者是一种仅用于兽医的广谱抗生素。本研究研究了河口鳄鱼以两种不同剂量（2 和 4 mg/kg 体重）肌肉注射 MBF 后的药代动力学，并估计了药代动力学/药效学 (PK/PD) 替代参数，以优化剂量方案。 根据平行研究设计，使用随机化程序将十只接受治疗的河口鳄鱼分为两组（n = 5）。在指定时间采集血样，最长可达 168 小时。MBF 血浆样品采用液-液萃取进行净化，并使用经过验证的高效液相色谱法和荧光检测进行分析。采用非隔室方法来拟合每只鳄鱼的 MBF 血浆浓度与时间的关系曲线。两组的 MBF 血浆浓度可在长达 168 小时内进行定量。MBF 的消除半衰期值较长（2 mg/kg 和 4 mg/kg 分别为 33.99 和 39.28 小时），组间无显着差异。MBF的平均血浆蛋白结合率为30.85%。根据替代 PK/PD 参数（AUC _0–24与 MIC 比率 >100–125），2 和 4 mg/kg 剂量率对于 MIC 值低于 0.125 μg/mL 和 0.35 μg 的细菌应该有效。 /mL，分别。