Department of Pharmacology, Faculty of Veterinary Medicine, Kasertsart University, Bangkok 10900, Thailand.
Department of Pharmacology, University of Murcia, Campus de Espinardo, Murcia 30100, Spain.
Vet J. 2024 Jun;305:106130. doi: 10.1016/j.tvjl.2024.106130. Epub 2024 May 10.
Tildipirosin is a macrolide antimicrobial. It is authorised for the treatment and prevention of respiratory disease in cattle and pigs. There are no data on its administration in crocodiles. Therefore, this study evaluated the disposition kinetics of tildipirosin after intravenous (dose: 2 mg/kg) and intramuscular (doses: 2 and 4 mg/kg) administration in two crocodilian species (estuarine and freshwater; n = 5). Tildipirosin plasma concentrations were quantified by a validated HPLC method. Plasma concentrations obtained at each extraction time were analysed by non-compartmental methods. In the estuarine and freshwater crocodiles, the apparent volumes of distribution of tildipirosin after intravenous administration were 0.36 ± 0.10 and 1.48 ± 0.26 L/kg, respectively. These values, suggesting poorer tissue distribution, were much lower than those obtained in mammals. There was complete bioavailability of tildipirosin after intramuscular route at a dose of 2 mg/kg; however, at a dose of 4 mg/kg the bioavailability decreased by about 20-25 %. Furthermore, the pharmacokinetics of tildipirosin were markedly different in the two crocodilian species. Considering a MIC of 0.5 µg/mL, the surrogate marker AUC/MIC indicates that tildipirosin would greatly exceed the value of 65 h for both crocodile species and dose levels tested. This suggests that both doses (2 and 4 mg/kg) may provide a bactericidal effect. Therefore, based on the absence of adverse reactions following the administration of tildipirosin in both crocodilian species, and considering its favourable pharmacokinetic properties, tildipirosin may be useful in treating infections in these reptiles.
替米考星是一种大环内酯类抗菌药物。它被批准用于治疗和预防牛和猪的呼吸道疾病。目前尚无关于其在鳄鱼中使用的数据。因此，本研究评估了替米考星在两种鳄鱼物种（河口和淡水；n = 5）中静脉（剂量：2 mg/kg）和肌肉内（剂量：2 和 4 mg/kg）给药后的处置动力学。替米考星的血浆浓度通过验证的 HPLC 方法进行定量。通过非房室分析方法分析每个提取时间获得的血浆浓度。在河口鳄和淡水鳄中，替米考星静脉给药后的表观分布体积分别为 0.36 ± 0.10 和 1.48 ± 0.26 L/kg。这些值表明组织分布较差，远低于哺乳动物的分布值。在 2 mg/kg 的剂量下，替米考星经肌肉途径给药具有完全的生物利用度；然而，在 4 mg/kg 的剂量下，生物利用度降低了约 20-25%。此外，替米考星在两种鳄鱼物种中的药代动力学有明显差异。考虑到 MIC 为 0.5 µg/mL，替代标志物 AUC/MIC 表明替米考星在两种鳄鱼物种和测试剂量水平下均将大大超过 65 h 的值。这表明两种剂量（2 和 4 mg/kg）都可能具有杀菌作用。因此，鉴于替米考星在两种鳄鱼中给药后均未出现不良反应，并且考虑到其有利的药代动力学特性，替米考星可能对治疗这些爬行动物的感染有用。
