The aim of this study was to determine the pharmacokinetics and bioavailability of tolfenamic acid in goats after intravenous (IV), intramuscular (IM), subcutaneous (SC), and oral (PO) administrations at 2 mg/kg dose. In this study, eight clinically healthy goats were used. The study comprised four periods, according to a crossover design with at least a 15-day washout period between treatments. Plasma concentrations of tolfenamic acid were determined by HPLC-UV, and the pharmacokinetic parameters were estimated using a non-compartmental method. Following IV administration, terminal elimination half-life, volume of distribution at steady state, and total clearance were 1.60 h, 0.37 L/kg, and 0.27 L/h/kg, respectively. The mean peak plasma concentration following IM, SC, and PO administrations was 1.77, 1.22, and 0.30 μg/ml, respectively. The mean bioavailability following IM, SC, and PO administrations was 64.46, 55.43, and 19.46%, respectively. The PO route, which exhibits both the low plasma concentration and bioavailability, is not recommended in goats. The IV, IM, and SC routes, which show comparable pharmacokinetic profiles, may be proposed for use in goats. However, the multi-dose and pharmacodynamic studies are necessary to establish more accurately its safety and efficacy in the goat.

中文翻译：

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不同给药途径后托芬那酸在山羊体内的药代动力学

本研究的目的是确定以 2 mg/kg 剂量静脉内 (IV)、肌内 (IM)、皮下 (SC) 和口服 (PO) 给药后，托芬那酸在山羊体内的药代动力学和生物利用度。在这项研究中，使用了八只临床健康的山羊。根据交叉设计，该研究包括四个阶段，治疗之间至少有 15 天的清除期。通过 HPLC-UV 测定托芬那酸的血浆浓度，并使用非隔室法估计药代动力学参数。IV 给药后，终末消除半衰期、稳态分布容积和总清除率分别为 1.60 h、0.37 L/kg 和 0.27 L/h/kg。IM、SC 和 PO 给药后的平均峰值血浆浓度分别为 1.77、1.22 和 0.30 μg/ml。IM、SC 和 PO 给药后的平均生物利用度分别为 64.46、55.43 和 19.46%。不推荐在山羊中使用同时表现出低血浆浓度和生物利用度的 PO 途径。IV、IM 和 SC 途径显示出可比较的药代动力学特征，可建议用于山羊。然而，多剂量和药效学研究对于更准确地确定其在山羊中的安全性和有效性是必要的。