The present study aimed to determine the pharmacokinetic profiles of ceftiofur (as measured by ceftiofur and its active metabolites concentrations) in a small‐size dog breed, Peekapoo, following a single intravenous or subcutaneous injection of ceftiofur sodium. The study population comprised of five clinically healthy Peekapoo dogs with an average body weight (BW) of 3.4 kg. Each dog received either intravenous or subcutaneous injection, both at 5 mg/kg BW (calculated as pure ceftiofur). Plasma samples were collected at different time points after the administration. Ceftiofur and its active metabolites were extracted from plasma samples, derivatized, and further quantified by high‐performance liquid chromatography. The concentrations versus time data were subjected to noncompartmental analysis to obtain the pharmacokinetic parameters. The terminal half‐life (t _1/2λz ) was calculated as 7.40 ± 0.79 and 7.91 ± 1.53 hr following intravenous and subcutaneous injections, respectively. After intravenous treatment, the total body clearance (Cl) and volume of distribution at steady‐state (V _SS) were determined as 39.91 ± 4.04 ml hr⁻¹ kg⁻¹ and 345.71 ± 28.66 ml/kg, respectively. After subcutaneous injection, the peak concentration (C _max; 10.50 ± 0.22 μg/ml) was observed at 3.2 ± 1.1 hr, and the absorption half‐life (t _1/2ka ) and absolute bioavailability (F ) were calculated as 0.74 ± 0.23 hr and 91.70%±7.34%, respectively. The pharmacokinetic profiles of ceftiofur and its related metabolites demonstrated their quick and excellent absorption after subcutaneous administration, in addition to poor distribution and slow elimination in Peekapoo dogs. Based on the time of concentration above minimum inhibitory concentration (T  > MIC) values calculated here, an intravenous or subcutaneous dose at 5 mg/kg of ceftiofur sodium once every 12 hr is predicted to be effective for treating canine bacteria with a MIC value of ≤4.0 μg/ml.

中文翻译：

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单次静脉内和皮下注射后，头孢噻呋钠在Peekapoo狗中的药代动力学。

本研究旨在确定在单次静脉内或皮下注射头孢噻呋钠后，在小型犬种Peekapoo中头孢噻呋的药代动力学特征（通过头孢噻呋及其活性代谢物浓度测量）。研究人群包括五只临床健康的Peekapoo狗，平均体重（BW）为3.4千克。每只狗接受静脉内或皮下注射，剂量均为5 mg / kg体重（以纯头孢噻呋计）。给药后不同时间点收集血浆样品。从血浆样品中提取头孢噻呋及其活性代谢物，进行衍生化，然后通过高效液相色谱法进一步定量。对浓度相对于时间的数据进行非小室分析以获得药代动力学参数。在静脉内和皮下注射后，t _{1/ 2λz} ）分别为7.40±0.79和7.91±1.53小时。静脉内治疗后，全身清除率（Cl）和稳态分布量（V _SS）分别为39.91±4.04 ml·hr ^-1  kg ^-1和345.71±28.66 ml / kg。皮下注射后，在3.2±1.1小时观察到峰值浓度（C _max； 10.50±0.22μg/ ml），吸收半衰期（t _{1/2 ka} ）和绝对生物利用度（F）分别计算为0.74±0.23小时和91.70％±7.34％。头孢噻呋及其相关代谢产物的药代动力学曲线表明，皮克农犬皮下给药后，头孢噻呋及其相关代谢产物具有快速，优异的吸收作用，此外分布较差且消除速度较慢。根据高于 此处计算的最小抑菌浓度（T > MIC）值的时间，预计每12小时一次5 mg / kg头孢噻呋钠的静脉内或皮下剂量可有效治疗MIC值为15的犬细菌。 ≤4.0微克/毫升