Fernández-Varón Emilio, Cárceles Carlos M, Marín Pedro, Martos Nieves, Escudero Elisa, Ayala Ignacio
Department of Pharmacology, Faculty of Veterinary Medicine, University of Murcia, Campus de Espinardo, 30.071-Murcia, Spain.
Am J Vet Res. 2006 Jun;67(6):1076-81. doi: 10.2460/ajvr.67.6.1076.
To study the pharmacokinetics of difloxacin (5 mg/kg) following IV, IM, and intragastric (IG) administration to healthy horses.
6 healthy mature horses.
A crossover study design with 3 phases was used (15-day washout periods between treatments). An injectable formulation of difloxacin (5%) was administered IV and IM in single doses (5 mg/kg); for IG administration, an oral solution was prepared and administered via nasogastric tube. Blood samples were collected before and at intervals after each administration. A high-performance liquid chromatography assay with fluorescence detection was used to determine plasma difloxacin concentrations. Pharmacokinetic parameters of difloxacin were analyzed. Plasma creatine kinase activity was monitored to assess tissue damage.
Difloxacin plasma concentration versus time data after IV administration were best described by a 2-compartment open model. The disposition of difloxacin following IM or IG administration was best described by a 1-compartment model. Mean half-life for difloxacin administered IV, IM, and IG was 2.66, 5.72, and 10.75 hours, respectively. Clearance after IV administration was 0.28 L/kg.h. After IM administration, the absolute mean +/- SD bioavailability was 95.81 +/- 3.11% and maximum plasma concentration (Cmax) was 1.48 +/- 0.12 mg/L. After IG administration, the absolute bioavailability was 68.62 +/- 10.60% and Cmax was 0.732 +/- 0.05 mg/L. At 12 hours after IM administration, plasma creatine kinase activity had increased 7-fold, compared with the preinjection value.
Data suggest that difloxacin is likely to be effective for treating susceptible bacterial infections in horses.
研究在健康马匹静脉注射、肌肉注射和胃内给药（灌胃）后，地氟沙星（5毫克/千克）的药代动力学。
6匹健康成年马。
采用具有3个阶段的交叉研究设计（治疗之间有15天的洗脱期）。静脉注射和肌肉注射单剂量（5毫克/千克）的地氟沙星注射用制剂（5%）；对于灌胃给药，制备口服溶液并通过鼻胃管给药。在每次给药前和给药后的不同时间间隔采集血样。采用荧光检测的高效液相色谱法测定血浆地氟沙星浓度。分析地氟沙星的药代动力学参数。监测血浆肌酸激酶活性以评估组织损伤。
静脉注射后地氟沙星血浆浓度与时间的数据最适合用二室开放模型描述。肌肉注射或灌胃给药后地氟沙星的处置情况最适合用一室模型描述。静脉注射、肌肉注射和灌胃给药的地氟沙星平均半衰期分别为2.66、5.72和10.75小时。静脉注射后的清除率为0.28升/千克·小时。肌肉注射后，绝对平均±标准差生物利用度为95.81±3.11%，最大血浆浓度（Cmax）为1.48±0.12毫克/升。灌胃给药后，绝对生物利用度为68.62±10.60%，Cmax为0.732±0.05毫克/升。肌肉注射后12小时，血浆肌酸激酶活性与注射前值相比增加了7倍。
数据表明，地氟沙星可能对治疗马匹易感细菌感染有效。
