Brown M P, Gronwall R R, Houston A E
Am J Vet Res. 1986 Aug;47(8):1734-8.
Four healthy adult mares were each given a single injection of sodium cefoxitin (20 mg/kg of body weight, IV), and serum cefoxitin concentrations were measured serially during a 6-hour period. The mean elimination rate constant was 1.08/hour and the elimination half-life was 0.82 hour. The apparent volume of distribution (at steady state) and the clearance of the drug were estimated at 0.12 L/kg and 259 ml/hr/kg, respectively. Each mare and 2 additional mares were then given 4 consecutive IM injections of sodium cefoxitin (400 mg/ml) at a dosage of 20 mg/kg. Cefoxitin concentrations in serum, synovial fluid, peritoneal fluid, CSF, urine, and endometrium were measured serially. After IM administration, the highest mean serum concentration was 23.1 micrograms/ml 30 minutes after the 2nd injection. The highest mean synovial concentration was 11.4 micrograms/ml 1 hour after the 4th injection. The highest mean peritoneal concentration was 10.4 micrograms/ml 2 hours after the 4th injection. The highest mean endometrial concentration was 4.5 micrograms/g 4 hours after the 4th injection. Mean urine concentrations reached 11,645 micrograms/ml. Cefoxitin did not readily penetrate the CSF. Bioavailability of cefoxitin given IM was 65% to 89% (mean +/- SEM = 77% +/- 5.9%). One of the 6 mares developed acute laminitis during the IM experiment.
给4匹健康成年母马每匹静脉注射一次头孢西丁钠（20毫克/千克体重），并在6小时内连续测量血清中头孢西丁浓度。平均消除速率常数为1.08/小时，消除半衰期为0.82小时。药物（稳态时）的表观分布容积和清除率分别估计为0.12升/千克和259毫升/小时/千克。然后给每匹母马和另外2匹母马连续4次肌肉注射头孢西丁钠（400毫克/毫升），剂量为20毫克/千克。连续测量血清、滑液、腹腔液、脑脊液、尿液和子宫内膜中的头孢西丁浓度。肌肉注射后，第二次注射后30分钟血清平均最高浓度为23.1微克/毫升。第四次注射后1小时滑液平均最高浓度为11.4微克/毫升。第四次注射后2小时腹腔平均最高浓度为10.4微克/毫升。第四次注射后4小时子宫内膜平均最高浓度为4.5微克/克。尿液平均浓度达到11645微克/毫升。头孢西丁不易穿透脑脊液。肌肉注射头孢西丁的生物利用度为65%至89%（平均值±标准误=77%±5.9%）。6匹母马中有1匹在肌肉注射实验期间发生了急性蹄叶炎。
