Chisholm D R, DeRegis R G, Behr D A
Antimicrob Agents Chemother. 1986 Jul;30(1):105-9. doi: 10.1128/AAC.30.1.105.
The therapeutic efficacies of cefadroxil and cephalexin were compared in a Streptococcus pyogenes-induced lung infection in rats. Although MICs, rates of in vitro killing in rat serum, and antibiotic serum levels after oral administration were similar for both drugs, cefadroxil was about eight times more effective than cephalexin in reducing the number of viable streptococci at the site of infection. This excellent in vivo bactericidal activity of cefadroxil in lung tissue and bronchial secretions was reflected in the 50% protective dose (PD50) after single or multiple oral treatments. A single treatment given 24 h after infection resulted in a PD50 of 2.8 mg of cefadroxil per kg, compared with 21 mg of cephalexin per kg. When treatment was administered three times, at 24, 27, and 30 h postinfection, the PD50s of cefadroxil and cephalexin were 0.7 and 8.0 mg/kg, respectively. In infected animals, treated 24 h postinfection, the area under the lung tissue concentration versus time curve for cefadroxil was significantly greater than that of cephalexin. This difference in pharmacokinetic behavior may account, at least in part, for the superior therapeutic results obtained with cefadroxil in this experimental pulmonary infection.
在大鼠由化脓性链球菌引起的肺部感染中，比较了头孢羟氨苄和头孢氨苄的治疗效果。尽管两种药物的最低抑菌浓度、在大鼠血清中的体外杀菌率以及口服给药后的抗生素血清水平相似，但头孢羟氨苄在减少感染部位存活的链球菌数量方面比头孢氨苄有效约八倍。头孢羟氨苄在肺组织和支气管分泌物中的这种出色的体内杀菌活性在单次或多次口服治疗后的50%保护剂量（PD50）中得到体现。感染后24小时给予单次治疗，头孢羟氨苄的PD50为每千克2.8毫克，而头孢氨苄为每千克21毫克。当在感染后24、27和30小时进行三次治疗时，头孢羟氨苄和头孢氨苄的PD50分别为0.7和8.0毫克/千克。在感染后24小时接受治疗的感染动物中，头孢羟氨苄的肺组织浓度-时间曲线下面积明显大于头孢氨苄。这种药代动力学行为的差异可能至少部分解释了在这种实验性肺部感染中头孢羟氨苄获得的更好治疗效果。
