Unowsky J, Sattler J, Patel I H
Hoffmann-La Roche Inc., Nutley, N.J.
Chemotherapy. 1989;35(5):338-44. doi: 10.1159/000238692.
Ceftriaxone and cefotaxime are third-generation cephalosporins with similar in vitro potencies and spectra. However, previous studies have shown that ceftriaxone had superior in vivo activity (mouse PD50 values greater than or equal to 2-fold lower) compared to cefotaxime in 23 of 46 tested enterobacteriaceae. This superior activity was thought to be due to ceftriaxone's 5- to 8-fold longer half-life. The relationship between half-life (ceftriax-one 6 h, cefotaxime 1 h) and potency was examined by following bacterial kill curves in a single chamber, open-ended perfusion model over an 8-hour period. Both antibiotics were compared for efficacy at both half-lives against four gram-negative bacteria. For two of the bacterial strains antibiotic potency differences in the perfusion model were determined largely by pharmacokinetics. For the other two strains intrinsic bacterial and antibiotic properties were of prime importance.
头孢曲松和头孢噻肟是第三代头孢菌素，体外效力和抗菌谱相似。然而，先前的研究表明，在46种测试的肠杆菌科细菌中，有23种细菌头孢曲松的体内活性优于头孢噻肟（小鼠半数有效剂量值低2倍以上或等于2倍）。这种优越的活性被认为是由于头孢曲松的半衰期长5至8倍。通过在单腔开放式灌注模型中跟踪8小时内的细菌杀灭曲线，研究了半衰期（头孢曲松6小时，头孢噻肟1小时）与效力之间的关系。比较了两种抗生素在两个半衰期对四种革兰氏阴性菌的疗效。对于其中两种细菌菌株，灌注模型中的抗生素效力差异在很大程度上由药代动力学决定。对于另外两种菌株，细菌内在特性和抗生素特性至关重要。
