Distribution and Antimicrobial Activity of Ciprofloxacin in Human Soft Tissues

Interstitial ciprofloxacin concentrations in soft tissues were measured by microdialysis following intravenous administration of 200 mg to each of eight healthy volunteers. Interstitial ciprofloxacin concentrations were significantly lower than corresponding total serum drug concentrations; the interstitium-to-serum concentration ratios ranged from 0.55 to 0.73. An in vitro simulation based on interstitial pharmacokinetics showed a substantially lower antimicrobial activity than did the simulation based on serum pharmacokinetics. Thus, ciprofloxacin concentrations at the site of effect may be subinhibitory although effective concentrations are attained in serum.

对8名健康志愿者静脉给予200mg环丙沙星（ciprofloxacin）后，采用微透析（microdialysis）技术检测其软组织间质液中的环丙沙星浓度。软组织间质液中的环丙沙星浓度显著低于对应时点的血清总药物浓度，间质-血清浓度比值介于0.55至0.73之间。基于间质药代动力学（pharmacokinetics）的体外（in vitro）模拟实验显示，其抗菌活性显著低于基于血清药代动力学的模拟实验结果。因此，尽管血清中可达到有效药物浓度，但效应部位的环丙沙星浓度可能处于亚抑菌水平。