Penetration of pefloxacin into gynaecological tissues

In a prospective pharmacokinetic study, the plasma and tissue concentrations of pefloxacin were studied. Twelve patients were premedicated with pefloxacin 400 mg bd orally for three days followed by 400 mg iv preoperatively. Tissue samples during surgery were taken from the skin, peritoneum, ovary, myometrium and fallopian tubes. Pefloxacin concentrations were measured by high performance liquid chromatography with fluorescence detection. The mean elimination half-life of pefloxacin was 11.3 h, the mean residence time (MRT) was 15.8 h and the apparent volume of distribution 1.52 +/- 0.525 L/kg. Pefloxacin concentrations in myometrium, ovary and fallopian tubes exceeded four- to six-fold the corresponding plasma concentrations 3.5 h after the last drug intake. At the start of surgery, about 2.5 h after the last dose, the skin/plasma concentration ratio and the peritoneum/plasma concentration ratio were 2.65 and 1.18, respectively. At the end of surgery, these ratios were 4.65 and 1.5. The tissue concentrations exceeded the MIC90 for most common pathogens implicated in gynaecological infections.