Influence of sex on the pharmacokinetics of ciprofloxacin and ofloxacin.

The pharmacokinetics of orally administered ciprofloxacin and ofloxacin were studied in healthy volunteers to assess the influence of sex on drug bioavailability. The first group of subjects (9 males and 9 females) received a single oral dose of 200 mg ofloxacin, and the second group of volunteers included 24 subjects (12 males and 12 females) treated with a single oral dose of 100 mg ciprofloxacin. Blood samples (3 ml) were collected and investigated in this parallel design study in both groups, and ciprofloxacin and ofloxacin concentrations were determined. These experimental data, which had not been changed by any mathematical operation, were collected and used to determine the effect of sex on the pharmacokinetic profile using parametric and non-parametric tests as well as multivariate classification tools like cluster analysis (CA) and principal component analysis (PCA). The following variables demonstrated significant differences (p < 0.05) in c(0.5), c(1.5), c(2.0), c(4.0), c(10), c(12.0), c(24) and c(6.0), c(8.0), c(10.0) for ofloxacin and ciprofloxacin, respectively, using Student's t test and ANOVA. Therefore the alternative hypothesis about sex differences between males and females was accepted. The CA and PCA plot separated females from males and allowed to select subjects accounting for differences between males and females. Data on the whole pharmacokinetic profile enabled to determine subtle sex differences between males and females.