Pharmacokinetics of enoxacin and its oxometabolite after multiple oral dosing and penetration into prostatic tissue

The objective of this study was to determine the concentrations of enoxacin and its oxometabolite in human prostatic tissue after multiple oral doses (400 mg bd) in 13 patients. On the first day of treatment, elimination half -lives were 6.8 h for enoxacin and 7.1 h for its metabolite; they were incr eased on day 4 (10.3 and 13.2 h, respectively). The ratios of drug concentr ation in prostatic tissue and plasma averaged 2.2 for enoxacin and 1.4 for its metabolite. In conclusion, concentrations of enoxacin achieved within t he prostatic tissue were higher than plasma concentrations suggesting that there was an active transport mechanism.