Bioavailability of ciprofloxacin and fleroxacin: Results of a preliminary investigation in healthy adult Nigerian male volunteers

The absolute bioavailability (BA) of ciprofloxacin and fleroxacin were eval uated in 19 adult Nigerian male volunteers. Subjects meeting the selection criteria were randomized to receive treatment either with fleroxacin (200 m g-i.v. and 200 mg oral dose) or ciprofloxacin (200 mg-i.v. and 250 mg oral dose). The i.v./oral or oral/i.v. switch was made after a one week washout period. Blood and urine samples were collected at pre-determined time inter vals over a 72 h period for analysis of drug levels. Following intravenous administration the maximum serum concentration (C-max ) was 2.7 +/- 1.06 mg/l for ciprofloxacin and 0.99 +/- 0.41 mg/l for flerox acin; the area under the blood level curve (AUC) was 8.82 +/- 3.19 mg.h/l w ith ciprofloxacin and 8.52 +/- 3.83 mg.h/l with fleroxacin. Following oral administration the C-max was 1.52 +/- 0.94 mg/l with ciprofloxacin and 0.57 +/- 0.08 mg/l with fleroxacin; the AUC was 9.87 +/- 4.10 and 7.55 +/- 1.42 mg hn, respectively. The absolute BA following oral administration was fou nd to he 0.79 +/- 0.37 for ciprofloxacin and 1.01 +/- 0.78 for fleroxacin. When these BA results were corrected for renal clearance (CI,) and eliminat ion half-life (t(1/2)) the values were reduced to 0.37 +/- 0.17 and 0.31 +/ - 0.18, respectively, for ciprofloxacin and 0.53 +/- 0.23 and 0.99 +/- 0.38 . respectively, for fleroxacin, Only 38% with ciprofloxacin and 59% with fl eroxacin, of the administered dose, was excreted unchanged following oral a dministration. More work, however, needs to be done on ciprofloxacin to support and/or con firm the above findings. Fleroxacin, on the one hand, exhibited a different trend from that observed in the literature with respect to C-max and AUC w here the values observed in this study were 3-4 fold lower than expected fo llowing identical doses, whilst on the other hand the observed BA profile i n this study was consistent with Literature trends.