Trans-epithelial intestinal elimination of moxifloxacin in rabbits

The intestinal trans-epithelial elimination of moxifloxacin was measured in the jejunum, ileum, caecum and in the bile in a rabbit model. Over a 120 min period following a single parenteral administration of moxifloxacin 15 mg/kg, peak serum concentration was 3.1 (± 1.1) mg/L. The elimination constants were: 0.019 (± 0.017) μg/cm²/min, 0.011 (± 0.014) μg/cm²/min and 0.002 (± 0.002) μg/cm²/min in the jejunum, ileum and caecum, respectively. Per loop, over 120 min, the respective eliminated quantities were: 9.59 (± 9.37) μg, 8.26 (± 6.74) μg and 1.92 (± 1.86) μg. Biliary moxifloxacin concentrations varied between 1.30 and 5.16 mg/L and exceeded serum levels from 45 min onwards. Intestinal concentrations paralleled serum moxifloxacin levels. Altogether, approximately 4.5% of the moxifloxacin dose was eliminated trans-epithelially in the digestive tract over the 120 min experimental period.