Bone penetration of enoxacin in patients with and without osteomyelitis

Enoxacin concentrations in bone were measured in 24 patients without infection and in 7 with osteomyelitis after one or two doses of 400 mg of enoxacin administered orally or intravenously. Enoxacin concentrations were measured in serum and bone (cortical and cancellous) by high-pressure liquid chromatography. The mean concentration in serum was 2.4 +/- 1.0 micrograms/ml (range, 1.3 to 5.2 micrograms/ml) and was highest after two intravenous doses (3.1 +/- 0.9 micrograms/ml). The mean concentration in cortical bone was 1.0 +/- 0.9 micrograms/g (range, 0.4 to 4.8 micrograms/g) and was highest in patients with osteomyelitis (1.3 +/- 1.6 micrograms/g), but this was not statistically significant. The concentration of enoxacin in cancellous bone was significantly higher than that in cortical bone, with a penetration of 82 versus 40%. Oral enoxacin in practical doses can provide significant levels in bone, and further studies are warranted to determine its therapeutic efficacy in osteomyelitis.