Concentrations of ofloxacin in human bone and in cartilage.

Concentrations of ofloxacin were determined in bone, cartilage and serum of 23 patients (8 male, 15 female; age 29-85 years) who underwent total hip replacement for osteoarthritis. A single dose of 200 mg ofloxacin was infused over a period of 20 min. Blood specimens (total 89), bone (45), and cartilage specimens were taken up to 720 min after the infusion. Ofloxacin was determined by high performance liquid chromatography. Bone was extracted with buffer three times to obtain a complete extraction. An average bone density of 1.9 kg/l was assumed in order to convert concentrations from mg/kg to mg/l bone. Mean serum concentrations decreased from 7.2 +/- 2.6 (0 min) to 0.5 +/- 0.1 (720 min). Mean tissue concentrations (mg/l) at 98, 246 and 716 min after the end of infusion were, in cortical bone 0.64 +/- 0.29, 0.86 +/- 0.55 and 0.59 +/- 0.14; in cancellous bone, 1.70 +/- 0.72, 1.47 +/- 1.00 and 0.99 +/- 0.43, and in cartilage 1.38 +/- 1.05; 2.19 +/- 1.56 and 2.18 +/- 0.45. The half-life of ofloxacin in tissues was longer than in serum. No side effects were observed.