[Diffusion of ceftriaxone in human bone tissue]. / Diffusion de la ceftriaxone dans le tissu osseux humain.

Ceftriaxone diffusion into spongious and cortical bone after single 2 g dose by intravenous injection was studied in 40 patients undergoing total hip replacement. Serum and tissue assays were performed by HPLC and microbiological method 2, 4, 12 and 24 hours after administration. Both methods produced similar results. Antibiotic levels (HPLC) were 19.3 +/- 7.3; 16.9 +/- 9.2; 11.2 +/- 4.7 and 5.6 +/- 2.7 micrograms/g in spongious bone at hours 2, 4, 12 and 24, and 6.5 +/- 1.6; 3.1 +/- 0.7; 3.3 +/- 1.1 and 2.2 +/- 0.4 micrograms/g in cortical bone at the same times. The tissue/serum ratios were 14% for spongious bone and 5% for cortical bone after 2 hours. At hour 24 these ratios were 21% and 8% in spongious and cortical bone respectively. These tissue levels remain higher than ceftriaxone MIC for most Enterobacteriaceae strains until hour 24.

[Penetration of cloxacillin into human bone tissue after oral administration (author's transl)]. / Diffusion de la cloxacilline dans le tissu osseux humain après administration par voie orale.

Cloxacillin diffusion into spongious and cortical bone was studied in 20 patients undergoing total replacement of the hip, after an oral single-dose of 1 g (10 patients) or an oral dose of 1 g every 8 hours (10 patients). Serum and bone samples were collected 2 and 3 hours after the last dose and assayed for antibiotic concentration by a microbiological method. Bone levels were similar in any group of patients, but significantly higher in spongious bone than in cortical bone. The bone/serum concentration ratios were 0.15 for spongious bone and 0.10 for cortical bone. Calculations from these data showed that adequate local levels inhibitory to Staphylococcus aureus, would be achieved by cloxacillin administration of 1 g dose every 4 hours orally.

[Rifampicin diffusion in non-infected human bone (author's transl)]. / Diffusion de la rifampicine dans l'os non infecté chez l'homme.

Rifampicin levels in serum, cortical bone and spongious bone were measured by a biological assay in 13 non-infected patients undergoing total replacement of the hip. Samples were collected after 24-72 hours rifampicin administration (daily oral dose: 600 mg). The mean level was 0.67 +/- 0.48 microgram/g in cortical bone and 3.35 +/- 0.72 microgram/g in spongious bone. Rifampicin diffusion was also assessed in normal bone from crista iliaca needle biopsy specimens in 7 patients treated for osteitis or septic arthritis. Bone and serum levels did not appear linearly correlated but, in any case, bone levels were much higher than MIC for Staphylococcus aureus which is usually involved in bone and joint infections.