[Diffusion of roxithromycin in gingival tissue].

The gingival penetration of roxithromycin was evaluated at steady-state in twenty nine patients treated by 150 mg orally every 12 h during five days. Tissue specimen were sampled at 2 h (n = 6), 4 h (n = 6), 6 h (n = 5), 8 h (n = 6) and 12 h (n = 6) after the 10th administration. One blood sample was drawn at the same times. Serum and tissue concentrations of roxithromycin were measured by high performance liquid chromatography (HPLC). Serum peak level, measured at the 4th h, reached 6.60 +/- 1.15 micrograms/ml. The tissue peak concentration was 4.63 +/- 1.84 micrograms/g at the 8th h. Between the 4th and 10th hour after administration, the tissue concentrations are above 2 micrograms/g, i.e. above roxithromycin MIC 90 against most of the encountered pathogens in stomatologic infections.