Kinetics of spiramycin/metronidazole (Rodogyl) in human gingival crevicular fluid, saliva and blood.

The peripheral distribution of spiramycin and metronidazole, which are combined in the proprietary drug "Rodogyl", has been studied in gingival fluid, saliva and blood after a single administration to 12 healthy volunteers and after repeated administration to 4 patients with recurring severe periodontitis. Analysis of the 2 antibiotics have been performed at regular intervals during the 24-h period immediately following the administration to the volunteers and after the 1st and the 15th days of repeated administration to the patients. The results show that gingival fluid contains concentrations of spiramycin and metronidazole higher than those needed to inhibit the growth of periodontopathic bacteria. Spiramycin was found at higher concentrations in GCF than in blood, although this feature was not found for metronidazole, which was administered simultaneously and showed similar concentrations in both fluid and serum. Such high concentrations persist for a long time, and suggest the potential of this compound in the treatment of severe cases of periodontitis.