SECNIDAZOLE CONCENTRATIONS IN PLASMA AND CREVICULAR FLUID AFTER A SINGLE ORAL DOSE

Metronidazole and related nitroimidazole derivatives, including ornida zole and tinidazole, have been used successfully in the treatment of p eriodontal diseases. The purpose of this study was to measure secnidaz ole (another nitroimidazole derivative) concentrations in plasma and g ingival crevicular fluid (GCF) after intake of a single oral dose. Sec nidazole concentrations were estimated in 11 human healthy volunteers after a single dose of 2 g taken orally. Samples of blood and GCF were collected before intake and during the following 72 h. A high-perform ance liquid chromatography (HPLC) method has been developed for the de termination of secnidazole in microsamples (1 to 3 mul) of GCF. The me an peak blood and GCF levels were equal to 40.5 +/- 9.4 mug ml-1 at 2 h in blood and 26.4 +/- 7.0 mug ml-1 at 1 h in GCF, respectively. Appa rent elimination half-life was 28.8 h (blood) and 30.4 h (GCF), respec tively. These results show that the rate and extent-absorption of secn idazole are slightly higher in blood than in GCF, but the elimination of the drug is similar in the two body fluids.