[Kinetics of mofebutazone in plasma and synovial fluid]

The kinetics of mofebutazone in the plasma and in the synovial fluid was investigated in a pharmacokinetic study. To this purpose 7 volunteers and 36 patients were injected with one ampule Mofesal (650 mg mofebutazone sodium) i.m. The determination of mofebutazone in the plasma and in the synovial fluid was carried out by means of high performance liquid chromatography. The kinetics in the plasma and in the synovial fluid showed a dissociated course of development. Maximum concentrations of the active substance were reached after 1.4h in the plasma and after approx. 2 h in the synovial fluid. While mofebutazone in the plasma is eliminated with a half life time of 1.9 h, the half life time in the synovial fluid amounted to 7.7 h. According to pharmacokinetic simulation calculations no accumulation in the plasma occurred even after the administration of 1 ampule Mofesal three times daily, on the other hand a steady state is presumably reached in the synovia after 4-5 injections. On the basis of this study we regard it once again as essential that the kinetics in the synovial fluid should without doubt be preferred to the kinetics in the plasma for the calculation of a dosage schedule for non-steroidal antiphlogistics.