Pharmacokinetics of pirazolac, a new anti-inflammatory drug, in human volunteers. III. Steady state plasma levels.

Seven male, young subjects received twice daily 300 mg of pirazolac (PAA) for one week and twice daily 600 mg PAA for a further week as tablet. Plasma levels of PAA were monitored every day just before dosing and up to 72 hours after the last dose using a specific HPLC-method. During the first week of treatment trough steady state levels of Cssmin = 24 +/- 8 micrograms/ml were reached at day 4. After changing of dose regimen to twice daily 600 mg a new steady was established four days later with Cssmin = 62 +/- 15 micrograms/ml. PAA in the plasma was highly (99.2 +/- 0.8%) bound to plasma proteins. Time course of the decay of PAA levels in the plasma after the last dose was similar to that after a single administration.