Pharmacokinetics of pirazolac--a new anti-inflammatory drug--in human volunteers. I. Absorption, disposition, biotransformation and excretion.
The absorption, disposition, biotransformation and excretion of the nonsteroidal anti-inflammatory drug pirazolac were investigated in 6 volunteers (3 males, 3 females, age 50 greater than years) after intravenous and oral administration of 50 mg 14C-pirazolac as an aqueous solution of the sodium salt. Pirazolac was very rapidly and completely absorbed and bioavailable when orally administered in a dose of 50 mg in solution. Maximum pirazolac levels in plasma of 6 micrograms/ml (30% of dose in total plasma volume) were already reached after approx. 20 minutes. No metabolites were detectable in the plasma. Pirazolac was eliminated from the plasma in two phases with half-lives of 3 hours and 16 hours, respectively, regardless of administration route. After intravenous and oral administration approximately 80% of the dose was excreted with the urine and approximately 15% with the feces within 7 days, indicating a complete excretion of 14C-radioactivity. In urine, approximately 10% of the dose was identified as unchanged pirazolac and 70% as pirazolac ester glucuronide.
D000284:Administration, Oral; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000097:blood / Q000378:metabolism* / Q000652:urine; D001711:Biotransformation; D005260:Female; D005965:Glucuronates / Q000378:metabolism; D006801:Humans; D007275:Injections, Intravenous; D007408:Intestinal Absorption; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D011720:Pyrazoles / Q000097:blood / Q000378:metabolism* / Q000652:urine; D014018:Tissue Distribution
D000893:Anti-Inflammatory Agents; D005965:Glucuronates; D011720:Pyrazoles; C046317:pirazolac