Summary
The absorption, disposition, biotransformation and excretion of the nonsteroidal anti-inflammatory drug pirazolac were investigated in 6 volunteers (3 males, 3 females, age 50 > years) after intravenous and oral administration of 50 mg14C- p i r a z o l a c 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 μg/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 t h e dose was excreted with the urine and approximately 15% with the feces within 7 days, indicating a complete excretion of l14C-radioactivity. In urine, approximately 10% of t h e dose was identified as unchanged pirazolac a n d 70% as pirazolac ester glucuronide.
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Tauber, U., Weiss, C., Krause, W. et al. Pharmacokinetics of pirazolac — A new anti-inflammatory drug — in human volunteers I. Absorption, disposition, biotransformation and excretion. European Journal of Drug Metabolism and Pharmacokinetics 10, 41–53 (1985). https://doi.org/10.1007/BF03189696
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DOI: https://doi.org/10.1007/BF03189696