Ketoprofen is a non-selective, non-steroidal, anti-inflammatory drug exhibiting IC50 values of 0.5 and 2.33 μM for human recombinant COX-1 and COX-2 , respectively. Ketoprofen is commonly used in vivo as a racemic mixture of (R)- and (S)-enantiomers. (S)-Ketoprofen is a potent inhibitor of COX-1 and COX-2 (IC50s = 1.9 and 27 nM, respectively), whereas the (R)-enantiomer is 100 to 1,000 times less potent. Notably, (S)-ketoprofen is known to be formed from the (R)-enantiomer in several animal species, except in humans and guinea pigs. Also, the pharmacokinetics of ketoprofen enantiomers and their glucuronide metabolites are altered in humans with rheumatoid arthritis or renal disease.
