ABSTRACT
The metabolism and pharmacokinetics of ibuprofen are of considerable interest because of the widespread use of the drug and its stereospecific metabolism. Being an asymmetric molecule it exists as an enantiomeric pair, like the other propionates that are used as non-steroidal anti-inflammatory drugs (NSAIDs). Ibuprofen is generally used as the racemic mixture of the two enantiomers, although S-ibuprofen is now available in some countries. There are several differences in the metabolism and pharmacokinetics of the two enantiomers, but the most significant aspect is the conversion of the R enantiomer to the pharmacologically active S enantiomer. Interactions of R-ibuprofen with lipid metabolism also occur, although significant clinical consequences of such interactions have not been demonstrated. Like aspirin and paracetamol, ibuprofen is administered in large doses, and it has been used as a prototype drug to investigate general principles of drug metabolism. Ibuprofen has also been used as a substrate to develop methods of drug metabolism, examples being the use of nuclear magnetic spectroscopy to study its metabolism (Shieh et al., 1993; Spraul et al., 1993).
