The Pharmacokinetics of Ibuprofen in Humans and Animals

The pharmacokinetic properties of ibuprofen have been studied intensely. It was the first 2-arylpropionic acid (2-APA) non-stereoidal anti-inflammatory drug (NSAID) developed and marketed for treatment of arthritic disorders, and in many countries it has been granted non-prescription status for treatment of pain and fever. Most oral formulations of ibuprofen display almost complete systemic bioavailability, regardless of their rate of absorption. Similarly to other NSAIDs, ibuprofen displays extensive (99%) binding to plasma proteins. Non-linear pharmacokinetics have been reported for ibuprofen and have been attributed to saturation of plasma protein binding. Ibuprofen is extensively metabolized in humans to pharmacologically inactive metabolites. Chiral inversion of ibuprofen occurs in many species and, with the exception of one study, the inversion process has mostly been observed to occur in a unidirectional manner from the R to the S enantiomer. Many studies have examined interactions between ibuprofen and other drugs.