%0 Journal Article %A R J Bopp %A J F Nash %A A S Ridolfo %A E R Shepard %T Stereoselective inversion of (R)-(-)-benoxaprofen to the (S)-(+)-enantiomer in humans. %D 1979 %J Drug Metabolism and Disposition %P 356-359 %V 7 %N 6 %X The enantiomeric composition of benoxaprofen [(RS)-2-(P-chlorophenyl)-alpha-methyl-5-benzoxazoleacetic acid] in plasma and urine was determined after oral administration of both the racemic mixture and the (R)-(-)-enantiomer to normal human volunteers. Resolution of the diastereomeric amides, formed by the reaction of the enantiomers with (S)-(-)-apha-methylbenzylamine, was accomplished by gas chromatography. The (R)-(-1)-enantiomer of the parent drug was stereoselectively inverted to its (S)-(+) isomer in humans. %U https://dmd.aspetjournals.org/content/dmd/7/6/356.full.pdf