DISPOSITION OF IBUPROFEN ENANTIOMERS FOLLOWING THE ORAL-ADMINISTRATION OF A NOVEL CONTROLLED RELEASE FORMULATION TO HEALTHY-VOLUNTEERS

The enantiomeric composition of ibuprofen in plasma has been investigated following the oral administration of the racemic drug in a novel controlled release (CR) formulation to healthy subjects. The plasma concentration-time profiles suggest that drug release from the CR preparation was suitably modified and that the fluctuation between the peaks and troughs observed following a conventional tablet formulation were reduced. The plasma concentrations of (S)-ibuprofen were greater than those of the (R)-enantiomer following either formulation, and the enantiomeric plasma ratio (S/R) was reduced, both in magnitude and variability, following the CR preparation. The proportion of the total area under the plasma concentration-time curves, due to (S)-ibuprofen were slightly reduced following the CR formulation compared to the tablet formulation. The importance of a consideration of stereochemistry in bioequivalence studies of chiral drugs is discussed.