The d-tertiary hydroxy metabolite, which was isolated from rat urine after oral administration of 3, 3, 3-d3-l-2-(2-isopropylindan-5-yl) propionic acid (IIPA), was confirmed to retain the intact CD3 group on the basis of the MS and NMR spectral analyses. This finding is not compatible with the exomethylene intermediate mechanism proposed for the same epimerization reaction of 2-(4-isobutylphenyl) propionic acid (ibuprofen) in human.
