High-performance liquid chromatography coupled to high-field proton nuclear magnetic resonance spectroscopy: application to the urinary metabolites of ibuprofen.

The use of coupled reversed-phase high-performance liquid chromatography and high-field proton nuclear magnetic resonance spectroscopy (HPLC-NMR) for the detection and identification of the urinary metabolites of ibuprofen is described. Urine was obtained from a healthy human volunteer following a normal therapeutic dose of 400 mg of ibuprofen. Analysis was performed on both a freeze-dried urine concentrate and partially purified extracts obtained by solid-phase extraction onto C-18 bonded silica gel. Both continuous and stop-flow methods were used to obtain spectra enabling the major urinary metabolites of ibuprofen to be detected and identified.