title: Identification in man of urinary metabolites of a new bronchodilator, MDL 257, using triple stage quadrupole mass spectrometry-mass spectrometry.
abstract: The structure elucidation of drug metabolites directly from urine by tandem mass spectrometry (MS/MS) for a new bronchodilator is described. When urine samples from human subjects dosed with 400 mg of MDL 257 were examined by MS/MS, three major urinary metabolites previously characterized in animal studies were confirmed and two previously unsuspected metabolites were identified. Using the operational modes of a triple stage quadrupole mass spectrometer, it is possible both to detect and to identify possible metabolites. Since the pure drug and its metabolites often contain common structural daughter ions, the parent spectra of these common daughter ions should contain some or all of the molecular ions of possible metabolites. Daughter spectra of these suspected molecular ions were obtained and the resulting daughter spectra were interpreted for structural information of suspected metabolites. This study confirms the utility of MS/MS to do rapid metabolic profiling and identification directly from complex samples such as urine, with minimal time for sample preparation and analysis. This technique can provide unique and complimentary data when combined with the more classical approaches such as HPLC profiling, isolation, and off-line spectroscopy.
mesh_terms: D000328:Adult; D001993:Bronchodilator Agents / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry; D011724:Pyridazines / Q000652:urine*
chemical_list: D001993:Bronchodilator Agents; D007202:Indicators and Reagents; D011724:Pyridazines; C053632:zindotrine