Identification of the metabolites of lesogaberan using linear trap quadrupole orbitrap mass spectrometry and hydrophilic interaction liquid chromatography

Xenobiotica. 2013 May;43(5):461-7. doi: 10.3109/00498254.2012.725486. Epub 2012 Oct 3.


1. In this study, hydrophilic interaction liquid chromatography (HILIC), radiochemical activity monitoring and linear trap quadrupole orbitrap mass spectrometry (MS) and tandem mass spectrometry (MS/MS) were used to identify the metabolites of a highly polar novel γ-aminobutyric acid type-B receptor agonist, lesogaberan, in rats. 2. Urine was collected from three male Wistar rats for 24 h after dosing with (14)C-labelled lesogaberan (170 mg/kg, 10 MBq/kg); plasma samples were taken 2 and 24 h after dosing. Pooled samples were separated by HILIC and eluents were analysed by radiochemical activity monitoring, MS and MS/MS. 3. Only the parent compound was detected in plasma, but six metabolites (M1-M6) were detected in urine. Analysis of MS and MS/MS data and comparison with synthetic reference standards enabled the identification of the structure of each metabolite. M1 was identified as the N-acetylated species [(2R)-3-acetamido-2-fluoropropyl]-phosphinic acid, and M6 as [(2R)-3-amino-2-fluoropropyl]-phosphonic acid. Metabolites M2 and M5 were the alcohol and carboxylic acid species 3-hydroxypropyl-phosphinic acid and 3-hydroxyphosphonoyl-propanoic acid, respectively, both of which had lost the fluorine atom present in the parent compound. M3 was the corresponding carboxylic acid species retaining the fluorine atom, (2R)-2-fluoro-3-hydroxyphosphonoyl-propanoic acid. Finally M4 was identified as [(2R)-2-fluoro-3-guanidino-propyl]-phosphinic acid.

MeSH terms

  • Animals
  • Chromatography, Liquid
  • GABA-A Receptor Agonists / chemistry
  • GABA-A Receptor Agonists / metabolism*
  • Hydrophobic and Hydrophilic Interactions
  • Male
  • Phosphinic Acids / chemistry
  • Phosphinic Acids / metabolism*
  • Propylamines / chemistry
  • Propylamines / metabolism*
  • Rats
  • Rats, Wistar
  • Tandem Mass Spectrometry
  • gamma-Aminobutyric Acid / metabolism


  • GABA-A Receptor Agonists
  • Phosphinic Acids
  • Propylamines
  • lesogaberan
  • gamma-Aminobutyric Acid