title: Identification of the metabolites of lesogaberan using linear trap quadrupole orbitrap mass spectrometry and hydrophilic interaction liquid chromatography.
abstract: 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.
authors.affiliation: AstraZeneca R&D, Mölndal, Sweden. Anja.Ekdahl@astrazeneca.com
authors.forename: Anja
authors.initials: A
authors.lastname: Ekdahl
authors.forename: Ann
authors.initials: A
authors.lastname: Aurell-Holmberg
authors.forename: Neal
authors.initials: N
authors.lastname: Castagnoli
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D058785:GABA-A Receptor Agonists / Q000737:chemistry / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D010721:Phosphinic Acids / Q000737:chemistry / Q000378:metabolism*; D011437:Propylamines / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D058785:GABA-A Receptor Agonists; D010721:Phosphinic Acids; D011437:Propylamines; C545087:lesogaberan; D005680:gamma-Aminobutyric Acid