title: Analysis of trans-2,6-difluoro-4'-(N,N-dimethylamino)stilbene (DFS) in biological samples by liquid chromatography-tandem mass spectrometry: metabolite identification and pharmacokinetics.
abstract: The metabolism of a promising antineoplastic agent, trans-2,6-difluoro-4'-(N,N-dimethylamino)stilbene (DFS), was studied in mouse, rat, and human liver microsomes using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the multiple reaction monitoring-information-dependent acquisition-enhanced product ion scan (MRM-IDA-EPI) method. Ten putative metabolites were identified and the structures of four metabolites were confirmed using authentic standards. Since trans-2,6-difluoro-4'-(N-methylamino)stilbene (DMDFS, M1) was present in all species as metabolite and displayed in vitro growth inhibition superior to DFS, its pharmacokinetic profiles were examined in Sprague-Dawley rats using DFS as a comparator. A reliable LC-MS/MS multiple reaction monitoring (MRM) method was subsequently developed and validated for the simultaneous quantification of both DFS and DMDFS in rat plasma for this purpose. Upon intravenous administration (4 mg/kg), DFS had a moderate clearance (Cl = 62.7 ± 23.2 mL/min/kg), terminal elimination half-life (t 1/2 λZ  = 299 ± 73 min), and mean transit time (MTT = 123 ± 14 min) with demethylation metabolism accounting for about 10 % of its total clearance. DMDFS possessed an intravenous pharmacokinetic profile similar to DFS. During oral dosing (10 mg/kg) where both DFS and DMDFS were absorbed rapidly, the oral bioavailability of DFS was approximately 2-fold greater than that of DMDFS (DFS: F = 42.1 ± 12.8 %; DMDFS: F = 18.7 ± 3.9 %). Interestingly, the DMDFS exposure after oral dosing of DFS (10 mg/kg) was comparable to that after oral administration of DMDFS (10 mg/kg) alone. As DFS displayed potent anticancer activities and excellent pharmacokinetic profiles, it appears to be a favorable candidate for further pharmaceutical development.
authors.affiliation: Department of Pharmacy, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore.
authors.forename: Samuel Chao Ming
authors.initials: SC
authors.lastname: Yeo
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40506-0509, USA.|Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, 40506-0509, USA.
authors.forename: Vitaliy M
authors.initials: VM
authors.lastname: Sviripa
authors.affiliation: Department of Pharmacy, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore.
authors.forename: Meng
authors.initials: M
authors.lastname: Huang
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40506-0509, USA.|Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, 40506-0509, USA.
authors.forename: Liliia
authors.initials: L
authors.lastname: Kril
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40506-0509, USA.|Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, 40506-0509, USA.|Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY, 40536-0093, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Watt
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, 40506-0509, USA.|Lucille Parker Markey Cancer Center, University of Kentucky, Lexington, KY, 40536-0093, USA.
authors.forename: Chunming
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Pharmacy, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore. phalh@nus.edu.sg.
authors.forename: Hai-Shu
authors.initials: HS
authors.lastname: Lin
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013267:Stilbenes / Q000032:analysis* / Q000493:pharmacokinetics*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: C000608453:2,6-difluoro-4'-(N,N-dimethylamino)stilbene; D013267:Stilbenes
keywords: Liquid chromatography-tandem mass spectrometry; Metabolite identification; Pharmacokinetics; trans-2,6-Difluoro-4′-(N,N-dimethylamino)stilbene; trans-2,6-Difluoro-4′-(N-methylamino)stilbene