title: Measurement of dexfenfluramine metabolism in rat liver microsomes by gas chromatography-mass spectrometry.
abstract: A specific and useful method was developed for the determination of dexfenfluramine metabolism by microsomal systems utilising GC-MS. The synthesis of two metabolites 1-(3-trifluoromethylphenyl)propan-2-ol ('alcohol') and 1-(3-trifluoromethylphenyl)-1,2-propanediol ('diol') via straightforward routes, were confirmed by MS and NMR spectra. The conditions for extraction from alkalinised microsomal mixtures of the metabolites nordexfenfluramine, 1-(3-trifluoromethylphenyl)propan-2-one ('ketone'), alcohol and diol, their conversion to trifluoroacetate derivatives and analysis by GC-MS-SIM are described. Calibration curves were constructed between 48 and 9662 nM and fitted to quadratic equations (r2>0.999). The method precision was good over low (121 nM) medium (2415 nM) and above medium (9662 nM) concentrations for all metabolites; the within- and day-to-day coefficients of variation ranged between 2.5-12.4% and 6.7-17.5%, respectively. The accuracy, measured as bias, was very good both within- and day-to-day (range: -0.4-12.6%, 0.8-18.9%). For most metabolites, the C.V. for the assay and bias increased at 121 nM. Dexfenfluramine metabolism by rat liver microsomes was investigated using the assay method and showed a concentration dependent increase in nordexfenfluramine and ketone metabolites over the substrate range of 5-200 microM.
authors.affiliation: Key Centre for Applied and Nutritional Toxicology, RMIT-University, Melbourne, Victoria, Australia.
authors.forename: V S
authors.initials: VS
authors.lastname: Haritos
authors.forename: M S
authors.initials: MS
authors.lastname: Ching
authors.forename: H
authors.initials: H
authors.lastname: Ghabrial
authors.forename: J T
authors.initials: JT
authors.lastname: Ahokas
mesh_terms: D000818:Animals; D001067:Appetite Depressants / Q000032:analysis / Q000378:metabolism*; D005277:Fenfluramine / Q000031:analogs & derivatives / Q000032:analysis / Q000138:chemical synthesis / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001067:Appetite Depressants; C037763:1-(3-trifluoromethylphenyl)-1,2-propanediol; D005277:Fenfluramine; C037762:1-(3-trifluoromethylphenyl)-2-propanol