title: High-resolution mass spectrometric investigation of the phase I and II metabolites of finasteride in pig plasma, urine and bile.
abstract: 1. The metabolite profile of the 5α-reductase type II inhibitor finasteride has been studied in pig plasma, urine and bile using high-resolution mass spectrometry. The porcine biotransformation products were compared to those formed by human liver microsomes and to literature data of recently identified human in vivo metabolites. The objective of this study was to gain further evidence for the validity of using pigs for advanced, invasive drug-drug interaction studies that are not possible to perform in humans. 2. The use of high-resolution mass spectrometry with accurate mass measurements enabled identification of the metabolites by calculation of their elemental compositions as well as their fragmentation patterns. 3. There was an excellent match between the porcine and human metabolic profiles, corroborating the pig as a model of human drug metabolism. The glucuronides of the two recently described human hydroxylated metabolites MX and MY and the carboxylated metabolite M3 were identified as the major biotransformation products of finasteride in pig urine and bile. 4. Furthermore, the CYP enzymes involved in the formation of the hydroxylated metabolites were characterized. Human recombinant CYP3A4 could produce the two major hydroxylated metabolites MX and MY, whereas human recombinant CYP2D6 formed MY only.
authors: Department of Pharmacy, Uppsala University , Uppsala , Sweden .
authors: Anna
authors: A
authors: Lundahl
authors: Annica
authors: A
authors: Tevell Åberg
authors: Ulf
authors: U
authors: Bondesson
authors: Hans
authors: H
authors: Lennernäs
authors: Mikael
authors: M
authors: Hedeland
mesh_terms: D000818:Animals; D001646:Bile; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D018120:Finasteride / Q000032:analysis* / Q000097:blood / Q000378:metabolism* / Q000652:urine; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D050216:Metabolic Detoxication, Phase I; D050217:Metabolic Detoxication, Phase II; D008862:Microsomes, Liver / Q000378:metabolism; D008970:Molecular Weight; D012015:Reference Standards; D034421:Sus scrofa / Q000097:blood* / Q000652:urine*
chemical_list: D018120:Finasteride; D003577:Cytochrome P-450 Enzyme System