title: Characterization of verlukast metabolites arising from an epoxide intermediate produced with hepatic microsomes from beta-naphthoflavone-treated rodents (P-4501A1).
abstract: Verlukast, (R)3-((((3-(2-(7-chloroquinolin-2-yl)-(E)-ethenyl)phenyl)-3- dimethylamino-3-oxopropylthio)methyl)thio)-propionic acid (also known as MK-0679 and L-668,019), is a potent leukotriene D4 antagonist. Verlukast was incubated with hepatic microsomes from beta-naphthoflavone (beta NF) or isosafrole-treated rodents to evaluate whether P-4501A1 or 1A2 mediated biotransformations could occur. With beta NF-induced mouse or rat microsomes, in which the induction of P-4501A1 had been proven by Western blot analysis, incubations produced new metabolites that were separated by reversed-phase HPLC and were initially characterized by UV (photodiode array). Metabolites were subsequently isolated and characterized by NMR and MS, and were assigned as the 5",6"-dihydrodiol and 6"-phenol (on the quinoline ring). The presumed 5",6"-epoxide intermediate was also detected and was characterized by UV (photodiode array) and MS. Microsomes from isosafrole-treated rodents produced the dihydrodiol to a much lesser extent and did not yield any other new metabolites. alpha-Naphthoflavone inhibited the dihydrodiol formation in incubations with microsomes from isosafrole- and beta NF-treated rats. In incubations with microsomes from beta NF-treated rats, to which the epoxide hydrolase inhibitor 3,3,3-trichloropropene 1,2-oxide had been added, the formation of dihydrodiol was inhibited, consistent with a microsomal epoxide hydrolase hydrolysis of the epoxide intermediate. When glutathione was added to incubations with microsomes from beta NF-treated rats, the dihydrodiol, phenol, and epoxide peaks were reduced in size and a new material, the glutathione adduct, was formed.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicinal Chemistry, Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Quebec, Canada.
authors.forename: D A
authors.initials: DA
authors.lastname: Nicoll-Griffith
authors.forename: N
authors.initials: N
authors.lastname: Chauret
authors.forename: J A
authors.initials: JA
authors.lastname: Yergey
authors.forename: L A
authors.initials: LA
authors.lastname: Trimble
authors.forename: L
authors.initials: L
authors.lastname: Favreau
authors.forename: R
authors.initials: R
authors.lastname: Zamboni
authors.forename: S J
authors.initials: SJ
authors.lastname: Grossman
authors.forename: J
authors.initials: J
authors.lastname: Drey
authors.forename: E
authors.initials: E
authors.lastname: Herold
mesh_terms: D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology*; D001711:Biotransformation; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D005978:Glutathione / Q000494:pharmacology; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism / Q000493:pharmacokinetics*; D011804:Quinolines / Q000378:metabolism / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors; D019324:beta-Naphthoflavone
chemical_list: D001571:Benzoflavones; D004852:Epoxy Compounds; D011422:Propionates; D011804:Quinolines; D011971:Receptors, Immunologic; C059141:verlukast; D019324:beta-Naphthoflavone; D003577:Cytochrome P-450 Enzyme System; D005978:Glutathione