Identifying a Selective Substrate and Inhibitor Pair for the Evaluation of CYP2J2 Activity

• DOI: 10.1124/dmd.111.043505
• Publication Date: 2012-02-11T05:30:06Z
• Authors: Caroline A. Lee; J.P. Jones; Jonathan Katayama; Rüdiger Kaspera; Ying Jiang; Sascha Freiwald; Evan Smith; Gregory S. Walker; Rheem A. Totah
• Keywords: Astemizole; Terfenadine; Epoxygenase; Hydroxylation

CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess CYP2J2 drug metabolism, a selective substrate potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled determination liver relative activity factor intersystem extrapolation CYP2J2. correlated O-demethylation but not protein content sample human microsomes. identify inhibitor, 138 drugs were screened using terfenadine probe substrates recombinant Forty-two inhibited by ≥50% at 30 μM, inhibition was substrate-dependent. Of these, danazol both hydroxylation (IC₅₀ = 77 nM) (<i>K</i>_i 20 nM), mostly competitive. Danazol CYP2C9, CYP2C8, CYP2D6 IC₅₀ values 1.44, 1.95, 2.74 respectively. included seven-probe cocktail cytochrome P450 (P450) drug-interaction screening potential, demonstrated better profile because it did appreciably interact probes. Thus, danazol, amiodarone, will facilitate ability to determine metabolic hepatic extrahepatic tissues.