1. In vitro and in vivo metabolism of a novel cannabinoid-1 receptor inverse agonist, taranabant, in rats and monkeys.
- Author
-
Reddy VB, Doss GA, Karanam BV, Samuel K, Lanza TJ Jr, Lin LS, Yu NX, Zhang AS, Raab CE, Stearns RA, and Kumar S
- Subjects
- Amides blood, Amides chemistry, Amides pharmacokinetics, Animals, Antibodies, Monoclonal pharmacology, Body Fluids metabolism, Brain drug effects, Brain metabolism, Female, Haplorhini, Humans, Ketoconazole pharmacology, Magnetic Resonance Spectroscopy, Male, Mass Spectrometry, Microsomes, Liver drug effects, Microsomes, Liver metabolism, Pyridines blood, Pyridines chemistry, Pyridines pharmacokinetics, Radioactivity, Rats, Amides metabolism, Drug Inverse Agonism, Pyridines metabolism, Receptor, Cannabinoid, CB1 agonists, Receptor, Cannabinoid, CB1 antagonists & inhibitors
- Abstract
The metabolism and excretion of taranabant (MK-0364, N-[(1S,2S)-3-(4-chlorophenyl)-2-(3-cyanophenyl)-1-methylpropyl]-2-methyl-2{[5-(trifluoromethyl)pyridine-2-yl]oxy}propanamide), a potent cannabinoid-1 receptor inverse agonist, were evaluated in rats and rhesus monkeys. Following administration of [¹⁴C]taranabant, the majority of the radioactivity was excreted within 72 h. In both rats and rhesus monkeys, taranabant was eliminated primarily via oxidative metabolism, followed by excretion of metabolites into bile. Major pathways of metabolism that were common to rats and rhesus monkeys included hydroxylation at the benzylic carbon adjacent to the cyanophenyl ring to form a biologically active circulating metabolite M1, and oxidation of one of the two geminal methyl groups of taranabant or M1 to the corresponding diastereomeric carboxylic acids. Oxidation of the cyanophenyl ring, followed by conjugation with glutathione or glucuronic acid, was a major pathway of metabolism only in the rat and was not detected in the rhesus monkey. Metabolism profiles of taranabant in liver microsomes in vitro were qualitatively similar in rats, rhesus monkeys and humans and included formation of M1 and oxidation of taranabant or M1 to the corresponding carboxylic acids via oxidation of a geminal methyl group. In human liver microsomes, metabolism of taranabant was mediated primarily by CYP3A4.
- Published
- 2010
- Full Text
- View/download PDF