Bioactivation Pathways of the Cannabinoid Receptor 1 Antagonist Rimonabant
| Autor: | Claire E. Milne, Emre M. Isin, Neal Castagnoli, Moa Andresen Bergström |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
medicine.medical_treatment
Metabolite Potassium cyanide Pharmaceutical Science Hydroxylamines Hydroxylation chemistry.chemical_compound Cytochrome P-450 Enzyme System Piperidines Receptor Cannabinoid CB1 Rimonabant medicine Animals Cytochrome P-450 CYP3A Cytochrome P-450 Enzyme Inhibitors Humans Potassium Cyanide Biotransformation Pharmacology CYP3A4 Rats chemistry Biochemistry Microsomes Liver Microsome Pyrazoles Cannabinoid Oxidation-Reduction Protein Binding medicine.drug |
| Zdroj: | Drug Metabolism and Disposition. 39:1823-1832 |
| ISSN: | 1521-009X 0090-9556 |
| Popis: | In the present work, the characterization of the biotransformation and bioactivation pathways of the cannabinoid receptor 1 antagonist rimonabant (Acomplia) is described. Rimonabant was approved in Europe in 2006 for the treatment of obesity but was withdrawn in 2008 because of a significant drug-related risk of serious psychiatric disorders. The aim of the present work is to characterize the biotransformation and potential bioactivation pathways of rimonabant in vitro in human and rat liver microsomes. The observation of a major iminium ion metabolite led us to perform reactive metabolite trapping, covalent binding to proteins, and time-dependent inhibition of cytochrome P450 3A4 studies. The major biotransformation pathways were oxidative dehydrogenation of the piperidinyl ring to an iminium ion, hydroxylation of the 3 position of the piperidinyl ring, and cleavage of the amide linkage. In coincubations with potassium cyanide, three cyanide adducts were detected. A high level of covalent binding of rimonabant in human liver microsomes was observed (920 pmol equivalents/mg protein). In coincubations with potassium cyanide and methoxylamine, the covalent binding was reduced by approximately 40 and 30%, respectively, whereas GSH had no significant effect on covalent binding levels. Rimonabant was also found to inhibit cytochrome P450 3A4 irreversibly in a time-dependent manner. In view of these findings, it is noteworthy that, to date, no toxicity findings related to the formation of reactive metabolites from rimonabant have been reported. |
| Databáze: | OpenAIRE |
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