Metabolism of the alpha-1A-adrenergic receptor antagonist, pyridine-phenylpiperazine analog (RWJ-69597), in rat, dog and human hepatic S9 fractions -API-MS/MS identification of metabolites.
The In vitro metabolism of the alpha-1A-adrenergic antagonist, RWJ-69597, an analog of pyridine-phenylpiperazines, was conducted after incubation with rat, dog and human hepatic S9 fractions in the presence of an NADPH-generating system. Unchanged RWJ-69597 (> or =43% of the sample in all species) plus 9 metabolites were profiled, quantified, and tentatively identified on the basis of API-MS and MS/MS data. The four metabolic pathways for the formation of RWJ-69597 metabolites are: 1. methyl/phenyl/piperazinylhydroxylation, 2. N/Odealkylation, 3. N-dephenylation, and 4. dehydration. Pathway 1 formed 1 major (8-36%) and 3 minor (<1-3%) hydroxylated metabolites. Pathway 2 produced 2 moderate/minor N/O-dealkylated metabolites (<1- < or =11%), and in conjunction with pathway 1, formed 1 minor diol metabolites (< or =2%). Pathways 3 and 4 generated 2 minor metabolites, N-desphenyl RWJ-69597 (< or =4%) and dehydrated RWJ-69597 (< or =2%), respectively. RWJ-69597 is more extensively metabolized in the rat than the dog or the human in this hepatic system.
Wu
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Johnson & Johnson Pharmaceutical Research & Development, L.L.C., Spring House, PA, USA.
McKown
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Kuo
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D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000378:metabolism*; D000818:Animals; D004285:Dogs; D006801:Humans; D013058:Mass Spectrometry; D008862:Microsomes, Liver / Q000378:metabolism*; D010879:Piperazines / Q000378:metabolism*; D011725:Pyridines / Q000378:metabolism*; D051381:Rats
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D011725:Pyridines; C504277:RWJ-69597