PT - JOURNAL ARTICLE AU - D R Knapp AU - N H Holcombe AU - S A Krueger AU - P J Privitera TI - Qualitative metabolic fate of phenoxybenzamine in rat, dog, and man. Use of 15N-labeling. DP - 1976 Mar 01 TA - Drug Metabolism and Disposition PG - 164--168 VI - 4 IP - 2 4099 - http://dmd.aspetjournals.org/content/4/2/164.short 4100 - http://dmd.aspetjournals.org/content/4/2/164.full SO - Drug Metab Dispos1976 Mar 01; 4 AB - Administration of an equimolar mixture of unlabeled and 15N-labeled phenoxybenzamine to rats and dogs facilitated identification of urinary metabolites by gas chromatography/chemical-ionization mass spectrometry by virtue of the the conspicuous equal-intensity ion pairs produced. By use of this technique N-benzyl-N-phenoxyisopropylamine (III), N-benzyl-N-(p-hydroxy-phenoxyisopropyl)amine (IV), and 2-benzylamino-1-propanol (VI) were identified as metabolites in rats. Phenoxyisopropylamine (V) as well as III and IV were identified in dogs. Compound IV was identified in humans under clinical treatment with phenoxybenzamine. The metabolites were screened for cardiovascular activity in rats. Compound III had weak alpha-adrenergic blocking activity and V elicited a hypertensive response.