Biotransformation of the partial beta-agonist doxaminol in dog

The biotransformation of the positive inotropic compound doxaminol (N-methyl-N-(2-hydroxy-3-phenoxy-propyl)-11-(2-amino-ethyl)-6,11- dihydrodibenz[b,e]oxepine, neutral fumarate; BM 10.188) was examined in bastard shepherd dogs. Metabolic products, formed by oxidative cleavage of various side chain carbon atoms of the molecule, as well as conjugated complexes with glucuronic and sulfuric acid, were isolated from urine and plasma. As main metabolites 2-hydroxy-3-phenoxy-propionic acid and phenoxyacetic acid were formed. By means of 1HNMR and 13C-NMR spectroscopy and various mass spectroscopic methods, the chemical structures of the metabolites were elucidated.