CHARACTERIZATION OF METABOLITES OF DELTA(8,9)-DEHYDROESTRONE IN DOGS

Delta(8,9)-Dehydroestrone is the fifth most abundant component in the conjugated equine estrogen preparation Premarin(R), representing about 2 to 6% of the total steroids in the tablet. The metabolism of this e strogen has been determined in female beagle dogs after acute peroral administration. 17 beta-Dihydro-Delta(8,9)-dehydroestrone(17 beta-Delt a(8,9)-dehydroestradiol) and 17 alpha-dihydro-Delta(8,9)-dehydroestron e(17 alpha-Delta(8,9)-dehydroestradiol) have been identified as the ma jor metabolites in plasma and urine. These metabolites, along with the unchanged drug, were isolated and purified by ether extraction and th in-layer chromatography of the urine samples after enzyme hydrolysis. The trimethylsilyl ether derivatives of the isolated metabolites were characterized by comparison of their mass spectra and chromatographic properties with those of synthetic reference standards.