Microbial Metabolism. Part 11. 1) Metabolites of Flutamide

The yeast culture, Rhodotorula mucilaginosa (ATCC 20129) transformed flutamide (1) to three metabolites: 4-nitro-3-(trifluoromethyl) aniline (2), 2-methyl-N-[4-amino-3-(trifloromethyl)phenyl]propanamide (3) and N-[4-amino-3-(trifluoromethyl)phenyl]acetamide (4). The structures were established by spectroscopic methods. Flutamide, a nonsteroidal antiandrogen is a commonly used drug to treat advanced prostate cancer, 2) which is one of the leading causes of death in men in the United States. 3) It is absorbed rapidly from the gastrointestinal track of humans and rats after oral administration and undergoes extensive metabolism in the liver 3-5) through hydrolysis, hydroxylation, N-acetylation and nitroreduction to yield several metabolites. 6) The major metabolites detected in plasma are 2-hydroxyflutamide (OH-FLU) and 4-nitro-3-(trifluoromethyl)phenylamine (FLU-1)7) with concentrations higher than that of flutamide. 8) It is suggested that the antiandrogen activity of flutamide is largely associated with its main metabolite, 2-hydroxyflutamide. 6)