Biological conversion of N-phenyl-2-naphthylamine to 2-naphthylamine in the Sprague-Dawley rat

The metabolism of a widely used plastic and rubber antioxidant, N-Phenyl-2-Naphthylamine, was investigated in Sprague-Dawley rats. After repeated oral administration of this compound, urine and feces were collected for several days and analyzed for the presence of metabolites. Identification techniques included a preliminary clean-up followed by thin-layer chromatography of amines and gas chromatography-mass spectrometry of their hexafluoroacyl derivatives (HFBA). The compounds identified in both urine and feces were characterized as N-Phenyl-2-Naphthylamine (PBNA) and 2-Naphthylamine (BNA). Data obtained on urinary excretion of BNA seem to indicate that repeated administration of PBNA enhances its own metabolism.