Acute and short-term toxicity studies on p-aminodiphenylamine.

p- Aminodiphenylamine (p-ADPA), an aromatic amine of wide industrial applications, also finds human exposure through hair dye preparations or via ingestion of a common food colouring metanil yellow. Acute and short-term toxicity studies in albino rats have been done following the biochemical markers, hematology and tissue histopathology. The acute LD50 value of p-ADPA is 0.847 g/kg body weight which qualifies for the 'moderately toxic' category. In short-term studies, animals were fed p-ADPA, mixed in routine laboratory diet at the concentrations of 0.0 (control), 0.1, 0.25, 0.5 and 0.75% (w/w), daily for 90 days. Feed intake and body weight gain in the highest dosed group were reduced. Hematological examinations exhibited moderate anemic conditions with decreased red blood cells, increased erythrocyte sedimentation rate and lowered packed cell volume suggesting normocytic normochromic anemia at 0.25% onward levels of p-ADPA intake. There was significant increase in the activities of acid/alkaline phosphatases and GOT/GPT in serum with simultaneous depletion from liver at the levels of 0.5 and 0.75% p-ADPA intake, suggesting biochemical lesions of the liver. Testicular LDH and hyaluronidase were lowered at 0.5 and 0.75% levels indicating partial arrest of spermatogenesis. These findings were supported histopathologically. The study warrants careful consideration on its exposure, industrially or through common food color or hair dye preparations.