Tissue Distribution, Metabolism, and Excretion of 2,4,4'-Trichlorobiphenyl (Cb-28) in the Rat

The tissue distribution, metabolism, and excretion of 14C-labeled 2,4,4' trichlorobiphenyl (CB-28) were studied in the rat. Following intravenous administration, radioactivity was removed from the blood rapidly and distributed to tissues. The time-courses of varying concentrations of CB-28 in tissues and blood were described mathematically using nonlinear regression analysis. The highest concentrations of radioactivity were found in the adipose and skin, which showed distinct uptake phases. High levels were seen at 30 minutes in liver and brain, but quickly declined. Fifty-two percent of the given dose was excreted in feces within 14 days. Intraperitoneal administration to three female rats for five consecutive days provided tissues which were analyzed for metabolites.