Toxicokinetics of complex mixtures

In an attempt to further define more clearly the problems involved in the toxicokinetics of complex hydrocarbon mixtures, the authors have designed experiments to determine the influence of a variety of dermally applied mixtures on the pharmacokinetics of simultaneously applied marker compounds, i.e., B(a)P, aza B(a)P, and HgCl2. The basic procedure was to apply the complex mixture and radioactive marker to the skin, and at intervals determine the subsequent tissue distribution and excretion of radioactivity. Male BALB/c Bd mice were shaved on the back and sides, and 10 μ1 each of the test mixture and of the radiolabeled marker were applied to the animal's back. No more than 40 μCi were applied to each mouse. Nine treated mice were placed together in a metabolism cage that allowed separate collection of urine and feces. At 1, 6, and 24 h, three mice were sacrificed to obtain tissues which were assayed for radioactivity along with the urine an feces. Organs assayed were liver, kidney, thymus, spleen, testis, brain, and lung. As a first approach to analysis of the distribution data, radioactivity of the seven organs was combined and expressed as a percent of the applied dose as were excretion values. Studies with three markers have been completed - 3HB(a)P, aza 3HB(a)P, and 203HgCl2