Metabolic and toxic behavior of phthalimide derivates. I. Fate of imidan in the fetus.

The organophosphate insecticide imidan includes a phthalimide group. Because of the structural relationship to the teratogenic compound thalidomide we have investigated its placental transfer and metabolic fate in rats. Its passage to embryonic tissues could be confirmed. After intraamniotic injection to the first amniotic cavity of the left uteri we could establish a distribution of imidan and 32P compounds throughout the uteri, the concentration depending upon the incubation time and the distances from the place of injection. The half-life of imidan, detected in the exterioized fetuses or in newborns, was 50--70 min. Imidoxon, i.e., the oxidized form of imidan, has a diminished half-life. This fact explicates the presence of imidoxon only in small concentrations after application of imidan.