Skin penetration by 2,4-diaminoanisole in the rat

The absorption of sup1sup4C-labelled 2.4-diaminoanisole together with its reaction products was investigated after application to the skin of rats. 2.4-diamino(sup1sup4C)anisole was applied as an ingredient of three different hair-dyeing formulations using procedures approximating to realistic conditions of use. Percutaneous absorption of the compound ranged from 0.26 to 1.1 % of the administered dose, according to the formulation used. Elimination occured mainly in the urine, with a smaller proportion in the faeces. Very small amounts were detected in the expired air. Complementary investigations involving subcutaneous or oral application of a solution of 2.4-diamino(sup1sup4C)anisole. 2HCl showed that radioactivity was rapidly eliminated in the urine and faeces. Biliary excretion was demonstrated after oral administration. (Author)