Safety evaluation of zinc 2-pyridinethiol 1-oxide in a shampoo formulation

Abstract

Safety evaluation data have been presented for a shampoo formulation containing zinc 2-pyridinethiol 1-oxide at 2% and 10% levels. In addition toxicity studies have been carried out in dogs with a w o emulsion of ZnPT. The dog seems to be the species most susceptible to the effects of the compound itself, but it shows no effects to the shampoo formulation. The Rodentia show paralytic symptoms when the material is ingested in the diet at rather low levels for a period of several weeks. No ocular toxicity is observed in rabbits, rats, or monkeys, but it is observed in the dog. The shampoo containing ZnPT did not produce sensitization or undue irritation of the skin. In addition the effect of the shampoo vehicle on rabbit eyes was not increased by the incorporation of ZnPT. Since the shampoo formulation investigated is emetic and does not penetrate the skin, there would appear to be no hazard associated with its use.