Toxicology of benzalkonium chloride given orally in milk or water to rats and dogs

Abstract

Benzalkonium chloride was well tolerated by male albino rats when administered orally in single daily doses of 50.0 mg/kg in milk or water for 12 weeks, or to beagle dogs in doses of 12.5 mg/kg in milk or water for one year. Slight depression of body weight gain was observed in rats given 100.0 mg/kg in water, but no depression occurred at the same dose in milk. No gross or histologic changes were observed in the tissues of these rats. Several dogs died that were medicated at 25.0 or 50.0 mg/kg in water, whereas none died when the milk vehicle was used. Conditioned salivation, vomiting, and enteritis were frequently observed in the dogs. The severity of these signs was directly related to the dosage and was more intense with the water than with the milk vehicle. The data from this presentation and those of Fitzhugh and Nelson (1948) and Alfredson et al. (1951) indicate that benzalkonium chloride was well tolerated at dose levels much higher than the recommended sanitary use concentrations of benzalkonium chloride when the data are compared on a calculated dose for dose basis (dietary vs. stomach tube).