Nasal irritation and pulmonary toxicity of aliphatic amines in mice

The expiratory bradypnoea indicative of upper airway irritation in mice was evaluated during a 15-min oronasal exposure to increasing concentrations of twenty aliphatic amines. The airborne concentration resulting in a 50% decrease in the respiratory rate of mice (RD50) was calculated for each test compound. Moreover, eight out of the twenty amines were tested for pulmonary toxicity in mice and for the effects of a 120-min exposure on the respiratory rates of non-anaesthetized, tracheally cannulated mice (RD50TC). Both allylamine and diallylamine showed RD50 values of 9 ppm and 4 ppm, respectively, while the RD50 values associated with exposure to saturated amines ranged from 50 to 200 ppm. Among the eight amines tested for both upper airway irritation and pulmonary toxicity, diisopropylamine and di-n-butylamine showed a RD50TC/RD50 ratio of less than 1, indicating that the respiratory toxicity induced by these two amines would be related primarily to pulmonary effects. On the basis of prior predictions proposed for upper airway irritants, tentative standards are given for ten amines. Moreover, it is suggested that the basis of standards for industrial exposure to diisopropylamine and di-n-butylamine should be specified.