Sensory irritation, pulmonary irritation, and acute lethality of a polymeric isocyanate and sensory irritation of 2,6-toluene diisocyanate.
Weyel-DA; Rodney-BS; Alarie-Y
Toxicol Appl Pharmacol 1982 Jul; 64(3):423-430
The sensory irritation, pulmonary irritation, and acute lethality of a polymeric isocyanate (DES-N) and 2,6-toluene-diisocyanate (91087) (26TDI) were studied in mice. DES-N was based on hexamethylene- diisocyanate (822060) (HDI). Male Swiss-Webster-mice were exposed to 0 to 131 milligrams per cubic meter (mg/m3) DES-N for 3 hours by inhalation or tracheal instillation and the effects on respiration rate were monitored. Chamber air samples were collected and analyzed for HDI. Mice were exposed to DES-N for 4 hours and mortality was recorded. The lungs were removed from some animals 2, 4, or 24 hours after exposure and weighed. Mice were exposed to 0 to 7.6mg/m3 26TDI vapor and the effect on respiratory rate were monitored. Mice exposed to 25 to 131mg/m3 DES-N showed a progressive decrease in respiration rate, the concentration necessary for reducing the respiration rate by 50 percent (RD50) being 57.1mg/m3. In mice exposed by tracheal instillation, no effect on respiration rate was seen until 60 to 120 minutes after exposure started. This indicated that the effect of DES-N on respiration rate was primarily irritative in nature affecting both the upper and lower respiratory tract. The median lethal concentration of DES-N was 91.2mg/m3. The DES-N concentration required to increase lung weight by 50 percent was 45mg/m3. HDI was detected in all chamber air samples. Its mean concentration was consistently 0.35 percent for DES-N concentrations of 25 to 131mg/m3. 26TDI decreased the respiration rate, the RD50 being 1.8mg/m3. The primary mechanism for this action was sensory irritation rather than pulmonary irritation. The authors conclude that DES-N decreases respiratory rate primarily as a result of pulmonary irritation. The threshold limit value for 26TDI should be set equal to that for 2,4-toluene-diisocyanate, 0.04mg/m3.
NIOSH-Publication; NIOSH-Grant; Pulmonary-system-disorders; Isocyanates; Laboratory-animals; In-vivo-studies; Inhalation-studies; Dose-response; Physiological-response; Mortality-rates
Occupational Health University of Pittsburgh 130 DE Soto Street Pittsburgh, PA 15213
Toxicology and Applied Pharmacology
University of Pittsburgh, Pittsburgh, Pennsylvania