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Inhalation toxicity of tetramethylurea in rats
A J O'Neill1, J F Hansen, G S Elliott
1E. I. du Pont de Nemours and Company, Inc., Haskell Laboratory for Toxicology and Industrial Medicine, 1090 Elkton Road, Newark, DE 19714, USA.
Drug and Chemical Toxicology
|October 23, 2001
Summary
Tetramethylurea (TMU) inhalation in rats showed no adverse effects at 20 ppm. Higher concentrations (100 ppm) caused nasal tissue damage, indicating TMU
Area of Science:
- Toxicology
- Inhalation Toxicology
- Occupational Health
Background:
- Tetramethylurea (TMU) is a chemical compound with CAS No. 632-22-4.
- Understanding TMU's toxicity is crucial for occupational safety and risk assessment.
Purpose of the Study:
- To evaluate the inhalation toxicity of Tetramethylurea (TMU) in male rats.
- To determine the no-observed-adverse-effect level (NOAEL) for TMU following repeated exposures.
Main Methods:
- Male rats were exposed whole-body to TMU (0, 2, 20, 100 ppm) for 6 hours/day, 5 days/week over 2 weeks (9 exposures total).
- Clinical signs, body weight, clinical pathology, and tissue pathology were assessed immediately after exposure and after an 18-day recovery period.
Main Results:
- Reduced body weight gain was observed in rats exposed to 100 ppm TMU.
- Microscopic examination revealed degeneration, necrosis, and ulceration of olfactory mucosa in the 100 ppm group, which showed signs of healing during the recovery period.
- No significant clinical signs or clinical pathology changes were noted at any exposure level.
Conclusions:
- The no-observed-adverse-effect level (NOAEL) for TMU inhalation in rats was determined to be 20 ppm.
- TMU exposure at 100 ppm can cause reversible damage to the upper respiratory tract, specifically the olfactory mucosa.