Registration Dossier

Diss Factsheets

Toxicological information

Acute Toxicity: inhalation

Currently viewing:

Administrative data

acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2007-11-07 - 2008-05-28
1 (reliable without restriction)

Data source

Materials and methods

Test guideline
according to guideline
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
yes (incl. QA statement)
Federal State Authority, North Rhine-Westphalia, Germany
Test type:
standard acute method
Limit test:

Test animals


Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
clean air
Analytical verification of test atmosphere concentrations:
CaTG aerosol sampled by gravimetric analysis was eluted from the filter and then determined by HPLC.
Duration of exposure:
4 h
Four groups of rats were nose-only exposed to a solid aerosol in concentrations of 483, 1022, 2208, and 2729 mg/m3 air.
No. of animals per sex per dose:
Control animals:

Results and discussion

Effect levelsopen allclose all
Dose descriptor:
Effect level:
> 2 729 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Dose descriptor:
Effect level:
483 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Mortality did not occur in any concentration-dependent manner. The particle size distribution was not essentially different between groups with mortality. The LC50 was greater than 2729 mg/m3. No animals died at 483 mg/L (0/10 animals, 4 h exposure).
Clinical signs:
other: The signs of importance for the toxicological evaluation of the highest dose group can be qualitatively described as follows: bradypnea, labored breathing patterns, stridor, motility reduced, flaccidity, piloerection, hair-coat ungroomed, nose reddened, a
Body weight:
Comparison between control and exposure groups revealed consitent, concentration-dependent decrease in body weights.
Gross pathology:
Findings of toxicological importance and for toxicological evaluation can be summarized as follows:
Animals sacrificed at the end of the observation period: The macroscopic findings were essentially indistinguishable amongst exposure and control groups.
Animals succumbing during the observation period: nose-/muzzle area: red encrustations with somewhat occlude nostrils, trachea with white foamy content, lung less collapsed and with dark-red discolorations, gastrointestinal tract: black-red focal discolorations of mucosa and dark-red content in the lumen.
Other findings:
Statistical comparisons between the control and the exposure groups revealed significant changes in body temperature in groups 3 and above.

Applicant's summary and conclusion

Interpretation of results:
moderately toxic
Migrated information Criteria used for interpretation of results: OECD GHS
The aerosolized CaTG (solid aerosol, dry powder) proved to have a low acute inhalation toxicity in rats. Thus, the LC50 is greater than 2729 mg/m3. However, the observed signs demonstrated that the respirable dust of this test substance (in its micronized form) may cause marked and prolonged respiratory tract irritation.
Executive summary:

A study on the acute inhalation toxicity of CaTG on rats has been conducted in accordance with OECD Guideline No. 403. Mortality occurred in a few rats at 1022 mg/m3and above. However, any concentration-dependence or particular sex-dependence was not observed. The maximum technically achievable concentration was 2729 mg/m3. The exposure to this exposure level caused lingering and pronounced irritant effects in the upper and lower respiratory tract. Mortality is considered to be linked to acute lung edema. Due to the absence of concentration-dependent changes in particle size, the LC50is greater than the maximum technically attainable concentration. Due to technical aspects as well as animal welfare considerations, the testing of CaTG at around 3000 mg/m3is considered to meet the criteria of limit-test of contemporary testing guidelines.