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Toxicological information

Specific investigations: other studies

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Administrative data

Endpoint:
specific investigations: other studies
Type of information:
experimental study
Adequacy of study:
other information
Study period:
1996
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Although the study per se is reliable (RL2), the result is of unclear relevance with respect to the endpoint respiratory irritation.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1996
Report date:
1996

Materials and methods

Principles of method if other than guideline:
Acute inhalation toxicity test (Alarie-test)
GLP compliance:
not specified
Type of method:
in vivo
Endpoint addressed:
respiratory irritation

Test material

Constituent 1
Chemical structure
Reference substance name:
3,5,5-trimethylhexanoic acid
EC Number:
221-975-0
EC Name:
3,5,5-trimethylhexanoic acid
Cas Number:
3302-10-1
Molecular formula:
C9H18O2
IUPAC Name:
3,5,5-trimethylhexanoic acid
Test material form:
liquid
Details on test material:
Name of test material (as cited in study report): isononanoic acid

Test animals

Species:
mouse
Strain:
Swiss Webster
Sex:
male

Administration / exposure

Route of administration:
inhalation: aerosol
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
gravimetric analysis of mist
Duration of treatment / exposure:
after a control period of 20 min (air): exposure duration 180 min
Frequency of treatment:
single exposure
Post exposure period:
followed by 20 min recovery
Doses / concentrations
Remarks:
Doses / Concentrations:
172-755 mg/m3
Basis:
analytical conc.
No. of animals per sex per dose:
4
Control animals:
other: internal control prior to exposure

Examinations

Examinations:
Measurement of respiration by pressure transducers
A decrease in respiratory frequency could be the effect of
- sensory irritation following stimulation of the N.trigeminus, which led to glottic obstruction and increasing laryngeal resistance, reversibel after 1 h
- irritating effect upon the lung, following stimulation of N. vagus.

Results and discussion

Details on results:
A dose-related decrease in respiratory frequency was observed, based mainly on pulmonary irritation (during 0-3 h, with response plateau at 1 h). Sensory irritation was observed initially and transient.

The RD50 concentration (concentration producing a 50% decrease in repiratory frequency, mainly due to pulmonary irritation) was 420 mg/m³.

Applicant's summary and conclusion

Conclusions:
Under the conditions of this study the test substance produced predominantly pulmonary irritation in mice. The RD50 was 420 mg/m3.
Executive summary:

When male mice were exposed to the test substance for 180 min in varying concentrations, there was a initial, transient sensory irritation. The decrease in respiratory frequency was mainly caused by pulmonary irritation.The RD50 (concentration producing a 50% decrease in respiratory frequency) was 420 mg/m3 (Detwiler-Okabayashi and Schaper, 1996).

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