3,5,5-trimethylhexanoic acid

Specific investigations: other studies

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

Test material information

Constituent 1

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).