Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
GLP compliance:
not specified
Test type:
standard acute method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): iso-butyl-t-butylether.
- Physical state: clear, colourless liquid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Labaz, Brussels, Belgium
- Weight at study initiation: mean ca. 200 g (males and females)
- Housing: 5/cage in stainless steel cages
- Diet (e.g. ad libitum): Institute's stock diet for rats; ad libitum
- Water (e.g. ad libitum): bottled unfluoridated water; ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 23
- Humidity (%): 50 - 60

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
other: unchanged (no vehicle)
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: glass cylinders (0.90 x 0.15 m) with sampling ports at both ends, and a stainless steel interior
- Source and rate of air: filtered, compressor generated main airflow, 6 l/min
- System of generating particulates/aerosols: by passing a filtered compressor generated airflow through a glass evaporator containing the test substance
- Temperature, humidity: 23 - 27 °C, 65 -80%


TEST ATMOSPHERE
- Brief description of analytical method used: by gaschromatography
- Samples taken from breathing zone: no
Analytical verification of test atmosphere concentrations:
yes
Remarks:
Samples of the test atmospheres were taken from the sampling ports at both sides 2 to 4 times/hour and were analyzed by gas chromatography, using an "Intersmat" gaschromatograph with a FID (flame ionisation detector) and a stainless steel column.
Duration of exposure:
4 h
Concentrations:
8029, 10754, 13679 ppm (ca. 42.9, 57.7, 73.2 mg/l)
No. of animals per sex per dose:
10
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: regulary
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Results and discussion

Effect levelsopen allclose all
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 73 mg/L air
Exp. duration:
4 h
Remarks on result:
other: vapor
Sex:
female
Dose descriptor:
LC50
Effect level:
> 73 mg/L air
Exp. duration:
4 h
Sex:
male
Dose descriptor:
LC50
Effect level:
ca. 58.8 mg/L air
Exp. duration:
4 h
Mortality:
- 73.2 mg/l air: 2/10 males died within 3 h; 6/10 males and 2/10 females died within 4 h; 8/10 males and 2/10 females died within 14 days
- 57.5 mg/l air: 4/10 males died within 4 h
- 42.9 mg/l air: no mortality
Clinical signs:
During the first 30 minutes of the exposure period the animals were very restless, kept their eyes half-closed and showed nasal discharge and salivation, especially the rats of the mid and high dose groups. In the mid-dose group the animals showed tremors after about 45 minutes, in the high dose group this phenomenon was seen already after 30 minutes. Mouth breathing and laboured respiration occurred during the second half of the exposure period.
Body weight:
The mean body weights was only slightly retarded in females of the mid-dose group.
Gross pathology:
Macroscopic examination at autopsy revealed overfilled urinary bladders and red (congested) lungs in all animals of the high dose group that died during the exposure period. No abnormalities were observed in animals of the intermediate dose group that died during the exposure period.
In animals autopsied after the observation period slight lesions were observed in the high dose group only. They consisted of red spots in the lungs
of one male and petechia in the lungs of two females.

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Remarks:
Migrated information Criteria used for interpretation of results: EU