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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
significant methodological deficiencies
Remarks:
No test material purity is stated in the study report.

Data source

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

Materials and methods

Test guideline
Qualifier:
no guideline followed
GLP compliance:
no
Test type:
other: no standard protocol
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Silicone A-164
- Physical state: light yellow liquid

Test animals

Species:
rat
Strain:
other: Wistar-derived
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 3 - 4 weeks
- Weight at study initiation: 90 - 120 g
- Fasting period before study: none
- Diet: ad libitum (not further specified)
- Water: ad libitum (not further specified)

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
air
Details on inhalation exposure:
A substantially saturated vapor is prepared by spreading 50 to 100 g of the test material over 200 cm² area on shallow tray placed near the top of a 120 L Plexiglas chamber which is then sealed for at least 16 h while an intermittently operated fan agitates the internal chamber atmosphere. Rats are then introduced in a gasketed drawer-type cage designed and operated to minimize vapor loss.
Analytical verification of test atmosphere concentrations:
no
Duration of exposure:
29 - 225 min
Concentrations:
saturated vapor
No. of animals per sex per dose:
6 males
Control animals:
no
Details on study design:
- Necropsy of survivors performed: yes

Results and discussion

Effect levels
Sex:
male
Dose descriptor:
other: LT50
Effect level:
54 other: min
Based on:
test mat.
Remarks on result:
other: Exposure duration: 29 - 225 min
Mortality:
Mortality occurred 29 min (1/6), 57 min (3/6), 113 min (6/6) and 225 min (6/6) after exposure to a saturated vapor of the test material.
Clinical signs:
other: Clinical signs such as lacrimation, ataxia, dyspnea, prostration and audible respiration were recorded in all exposure groups.
Body weight:
Mean body weight changes seen throughout the study period were:
29 min: 56 - 79 g
57 min: 57 - 64 g
113 min: 5/6 animals died during the exposure period, 1/6 animal died 1.25 h after the exposure period
225 min: 6/6 animals died during the exposure period
Gross pathology:
Gross pathology of dead animals revealed dark red lungs and gas-filled stomachs and intestines. No abnormalities were found in surviving animals.

Applicant's summary and conclusion

Interpretation of results:
study cannot be used for classification
Conclusions:
An LC50 could not be established in an acute inhalation toxicity study, in which rats were exposed to a saturated vapor (concentration not report) for 29 to 225 minutes. Mortality did occur as follows at all exposure time points: 1/6 at 29 min; 3/6 at 57 min; 6/6 at 113 min; and 6/6 at 225 min. Because of the lack of data on concentration, this study cannot be used for classification.