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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
A comprehensive substance description is missing.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report Date:
1986

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Isooctyltrimethoxysilane
- Substance type: Organosilane
- Physical state: clear liquid
- Expiration date of the lot/batch: No data
- Stability under test conditions: No data
- Storage condition of test material: Refrigerator at 4°C

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hoechst AG, Kastengrund; SPF-breeding
- Age at study initiation: 8 - 10 weeks
- Weight at study initiation: Males 212 g (207 - 225 g); Females 175 g (170 - 181 g)
- Fasting period before study: No data
- Housing: Fully air-conditioned; Macrolon cages with softwood granulate; 5 animals per cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 50 +/- 20
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
other: air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Nose only inhalation chamber, cylindrical stainless steel column (60 L)
- Exposure chamber volume: 60 L
- Method of holding animals in test chamber: rodent tube; animals were secured in plastic animal holders
- Source and rate of air: compressed air; 800 L/h
- Method of conditioning air: Purification of compressed air by oil separator filter and total filter; in addition direct feed of moistened air into the inhalation chamber
- System of generating particulates/aerosols: special nozzle; round bottom flask to create a primary aerosol; small particles (secondary aerosol) reach the inhalation chamber via riser
- Method of particle size determination: Particle counting system APS 33 Aerodynamic Particle Sizer (TSI Inc.)
- Treatment of exhaust air: gas purification, neutralization
- Temperature, humidity, pressure in air chamber: Temperature/humidity/CO/CO2/O2: Continuous measurement by a air control system


TEST ATMOSPHERE
- Brief description of analytical method used: GC measurement of the substance after absorption in acetone
- Samples taken from breathing zone: No data


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: 100% of the aerosol < 15.4 µm; approx. 16% < 4 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 50% of the aerosol < 7.77 µm
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
ca. 4 h
Concentrations:
11.2 mg/l
No. of animals per sex per dose:
Five
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 d
- Frequency of observations and weighing: twice/day; weighing: start of the test, day 7 and 14 after exposure
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, mortality
Statistics:
None

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 11.2 mg/L air
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: No deaths
Mortality:
No deaths
Clinical signs:
other: Irregular, intermittent, noisy breathing; gasping for breath; salivation; long-legged, uncoordinate, reeled gait; prone position,contracted abdomen flank; cornea , movement and paws pinch reflexes are attenuated or absent; narcosis; sneezing. From day 4 a
Body weight:
No effect; expected body weight gain.
Gross pathology:
No findings.

Any other information on results incl. tables

Differentiation between vapour and dust exposure has not been performed. Aerosol/vapor exposure is possible.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In a good quality study (reliability score 2) exposure of wistar rats to an aerosol of isooctyltrimethoxysilane at a concentration of 11.2 mg/l air did not cause any deaths. Therefore the LC50 was greater than 11.2 mg/l.
Executive summary:

The acute inhalation toxicity of Isoocytltrimethoxysilane was studied by nose-only exposure of two groups of five male and five female Wistar rats each, for a 4 -hour period to a test atmosphere containing an aerosol of the substance at the maximum attainable concentration of 11.2 mg isooctyltrimethoxysilane/l air. After exposure, the animals were kept for a 14 -day observation period. No mortality has been observed. During and after exposure the following clinical signs have been observed: Irregular, intermittent, noisy breathing; gasping for breath; salivation; long-legged, uncoordinate, reeled gait; prone position,contracted abdomen flank; attenuation or absence of cornea , movement and paws pinch reflexes; narcosis; sneezing. From day 4 after exposure all animals were free of clinical signs. There was no effect on body weight and body weight gain. A gross pathology examination was conducted on all animals. There were no macroscopic findings. The LC50 was greater than 11.2 mg/l.