Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 Aug - 30 Dec 1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
(1981)
Deviations:
yes
Remarks:
(no gross necropsy was done at the end of the observation period, no justification for the use of a whole-body inhalation system is given)
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): Methyldimethoxysilane
- Lot/batch No.: A80530

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: charles River Breeding Laboratories
- Weight at study initiation: 175 - 200 g
- Fasting period before study:
- Housing: in stainless steel wire mesh bottomed cages
- Diet: Purina rodent chow, ad libitum, except during exposure
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 - 50
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
clean air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: stainless steel and glass exposure chamber under dynamic conditions, Airflow rates through the chambers were monitored continously by calibrated Magnehelic gauges connected across orifices at the chamber inlets. Chamber temperature and relative humidity were monitored with cole-Parmer Model No. 3310-40 (certified) temperature and humidity gauges. Gauge readings were recorded hourly during the exposure period.
- Exposure chamber volume: 450 L
- Source and rate of air: laboratory air
- Method of conditioning air: The test material was introduced into the test chamber through a specially designed glass J-tube with a flow FMI Lab pump. Laboratory air filtered and dried with Matheson #462 cartridge filter passed through the J-tube. The air/vapor mixture entered the top of the chamber where it was diluted with room air. Heating tape was used to heat the air which passed through the J-tube and glass beads were used to further help vaporize the test material.
- Treatment of exhaust air: the exhaust air was filtered (hepa and carbon) cleaned with water cyclone and then exhausted from the roof of the building.


TEST ATMOSPHERE
- Brief description of analytical method used: Airflow rates through the chambers were monitored continuously by calibrated Magnehelic gauges connected across orifices at the chamber inlets. Gauge readings were recorded hourly during the exposure Period. Chamber temperature and relative humidity were monitored with Cole-Parmer Model No. 3310-40 (certified) temperature and humidity gauges. Gauge readings were recorded hourly during the exposure Period.
Analytical verification of test atmosphere concentrations:
yes
Remarks:
calculated by weight
Duration of exposure:
4 h
Concentrations:
5000 mg/m³ (nominal), 4600 mg/m³ (analytical)
No. of animals per sex per dose:
5 males and females
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: animals observed daily on weekdays, body weight was determined prior to exposure and on day7 and 14 post exposure
- Necropsy of survivors performed: no
- Other examinations performed: clinical signs, body weight

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4 600 mg/m³ air (analytical)
Based on:
test mat.
Remarks:
calculated by weight
Exp. duration:
4 h
Remarks on result:
other: no adverse effects or mortalities were observed
Mortality:
No mortalities were observed during the study period.
Clinical signs:
other: No other clinical signs were observed during the study period.
Body weight:
No effects on body weight were observed during the study period.

Applicant's summary and conclusion

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
In conclusion, under the conditions chosen for this experiment (according to OECD 403), the test substance was found not to be toxic by inhalation, since no mortalities or clinical signs of toxicity were observed at the maximum attainable concentration.