Dimethoxydimethylsilane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30-08-1988 to 12-09-1988

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to the appropriate OECD test guideline, and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

Report lacking data on whether clinical examination and physical measurements were conducted.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

1

Reference substance name:

Dimethoxydimethylsilane

EC Number:

214-189-4

EC Name:

Dimethoxydimethylsilane

Cas Number:

1112-39-6

Molecular formula:

C4H12O2Si

IUPAC Name:

dimethoxydimethylsilane

Details on test material:

- Name of test material (as cited in study report): Dimethyldimethoxysilane
- Substance type: Alkoxysilane
- Physical state: A clear liquid

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Not reported.
- Weight at study initiation: 175-200 g ( Males and Females).
- Housing: The rats were housed in stainless steel, wire mesh bottomed cages of conventional design. At the onset of experiment, the animals were moved into special stainless steel cages. These cages were designed to house the animals during the exposure periods. The animals were returned to their original housing after the exposure period.
- Diet : The animals were fed PURINA Rodent Chow ad libitum except during the exposure period.
- Water : The animals were fed water ad libitum except during the exposure period.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 -50
- Air changes (per hr): 14 - 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: Not reported

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Exposure was conducted in stainless steel and glass exposure chambers. The chambers were operated under dynamic conditions.
- Exposure chamber volume: 450-litre
- Method of holding animals in test chamber: Not reported.
- Source and rate of air: Airflow rates through the chambers were monitored continuously by calibrated Magnehelic gauges connected across orifices at the chamber inlets.
- Method of conditioning air: Not reported
- System of generating particulates/aerosols: Test material was introduced into the test chamber through a specially designed glass J-tube with a flow FMI Lab pump. Laboratory air filtered with a Matheson 462 cartridge filter passed through the J-tube. The air/vapour 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. After the exposure period, the vapour generating equipment was turned off and the vapour concentration in the chamber was allowed to return to zero.
- Method of particle size determination: Not reported.
- Treatment of exhaust air: The exhaust air was filtered (hepa and carbon), cleaned with a water cyclone, then exhausted from the roof of the building.
- Temperature, humidity, pressure in air chamber: Chamber temperature and relative humidity were monitored with Cole-Parmer Model No.3310-40 (certified) temperature and humidity gauges.

TEST ATMOSPHERE
- Brief description of analytical method used: Not reported

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

4 h

Concentrations:

The test material target concentration was 5.0 mg/l. The actual nominal chamber concentration was 4.7 mg/l (calculation by weight).

No. of animals per sex per dose:

5 males and 5 females.

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Gauge readings were recorded hourly during the chamber period. Animals were observed once a day during weekdays. Individual animal body weights were taken prior to exposure and on days 7 and 14 after exposure.
- Necropsy of survivors performed: Not reported
- Other examinations performed: body weight

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 4 700 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortalities were observed in either groups during the exposure or post-exposure periods.

Clinical signs:

other: Not reported.

Body weight:

No apparent test material related effect on body weights.

Gross pathology:

Not reported.

Any other information on results incl. tables

 Table 2. Mortality Data.

Test Material Concentration (mg/l)	Number of Dead/Number exposed
	Males	Females
0	0/5	0/5
4.7	0/5	0/5

 

Table 3. Mean Body Weight Data (g).

Days After Exposure	Group I, Control		Test Group II
	Males	Females	Males	Females
0	189 ± 5	183 ± 10	188 ± 5	183 ± 12
7	242 ± 8	214 ± 15	248 ± 9	205 ± 15
14	295 ± 13	233 ± 21	305 ± 15	230 ± 20

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No 1272/2008

Conclusions:

In an acute inhalation (vapour) study conducted in compliance with OECD 403 and GLP, in which rats were exposed to to >4700 mg/m³ dimethoxydimethylsilane for four hours resulted in no mortality. Therefore, LC50 was determined to be >4700 mg/m³.