2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 July 1987 - 03 August 1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane

EC Number:

219-863-1

EC Name:

2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane

Cas Number:

2554-06-5

Molecular formula:

C12H24O4Si4

IUPAC Name:

2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 175-250 g
- Housing: Standard stainless steel, wire mesh bottomed cages of conventional design.
- Diet: ad libitum, except during exposure
- Acclimation period: Seven days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/-2
- Humidity (%): 30-50
- Photoperiod (hrs dark / hrs light): 12/12

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 chamber volume: 450 litre stainless steel and glass exposure chamber.
- Method of holding animals in test chamber:
- System of generating particulates/aerosols: Test material was introduced into the test chamber through a specifically designed glass J-tube with a low flow FMI Lab pump. Laboratory air filtered and dried with a Matheson #462 cartridge filter and Drierite cartridge passed through the J-tube. The air/vapour mixture entered the top of the chamber where it was diluted with room air to its maximum attainable concentration. Heating tape was used to heat the air which passed through the J-tube, and glass beads were used to further vapourise the test material.
- 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: The chamber air was filtered (hepa and carbon) and temperature and humidity controlled. Chamber airflows were recorded hourly during the exposure period. Chamber temperature and relative humidity were monitored with Cole-Parmer Model No. 3310-40 (ceritfied) temperature and humidity gauges. Chamber temperature ranged from 23-24C. Percent relative humidity fell between 40% and 51% and chamber airflows were recorded as 107 to 114 L.P.M (corresponding to 14-15 air changes per hour).

TEST ATMOSPHERE
- Brief description of analytical method used: Not reported
- Samples taken from breathing zone: yes


TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: Not reported
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): Not reported

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

4 h

Concentrations:

Analytical concentration for test group 1.32 mg/l, control group was exposed to filtered air. (A concentration of 5 mg/l was attempted but unsuccesful due to the low vapour pressure of the test material.

No. of animals per sex per dose:

5 males, 5 females

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: Prior to exposure, animals were weighed and those within the acceptable weight range were randomized using a computer program. Individual observation records were maintained for each animal. 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: yes

- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: The trachea was exposed and clamped such that the lungs could be removed and observed in an inflated state. Special attention was paid to the respiratory tract.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1.32 mg/L air (analytical)

Exp. duration:

4 h

Mortality:

There was no mortality observed in test or control group.

Clinical signs:

other: No apparent abnormalities were observed in either the control or test groups during the exposure or post-exposure periods.

Body weight:

There were no significant body weight differences exhibited by any test animals when compared to control animals.

Gross pathology:

No remarkable findings reported.

Other findings:

None reported.

Any other information on results incl. tables

On the basis of these results, it is concluded that the test material most likely does not pose an acute vapour inhalation hazard at the concentration attained.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The LC50 was > 1.32mg/l which was the maximum achievable concentration.