1,1,3,3-tetramethyldisiloxane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994-6-27 to 1994-7-11

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

The limit concentration according to the current OECD TG 403 is 20 mg/l (vapour). The limit concentration tested at this study is below the current limit value.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,1,3,3-tetramethyldisiloxane

EC Number:

221-906-4

EC Name:

1,1,3,3-tetramethyldisiloxane

Cas Number:

3277-26-7

Molecular formula:

C4H14OSi2

IUPAC Name:

1,1,3,3-tetramethyldisiloxane

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Kingston, Stone Ridge, NY, USA
- Age at study initiation: 49 days
- Weight at study initiation: 159-165 g (m); 107-119 g (f)
- Housing: individual stainless wire mesh cages
- Diet: standard diet ad libitum except during exposure
- Water: drinking water ad libitum
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 25
- Humidity (%): 9% (during exposure - no details given for observation period)
- Air changes (per hr): 40L/min
- Photoperiod (hrs dark / hrs light): 12h/12 h

IN-LIFE DATES: From: 27 June 1994 To: 11 July 1994

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: stainless steel/glass exposure chamber
- Exposure chamber volume: 160 L
- Method of holding animals in test chamber: caged
- Source and rate of air: compressed air system
- System of generating vapour: compressed air through glass vapourization collumn containing glass beads. Additional dilution air sweeps vapour into exposure chamber
- Method of particle size determination: conducted to ensure no aerosol (Andersen 8-stage cascade impactor)
- Temperature, humidity, pressure in air chamber: 25 deg C, 9% humidity

TEST ATMOSPHERE
- Brief description of analytical method used: gas chromatographic method (details in appendix not included with report)
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Remarks:

GC

Duration of exposure:

4

Concentrations:

nominal 5 mg/l
measured 5.8 mg/l

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: body weight days 0, 7, 14; general observations twice daily for 14 days
- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.8 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: The recommended limit concentration according to the current guideline is 20 mg/l (vapour).

Mortality:

0/10 deaths

Clinical signs:

other: Rapid respiration and salivation.

Body weight:

All exposed animals gained weight.

Gross pathology:

No treatment-related abnormalities reported.

Any other information on results incl. tables

Table 1: Concentrations, mortality or evident toxicity

Sex	Analytical Conc. (mg/l)	Mortality (No./total)	Overt toxicity	Number with remarkable gross pathology
males	5.8	0/5	Rapid respiration and salivation. No treatment-related effects at 7 and 14 days.	0/5
females	5.8	0/5	Rapid respiration and salivation. No treatment-related effects 14 days.	0/5

 

 

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The key acute inhalation toxicity study, conducted according to OECD Test Guideline 403 with acceptable restrictions and in compliance with GLP, concluded a 4-hour LC50 value of >5.8 mg/l as vapour (measured) (Dow Corning Corporation, 1994). The restriction of the study was that the limit concentration tested is below the recommended limit concentration according to the most recent guideline (20 mg/l).