Hexamethyldisiloxane

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

not in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Principles of method if other than guideline:

Hilltop-Wistar albino rats, weighing between 200 and 300 g, received the test material by stomach intubation with a ball-end stainless steel needle.  The sample was injected through the needle by means of a syringe and doses were varied by adjusting the volume of the test material.  The rats were fasted overnight before dosing.  Five males and 5 females were included on each level (16.0 and 8.0 ml/kg). 

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hexamethyldisiloxane

EC Number:

203-492-7

EC Name:

Hexamethyldisiloxane

Cas Number:

107-46-0

Molecular formula:

C6H18OSi2

IUPAC Name:

trimethyl[(trimethylsilyl)oxy]silane

Test animals

Species:

rat

Strain:

other: Hilltop-Wistar albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

weighing between 200 and 300 g

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

VEHICLE: Not applicable

MAXIMUM DOSE VOLUME APPLIED: Not stated

Doses:

8.0 and 16.0 ml/kg

No. of animals per sex per dose:

5/sex/group

Control animals:

no

Details on study design:

Hilltop-Wistar albino rats, weighing between 200 and 300 g, received the test material by stomach intubation with a ball-end stainless steel needle.  The sample was injected through the needle by means of a syringe and doses were varied by adjusting the volume of the test material.  The rats were fasted overnight before dosing.  Five males and 5 females were included on each level (16.0 and 8.0 ml/kg).  The animals were maintained on appropriate commercial diet and municipal water.  Both were available ad libitum except during period of fasting, manipulation or restraint.   Animal weights were recorded at 0 days (before dose), 7 days and 14 days (just prior to sacrifice).  At death or sacrifice, each animal was subjected to gross pathologic evaluation.

Statistics:

 LD50s were calculated by the moving average method (Thompson, 1947) and were based on a 14-day observation period.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 16 mL/kg bw

Based on:

test mat.

Remarks on result:

other: corresponding to 12.16 g/kg

Mortality:

MALES:
 16.0 ml/kg Dead/Dosed: 0/5
8.0 ml/kg Dead/dosed: 1/5

FEMALES:
 16.0 ml/kg Dead/Dosed: 0/5
8.0 ml/kg Dead/Dosed: 0/5

Clinical signs:

other: MALES: 16.0 ml/kg  None noted.  8.0 ml/kg: In the animal that died, sluggishness, unsteady gait at 4 min; death at 15 min.  In survivors, none noted. FEMALES:  16.0 ml/kg None noted. 8.0 ml/kg  None noted.

Gross pathology:

MALES:
 16.0 ml/kg : Nothing remarkable.
 8.0 ml/kg  In animal that died, lungs with dark spots; liver dark; stomach liquid-filled, injected; intestines and kidneys red.  In survivors, nothing remarkable.

FEMALES:
 16.0 ml/kg : Nothing remarkable.
8.0 ml/kg  Nothing remarkable.

Other findings:

No other findings reported.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral LD50 was determined to be > 16.0 ml/kg, dosed as received, in both male and female rats.