1,1,1,3,3,3-hexamethyldisilazane

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline. It was not compliant with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1,3,3,3-hexamethyldisilazane

EC Number:

213-668-5

EC Name:

1,1,1,3,3,3-hexamethyldisilazane

Cas Number:

999-97-3

Molecular formula:

C6H19NSi2

IUPAC Name:

bis(trimethylsilyl)amine

Details on test material:

- Name of test material (as cited in study report): Hexamethyldisilazane; Organofunctional Silane A-166; 1,1,1,3,3,3-hexamethyldisilazane.


No further details available

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data
- Age at study initiation: No data
- Weight at study initiation: 2-3 Kg
- Fasting period before study: No data
- Housing:No data
- Diet (e.g. ad libitum): No data
- Water (e.g. ad libitum): No data
- Acclimation period: No data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data
- Humidity (%): No data
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): No data


IN-LIFE DATES: No data

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: No data
- % coverage: No data
- Type of wrap if used: Impervious sheet


REMOVAL OF TEST SUBSTANCE
- Washing (if done): Yes
- Time after start of exposure: 24 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Males: 1.0, 0.71 and 0.5 ml/kg bw; females: 16.0, 4.0, 1.0, 0.5 and 0.25 ml/kg bw
- Concentration (if solution): Undiluted
- Constant volume or concentration used: yes

Duration of exposure:

24 hours

Doses:

1.0, 0.71, and 0.50 mL/kg bw (770, 550, and 385 mg/kg bw based on a density of 0.77 g/cm3) in males and 16.0, 4.0, 1.0, 0.5, and 0.25 mL/kg bw (12,320, 3080, 770, 385, 193 mg/kg bw based on a density of 0.77 g/cm3) in females

No. of animals per sex per dose:

Four (except 16 and 4 ml/kg bw levels used two females each)

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations were made daily. Weights were measured before dosing and on Days 7 and 14.
- Necropsy of survivors performed: yes

Statistics:

LD50s were calculated using the 'moving average method'.

Results and discussion

Effect levels

Effect levels 1

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

585 mg/kg bw

Based on:

test mat.

Effect levels 2

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

544 mg/kg bw

Based on:

test mat.

Mortality:

Males: 4/4, 1/4 and 0/4 at 1.0, 0.71 and 0.5 ml/kg bw, respectively.
Females: 2/2, 2/2, 4/4, 0/4 and 0/4 at 16.0, 4.0, 1.0, 0.5 and 0.25 ml/kg bw, respectively.

Clinical signs:

other: See Table 1

Gross pathology:

See Table 1

Other findings:

See table 1

Any other information on results incl. tables

Table 1 Summary of mortality, clinical and necropsy findings.

Group (ml/kg bw)	Number of deaths/total exposed	Time to death (d)	Clinical observations	Necropsy findings
Males
0.5	0/4	-	Sluggishness on Days 1 and 2 (2/4), skin erythema, edema, necrosis on Day 1 and desquamation by Day 14.	Trachea red (1/4), liver with tan foci (coccodiae; 1/4)
0.71	1/4	3	Prostration in one animal, skin erythema and necrosis, and scabs by Day 14.	Nothing remarkable
1.0	4/4	1, 1, 2, 3	Prostration in two animals, skin erythema, edema and necrosis	Lung & liver dark (1/4), trachea red (2/4), bladder distended filled with red/yellow liquid (1/4)
Females
0.25	0/4	-	Capillary injection, erythema, necrosis, spots of ecchymosis on Day 1, desquamation, scabs at 14 days.	Lungs mottled dark red (2/4) and trachea slight redness along mucous lining (1/4)
0.5	0/4	-	Sluggishness on Day 1, skin erythma, edema and necrosis on Day 1 with desquamation and scabs by Day 14.	Lungs and trachea dark red (1/4)
1.0	4/4	1, 1, 1, 3	Lethargy, slow and shallow breathing (1 hour), skin erythema and necrosis	Lungs mottled dark red (2/4) and trachea dark red (1/4)
4.0	2/2	1, 1	Signs of discomfort, lethargy slow and shallow breathing (30 mins), skin erythema and necrosis	Lungs with dark red patches
16.0	2/2	0, 0 (within 2 hours)	Signs of discomfort, skin erythema and necrosis	Nothing remarkable

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

In an acute dermal toxicity study conducted according to a protocol that was comparable to OECD Test Guideline 402, but without information on GLP compliance, the LD50s for 1,1,1,3,3,3-hexamethyldisilazane (CAS 999-97-3) was concluded to be 544 mg/kg bw in females and 585 mg/kg bw in males (based on density of 0.77 g/cm3).