Dichloro(dimethyl)silane

Endpoint summary

Description of key information

The key study (Bayer AG, 1984) tested under semi-occlusive conditions for four hours, in New Zealand white rabbits showed dichloro(dimethyl)silane to be corrosive. The conclusion was supported by findings in other studies. There are no reliable studies available for eye irritation; however, an old, non-guideline study (Mellon Institute, 1951) showed the test substance to be corrosive to the eyes. Further testing was not required as the test substance is classified as corrosive to skin. Although there was no specific study to investigate respiratory irritation, pathology examination in the key acute inhalation study (Dow Corning Corporation , 1997) showed signs of respiratory irritation/corrosion.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Hacking and Churchill Ltd, UK
- Age at study initiation: No data (needs translation)
- Weight at study initiation: 3.7 kg
- Housing: No data
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: No data (needs translation)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 40-60
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: November 1984

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 ml

Duration of treatment / exposure:

Four hours

Observation period:

14 days

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: Flanks
- % coverage: No data (6 x 6cm)
- Type of wrap if used: Semiocclusive


REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, with water
- Time after start of exposure: four hours


SCORING SYSTEM: Draize

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: skin induration and pale yellow or light-red bordered skin at the application site was observed at 24 and 48 hours; at 72 hours necrosis of the whole application site was observed.

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: skin induration and pale yellow or light-red bordered skin at the application site was observed at 24 and 48 hours; at 72 hours necrosis of the whole application site was observed.

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: skin induration and pale yellow or light-red bordered skin at the application site was observed at 24, 48 and 72 hours; day 4 necrosis of the whole application site was observed.

Irritant / corrosive response data:

Eschar formation observed.

Other effects:

Signs of corrosion were observed from 1 hour to 14 days.

Corrosion was reported rather than scores being given.

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

In a well conducted skin irritation study (reliability score 2) comparable to OECD 404, but not to GLP, dichlorodimethylsilane was corrosive to rabbit skin.

Executive summary:

In a well conducted skin irritation study (reliability score 2) comparable to OECD 404, but not to GLP, 0.5 ml undiluted dichlorodimethylsilane was applied to the shaved flanks of six New Zealand white rabbits under a semi-occlusive dressing for four hours. The application site was then washed with water, and the site assessed for signs of irritation for 14 days. Eschar formation was noted, as a result of the corrosive activity of the test substance.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Dichloro(dimethyl)silane is rapidly hydrolysed to dimethylsilanediol and hydrogen chloride in the presence of moisture. Therefore the signs of skin and eye irritation/corrosion noted in studies are considered due to the hydrolysis product HCl.

In the key skin irritation study (Bayer AG, 1984) dichloro(dimethyl)silane was tested under semi-occlusive conditions for four hours in New Zealand white rabbits and found to be corrosive to skin. This finding was consistent with those of supporting skin irritancy studies. There are no reliable studies available for eye irritation; however, an old, non-guideline study (Mellon Institute, 1951) showed the test substance to be corrosive to the eyes. Further testing was not required as the test substance is classified as corrosive to skin.

No information is available for respiratory tract irritation, in either animals or humans. However, the pathology examination in the key acute inhalation study (Dow Corning Corporation, 1997) revealed signs of respiratory irritation/corrosion.

Justification for classification or non-classification

Based on the available data dichloro(dimethyl)silane is classified 'Skin Corr. 1A' and 'Eye Dam. 1', with hazard statement H314 'Causes severe skin burns and eye damage’ according to Regulation (EC) No 1272/2008.

This is based on the skin irritation/corrosion data that show the test substance to be clearly corrosive to the skin. It is assumed that substances that are corrosive to the skin are also damaging to the eyes, so there is no separate labelling for the eyes. There are no specific data for respiratory irritation. However, the pathology examination in the key acute inhalation study revealed signs of respiratory irritation/corrosion. The test substance has the additional label 'EUH071 Corrosive to the respiratory tract'.