Dodecamethylcyclohexasiloxane

Endpoint summary

Description of key information

The key skin irritation/corrosion study with dodecamethylcyclohexasiloxane (D6) (NOTOX, 1999c), conducted according to OECD Test Guideline 404 and in compliance with GLP, concluded that D6 was not irritating to skin.

The key eye irritation/corrosion study with dodecamethylcyclohexasiloxane (D6) (NOTOX, 1999d), conducted according to OECD Test Guideline 405 and in compliance with GLP, concluded that D6 was not irritating to eyes.  

Minimal to mild findings indicative of irritancy in the nasal tissues were noted in the repeated dose 90-day inhalation toxicity study with dodecamethylcyclohexasiloxane (D6) (Dow Corning Corporation, 2013).

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:

1999/06/09-1999/06/12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Source: Charles River Nederland, The Netherlands

- Age at study initiation: at least 6 weeks

- Weight at study initiation: <3.5kg

- Housing: Individually housed in labelled cages with perforated floors.

- Diet: Standard laboratory rabbit diet, ca. 100g/day

- Water: tap water, ad libitum

- Acclimation period: min. 5 days


ENVIRONMENTAL CONDITIONS

- Temperature (°C):21

- Humidity (%): 50

- Air changes (per hr): ca.15

- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

other: Adjacent areas of skin of each animal served as controls.

Amount / concentration applied:

TEST MATERIAL

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

- Concentration (if solution): undiluted

Duration of treatment / exposure:

4 hour(s)

Observation period:

Observations were made 1, 24, 48, and 72 hours after exposure.
Observations performed: The animals were observed for mortality/viability twice daily. Signs of toxicity were recorded at least once daily. Body weights were recorded on the day of treatment (prior to application).

Number of animals:

3

Details on study design:

TEST SITE

- Area of exposure: skin of flank

- Type of wrap if used: The test substance on the skin was covered with a Metalline patch of 2x3cm, mounted on with Micropore tape which was wrapped around the abdomen and secured with Coban elastic bandage.


REMOVAL OF TEST SUBSTANCE

- Washing (if done): Skin was cleaned of residual test substance using water.

- Time after start of exposure: 4 hours


SCORING SYSTEM: According to guideline

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24/48/72h

Score:

0

Max. score:

0

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No skin irritation was observed by 4 hours exposure to the test substance.

Other effects:

There was no evidence of corrosive effect on the skin. No staining of the treated skin by the test material was observed. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

GHS criteria not met

Conclusions:

The skin irritation/corrosion study with dodecamethylcyclohexasiloxane (D6), conducted according to OECD Test Guideline 404 and in compliance with GLP, concluded D6 to be not irritating to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999/06/21 - 1999/06/24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS

- Source: Charles River Nederland, The Netherlands

- Age at study initiation: at least 6 weeks old

- Weight at study initiation: 1223g, 1559g, 1569g (each)

- Housing: Individually housed in labelled cages with perforated floors.

- Diet: standard laboratory rabbit diet, ca. 100g/day

- Water: tap water, ad libitum

- Acclimation period: min. 5 days


ENVIRONMENTAL CONDITIONS

- Temperature (°C): 21

- Humidity (%): 50

- Air changes (per hr): ca.15

- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

other: Untreated eye.

Amount / concentration applied:

TEST MATERIAL

- Amount(s) applied (volume or weight with unit): 0.1ml

- Concentration (if solution): undiluted

Duration of treatment / exposure:

Single instillation.

Observation period (in vivo):

Observations were made after 1, 24, 48 and 72 hours after instillation.

Number of animals or in vitro replicates:

3M

Details on study design:

REMOVAL OF TEST SUBSTANCE

- Washing (if done): solution of 2% fluorescein in water was instilled in both eyes of each animal to quantitatively determine corneal damage

- Time after start of exposure: 24h


SCORING SYSTEM: According to guideline.


TOOL USED TO ASSESS SCORE: fluorescein/ophthalmic examination lamp

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24/48/72h

Score:

0

Max. score:

0

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Instillation of the test substance resulted in irritation of the conjunctivae, which was seen as redness. The irritation had completely resolved within 24 hours in all animals. No iridial irritation, corneal epithelial damage or corneal opacity were observed in any of the animals.

Other effects:

There was no evidence of ocular corrosion, no staining or peri-ocular tissues by the test substance was observed. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

GHS criteria not met

Conclusions:

The eye irritation/corrosion study with dodecamethylcyclohexasiloxane (D6), conducted according to OECD Test Guideline 405 and in compliance with GLP, concluded D6 to be not irritating to eyes.  

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

In the key skin irritation/corrosion study with dodecamethylcyclohexasiloxane (D6) (NOTOX, 1999c), conducted according to OECD Test Guideline 404 and in compliance with GLP, 0.5 ml of undiluted test material was applied onto the skin of 3 rabbits for 4 hours under semiocclusive dressing. Skin observations were made at 1, 24, 48, and 72 hours after exposure. The animals were observed for mortality/viability twice daily. Signs of toxicity were recorded at least once daily. Body weights were recorded on the day of treatment (prior to application). There was no evidence of irritant or corrosive effects on the skin. No staining of the treated skin by the test material was observed. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred. D6 was concluded to be not irritating to skin.

In the key eye irritation/corrosion study with dodecamethylcyclohexasiloxane (D6) (NOTOX, 1999d), conducted according to OECD Test Guideline 405 and in compliance with GLP, 0.1 ml of undiluted test material was instilled into the eyes of 3 rabbits. Observations were made at 1, 24, 48, and 72 hours after exposure. At 24 hours following exposure, solution of 2% fluorescein in water was instilled into both eyes of each animal to quantitatively determine corneal damage. Mortality and viability of the test animals were checked twice daily. Signs of toxicity were evaluated at least once daily. Body weight was recorded on the day of treatment prior to instillation. Instillation of the test substance resulted in irritation of the conjunctivae, which was seen as redness. The irritation had completely resolved within 24 hours in all animals. No iridial irritation, corneal epithelial damage or corneal opacity were observed in any of the animals. There was no evidence of ocular corrosion. No staining of peri-ocular tissues by the test substance was observed. No symptoms of systemic toxicity were observed in any of the animals during the test period and no mortality occurred. D6 was concluded to be not irritating to eyes.

Minimal to mild findings indicative of irritancy in the nasal tissues were noted in the repeated dose 90-day inhalation toxicity study with dodecamethylcyclohexasiloxane (D6) (Dow Corning Corporation, 2013). The findings included increased incidence and severity of inflammation and hyperplasia consistent with a mucosal irritant.

Justification for classification or non-classification

Based on reliable in vivo skin and eye irritation studies, D6 does not require classification for skin or eye irritation according to Regulation (EC) No. 1272/2008.