2,2,4,4,6,6-hexamethylcyclotrisilazane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: 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:

1973

Report date:

1973

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

the animals were exposed to test substance for 24 hours, observation was not continued for 14 days to determine reversibility

GLP compliance:

no

Remarks:

The study pre-dates GLP

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4,4,6,6-hexamethylcyclotisilazane

IUPAC Name:

2,2,4,4,6,6-hexamethylcyclotisilazane

Constituent 2

Reference substance name:

2,2,4,4,6,6-hexamethylcyclotrisilazane

EC Number:

213-773-6

EC Name:

2,2,4,4,6,6-hexamethylcyclotrisilazane

Cas Number:

1009-93-4

Molecular formula:

C6H21N3Si3

IUPAC Name:

2,2,4,4,6,6-hexamethyl-1,3,5,2,4,6-triazatrisilinane

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Very few details given in study report
Weight of animals at study initiation: 2.3 to 3.0 kg

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: The test substance was applied unchanged or as a 1%, 3%, 10% or 30% solution in peanut oil

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 ml
- Concentration (if solution): 1%, 3%, 10% or 30% solution in peanut oil

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

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

six rabbits per concentration

Details on study design:

TEST SITE
- Area of exposure: approximately 3 cm in diameter, therefore 4.5 cm²
- % coverage: no data
- Type of wrap if used: The test substance was applied on an aluminium disk kept in place with adhesive tape and a bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no information
- Time after start of exposure: 24 hours

SCORING SYSTEM: Draize

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

mean

Remarks:

the erythema score for every animal was 4

Time point:

other: 24 hours

Score:

4

Max. score:

4

Reversibility:

no data

Remarks on result:

positive indication of irritation

Results 2

Irritation parameter:

erythema score

Remarks:

Undiluted test material applied to intact skin

Basis:

mean

Remarks:

the erythema score for every animal was 4

Time point:

other: 72 hours

Score:

4

Max. score:

4

Reversibility:

no data

Remarks on result:

positive indication of irritation

Results 3

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #1

Time point:

other: 24 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Remarks on result:

probability of weak irritation

Results 4

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #2

Time point:

other: 24 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Remarks on result:

probability of weak irritation

Results 5

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #3

Time point:

other: 24 hours

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Results 6

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #4

Time point:

other: 24 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Remarks on result:

probability of weak irritation

Results 7

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #5

Time point:

other: 24 hours

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Results 8

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

animal #6

Time point:

other: 24 hours

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Results 9

Irritation parameter:

edema score

Remarks:

Undiluted test substance applied to intact skin

Basis:

mean

Time point:

other: 72 hours

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

The data for lower concentrations showed a similar pattern to that seen with undiluted test substance, reducing in severity with reducing concentration:
30%: erythema 4 in all animals at 24 and 72 hours; edema 0 at 24 and 72 hours;
10%: erythema 4 in five out of six animals at 24, decreasing to 4 at 72 hours, no erythema in one rabbit; edema 0 at 24 and 72 hours;
3%: no erythema or edema observed in any animal.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

2,2,4,4,6,6-hexamethylcyclotrisilazane has been tested in a study similar to an OECD 404, prior to OECD GLP criteria being adopted. Application of undiluted substance to the intact skin of six New Zealand white rabbits for 24 hours resulted an erythema score of 4/4 in all animals at 24 and 72 hours. No further observations were made and there is no information on reversibilty of the observed erythema. Edema (score 1/4) was observed in three out of six animals at 24 hours, fully reversible within 72 hours. Test substance diluted in oil also resulted in erythema, but not edema. A 30% solution in peanut oil also resulted an erythema score of 4/4 in all animals at 24 and 72 hours. A 10% solution caused erythema in five out of six rabbits, with a score of 3/4 at 24 hours increasing to 4/4 at 72 hours. No erythema was observed at 24 hours after application of a 3% solution. It is concluded that the substance is irritating to the skin.