2,4,6,8,10-pentamethylcyclopentasiloxane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Dec 18, 2000 to Jan 10, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Remarks:

No sentinel animal, not yet required in 2001

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2370-99-0

IUPAC Name:

2370-99-0

Constituent 2

Reference substance name:

2,4,6,8,10-pentamethylcyclopentasiloxane

EC Number:

228-204-7

EC Name:

2,4,6,8,10-pentamethylcyclopentasiloxane

Cas Number:

6166-86-5

Molecular formula:

C5H20O5Si5

IUPAC Name:

2,4,6,8,10-pentamethyl-1,3,5,7,9,2,4,6,8,10-pentaoxapentasilecane

Constituent 3

Reference substance name:

2,4,6,8-tetramethylcyclotetrasiloxane

EC Number:

219-137-4

EC Name:

2,4,6,8-tetramethylcyclotetrasiloxane

Cas Number:

2370-88-9

Molecular formula:

C4H16O4Si4

IUPAC Name:

2,4,6,8-tetramethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane

Specific details on test material used for the study:

Test substance identified as mixture of 2,4,6,8,10-pentamethylcyclopentasiloxane (CAS 6166-86-5) (45%) and 2,4,6,8-tetramethylcyclotetrasiloxane (CAS 2370-88-9) (54%) and the impurity 0.9% hexamethylcyclohexasiloxane.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

- three young adult females, at least 12 weeks old
- weight 3025g-3137g at initiation
- identification by eartag & cage card
- housed in individual suspended cages
- inspection upon arrival; acclimatisation for at least 7 days, observed twice daily
- Diet: Certifeid Rabbit LabDiet(r) 5322 ~a50 gr/animal/day. Tap water at lib. Food and water regularly analysed
- controlled temperature (69-71 degr. F), humidity (50-64%) light (12/12) and ventilation (10-15 changes / days)

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.5 ml / site

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3

Details on study design:

application to skin area approx 2.5 x 2.5, covered with 8-ply surgical gauze held in place with surgical porous tape. Overwrapped with gauze bandaging and secured with non-irritating tape; Animals were given restraint collars.
Duration of application 4 hours, after which bandages were removed and sites wiped clean with disposable paper towels moistened with deionized water.

Results and discussion

In vivo

Results

Results 1

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

Results 2

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

Results 3

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

Results 4

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

Results 5

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

Results 6

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 animals showed any signs of irritation at any point in time

Other effects:

slight weight loss (,1%) in one animal, not uncommmon in animals of this weight range and strain; not considered to be substance-related
no mortality.

Any other information on results incl. tables

Individual Irritation scores

	Erythema						Edema
Animal nr.	Sex	1 hr	24 hrs	48 hrs	72 hrs		1 hr	24 hrs	48 hrs	72 hrs
34044	female	0	0	0	0		0	0	0	0
34045	female	0	0	0	0		0	0	0	0
34046	female	0	0	0	0		0	0	0	0
Total		0	0	0	0		0	0	0	0
PPI calculated for all timepoints: ppi = (0+0+0)/9 + (0+0+0) /9 = 0 + 0 = 0

Individual body weights (in grams):

Animal nr.	Sex	Initiation (day 0)	Termination (day 3)
34044	female	3137	3289
34045	female	3025	3067
34046	female	3034	3020

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The mixture of structurally analogous substances 2,4,6,8,10-pentamethylcyclopentasiloxane (CAS 6166-86-5) and 2,4,6,8-tetramethylcyclotetrasiloxane (CAS 2370-88-9) showed no signs of skin irritation.

Executive summary:

A mixture of the two structurally analogous substances 2,4,6,8,10-pentamethylcyclopentasiloxane (CAS 6166-86-5) and 2,4,6,8-tetramethylcyclotetrasiloxane (CAS 2370-88-9) was tested for skin irritancy according to OECD 404 test method under GLP . The mixture showed no signs of skin irritation. Based on structural analogy, the conclusion applies directly to the registered substance as well as from read-across from the analogue.