2,4,6,8-tetramethylcyclotetrasiloxane

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Dec 18, 1201 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:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

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 / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

- three young adult rabbits, 2 females, one male, at least 12 weeks old
- weight 2531-2749 at study initiation
- identification by eartag & cage card
- housed in individual suspended cages
- inspection upon aarival; acclimatisation for at least 7 days, observed twice dayly
- Diet: Certified 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

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.1 ml /eye

Duration of treatment / exposure:

undefined. eyes were not washed at 1 hr post-treatment or later.

Observation period (in vivo):

72 hours

Number of animals or in vitro replicates:

3

Details on study design:

OBSERVATIONS
- twice daily for mortality
- body weights at beginning and end of study.
Ocular Observations:
before dosing and at 1, 24, 48 and 72 hrs, both eyes were observed by means of an ophthalmoscope for ocular abnormalities Pre-dosing and at 72 hrs observation included use of sodium fluoerescein for detection of corneal defects. Scoring according to Draize. Only animals without any ocular abnormalities were used in the study

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 2

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Results 3

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.7

Max. score:

3

Reversibility:

not fully reversible within: 72 hrs

Results 4

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 5

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 6

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Results 7

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.7

Max. score:

3

Reversibility:

fully reversible within: 72 hrs

Results 8

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 9

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Results 10

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Results 11

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.7

Max. score:

3

Reversibility:

fully reversible within: 72 hrs

Results 12

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

minimal redness of the coniunctivae in all animals at 4,24 and 48 hrs after instillation, completely reversible at 72 hrs
minimal chemosis at 4 hrs after instillation, completely reversible within 24 hrs

Other effects:

No other effects were observed at any timepoint . No weight loss, no mortality

Any other information on results incl. tables

Individual scores and mean scores over 24,48 an d 72 hrs:

		1 hr	24 hr	48 hr	72 hr	Mean score 24,48,72 hrs
Animal nr 34586, M	Cornea opacity	0	0	0	0	0
	Cornea area	0	0	0	0	0
	Iris	0	0	0	0	0
	Conjunctivae redness	1	1	1	0	0,7
	Conjunctivae chemosis	1	0	0	0	0
	Conjunctivae discharge	0	0	0	0	0
Animal nr. 34595, F	Cornea opacity	0	0	0	0	0
	Cornea area	0	0	0	0	0
	Iris	0	0	0	0	0
	Conjunctivae redness	1	1	1	0	0,7
	Conjunctivae chemosis	1	0	0	0	0
	Conjunctivae discharge	0	0	0	0	0
Animal nr. 34594, F	Cornea opacity	0	0	0	0	0
	Cornea area	0	0	0	0	0
	Iris	0	0	0	0	0
	Conjunctivae redness	1	1	1	0	0,7
	Conjunctivae chemosis	1	0	0	0	0
	Conjunctivae discharge	0	0	0	0	0

Individual body weights:

Animal nr	Sex	At initation	At 72 hrs
34586	male	2744	2834
34596	Female	2531	2720
34594	Female	2684	2695

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) produced minimal conjunctival redness at 4, 24 and 48 hrs fully reversible within 72 hours. There were no other sings of irritation and the test material was concluded to be not irritating to eyes.

Executive summary:

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) was tested in an in vivo eye irritation test according to OECD 405 under GLP. The mixture produced minimal conjunctival redness at 4, 24 and 48 hrs and minimal chemosis at 4 hrs, all fully reversible. The conclusion applies directly to the registered substance as well as indirectly by read-across from the structural analogue which is also present in the mixture.