5',5'''-[ethylenebis(p-phenyleneazo)]bis[1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-1,3'-bipyridinium] dilactate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Remarks:

source of read-across

Adequacy of study:

key study

Study period:

From 28th to 31st December, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

1981

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Similar substance 01

IUPAC Name:

Similar substance 01

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: David Percival Ltd., Moston, Sandbach, Cheshire, U.K.
- Age at study initiation: twelve to sixteen weeks old.
- Weight at study initiation: 2.23 - 2.67 g.
- Housing: animals were individually housed in suspended metal cages.
- Diet: Spillers Rabbit Diet, Dalgety Agriculture Ltd., Almondsbury, Bristol), ad libitum.
- Water: ad libitum.
- Acclimation period: minimum acclimatisation period of at least five days.

ENVIRONMENTAL CONDITIONS
- Temperature: 17 - 21 °C.
- Relative humidity: 52 - 62 %
- Air changes: approximately 15 changes per hour.
- Photoperiod: the lighting was controlled by a time switch to give 12 hours continuous light and 12 hours darkness.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

water

Controls:

yes, concurrent no treatment

Amount / concentration applied:

0.5 g of the test material, moistened with 0.5 ml of distilled water.

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

Three rabbits

Details on study design:

TEST SITE
- Area of exposure: on the day before the test each of a group of three rabbits was clipped free of fur from the dorsal/ flank area using veterinary clippers. Only animals with a healthy intact epidermis by gross observation were selected for the study. Test item moinstoned with water was introduced under a 2.5 cm × 2.5 cm gauze patch and placed in position on the shorn skin.
- Type of wrap if used: the patch was secured in position with a strip of surgical adhesive tape (BLENDERM: approximate size 2.5 cm × 4.0 cm). To prevent the animals interfering with the patches, the trunk of each rabbit was wrapped in an elasticated corset (TUBIGRIP).

REMOVAL OF TEST SUBSTANCE
- Removal: when the corset and patches were removed from each animal, any residual test material was removed by gentle swabbing with cotton wool soaked in diethyl ether.
- Time after start of exposure: four hours after application.

OBSERVATION TIME POINTS
Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation.

SCORING SYSTEM:
The test sites were examined and scored according to the following scale from Draize J.H. (1959) Association of Food and Drug Officials of the United States, Austin, Texas, "The Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics".

Evaluation of skin reactions
Erythema and Eschar Formation
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beet redness) to slight eschar formation (injuries in depth) 4

Oedema formation
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) 4

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal: 3/3

Time point:

24/48/72 h

Score:

< 2.3

Reversibility:

fully reversible within: 72 hours

Results 2

Irritation parameter:

edema score

Basis:

animal: 3/3

Time point:

24/48/72 h

Score:

< 2.3

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

The test material produced a primary irritation index of 0.3 and was classified as a mild irritant to rabbit skin, according to the Draize classification scheme.
No corrosive effects were noted.

Faint yellow-coloured staining caused by the test material was commonly noted during the study. This did not affect evaluation of skin responses.
Very slight erythema was noted at two treated skin sites one hour after patch removal and at the 24-hour observation and at one treated skin site at the 48-hour observation.
No adverse skin reactions were noted 72 hours after treatment.

Any other information on results incl. tables

Individual skin reactions

Skin reaction	Observation time (hrs)	Individual score
		176 (female)	181 (male)	186 (male)
Erythena	1	1STA	1STA	0STA
	24	1STA	1STA	0STA
	48	0STA	1STA	0STA
	72	0STA	0STA	0STA
Mean 24, 48, 72 hrs		0.3	0.7	0.0
Oedema	1	0	0	0
	24	0	0	0
	48	0	0	0
	72	0	0	0
Mean 24, 48, 72 hrs		0.0	0.0	0.0

STA = faint yellow-coloured staining

Applicant's summary and conclusion

Interpretation of results:

other: not classified, according to the CLP Regulation (EC1272/2008)

Conclusions:

Not irritant.

Executive summary:

A study was performed to assess the irritancy potential of the test material to the skin of the New Zealand White rabbit. The method used followed that described in the OECD guideline 404.

A single 4-hour, semi-occluded application of the test material to the intact skin of three rabbits produced very slight erythema. No adverse skin reactions were noted 72 hours after treatment. The test material produced a primary irritation index of 0.3 and was classified as a mild irritant to rabbit skin according to the Draize classification scheme. No corrosive effects were noted. Faint yellow-coloured staining caused by the test material was commonly noted during the study. This did not affect evaluation of skin responses. Very slight erythema was noted at two treated skin sites one hour after patch removal and at the 24-hour observation and at one treated skin site at the 48-hour observation. No adverse skin reactions were noted 72 hours after treatment.

Conclusion

Mean values from gradings at 24, 48 and 72 hours after patch removal were lower than 2.3 in all animals for both erythema/eschar and oedema reactions, thus the test item does not meet the criteria to be classified as irritating, according to the CLP Regulation (EC 1272/2008).