Disodium 7-amino-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Disodium 7-amino-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate

EC Number:

228-589-1

EC Name:

Disodium 7-amino-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate

Cas Number:

6300-50-1

Molecular formula:

C22H17N5O7S2.2Na

IUPAC Name:

disodium 7-amino-4-hydroxy-3-({4-[(4-sulfonatophenyl)diazenyl]phenyl}diazenyl)naphthalene-2-sulfonate

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

For the purpose of the study the test item was ground to a fine powder using a mortar and pestle and weighed out according to each animal’s individual body weight. The test item was moistened with distilled water prior to application.
The absorption of the test item was not determined.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

3.3.1 Animal Information
Five male and five female Wistar (RccHanTM:WIST) strain rats were supplied by Envigo RMS (UK) Limited, Oxon, UK. On receipt the animals were randomly allocated to cages. The females were nulliparous and non-pregnant. After an acclimatization period of at least 5 days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals weighed at least 200 g, and were 8 to 12 weeks of age. The weight variation did not exceed ±20% of the mean weight for each sex.
3.3.2 Animal Care and Husbandry
The animals were housed in suspended solid floor polypropylene cages furnished with woodflakes. The initial two animals were housed individually throughout the study. The further group of eight animals (four male and four female) were housed individually during the 24-Hour exposure period and in groups of four, by sex, for the remainder of the study. Free access to mains drinking water and food (2014C Teklad Global Rodent diet supplied by Envigo RMS (UK) Limited, Oxon, UK) was allowed throughout the study. The diet, drinking water and bedding were routinely analyzed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
The temperature and relative humidity were set to achieve limits of 19 to 25ºC and 30 to 70% respectively. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give 12 hours continuous light and 12 hours darkness.
The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

Applied on an area of shorn skin (approximately 10% of the total body surface area).

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5 males, 5 females

Control animals:

no

Details on study design:

On the day before treatment the back and flanks of each animal were clipped free of hair.

In the absence of data suggesting the test item was toxic, one male and one female rat were initially treated with the test item at a dose level of 2000 mg/kg.

The appropriate amount of test item, moistened with distilled water, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area). A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage. The animals were caged individually throughout the study. Shortly after dosing the dressings were examined to ensure that they were securely in place.

After the 24-Hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test item.

As no mortalities were noted a further group of animals (four males and four females) was similarly treated with the test item at a dose level of 2000 mg/kg body weight to give a total of five males and five females. The animals were caged individually for the 24-Hour exposure period. After the 24-Hour contact period the bandages were carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test item. These animals were returned to group housing for the remainder of the test period.

The animals were observed for deaths or overt signs of toxicity 30 minutes, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days.

After removal of the dressings and subsequently once daily for 14 days, the test sites were examined for evidence of primary irritation and scored according to the following scale:

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 (beef redness) to slight eschar formation (injuries in depth), 4

Edema Formation
No edema, 0
Very slight edema (barely perceptible), 1
Slight edema (edges of area well-defined by definite raising), 2
Moderate edema (raised approximately 1 millimeter), 3
Severe edema (raised more than 1 millimeter and extending beyond the area of exposure),4

Any other skin reactions, if present were also recorded.
Individual body weights were recorded prior to application of the test item on Day 0 and on Days 7 and 14.
At the end of the study the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

no indication of skin irritation up to the relevant limit dose level

Mortality:

There were no deaths.

Clinical signs:

other: There were no signs of systemic toxicity.

Gross pathology:

No abnormalities were noted at necropsy

Other findings:

Dermal Irritation. No signs of dermal irritation were noted at the test sites of the two initial treated animals. Very slight erythema was noted at the test sites of the further group of eight animals. Other signs of dermal irritation noted were small superficial scattered scabs, glossy skin and scab lifting to reveal glossy skin

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2000 mg/kg body weight.