Trisodium bis[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-4-hydroxy-5-nitrobenzenesulphonato(3-)]chromate(3-)

Endpoint summary

Description of key information

Not skin irritating.

Eye irrit. 2 (H319).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Test procedures cannot be subsumed under testing guideline today commonly used in the ambit of the REACH Regulation, nevertheless they followed other internationally accepted guideline, are well documented and scientifically acceptable. Justification for Read Across is detailed in the endpoint summary.

Principles of method if other than guideline:

The procedure adopted was the patch-test technique described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO).

GLP compliance:

no

Remarks:

pre GLP

Species:

rabbit

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Bred: rabbits of the Russian breed.
- Weight at study initiation: 1.5 to 2 kg
- Housing: in order to prevent injuries by bites the rabbits were kept separately in V2A wire cages.
- Diet: ad libitum, standard rabbit food - NAFAG, Gossau SG, rabbit food.
- Water: ad libitum.

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

other: polyethylene glycol (PEG 400)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 g

VEHICLE
- Concentration: before application a 50 % polyethylene glycol trituration (PEG 400) was made.

Duration of treatment / exposure:

24 hours

Number of animals:

3 males and 3 females

Details on study design:

TEST SITE
- Area of exposure: rabbits were shaved on the whole back and flanks two days before treatment with an electric clipper. The shaven skin on the left side was slightly scarified immediately before treatment.
- Application: a gauze patch 2.5 x 2.5 cm was soaked with the test substance and immediately applied to the prepared skin..
- Type of wrap if used: the patch was covered with a plastic film 5 x 5 cm, which was fixed to the body with adhesive tape.

SCORING SYSTEM
The reaction of the skin was appraised upon removal and 72 hours after it. The primary irritation index as the measure of the acute skin irritation provoked by the test substance is defined as the average of all the ratings found after 24 and 72 h on the intact and slightly scarified skin.
Compounds producing combined averages (primary irritation indexes) of 2 or less are only mildly irritating; whereas those with indexes from 2 to 5 are moderate irritants, and those with scores above 6 are considered severe irritants.

Score for skin irritation in rabbits:
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
Maximum possible: 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 mm): 3
Severe oedema (raised more than 1 mm and extending beyond area of exposure): 4

Irritation parameter:

erythema score

Basis:

animal: all tested animals

Time point:

24/48/72 h

Score:

0

Reversibility:

other: No dermal effects observed

Irritation parameter:

edema score

Basis:

animal: All tested animals

Time point:

24/48/72 h

Score:

0

Reversibility:

other: No dermal effects observed

Irritant / corrosive response data:

The primary irritation index as the measure of the acute irritation to the skin of rabbits was found to be 0.

Evaluation of the skin reaction

Animal No. (sex)	Skin Reaction	24 h after application		72 h after application
		Intact skin	Abraded skin	Intact skin	Abraded skin
1 M	Erythema	0	0	0	0
	Oedema	0	0	0	0
2 M	Erythema	0	0	0	0
	Oedema	0	0	0	0
3 M	Erythema	0	0	0	0
	Oedema	0	0	0	0
4 F	Erythema	0	0	0	0
	Oedema	0	0	0	0
5 F	Erythema	0	0	0	0
	Oedema	0	0	0	0
6 F	Erythema	0	0	0	0
	Oedema	0	0	0	0

Interpretation of results:

not classified

Remarks:

Migrated information according to the CLP Regulation Criteria used for interpretation of results: EU

Conclusions:

Not irritating.

Executive summary:

Method

The purpose of this test was to determine the primary-irritation index, which serves as a measure of the acute irritation, provoked by the compound on the skin of the rabbits. The procedure adopted was the patch-test technique described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO). Before treatment the whole back and the flank of the rabbits were shaved and immediately before treatment the shaven skin on the left side was slightly scarified. A gauze patch of 2.5 x 2.5 cm was soaked with the test substance (0.5 in 50 % PEG) and it was applied to the prepared abraded and intact skin. The patches were covered with a plastic film, which was fixed to the body with adhesive tape. The dressings were removed after a 24 hour exposure and the reaction of the skin was appraised upon removal and 72 hours after it.

Results

The primary irritation index as the measure of the acute irritation to the skin of rabbits was found to be 0.

Conclusion

The scoring system criteria used to record the hardness of the skin reactions followed in the current test are the same as those reported into the OECD guideline, therefore it is possible to re-evaluate the results, because the raw tables are included into the study report.

Despite the reaction scores at 48 hours were not reported, the mean value scored is reasonably expected to be less than 2.3 for erythema/eschar and for oedema in at least 2 of 3 tested animals from gradings at 24, 48 and 72 hours after patch removal, in both the cases of intact and abraded skin.

In conclusion, it is reasonable to state that the substance does not meet the criteria to be classified as skin irritant, according to the CLP Regulation (EC 1272/2008).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Currently, there is only a summary reporting some toxicological test results on Acid Red 357 (AR357); unfortunately the original study reports are not more available. Thus, in order to assess the potential irritation for both skin and eye of the Acid Red 357 (AR357), the available data on the structural analogue Acid Red 315 (AR315 - Similar Substance 01) were considered.

AR357 and AR315 have a comparable molecular weight, steric hindrance, polarisation of the whole molecule and both are very water soluble (418.11 g/l at 20 °C and pH 6.84 and 135 g/l at 20 °C, respectively). The respective partition coefficients (log Pow: -1.49 in the case of AR357 and log Pow: 1.15 in the case of AR315) show that both substances have a greater affinity with the water phase, than the octanol phase.

AR357 and AR315 are chromate pyrazol sodium salts: AR357 is a trisodium, while AR315 is a disodium salt. They share the same structure, except for the fact that AR357 has two sulphonated groups, instead one as AR315. These differences are expected to not impact the study outcomes, thus the read across can be considered as reliable.

SKIN IRRITATION

The available information included in the toxicological test results summary related to the AR357 indicates the substance as non skin irritating (DyStarColours Distribution GmbH, 1975).

Two tests are available on AR315, both the original study reports are missing of some information: amount of the tested substance in one case and raw tables reported all the data about the evaluation of the skin reactions in the other one.

The procedure adopted was the patch-test technique described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO). The test materials were applied to the prepared abraded and intact skin by occlusive coverage. The dressings were removed after a 24 hour exposure. The scoring system criteria used to record the hardness of the skin reactions followed in the current test are the same as those reported into the OECD guideline, therefore it is possible to re-evaluate the results according to the CLP Regulation (EC 1272/2008). Despite in the older study the reaction scores at 48 hours were not reported, the mean value scored is reasonably expected to be less than 2.3 for erythema/eschar and for oedema in at least 2 of 3 tested animals from gradings at 24, 48 and 72 hours after patch removal, in both the cases of intact and abraded skin, as observed in the other study.

EYE IRRITATION

The available information, included in the toxicological test results summary related to the AR357, indicates the substance as eye irritating and the classification under the Directive 67/548/EEC as R36 is reported (DyStarColours Distribution GmbH, 1975).

Two tests were performed on AR315, which were here reported in a weight of evidence approach because both the original study reports are missing of some information useful to conclude a classification according to the CLP Regulation (EC 1272/2008).

The substance was tested on 6 rabbits in both the experiments; amounts of 0.1 g of the test substance were introduced into the conjunctival sac. The eyes of 3 animals were rinsed 30 seconds after application. The eye irritation was appraised with a slit lamp on day 1, 2, 3, 4 and 7.

In one case the irritation index was calculated to be 13.9 for the cornea, 0 for the iris and 14.4 for the conjunctivae, showing a moderate overall eye irritation; in this case, rinsing the eyes following instillation increased the effect of the test substance (Huntsman Textile Effects (Germany) GmbH, 1978).

In the other test, the irritation index was found to be 8 for the cornea, 0 for the iris and 4.9 for the conjunctivae and the test substance was considered to be slightly irritating to the eye of rabbits (Huntsman Textile Effects (Germany) GmbH, 1975).

The criteria for the evaluation of the eye irritation potential followed in these tests are different from those reported into the OECD guideline. The scoring system used for the cornea opacity and degree of density, for the iris and conjunctivae redness and chemosis is the same of that reported into the OECD, but the timing for the removal of the substance are very different (30 seconds in the current study and 1 hours in the OECD).

Unfortunately, the raw tables are not included into the study report and thus, the results cannot be re-evaluated, according to the CLP Regulation (EC 1272/2008).

In both tests iris was not impacted. Cornea was impacted: in the older study the severity of reactions scored was lower than in the more recent one and the effects were recovered in 4/6 animals within 4 days. In a similar manner, conjunctivae appeared more affected in the more recent study, than in the older one.

Taken into account all the results and that in all cases and for all the injuries observed the severity of the reactions scored decreases day by day, a classification as substance able to cause serious eye irritation (Eye irrit. 2, H319) is proposed, according to the CLP Regulation (EC 1272/200).

REFERENCE

DyStarColours Distribution GmbH (1975). Ergebnis der gewerbetoxikologischen vorprüfung. Testing laboratory: BASF Aktiengesellschaft. Report no.: XXV. Owner company: DyStarColours Distribution GmbH. Report date: 1976-12-02.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.2 Skin corrosion/irritation section, skin Irritation means the production of reversible damage to the skin following the application of a test substance for up to 4 hours.

The mean value is reasonably less than 2.3 for erythema/eschar and for oedema in all the tested animals, from gradings at 24, 48 and 72 hours after patch removal.

In conclusion, the substance is not classify as skin irritant, according to the CLP Regulation (EC 1272/2008).

According to the CLP Regulation (EC 1272/2008) substances that have the potential to induce reversible eye irritation are classified in Category 2 (irritating to eyes) if, when applied to the eye of an animal, a substance produces at least in 2 of 3 tested animals, a positive response of corneal opacity ≥ 1 and/or iritis ≥ 1, and/or conjunctival redness ≥ 2 and/or conjunctival oedema (chemosis) ≥ 2, calculated as the mean scores following grading at 24, 48 and 72 hours after installation of the test material, and which fully reverses within an observation period of 21 days.

Iris is not impacted. Cornea can be injured at different grades of severity, nevertheless the effects can be recovered. Impact on conjunctivae cannot be judged, on the basis of the studies available.

Taken into account all the results and that in all cases and for all the injuries observed the severity of the reactions scored decreases day by day, a classification as substance able to cause serious eye irritation is proposed.

Thus, the test item is classified as irritating to eye, category 2 (H319) according to the CLP Regulation (EC 1272/2008).