Reaction mass of 5,5'-[sulphonylbis(3,1-phenyleneazo)]bis[6-amino-4-hydroxynaphthalene-2-sulphonic acid] and disodium 5,5'-[sulphonylbis(3,1-phenyleneazo)]bis[6-amino-4-hydroxynaphthalene-2-sulphonate]

Endpoint summary

Description of key information

Not skin irritating

Not eye irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

SKIN IRRITATION

The skin corrosion / irritation potential of the Target Substance was investigated using a specific QSAR model, developed to predict the skin corrosion / irritation for dyes. The existing QSAR models have strong limitations to predict ionic complex structures as the organic dyes are, and consequently they provide unreliable results. The QSAR modelling used was developed in accordance with the OECD principles (SKIN CORROSION / IRRITATION QSAR MODEL REPORT N. 15).

Based on the estimation, the substance is expected to be potentially not skin irritant. The estimation resulted to be in the applicability domain of the model.

 

In order to confirm the results obtained by the QSAR prediction, the investigations performed on two analogue substances (Similar Substance 01 and Similar Substance 02) are used as support of the prediction. Justification for Read Across is given in Section 13 of IUCLID.

 

The potential of the Similar Substance 01 to be irritant to the skin was investigated through an in vitro skin irritation study using a commercial reconstructed human epidermis (RhE) model named EPISKIN™. The experimental procedures were based on the OECD Guideline for testing of chemicals no. 439, in GLP. A preliminary test was carried out to evaluate the compatibility of the test item with the test system. In a first step, the test item was assayed for the ability of reducing MTT per se. An orange solution, without precipitate, was observed in the MTT suspension at the end of the incubation period, indicating that the test item could not interact with MTT. In a second step, the test item was assayed for the ability of colouring water per se. In the Main Assay, the test item was applied as supplied in three replicates at the treatment level of 20 mg/epidermis unit (15.4 mg of active constituent/epidermis unit), with positive and negative controls. The mean cell viability of the test item treated tissues, after the appropriate background subtraction, was 105.5 %. Therefore, the substance is not classified as skin irritant.

 

The potential of the Similar Substance 02 to be irritant to the skin was investigated through two in vivo tests.

The fist skin irritation test was performed to rabbit skin according to the OECD guideline 404.

The test substance was found to be not irritant when applied to clipped rabbit skin. The erythema scores were not possible to be assessed due to substance-related skin colour; after 8 days the erythema scores were 0 in all animals (mean values 24/48/72 hours). In two animals the oedema scores were 0 and in one rabbit was 0.33 (mean values 24/48/72 hours).

The second skin irritation test was performed to rabbit skin according to the Code of Federal Regulations" Title 16, Sections 1500.41". 0.5 g of the test item were applied to clipped and abraded skin of 6 rabbits. The duration of the application was 24 hours and the readings were performed after 1 and 48 hours and 7 days.

The purple colour of the test substance made the macroscopic examination of the erythema inaccurate at 1 hour-observation. The erythema and the oedema scores were calculated following the mean values after 24/48/72 h. For the scores at 48 h the greater value observed during the test was considered, as no observation was performed at this time-point. The erythema scores (mean values 24/48/72 hours) were 0.67 in four animals (animals #1,#3, #4 and #5), 1.33 in animal #2 and 0 in animal #6. The oedema scores (mean values 24/48/72 hours) were 0 in all animals.

EYE IRRITATION

The eye damage / irritation potential of the Target Substance was investigated using a specific QSAR model, developed to predict the eye damage / irritation potential for dyes. The existing QSAR models have strong limitations to predict ionic complex structures as the organic dyes are, and consequently they provide unreliable results. The QSAR modelling used was developed in accordance with the OECD principles (EYE DAMAGE / IRRITATION QSAR MODEL REPORT N. 14).

Based on the estimation, the substance is expected to potentially not eye irritant. The estimation resulted to be in the applicability domain of the model.

 

In order to confirm the results obtained by the QSAR prediction, the investigations performed on two analogue substances (Similar Substance 01 and Similar Substance 02) are used as support of the prediction. Justification for Read Across is given in Section 13 of IUCLID.

 

An vitro study was performed to assess the corneal damage potential of the Similar Substance, according to the OECD Guideline for the Testing of Chemicals, Method No. 437 and the EU Method B. 47 of the Regulation (EU) No. 1152/2010 amending Regulation (EC) No. 440/2008, in GLP. One valid experiment was performed. Bovine corneas were collected from slaughtered cattle which were between 12 and 60 months old. The test item was brought onto the cornea of a bovine eye which had been incubated with cMEM without phenol red at 32 °C for 1 hour and whose opacity had been measured. The test item was incubated on the cornea for 4 hours at 32 °C. After removal of the test item, opacity and permeability values were measured. The negative control (HBSS solution) and the positive control (20% imidazole solution) have met the validity criteria. No observations were made which might cause doubts concerning the validity of the study outcome. The test is considered valid. Under the conditions of this study, the test item showed effects on the cornea of the bovine eye. The calculated IVIS (in vitro irritancy score) is 21.97.

 

The potential of the Similar Substance 02 to be irritant to the skin was investigated through two in vivo tests.

The first eye irritation test was performed to rabbit eye according to the OECD guideline 405. Mean values at 24, 48 and 72 hours for iris and corneal opacity were 0.00 in all three animals. The test item caused staining of conjunctivae in all animals at the 1-hour reading. The conjunctivae scores as mean values at 24, 48 and 72 hours were: in animals #1 and #2 redness 0.67 and chemosis 0.33; in animal #3 redness 1 and chemosis 1. All effects observed were fully reversible within the end of the study period.

The second eye irritation test was performed according to the guideline inserted into the "Code of Federal Regulations", Title 16, Section 1500.42. 100 mg of the test item were introduced into the right eye of six rabbits; the left eye served as a control. Evaluations were made by comparison with the control eye. The readings were made 1, 24, 48 hours and 4 and 7 days after the administration of the test substance.

The substance was tested for eye irritation according to the guideline inserted into the "Code of Federal Regulations", Title 16, Section 1500.42. 100 mg of the test item were introduced into the right eye of six rabbits; the left eye served as a control. Evaluations were made by comparison with the control eye. The readings were made 1, 24, 48 hours and 4 and 7 days after the administration of the test substance. In all animals the effects on the cornea, iris or conjunctiva were reversible within the 7 day-study period. The only two effects that were not reversible within the observation period were chemosis (grade 1 in animal #3) and iritis (grade 1 in animal #6). It should be noted that the eyes were not rinsed. Moreover, considering that the rest of the effects were reversible within the observation period, it could be expected that the latest effects will reverse within the 21 day-period (as reported in the CLP Regulation) instead of the 7 day-observation period. Only three animals out of six showed a mean score (24/48/72 h)≥1 for corneal opacity and for iritis (#2, #3, #4 and #2, #3, #6 respectively). All animals showed conjunctival erythema (redness) and oedema (swelling) (chemosis)mean values (24/48/72 h) < 2, except for one animal (#2: chemosis 2.33).

Justification for classification or non-classification

SKIN IRRITATION

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. However, in vitro/in chemico alternatives that have been validated and/or accepted may also be used to make classification decisions.

Based on the results of skin irritation/corrosion, no classification for skin irritation/corrosion is warranted under the CLP Regulation (EC 1272/2008).

EYE IRRITATION/CORROSION

According to the CLP Regulation (EC 1272/2008), serious eye damage means the production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance, which is not fully reversible within 21 days of application. Eye irritation means the production of changes in the eye, which are fully reversible within 21 days of application. In vitro/in chemico alternatives that have been validated and/or accepted can be used to make classification decisions.

Based on the results of eye irritation/damage, no classification for eye irritation/damage is warranted under the CLP Regulation (EC 1272/2008).