Sodium 4(-2-hydroxy-1-naphthylazo)naphthalenesulphonate

Endpoint summary

Description of key information

not skin irritant

not eye irritant

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/CORROSION

The degree of primary skin irritation caused by the test item was evaluate in a study performed according to the OECD Guideline No. 404 (2002) and the Method B.4 of European Communities Commission Directive of 31 July 1992 (92/69/EEC). Initially three semiocclusive patches were applied with 0.5 g of test item simultaneously to one animal for 3 minutes, 1 and 4 hours, respectively. A semiocclusive patch with 0.5 g of test item was applied for 4 hours in the other two animals. The observation time points were at 1, 24, 48, 72 hours and 7, 14 days after the administration.

In all animals the mean scores (24/48/72 h) for erythema were 1, while for oedema the mean value was 0.33 in one animal (#1) and 0 in the other two animals (#2 and #3). No skin lesions were recorded in any of the animals during the observations made 7 and 14 days after removing the patch.

Additionally, another experimental study is available which confirms, for oedema scores, the absence of a skin irritanting potential of the substance.

Skin irritation and corrosion potential of the test item was evaluated in an experimental study. The left and right flanks of 6 male New Zealand White Albino Rabbits were clipped, and the right flanks were additionally scarred. 500 mg of moistened test item was applied to both flanks using a saturated gauze patch and an occlusive bandage. The trunk of the animal was wrapped, and the animals were immobilised for 24 hours, after which the bandage and test item were removed and a 24-hour irritation score for erythema and oedema was recorded. Additional irritation scores were taken at 48 hours, 72 hours and 8 days.

48-hour scores were emitted from the results reported in the study; therefore, in order to calculate the mean score of 24, 48 and 72 hours, a worst-case approach was used and either the 24-hour or 72-hour score was used for the 48-score, whichever was the higher. Erythema was not able to be evaluated as the test item discoloured the local skin area. Mean (24, 48 and 72 hour) oedema scores for the 6 test animals were not ≥2.3 in 4 out of 6 animals. Oedema was still present in one test animal at the end of the study period (8 days). According to the CLP Regulation (EC 1272/2008), irreversibility is determined if effects are present after 21 days, however the study duration used was only 8 days, therefore, reversibility is not able to be determined.

In conclusion, based on these findings, the test item is not expected to be irritating to the rabbit skin, however, a complete evaluation of the irritation potential is not possible.

 

EYE IRRITATION/CORROSION

The degree of primary eye irritation caused by the test substance was evaluated in a study performed according to the OECD Guideline No. 405 (2002) and the Method B.5 of the European Communities Commission Directive (92/69/EEC) of 31 July 1992d. 0.1 g of test item was administered to the right eye of three animals; the left eye remained untreated and was used as a control. The observations following the administration were at 1, 24, 48, 72 hour and 7, 14 day.

The mean values (24/48/72 h) for the iris were 0 in all animals, while for the corneal opacity were 0 in two animals (#1 and #3) and 0.67 in one animal (#2). The conjunctival oedema (chemosis) mean scores were 0.33 in all animals, while the conjunctival redness ones were 0.67 in one animal (#1) and 1.33 in the other two animals (#2 and #3). No ocular lesions were recorded in any of the treated animals 7 days after the administration.

Additionally, another experimental study is available which confirms the absence of an eye irritanting potential of the substance.

The eye irritation potential of the test item was evaluated in an experimental study. 100 µL of moistened test item was applied directly into the lower conjunctival sac of the right eye of 6 male, albino New Zealand White rabbits. Eyelids were held closed for 1 second and eyes were not rinsed. The left eye served as a negative control. Corneal opacity, iritis, conjunctival redness and conjunctival swelling were evaluated at 24, 48 and 72 hours and 8 days after application using an ophthalmoscope and 1 drop of fluorescein. Mean (24, 48 and 72 hour) irritation scores were calculated for each animal.

The mean (24, 48 and 72 hour) corneal opacity score of animal #1 was 1.0 and corneal opacity was reversible within 8 days. All other animals were allocated a corneal opacity score of 0. Iritis, conjunctival redness and chemosis scores for all animals were 0.0.

Justification for classification or non-classification

SKIN IRRITATION/CORROSION

According to the CLP Regulation (EC) No 1272/2008 substances that have the potential to induce reversible damage to the skin following the application of a test substance for up to 4 hours are classified in Category 2 (irritating to the skin) if:

-mean value of ≥ 2.3 ≤ 4.0 for erythema/eschar or for oedema in at least 2 of 3 tested animals from readings at 24, 48 and 72 h after patch removal or, if reactions are delayed, from grades on 3 consecutive days after the onset of skin reactions; or

-inflammation that persists to the end of the observation period normally 14 d in at least 2 animals, particularly taking into account alopecia (limited area), hyperkeratosis, hyperplasia, and scaling; or

-in some cases where there is pronounced variability of response among animals, with very definite positive effects related to chemical exposure in a single animal but less than the criteria above.

Based on the available experimental data of skin irritation, the mean scores (24/48/72h) of erythema and edema were lower than the range of ≥ 2.3 - ≤ 4.0; therefore the substance is not classified for skin irritation according to the CLP Regulation (EC) No 1272/2008.

 

EYE IRRITATION

According to the CLP Regulation (EC) No 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 h after installation of the test material, and which fully reverses within an observation period of 21 d.

Based on the available experimental data of eye irritation, the mean scores (24/48/72h) of corneal opacity and iritis were not ≥ 1 and conjunctival redness and conjunctival oedema (chemosis) were not ≥ 2. Moreover, all effects observed were fully reversible. Therefore, the substance is not classified for eye irritation according to the CLP Regulation (EC) No 1272/2008.