Sodium 3-hydroxy-2-naphthoate

Endpoint summary

Description of key information

The free acid was tested for skin and eye irritation in several studies (OECD SISDS SIAM 19). The substance caused mild to moderate irritationto skin under occlusive and semi-occlusive conditions. Application of the free acid into the conjunctival sac of the eye (OECD 405) caused moderate opacitiy, conjunctivitis and swelling. Corneal effects were not reversible within the 14 day observation period. It is expected that the sodium salt is less irritating than the free acid. Therefore the overall conclusion is "irritating to eyes".

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:

adverse effect observed (irritating)

Additional information

Reasons for read across

The test item is the sodium salt of the tested free acid. Data on the free acid is considered the worst case scenario due to the lower pH. Therefore, it is acceptable to derive irritation hazard from the free acid.

Statement of irritation potential (OECD SIDS SIAM 19)

In a skin irritation study performed under semi-occlusive conditions according to OECD TG 404, the moistened test substance was slightly irritating to the skin of rabbits (Draize scores of 0.3 each for erythema and edema). Very slight erythema and edema (both barely perceptible) were observed 1 hour and 24 hours after removal of the patches. The effects were completely reversible within 48 hours.

In another study, when the substance was applied to guinea pigs as a 12% solution in a mixtures of acetone and olive oil, and held in contact with the skin for 24 hours under occlusive conditions, the skin became edematous, necrotic, and there was some subcutaneous hemorrhage. In three guinea pigs, treated similiarly with 5-20 ml/kg of a 10% solution in a mixture of acetone and corn oil, it produced from slight to moderate irritation up to necroses, depending on the dose. Due to the use of acetone in the vehicle, this study is not considered for classification.

In an eye irritation study performed according to OECD TG 405, the moistened test substance (BONA free acid) caused serious damage to the eyes of rabbits. 1 hour after application, swelling and conjunctival injection as well as secretion (clear, tinted by the test substance) were observed in all three animals. At 24, 48 and 72 hours, conjunctivitis and diffuse corneal opacities were found. One animal showed iritis at 24 and 48 hours. Mean Draize scores (24-72 h): corneal opacity: 1.1, iris: 0.2, conjunctivitis: 1.9, conjunctival swelling: 1.3. At 7 days after the application, corneal erosion and vascularization were observed in all animals. The effects were not reversible until study end (14 days after treatment).

Conclusion

Moistened 3-hydroxy-2-naphthoic acid was slightly irritating to the skin of rabbits in a test performed according to OECD TG 404. Skin necroses and subcutaneous hemorrhages were observed in guinea pigs after occlusive exposure for 24 hours to the 10-12% solution in a mixture of acetone and olive oil or corn oil.

The substance caused serious damage to the eyes of rabbits in a test performed in accordance with OECD TG 405 (corneal vascularization / opacity).

For the sodium salt, the irritation effects are assumed to be less severe, so the effects are predicted to be reversible within 21 days.

Effects on eye irritation: irritating

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified as irritating for skin under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC. It is classified as irritating to eyes.

 

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is considered to be classified for eye irritation under Regulation (EC) No. 1272/2008.