Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Additional information:

Reasons for read across

The test item is the sodium salt of a naphthoic acid. Therefore, data on the free acid may give an indication on the allegenic potential of the sodium salt, the limitation being differences in irritating properties and the concentrations are suitable for testing.

Studies in Animals

3-Hydroxy-2-naphthoic acid (commercial grade) was sensitising in a modified guinea pig maximization test (Okada et al., 1985). The deviation from the OECD TG 406 was that the epicutaneous challenge was performed under open (and not occlusive) conditions. Since the test gave a positive result, this modification is not considered to compromise the validity and reliability of the test. At challenge, 6 out of 9 animals had positive reactions towards the 1 % preparation in acetone, but did not react towards a 0.1 % preparation, indicating an elicitation threshold between 0.1 and 1%. 3-Hydroxy-2-naphthoic acid (purity 98.5%) was not sensitising in a guinea pig maximization test performed with only 10 animals (challenge concentration 0.25%). Due to the small number of animals in the latter test, it cannot be concluded that 3-hydroxy-2-naphthoic acid is not a sensitizer; however, its potency may be low.

Studies in Humans

In humans, no skin sensitisation was seen when 36 subjects (28 healthy, 8 suffering from dermatitis) were patch-tested (48-hr covered contact) with 1% 3-hydroxy-2-naphthoic acid in petrolatum (Kozuka et al., 1980). Due to the small number of subjects, no final assessemant regarding the sensitising potential of 3-hydroxy-2-naphthoic acid in humans can be drawn from this study.

Conclusion

3-Hydroxy-2-naphthoic acid has a skin sensitisation potential. 3-Hydroxy-2-naphthoic acid (1% in acetone) was a sensitiser in a guinea pig maximization test after open epicutaneous challenge. Patch-tests in 36 humans gave no indication of a sensitising effect, however no conclusions can be drawn from these limited studies in humans regarding the skin sensitisation potential of 3 hydroxy- 2-napthoic acid.


Migrated from Short description of key information:
The free acid was tested for its allergenic potential in several studies in animal and human (OECD SISDS SIAM 19). The substance caused positive reactions in a modified maximization assay (Okada et al, 1985). Another guinea pig maximization assay (Hoechst 1988) and a patch test in human (Kozuka et al 1980) gave no positive results. Due to strong deviations from OECD protocols, the small number of animals or patients, respectively, the data are inconclusive and not suitable for a statement on classification.

Justification for classification or non-classification

The data mentioned above are from secondary sources. Due to strong deviations from OECD protocols, small numbers of animals or patients, respectively, the information are inconclusive and not suitable for a statement of classification.