Barium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate

Endpoint summary

Description of key information

Pigment Red 57:2 is not irritating to eyes and skin of rabbit based on data of the analogue Pigment Red 48:1 (BASF AG 1974 and Ciba 1973).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The substances displayed below are considered read-across analogues based on similar physico-chemical and toxicological properties of the pigments. The substance of this chemical sub-class (monohydrazone pigments, BONA pigment lakes) include an organic part, bearing an aminosulfonic acid coupled onto hydroxy-naphthoic acid, and an inorganic cation represented by an alkaline earth metal such as manganese, strontium or calcium. Thus, the read across is also based on structural similarities as a result of equal manufacturing processes. All BONA Metal Laked Pigments are of low solubility in water and octanol. Dissociation of these metal salt pigments, which is enhanced under a highly acidic condition (such as in the stomach), leads, at least partially, to the release of the metal cation and the organic acid. Therefore, the impact of the metal component and the organic acid is discussed separately. In addition, toxicological information on moieties is available, which provides supporting information regarding the effect of substituents on the toxicological profile. Moreover, reductive cleavage of the azo bond, catalysed by (microbial) azo-reductase or other reductive liver enzymes, may result in the release of these moieties which therefore represent (common) metabolites. Hazard assessment of the metals is assessed by inclusion of information on inorganic soluble salts of the metals.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Colour index name CAS number EINECS number
Pigment Red 57:1(Ca) 5281-04-9 226-109-5
Pigment Red 57(Sr) 73612-29-0 277-552-6
Pigment Red 57:2 (Ba) 17852-98-1 241-806-4
Pigment Red 48:1(Ba) 7585-41-3 231-494-8
Pigment Red 48:2(Ca) 7023-61-2 230-303-5
Pigment Red 48:3(Sr) 15782-05-5 239-879-2
Pigment Red 48:4(Mn) 5280-66-0 226-102-7
Pigment Red 52(Sr) 67828-72-2 267-291-6
Pigment Red 52:2(Mn) 12238-31-2 241-780-4

Tested products contain at least 80% of the colorant. Purities range from 80% to 90%. Typical impurities are low levels of the starting materials 3-hydroxy-2-naphthoic acid (BONA) and the coupling amine, water of crystallization and free water as depicted in Table 3. Due to the lacking process in synthesis, all substances contain a fraction of the corresponding sodium salt. No impurity was considered to cause any concern regarding human toxicology. Impurities were reported to have no classifications according to information provided by ECHA (https://echa.europa.eu/de/information-on-chemicals/cl-inventory-database).


3. ANALOGUE APPROACH JUSTIFICATION
It is referred to the attached pdf file.

4. DATA MATRIX
It is referred to the attached pdf file.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Species:

rabbit

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

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

Experimental data is available for Pigment Red 48:1, which differs from Pigment Red 57:2 by the presence of a chloro substituent at the sulfonated phenyl ring. This does not affect irritating properties.

Skin irritation was investigated in two rabbit studies (BASF AG 1974 and 1974, Ciba 1973). During the key study, two rabbits were treated with a commercial product for up to 20h using occlusive conditions. No abnormalities were detected at the 1 and 8 day readings (BASF AG 1974), but red residues on the skin interfered with erythema scoring. Very mild erythema and absence of edema were observed at the 24 and 72h reading in a study following the standard procedure of the The Food and Drug Administration of the U.S.A. in The Federal Register (17 September, 1964 § 191.11) (Ciba 1973). This involves 24h occlusive application and represents a worse case than the 4h semi-occlusive application required by the OECD testing guideline for skin irritation. Absence of irritating properties is given in valid experimental data on Bona metal laked pigments in general. The study performed with Pigment Red 57:1 in 1987 by K. O’Brian was chosen as key study for skin irritation because it was performed with a commercial sample according to the OECD testing guideline 404 (1981) and GLP and contains detailed sample information such as composition, origin and storage conditions in the study report. 

Overall, Pigment Red 57:2 is considered to be non irritating to skin.

 

Assessment of eye irritation was performed in two rabbit studies performed with commercial products of Pigment Red 48:1 according to a protocol similar to OECD testing guideline 405. The main difference is that there are limited details on non-irritation related parameters such as body weight. Slight and transient redness of conjunctivae and no findings on iris and cornea were observed (Ciba 1973, BASF AG 1974). Reliable data is also available for analogue Bona metal laked pigments: The key study for eye irritation (O’Brian 1987) was performed with a commercial product following OECD testing guideline 405 (1987) and the principles of GLP. The commercial product was of adequate pigment content and caused slight conjunctival redness in all animals at 1 hour and in one male and one female 24 hours after compound application. Minimal chemosis and a compound stained slight ocular discharge were seen in one male and one female 1 hour after application of the test article. All eyes were normal within 48 hours after application of the test article. The findings are attributed to the additives rather than the pigment itself and are typical for most studies. It is concluded that Pigment Red 57:2 is not irritating to eyes.

 

Experimental data on respiratory irritation is not available.

Justification for classification or non-classification

 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 not considered to be classified for skin and eye irritation under Regulation (EC) No. 1272/2008.