4-hydroxy-6-(methylamino)naphthalene-2-sulphonic acid

Endpoint summary

Description of key information

Skin irritation

The dermal irritation potential of target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was assessedin various experimental studies which were conducted on rabbits and rats for target chemical4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) and its structurally similar read across substancesDisodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7 –disulphonate [CAS No: 3567-69-9], 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7). The predicted data usingQSAR toolboxhas also been compared with the experimental data.Based on the available data for the target and read across substances and applying the weight of evidence approach, it can be concluded that chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) is unable to cause skin irritation and thus considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

 

Eye irritation

An ocular irritation potential of target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was assessedin various experimental studies which were conducted on rabbits for target chemical4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) and its structurally similar read across substances7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7). The predicted data usingQSAR toolboxhas also been compared with the experimental data.Based on the available data for the target and read across substances and applying the weight of evidence approach, it can be concluded that chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) is unable to cause eye damage and thus can be considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

Data is from OECD QSAR toolbox version 3.4 and QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: estimated data

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.4

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid
- Molecular formula: C11H11NO4S
- Molecular weight: 253.2769 g/mol
- Smiles notation: CNc1ccc2cc(cc(c2c1)O)S(=O)(=O)O
- InChl: 1S/C11H11NO4S/c1-12-8-3-2-7-4-9(17(14,15)16)6-11(13)10(7)5-8/h2-6,12-13H,1H3,(H,14,15,16)
- Substance type: Organic
- Physical state: Solid

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

No data available

Type of coverage:

occlusive

Preparation of test site:

clipped

Vehicle:

not specified

Controls:

not specified

Amount / concentration applied:

No data available

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

No data available

Details on study design:

No data available

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

72 h

Reversibility:

not specified

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No skin irritation was observed in treated group.

Estimation method: Takes mode value from the 10 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((("a" or "b" or "c" or "d" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and "i" )  and "j" )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and "p" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Secondary aromatic amine by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> N-Substituted Aromatic Amines AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid moiety AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.4

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Quinoneimines OR AN2 >>  Michael-type addition, quinoid structures >> Quinones and Trihydroxybenzenes OR AN2 >> Schiff base formation OR AN2 >> Schiff base formation >> Polarized Haloalkene Derivatives OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation >> Haloalkenes with Electron-Withdrawing Groups OR AN2 >> Thioacylation via nucleophilic addition after cysteine-mediated thioketene formation >> Polarized Haloalkene Derivatives OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Amino Anthraquinones OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide and Aminoalkylamine Side Chain OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines OR Non-covalent interaction >> DNA intercalation >> Quinones and Trihydroxybenzenes OR Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Amino Anthraquinones OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitro Azoarenes OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitroaniline Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR Radical >> Radical mechanism via ROS formation (indirect) >> Quinones and Trihydroxybenzenes OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR Radical >> ROS formation after GSH depletion (indirect) OR Radical >> ROS formation after GSH depletion (indirect) >> Quinoneimines OR SN1 OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Amino Anthraquinones OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Fused-Ring Primary Aromatic Amines OR SN1 >> Nucleophilic attack after nitrenium ion formation OR SN1 >> Nucleophilic attack after nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitro Azoarenes OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitroaniline Derivatives OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Haloalkenes with Electron-Withdrawing Groups OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polarized Haloalkene Derivatives OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> SN2 at sp3 and activated sp2 carbon atom OR SN2 >> SN2 at sp3 and activated sp2 carbon atom >> Polarized Haloalkene Derivatives by DNA binding by OASIS v.1.4

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> N-Substituted Aromatic Amines AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Acylation involving an activated (glucuronidated) carboxamide group OR Acylation >> Acylation involving an activated (glucuronidated) carboxamide group >> Carboxylic Acid Amides OR Acylation >> Acylation involving an activated (glucuronidated) ester group OR Acylation >> Acylation involving an activated (glucuronidated) ester group >> Arenecarboxylic Acid Esters OR Acylation >> Direct acylation involving a leaving group OR Acylation >> Direct acylation involving a leaving group >> Carboxylic Acid Amides OR Acylation >> Ester aminolysis OR Acylation >> Ester aminolysis >> Amides OR Acylation >> Ester aminolysis or thiolysis OR Acylation >> Ester aminolysis or thiolysis >> Activated aryl esters  OR AN2 >> Michael addition to activated double bonds OR AN2 >> Michael addition to activated double bonds >> alpha,beta-Unsaturated Carbonyls and Related Compounds OR AN2 >> Michael addition to alpha, beta-unsaturated acids and esters OR AN2 >> Michael addition to alpha, beta-unsaturated acids and esters >> alpha,beta-Unsaturated Carboxylic Acids and Esters OR AN2 >> Michael-type addition to quinoid structures  >> Carboxylic Acid Amides OR AN2 >> Michael-type addition to quinoid structures  >> Hydroxylated Phenols OR No alert found OR Nucleophilic addition OR Nucleophilic addition >> Addition to carbon-hetero double bonds OR Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones OR Schiff base formation OR Schiff base formation >> Schiff base formation with carbonyl compounds OR Schiff base formation >> Schiff base formation with carbonyl compounds >> Aromatic carbonyl compounds OR SN1 OR SN1 >> Carbenium ion formation (enzymatic) OR SN1 >> Carbenium ion formation (enzymatic) >> Carbenium ion OR SN2 OR SN2 >> SN2 Reaction at a sp3 carbon atom OR SN2 >> SN2 Reaction at a sp3 carbon atom >> Activated alkyl esters and thioesters  OR SNAr OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds OR SNAr >> Nucleophilic aromatic substitution on activated aryl and heteroaryl compounds >> Activated aryl and heteroaryl compounds by Protein binding by OASIS v1.4

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Reactive unspecified by Acute aquatic toxicity MOA by OASIS ONLY

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Bioavailable by Lipinski Rule Oasis ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Phenols by Skin irritation/corrosion Inclusion rules by BfR

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Esters of organic sulfonic or sulfuric esters by Skin irritation/corrosion Inclusion rules by BfR

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as (!Undefined)Group All Lipid Solubility < 0.01 g/kg AND (!Undefined)Group CNS Surface Tension > 62 mN/m AND Group All Melting Point > 200 C AND Group CNS log Kow < 0.5 AND Group CNS Melting Point > 120 C AND Group CNS Melting Point > 50 C by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Group CN Aqueous Solubility < 0.1 g/L by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "o"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.26

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is <= 4.88

Interpretation of results:

other: not irritating

Conclusions:

The chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated to be not irritating to the skin of New Zealand White rabbits. Based on the estimated result 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)can be considered to be not irritating to skin.

Executive summary:

The dermal irritation potential of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated using OECD QSAR toolbox version 3.4 with logPow as the primary descriptor. The chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated to be not irritating to the skin of New Zealand White rabbits. Based on the estimated result 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)can be considered to be not irritating to skin and can be classified under the category ˋ Not Classified’ as per CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

Data is from OECD QSAR toolbox version 3.4 and QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: estimated data

Principles of method if other than guideline:

Prediction is done using QSAR Toolbox version 3.4

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (IUPAC name): 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid
- Molecular formula: C11H11NO4S
- Molecular weight: 253.2769 g/mol
- Smiles notation: CNc1ccc2cc(cc(c2c1)O)S(=O)(=O)O
- InChl: 1S/C11H11NO4S/c1-12-8-3-2-7-4-9(17(14,15)16)6-11(13)10(7)5-8/h2-6,12-13H,1H3,(H,14,15,16)
- Substance type: Organic
- Physical state: Solid

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

No data available

Vehicle:

not specified

Controls:

not specified

Amount / concentration applied:

No data available

Duration of treatment / exposure:

single application

Observation period (in vivo):

48 hours

Duration of post- treatment incubation (in vitro):

No data available

Number of animals or in vitro replicates:

3

Details on study design:

No data available

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

48 h

Reversibility:

not specified

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No eye irritation was observed in treated rabbits.

Estimation method: Takes mode value from the 8 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((((("a" or "b" or "c" or "d" )  and "e" )  and "f" )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and "o" )  and "p" )  and "q" )  and ("r" and "s" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Secondary aromatic amine by DNA binding by OECD

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Strong binder, OH group by Estrogen Receptor Binding

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as AN2 AND AN2 >> Michael-type addition to quinoid structures  AND AN2 >> Michael-type addition to quinoid structures  >> N-Substituted Aromatic Amines AND AN2 >> Michael-type addition to quinoid structures  >> Substituted Phenols by Protein binding by OASIS v1.4

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid moiety AND Phenols by Aquatic toxicity classification by ECOSAR

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (Kb, pH 8)(Hydrowin) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (pH 6.5-7.4) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for Chromosomal aberration by OASIS v.1.2

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Acylation involving an activated (glucuronidated) carboxamide group OR Acylation >> Acylation involving an activated (glucuronidated) carboxamide group >> Carboxylic Acid Amides OR Acylation >> Direct acylation involving a leaving group OR Acylation >> Direct acylation involving a leaving group >> Carboxylic Acid Amides OR AN2 OR AN2 >> Michael addition to activated double bonds OR AN2 >> Michael addition to activated double bonds >> alpha, beta - Unsaturated Carbonyls and Related Compounds OR AN2 >> Michael addition to the quinoid type structures OR AN2 >> Michael addition to the quinoid type structures >> Carboxylic Acid Amides OR AN2 >> Michael addition to the quinoid type structures >> Hydroxylated Phenols OR AN2 >> Michael addition to the quinoid type structures >> N-Subsituted Aromatic Amines OR AN2 >> Michael addition to the quinoid type structures >> Quinoneimines OR AN2 >> Michael addition to the quinoid type structures >> Substituted Anilines OR AN2 >> Michael addition to the quinoid type structures >> Substituted Phenols by Protein binding alerts for Chromosomal aberration by OASIS v.1.2

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as No alert found by Respiratory sensitisation

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Pro-Michael Addition OR Pro-Michael Addition >> Pro-quinone and related OR Pro-Michael Addition >> Pro-quinone and related >> Aminophenols OR Pro-Michael Addition >> Pro-quinone and related >> Phenylenediamines by Respiratory sensitisation

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Aromatic amine AND Aryl AND Fused carbocyclic aromatic AND Naphtalene AND Phenol AND Sulfonic acid by Organic Functional groups

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Acrylamide OR Alcohol OR Aliphatic Amine, tertiary OR Alkane branched with quaternary carbon OR Alkane, branched with tertiary carbon OR Alkene OR Alkenyl halide OR Alkoxy OR Alkyl arenes by Organic Functional groups

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Aromatic amine AND Aryl AND Fused carbocyclic aromatic AND Naphtalene AND Phenol AND Sulfonic acid by Organic Functional groups

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Allyl OR Amidine OR Aniline by Organic Functional groups

Domain logical expression index: "o"

Similarity boundary:Target: CNc1ccc2cc(S(O)(=O)=O)cc(O)c2c1
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "p"

Similarity boundary:Target: CNc1ccc2cc(S(O)(=O)=O)cc(O)c2c1
Threshold=60%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "q"

Similarity boundary:Target: CNc1ccc2cc(S(O)(=O)=O)cc(O)c2c1
Threshold=50%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of log Kow which is >= -3.32

Domain logical expression index: "s"

Parametric boundary:The target chemical should have a value of log Kow which is <= 3.72

Interpretation of results:

other: not irritating

Conclusions:

The chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated to be not irritating into the eyes of New Zealand White rabbits. Based on the estimated result 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) can be considered to be not irritating to eye.

Executive summary:

The ocular irritation potential of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated using OECD QSAR toolbox version 3.4 with logPow as the primary descriptor. The chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) was estimated to be not irritating into the eyes of New Zealand White rabbits. Based on the estimated result 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) can be considered to be not irritating to eye and can be classified under the category ˋ Not Classified’ as per CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation:

Various studies has been investigated for the test chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) to observe the potential for dermal irritation to a greater or lesser extent. The studies are based on in vivo experiments in rabbits and rats for target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)and its structurally similar read across substances Disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7 –disulphonate [CAS No: 3567-69-9], 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;

 

In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, skin irritation potential was estimated for 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6). The substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)is considered to be not irritating to the skin of New Zealand White rabbits.

 

 This result was supported by the experimental study conducted in an OECD GLP laboratory (Sustainability Support Services (Europe) AB has the letter of access) for the structurally similar read across substance, Disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7 –disulphonate [CAS No:3567-69-9].The study was performed as per OECD Guidelines 402 and complying to the GLP procedures. The test item was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days. Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment.From the study, it can be concluded that the test substance ‘Disodium 4-hydroxy-3-[(4-sulphonatonaphthyl)azo] naphthalenesulphonate’ is nonirritant to the skin of Sprague Dawley rats when applied to the shorn skin of 5 male and 5 female animals at the tested dose level of 2000 mg/kg body weight. Also the erythema and edema score of rats was calculated as 0. Thus it can be concluded that the substance Disodium 4-hydroxy-3-[(4-sulphonatonaphthyl)azo] naphthalenesulphonate can be considered as not irritating to the skin.

 

The above results were supported by the skin irritation studies reported by GREIM H., et.al. (Chemosphere Vol. 28, No. 12, pp. 2203.2236, 1994) and BG Chemie (TOXIKOLOGISCHE BEWERTUNGEN; TOXICOLOGICAL EVALUATION last updated: 06/2000) for two structurally similar read across substances 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7) on 2 New Zealand White rabbits (male and female). In both the studies, the approx. 500 mg of test chemical was applied to the inner surface of the ears of 2 rabbits under an adhesive dressing for 24 hours and observations were made upto 7 days. At the end of the exposure period, the test substance was washed off with water and soap/ vegetable oil. No skin irritation was observed after 7 days. Hence the chemicals, 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7) was considered to be non-irritant to rabbit skin.

 

Based on the available data for the target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)and its structurally similar read across substances Disodium 5-acetylamino-4-hydroxy-3-(phenylazo)naphthalene-2,7 –disulphonate [CAS No:3567-69-9], 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7),it can be concluded that chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)is not able to cause skin irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

 

 

 

Eye irritation:

In different studies, the test chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) has been investigated to observe the potential for ocular irritation to a greater or lesser extent The studies are based on in vivo experiments in rabbits for target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)and its structurally similar read across substances 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7).The predicted data using the OECD QSAR toolbox has also been compared with the experimental data and summarized as below;

 

In a prediction done by SSS (2017) using the OECD QSAR toolbox with log kow as the primary descriptor, ocular irritation potential was estimated for 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) . The substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)is considered to be not irritating to the eyes of New Zealand White rabbits.

 

 The GREIM H., et.al. (Chemosphere Vol. 28, No. 12, pp. 2203.2236, 1994) and BG Chemie (TOXIKOLOGISCHE BEWERTUNGEN; TOXICOLOGICAL EVALUATION last updated: 06/2000) conducted an eye irritation study for structurally similar read across substance7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) in rabbits. In this study, 50 mg 7-amino-4-hydroxy-2-naphthalenesulfonic acid (I acid) was instilled into the conjunctival sac of 2 animals and each were observed for 7 days. No eye irritation was observed after 7 days. Hence the chemical 7-amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) can be considered non-irritant to rabbit eyes.

 

 

The above results were further supported by another eye irritation study conducted by GREIM H., et.al. (Chemosphere Vol. 28, No. 12, pp. 2203.2236, 1994) and BG Chemie (TOXIKOLOGISCHE BEWERTUNGEN; TOXICOLOGICAL EVALUATION last updated: 06/2000) for structurally similar read across substance 6-Amino-4-hydroxy-2-naphthalene-6-sulfonic acid in rabbit. In this test, 50 mg of test chemical was instilled into the conjunctival sac of 2 rabbits. One hour after application, slight reddening was observed, which cleared up completely after 3 days. Hence, the substance 6-Amino-4-hydroxy-2 -naphthalene-6-sulfonic acid was considered to be not irritating to rabbit eyes.

 

Based on the available data for the target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)and its structurally similar read across substances 7-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 87-02-5) and 6-Amino-4-hydroxy-2-naphthalenesulfonic acid (CAS No: 90-51-7),it can be concluded that chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6)is not able to cause eye irritation and considered as not irritating. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Justification for classification or non-classification

The skin and eye irritation potential of test chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) and its structurally similar read across substanceswere observed in various studies. The results obtained from these studies indicate that the chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) is unlikely to cause skin and eye irritation. Hence 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No:6259-53-6) can be classified under the category “Not Classified” for skin and eye as per CLP.