4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Gene mutation in vitro:

Ames assay:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl-1H- pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Chromosomal aberration assay:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, chromosomal aberration was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Chinese hamster ovary (CHO) cell line with and without S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl- 1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce chromosomal aberrations in Chinese hamster ovary (CHO) cell line in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Justification for type of information:

Data is from OECD QSAR Toolbox version 3.3 and the supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Prediction is done using OECD QSAR Toolbox version 3.3, 2017

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

- Name of test material: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid
- IUPAC name: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid
- Molecular formula: C16H13Cl2N5O3S
- Molecular weight: 426.283 g/mol
- Smiles :n1(c2ccccc2)c(c(\N=N\c2c(cc(S(O)(=O)=O)c(c2)Cl)Cl)c(n1)C)N
- InChl: 1S/C16H13Cl2N5O3S/c1-9-15(16(19)23(22-9)10-5-3-2-4-6-10)21-20-13-7-12(18)14(8-11(13)17)27(24,25)26/h2-8H,19H2,1H3,(H,24,25,26)/b21-20+
- Substance type: Organic

Target gene:

Histidine

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

No data

Metabolic activation:

with

Metabolic activation system:

S9 metabolic activation system

Test concentrations with justification for top dose:

No data

Vehicle / solvent:

No data

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

No data

Rationale for test conditions:

No data

Evaluation criteria:

Prediction is done considering a dose dependent increase in the number of revertants/plate

Statistics:

No data

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No data

Remarks on result:

no mutagenic potential (based on QSAR/QSPR prediction)

The prediction was based on dataset comprised from the following descriptors: "Gene mutation"
Estimation method: Takes highest mode value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" or "b" or "c" )  and ("d" and ( not "e") )  )  and "f" )  and "g" )  and ("h" and ( not "i") )  )  and ("j" and "k" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Acid moiety OR Anilines (Unhindered) OR Pyrazoles/Pyrroles by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SNAr OR SNAr >> Nucleophilic aromatic substitution OR SNAr >> Nucleophilic aromatic substitution >> Activated halo-benzenes by Protein binding by OECD ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Primary (unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding by OECD ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> 3-Methylindole derivatives OR AN2 >>  Michael-type addition, quinoid structures >> Quinones OR AN2 >> Carbamoylation after isocyanate formation OR AN2 >> Carbamoylation after isocyanate formation >> N-Hydroxylamines 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 Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Acridone, Thioxanthone, Xanthone and Phenazine Derivatives OR Non-covalent interaction >> DNA intercalation >> Amino Anthraquinones OR Non-covalent interaction >> DNA intercalation >> Aminoacridine DNA Intercalators OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Nitroaromatics OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines OR Non-covalent interaction >> DNA intercalation >> Quinones OR Non-specific OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    >> Specific Imine and Thione Derivatives OR Radical OR Radical >> Radical mechanism by ROS formation OR Radical >> Radical mechanism by ROS formation >> Acridone, Thioxanthone, Xanthone and Phenazine Derivatives OR Radical >> Radical mechanism by ROS formation >> Polynitroarenes 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) >> C-Nitroso Compounds OR Radical >> Radical mechanism via ROS formation (indirect) >> Conjugated Nitro Compounds OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Nitroaromatics OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> N-Hydroxylamines 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) >> Nitroarenes with Other Active Groups OR Radical >> Radical mechanism via ROS formation (indirect) >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR Radical >> Radical mechanism via ROS formation (indirect) >> p-Aminobiphenyl Analogs OR Radical >> Radical mechanism via ROS formation (indirect) >> Quinones OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Specific Imine and Thione Derivatives OR SN1 OR SN1 >> Alkylation after metabolically formed carbenium ion species OR SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation OR SN1 >> Nucleophilic attack after diazonium or carbenium ion formation >> Nitroarenes with Other Active Groups 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 metabolic nitrenium ion formation >> N-Hydroxylamines OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> p-Aminobiphenyl Analogs OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Conjugated Nitro Compounds OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Fused-Ring Nitroaromatics 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 >> Nitroarenes with Other Active Groups OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrobiphenyls and Bridged Nitrobiphenyls OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Nitrophenols, Nitrophenyl Ethers and Nitrobenzoic Acids OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Polynitroarenes OR SN1 >> Nucleophilic substitution after glutathione-induced nitrenium ion formation OR SN1 >> Nucleophilic substitution after glutathione-induced nitrenium ion formation >> C-Nitroso Compounds OR SN1 >> Nucleophilic substitution on diazonium ions OR SN1 >> Nucleophilic substitution on diazonium ions >> Specific Imine and Thione Derivatives OR SN2 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 >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Sulfonates and Sulfates OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 OR SN2 >> SN2 attack on activated carbon Csp3 or Csp2 >> Nitroarenes with Other Active Groups by DNA binding by OASIS v.1.3

Domain logical expression index: "f"

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

Domain logical expression index: "g"

Similarity boundary:Target: CC1C(N=Nc2cc(Cl)c(S(O)(=O)=O)cc2Cl)=C(N)N(c2ccccc2)N=1
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Benzene/ Naphthalene sulfonic acids (Less susceptible) Rank C OR Halobenzenes (Hepatotoxicity) Rank A OR Halobenzenes (Renal toxicity) Rank A OR Nitrophenols/ Halophenols (Energy metabolism dysfuntion) Rank B OR Thiocarbamates/Sulfides (Hepatotoxicity) No rank by Repeated dose (HESS)

Domain logical expression index: "j"

Parametric boundary:The target chemical should have a value of log Kow which is >= -0.794

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is <= 3.23

Conclusions:

4-[(5-amino-3-methyl-1-phenyl-1H- pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl-1H- pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

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 3.3 and the supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Prediction is done using OECD QSAR Toolbox version 3.3, 2017

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Specific details on test material used for the study:

- Name of test material: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid
- IUPAC name: 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid
- Molecular formula: C16H13Cl2N5O3S
- Molecular weight: 426.283 g/mol
- Smiles :n1(c2ccccc2)c(c(\N=N\c2c(cc(S(O)(=O)=O)c(c2)Cl)Cl)c(n1)C)N
- InChl: 1S/C16H13Cl2N5O3S/c1-9-15(16(19)23(22-9)10-5-3-2-4-6-10)21-20-13-7-12(18)14(8-11(13)17)27(24,25)26/h2-8H,19H2,1H3,(H,24,25,26)/b21-20+
- Substance type: Organic

Target gene:

Histidine

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

No data

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

No data

Metabolic activation:

with and without

Metabolic activation system:

S9 metabolic activation system

Test concentrations with justification for top dose:

No data

Vehicle / solvent:

No data

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

No data

Rationale for test conditions:

No data

Evaluation criteria:

The cell line was observed for chromosomal abberrations

Statistics:

No data

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No data

Remarks on result:

no mutagenic potential (based on QSAR/QSPR prediction)

The prediction was based on dataset comprised from the following descriptors: "chromosome aberration"
Estimation method: Takes highest mode value from the 9 nearest neighbours
Domain  logical expression:Result: In Domain

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

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Acid moiety OR Anilines (Unhindered) OR Pyrazoles/Pyrroles by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as SNAr OR SNAr >> Nucleophilic aromatic substitution OR SNAr >> Nucleophilic aromatic substitution >> Activated halo-benzenes by Protein binding by OECD ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Primary (unsaturated) heterocyclic amine OR SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding by OECD ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OASIS v1.3

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as 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 v1.3

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Group 14 - Carbon C AND Group 15 - Nitrogen N AND Group 16 - Oxygen O AND Group 16 - Sulfur S AND Group 17 - Halogens Cl AND Group 17 - Halogens F,Cl,Br,I,At by Chemical elements

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Group 17 - Halogens F by Chemical elements

Domain logical expression index: "h"

Similarity boundary:Target: CC1C(N=Nc2cc(Cl)c(S(O)(=O)=O)cc2Cl)=C(N)N(c2ccccc2)N=1
Threshold=20%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as 4,4'-Methylenedianilines/benzidines (Hepatobiliary toxicity) Rank B  by Repeated dose (HESS)

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Chlorphentermine (Hepatotoxicity) Alert by Repeated dose (HESS)

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Nitrobenzenes (Hemolytic anemia with methemoglobinemia) Rank A by Repeated dose (HESS)

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as 1,1-Diaminoalkene derivative [C=C(N)N]  AND Aliphatic Carbon [CH] AND Aliphatic Carbon [-CH2-] AND Aliphatic Carbon [-CH3] AND Aliphatic Nitrogen, one aromatic attach [-N] AND Aromatic Carbon [C] AND Aromatic Nitrogen, five-member ring AND Azo [-N=N-] AND Azomethine, aliphatic attach [-N=C] AND Chlorine, aromatic attach [-Cl] AND Chlorine, olefinic attach [-Cl] AND Hydrazine [>N-N<] AND Hydroxy, sulfur attach [-OH] AND Miscellaneous sulfide (=S) or oxide (=O) AND Nitrogen, two or tree olefinic attach [>N-] AND Olefinic carbon [=CH- or =C<] AND Suflur {v+4} or {v+6} AND Sulfinic acid [-S(=O)OH] AND Sulfonate, aromatic attach [-SO2-O] by Organic functional groups (US EPA)

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as Aliphatic Oxygen, two aromatic attach [-O-] by Organic functional groups (US EPA)

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Aliphatic Amine, primary AND Aryl AND Aryl halide AND Azo AND Overlapping groups AND Pyrazole AND Sulfonic acid by Organic Functional groups (nested)

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Unsaturated heterocyclic fragment by Organic Functional groups (nested)

Domain logical expression index: "s"

Parametric boundary:The target chemical should have a value of log Kow which is >= 1.08

Domain logical expression index: "t"

Parametric boundary:The target chemical should have a value of log Kow which is <= 2.53

Conclusions:

4-[(5-amino-3-methyl-1-phenyl- 1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce chromosomal aberrations in Chinese hamster ovary (CHO) cell line in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, chromosomal aberration was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Chinese hamster ovary (CHO) cell line with and without S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl- 1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce chromosomal aberrations in Chinese hamster ovary (CHO) cell line in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the predicted result it can be concluded that the substance is considered to not toxic as per the criteria mentioned in CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Gene mutation in vitro:.

Prediction model based estimation for the target chemical and data from target and read across chemicals have been reviewed to determine the mutagenic nature of 4-[(5-amino-3-methyl- 1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The studies are as mentioned below:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with and without S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl-1H- pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, chromosomal aberration was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid. The study assumed the use of Chinese hamster ovary (CHO) cell line with and without S9 metabolic activation system. 4-[(5-amino-3-methyl-1-phenyl- 1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid was predicted to not induce chromosomal aberrations in Chinese hamster ovary (CHO) cell line in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Gene mutation toxicity was predicted for 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid using the battery approach from Danish QSAR database (2017). The study assumed the use of Salmonella typhimurium bacteria in the Ames test. The end point for gene mutation has been modeled in the Danish QSAR using the three software systems Leadscope, CASE Ultra and SciQSAR. Based on predictions from these three systems, a fourth and overall battery prediction is made. The battery prediction is made using the so called Battery algorithm. With the battery approach it is in many cases possible to reduce “noise” from the individual model estimates and thereby improve accuracy and/or broaden the applicability domain. Gene mutation toxicity study as predicted by Danish QSAR for4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acidis negative and hence the chemical is predicted to not classify as a gene mutant in vitro.

The ability of 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid to induce chromosomal aberration was predicted using Chinese hamster ovary cells (CHO) using Danish QSAR database (2017). The end point for chromosome aberrations has been modeled in the Danish QSAR using the three software systems Leadscope, CASE Ultra and SciQSAR. Based on predictions from these three systems, a fourth and overall battery prediction is made. The battery prediction is made using the so called Battery algorithm. With the battery approach it is in many cases possible to reduce “noise” from the individual model estimates and thereby improve accuracy and/or broaden the applicability domain. 4-[(5-amino-3-methyl-1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid does notinduce chromosome aberrations inChinese hamster ovary cells (CHO)and hence is predicted to not classify as a gene mutant in vitro.

The predicted data is further supported by the data from target chemical and its read across chemicals as mentioned below:

SOS/umu assay was performed by Nakamura et al (Jpn J Ind Health, 1990) to evaluate the mutagenic response for the test chemical Yellow 49 (CAS no 12239 -15 -5). The test was performed using Salmonella typhimurium TA1535/pSK1002 in the presence and absence of metabolic activation system. The test chemical was dissolved in distilled water and used at dose levels of 0, 4, 12, 40, 120, 400 or 1200µg/mL. Concurrent solvent and positive control chemicals were also included in the study. Samples showingβ-galactosidase activity more than 1.5 fold of the background level was considered as genotoxic. Yellow 49did not induce reversionmore than 1.5 fold of the background level of theβ-galactosidase activity in Salmonella typhimurium TA1535/pSK1002 in the presence and absence of metabolic activation system and hence it is not likely to classify as a gene mutant in vitro.

Chromosomal aberration test was performed by Ishidate et al (Food and chemical toxicology, 1984) for the functionally similar read across chemical tartrazine (RA CAS no 1934 -21 -0) using Chinese hamster fibroblast cell line CHL. The cells were exposed to the test material at three different doses with 2.5 mg/plate being the highest dose for 24 and 48 hr. In the present studies, no metabolic activation systems were applied. The incidence of polyploid cells as well as of cells with structural chromosomal aberrations such as chromatid or chromosome gaps, breaks, exchanges, ring formations, fragmentations and others, was recorded on each culture plate. Untreated cells and solvent-treated cells served as negative controls, in which the incidence of aberrations was usually less than 3.0%. The results were considered to be negative if the incidence was less than 4.9%, equivocal if it was between 5.0 and 9.9%, and positive if it was more than 10.0%. The incidence of chromosome aberration in Chinese hamster fibroblast cell line for the test chemical tartrazine was considered to be more than 10% in the absence of metabolic activation system during the 48 hrs study duration and hence tartrazine is mutagenic in vitro.

In the same study by Ishidate et al (1984), Gene mutation toxicity study was performed to determine the mutagenic nature of functoinally similar read across chemical tartrazine (RA CAS no 1934 -21 -0). The study was performed using S. typhimurium strains TA92, TA1535, TA100, TA1537, TA94 and TA98 with and without S9 metabolic activation system. The test was performed as per the preincubation assay at six different concentrations with 5.0 mg/plate being the maximum concentration. The chemical was dissolved in distilled water. Preincubation was performed for 20 mins and the exposure duration was for 48 hrs. The result was considered positive if the number of colonies found was twice the number in the control (exposed to the appropriate solvent or untreated). Tartrazine did not induce a doubling of revertant colonies over the control using S. typhimurium strains TA92, TA1535, TA100, TA1537, TA94 and TA98 in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.

In another by Venturini and Tamaro (Mutation Research, 1979), Bacterial gene mutation test was performed to evaluate the mutagenic response for 60 -70% struturally and functionally similar read across chemical Xylene light yellow 2G (RA CAS no: 6359 -98 -4; C.I. acid yellow 17). The test was performed using Salmonella typhimurium strainsTA1535, TA100, TA1538, and TA98 in the presence and absence of S9 metabolic activation system. The test compound was dissolved in DMSO and used at dose levels of 100, 500 or 1000µg/plate. Concurrent positive control chemicals were also included in the study. Xylene light yellow 2G (C.I. acid yellow 17)did not induce reversion of mutation when applied to Salmonella typhimurium strainsTA1535, TA100, TA1538, and TA98 in the presence and absence of S9 metabolic activation system and hence it is not likely to classify as a gene mutant in vitro.

Based on the data available for the target chemical and its read across, 4-[(5-amino-3-methyl- 1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

Based on the data available for the target chemical and its read across, 4-[(5-amino-3-methyl- 1-phenyl-1H-pyrazol-4-yl)azo]-2,5-dichlorobenzenesulphonic acid (CAS no 12239 -15 -5) does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.