p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

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 p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl] sulphonyl]phenyl]azo]-3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic 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. p-[4,5-dihydro-4- [[2-methoxy-5-methyl-4- [[2-(sulphooxy) ethyl]sulphonyl]phenyl] azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic 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.

Link to relevant study records

Reference

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)

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:

bacterial reverse mutation assay

Specific details on test material used for the study:

- Name of test material: p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5-oxo-1H-pyrazol-1-yl] benzenesulphonic acid or Reactive Yellow 15 free acid
- IUPAC name: 4-{4-[(E)-2-{2-methoxy-5-methyl-4-[2-(sulfooxy)ethanesulfonyl]phenyl}diazen-1-yl]-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-1-yl} benzene-1-sulfonic acid
- Molecular formula: C20H22N4O11S3
- Molecular weight: 590.609 g/mol
- Smiles : O=S(=O)(OCCS(=O)(=O)c1c(cc(\N=N\[C@@H]2C(=O)N(c3ccc(S(=O)(=O)O)cc3)N=C2C)c(OC)c1)C)O
- Inchl: 1S/C20H22N4O11S3/c1-12-10-16(17(34-3)11-18(12)36(26,27)9-8-35-38(31,32)33)21-22-19-13(2)23-24(20(19)25)14-4-6-15(7-5-14)37 (28,29)30/h4-7,10-11,19H,8-9H2,1-3H3,(H,28,29,30)(H,31,32,33)/b22-21+
- Substance type: Organic
- Physical state: Solid

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 actvation 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:

not specified

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 8 nearest neighbours
Domain  logical expression:Result: In Domain

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

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Vinyl Sulfones by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Schiff base formation AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives AND Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives >> Pyrazolones and Pyrazolidinones  by Protein binding by OASIS v1.3

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acid moiety OR Amides OR Hydrazines by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct Acylation Involving a Leaving group OR Acylation >> Direct Acylation Involving a Leaving group >> Acetates OR SN2 OR SN2 >> SN2 reaction at sp3 carbon atom OR SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl diazo by Protein binding by OECD ONLY

Domain logical expression index: "e"

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

Domain logical expression index: "f"

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

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Flavonoids OR AN2 >>  Michael-type addition, quinoid structures >> Quinoneimines OR AN2 >>  Michael-type addition, quinoid structures >> Quinones OR AN2 >> Carbamoylation after isocyanate formation OR AN2 >> Carbamoylation after isocyanate formation >> Hydroxamic Acids OR AN2 >> Carbamoylation after isocyanate formation >> N-Hydroxylamines OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds OR AN2 >> Michael-type addition on alpha, beta-unsaturated carbonyl compounds >> Four- and Five-Membered Lactones OR AN2 >> Schiff base formation OR AN2 >> Schiff base formation >> Dicarbonyl compounds OR AN2 >> Schiff base formation >> Halofuranones OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation OR AN2 >> Schiff base formation by aldehyde formed after metabolic activation >> Geminal Polyhaloalkane Derivatives OR AN2 >> Shiff base formation after aldehyde release OR AN2 >> Shiff base formation after aldehyde release >> Specific Acetate Esters OR AN2 >> Shiff base formation for aldehydes OR AN2 >> Shiff base formation for aldehydes >> Geminal Polyhaloalkane Derivatives 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 >> Aminoacridine DNA Intercalators OR Non-covalent interaction >> DNA intercalation >> Coumarins OR Non-covalent interaction >> DNA intercalation >> DNA Intercalators with Carboxamide Side Chain 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 >> Generation of ROS by glutathione depletion (indirect) OR Radical >> Generation of ROS by glutathione depletion (indirect) >> Haloalkanes Containing Heteroatom OR Radical >> Radical mechanism by ROS formation OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA OR Radical >> Radical mechanism by ROS formation (indirect) or direct radical attack on DNA >> Organic Peroxy Compounds OR Radical >> Radical mechanism by ROS formation >> Acridone, Thioxanthone, Xanthone and Phenazine Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) 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) >> Coumarins OR Radical >> Radical mechanism via ROS formation (indirect) >> Flavonoids 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) >> Geminal Polyhaloalkane Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> Hydrazine Derivatives 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) >> p-Substituted Mononitrobenzenes 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 Radical >> ROS formation after GSH depletion (indirect) OR Radical >> ROS formation after GSH depletion (indirect) >> Quinoneimines 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 >> DNA bases alkylation by carbenium ion formed OR SN1 >> DNA bases alkylation by carbenium ion formed >> Diazoalkanes OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after carbenium ion formation >> Pyrrolizidine Derivatives OR SN1 >> Nucleophilic attack after carbenium ion formation >> Specific Acetate Esters 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 >> 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 >> p-Substituted Mononitrobenzenes 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 SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion OR SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion >> N-Acyloxy(Alkoxy) Arenamides OR SN1 >> SN1 reaction at nitrogen-atom bound to a good leaving group or on  nitrenium ion >> N-Aryl-N-Acetoxy(Benzoyloxy) Acetamides OR SN2 OR SN2 >> Acylation OR SN2 >> Acylation >> Hydroxamic Acids OR SN2 >> Acylation >> Specific Acetate Esters OR SN2 >> Acylation involving a leaving group  OR SN2 >> Acylation involving a leaving group  >> Geminal Polyhaloalkane Derivatives OR SN2 >> Acylation involving a leaving group after metabolic activation OR SN2 >> Acylation involving a leaving group after metabolic activation >> Geminal Polyhaloalkane Derivatives OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines 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 >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Alkylation, ring opening SN2 reaction OR SN2 >> Alkylation, ring opening SN2 reaction >> Four- and Five-Membered Lactones OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Coumarins OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> DNA alkylation OR SN2 >> DNA alkylation >> Alkylphosphates, Alkylthiophosphates and Alkylphosphonates OR SN2 >> DNA alkylation >> Vicinal Dihaloalkanes OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) OR SN2 >> Internal SN2 reaction with aziridinium and/or cyclic sulfonium ion formation (enzymatic) >> Vicinal Dihaloalkanes OR SN2 >> Nucleophilic substitution at sp3 Carbon atom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Haloalkanes Containing Heteroatom OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Halofuranones OR SN2 >> Nucleophilic substitution at sp3 Carbon atom >> Specific Acetate Esters OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation OR SN2 >> Nucleophilic substitution at sp3 carbon atom after thiol (glutathione) conjugation >> Geminal Polyhaloalkane Derivatives OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives OR SN2 >> SN2 at Nitrogen Atom OR SN2 >> SN2 at Nitrogen Atom >> N-acetoxyamines 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 OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group >> N-Acetoxyamines OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion >> N-Acyloxy(Alkoxy) Arenamides OR SN2 >> SN2 reaction at nitrogen-atom bound to a good leaving group or nitrenium ion >> N-Aryl-N-Acetoxy(Benzoyloxy) Acetamides by DNA binding by OASIS v.1.3

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as SN1 AND SN1 >> Nitrenium Ion formation AND SN1 >> Nitrenium Ion formation >> Aromatic azo AND SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding by OECD ONLY

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as H-acceptor-path3-H-acceptor AND Hydrazine by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as alpha,beta-unsaturated carbonyls OR Aromatic diazo OR Aromatic N-acyl amine OR No alert found by in vivo mutagenicity (Micronucleus) alerts by ISS

Domain logical expression index: "k"

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 log Kow < -2 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: "l"

Referential boundary: The target chemical should be classified as (!Undefined)Group CN Lipid Solubility < 0.4 g/kg OR (!Undefined)Group CNHal Lipid Solubility < 4 g/kg OR (!Undefined)Group CNHal Lipid Solubility < 400 g/kg OR Group All log Kow < -3.1 OR Group CN Aqueous Solubility < 0.0001 g/L OR Group CN Aqueous Solubility < 0.1 g/L OR Group CN log Kow > 4.5 OR Group CN log Kow > 5.5 OR Group CN Melting Point > 180 C OR Group CN Molecular Weight > 290 g/mol OR Group CN Molecular Weight > 540 g/mol OR Group CN Vapour Pressure < 0.001 Pa OR Group CNHal Aqueous Solubility < 0.001 g/L OR Group CNHal Aqueous Solubility < 0.1 g/L OR Group CNHal log Kow > 3.8 OR Group CNHal Molecular Weight > 370 g/mol OR Group CNHal Molecular Weight > 380 g/mol by Skin irritation/corrosion Exclusion rules by BfR

Domain logical expression index: "m"

Similarity boundary:Target: Cc1cc(N=NC2C(C)=NN(c3ccc(S(O)(=O)=O)cc3)C2=O)c(OC)cc1S(=O)(=O)CCOS(O)(=O)=O
Threshold=10%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "n"

Similarity boundary:Target: Cc1cc(N=NC2C(C)=NN(c3ccc(S(O)(=O)=O)cc3)C2=O)c(OC)cc1S(=O)(=O)CCOS(O)(=O)=O
Threshold=40%,
Dice(Atom centered fragments)
Atom type; Count H attached; Hybridization

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Alkyl arenes AND Aryl AND Azo AND Ether AND Pyrazolone AND Sulfate AND Sulfone AND Sulfonic acid AND Unsaturated heterocyclic amine AND Unsaturated heterocyclic fragment by Organic Functional groups ONLY

Domain logical expression index: "p"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.92

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of log Kow which is <= -0.0772

Conclusions:

p-[4,5-dihydro-4- [[2-methoxy-5-methyl-4- [[2-(sulphooxy) ethyl]sulphonyl]phenyl] azo]-3-methyl-5-oxo-1H-pyrazol-1-yl] benzenesulphonic 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 p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic 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. p-[4,5-dihydro-4- [[2-methoxy-5-methyl-4- [[2-(sulphooxy) ethyl]sulphonyl]phenyl] azo]-3-methyl-5-oxo-1H-pyrazol-1-yl] benzenesulphonic 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.

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 and data from read across chemicals have been reviewed to determine the mutagenic nature of

p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic acid or Reactive Yellow 15 free 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 p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic 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. p-[4,5-dihydro-4- [[2-methoxy-5-methyl-4- [[2-(sulphooxy) ethyl]sulphonyl]phenyl] azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic 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.

The predicted data for the target chemical is further spported by the data from read across chemicals. The data is as mentioned below:

Chromosomal aberration study was performed by Ishidate et al (Food and chemical toxicology, 1984) to determine the mutagenic nature of structurally and functionally similar read across chemical Food red 102 (RA CAS no 2611 -82 -7; IUPAC name: C.I. Acid Red 18). The cells were exposed to the test material at three different doses with 1 mg/mL being the maximum concentration for 24 and 48 hr. Colcemid (final concn 0.2µg/ml) was added to the culture 2 hr before cell harvesting. The cells were then trypsinized and suspended in a hypotonic KCI solution (0.075 M) for 13 min at room temperature. After centrifugation the cells were fixed with acetic acid-methanol (1:3, v/v) and spread on clean glass slides. After air-drying, the slides were stained with Giemsa solution for 12-15 min. A hundred well-spread metaphases were observed under the microscope. 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%. Food red 102 did not induce chromosomal aberration in chinese hamster fibroblast cell line CHL and hence is not likely to classify as a gene mutant in vitro.

Ishidate et al also performed bacterial reverse mutation assay with the same read across chemical. Gene mutation toxicity study was performed to determine the mutagenic nature of Food red 102 (RA CAS no 2611 -82 -7). 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 mg/plate being the maximum concentration. The chemical was dissolved in phosphate buffer. 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). Food red 102 failed to 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 is not likely to classify as a gene mutant in vitro.

Muzall and Cook (Mutation Research, 1979) peformed gene mutation toxicity for structurally and functionally similar read across chemical FD and C Red no. 2 (RA CAS no 915 -67 -3; IUPAC name: trisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonate). Spot test was performed at dose levels from 10-250 mg using Salmonella typhimurium strain TA98, TA1537, TA100, TA1535 with and without S9 metabolic activation system. Captan was used as positive control chemical and the solvent control used was DMSO. Mutagenicity was indicated by a clustering of revertant colonies directly around the test material or at the edge of the inhibitory zone. FD&C Red No. 2 did not induce clustering of revertant colonies directly around the test material or at the edge of the inhibitory zone using Salmonella typhimurium strain TA98, TA1537, TA100, TA1535 in the presence and absence of S9 metabolic activation system and hence is not likely to classify as a gene mutant in vitro.

In the same study by Muzall and Cook, Gene mutation toxicity study was performed to determine the mutagenic nature of structurally and functionally similar read across chemical FD&C Red No. 2 (RA CAS no 915 -67 -3; IUPAC name: trisodium (4E)-3-oxo-4-[2-(4-sulfonatonaphthalen-1-yl)hydrazin-1-ylidene]-3,4-dihydronaphthalene-2,7-disulfonate). The study was performed as per the plate incorporation assay using Salmonella typhimurium strain TA98, TA1537, TA100, TA1535 with and without S9 metabolic activation system. The 2 ml of liquid top agar was cooled to 45°C and 0.1 ml of a broth cultureof microorganism and test substance in volumes of≤0.4 ml of DMSO was added prior to placing on minimal agar plates. The plates were incubated for 48 h at 37°C and the colonies which reverted to the prototroph were counted and compared to counts on the control plate (containing no test substance) to demonstrate mutagenicity or toxicity. Materials which caused a 2-fold increase of revertants, as compared to the number of spontaneous revertants on the control plates, were denoted as mutagens. Those which reduced the number of revertants were considered inhibitory. FD&C Red No. 2 did not result in a 2-fold increase in the number of revertants as compared to the number of spontaneous revertants on the control plates in Salmonella typhimurium strain TA98, TA1537, TA100, TA1535 in the presence and absence of S9 metabolic activation system and hence is not likely to classify as a gene mutant in vitro.

Based on the data available for the target chemical and its read across, p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl] sulphonyl]phenyl]azo] -3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic 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, p-[4,5-dihydro-4-[[2-methoxy-5-methyl-4-[[2-(sulphooxy)ethyl] sulphonyl]phenyl] azo] -3-methyl-5 -oxo-1H-pyrazol-1-yl] benzenesulphonic acid or Reactive Yellow 15 free acid (CAS no 60958 -41 -0) 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.