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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 2-aminotoluene-4-sulphonic 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. 2-aminotoluene-4-sulphonic 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:
key study
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:
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 (IUPAC name): 2-aminotoluene-4-sulphonic acid
- Molecular formula: C7H9NO3S
- Molecular weight: 187.218 g/mol
- Smiles notation: O=S(=O)(O)c1ccc(c(N)c1)C
- InChl: 1S/C7H9NO3S/c1-5-2-3-6(4-7(5)8)12(9,10)11/h2-4H,8H2,1H3,(H,9,10,11)
- 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 considerng 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 10 nearest neighbours
Domain  logical expression:Result: In Domain

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

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Anilines (Acute toxicity) by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Moderate binder, NH2 group by Estrogen Receptor Binding

Domain logical expression index: "c"

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

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Radical OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR SN1 OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines by DNA binding by OASIS v.1.3 ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Radical AND Radical >> Radical mechanism via ROS formation (indirect) AND Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines AND SN1 AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation AND SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines by DNA binding by OASIS v.1.3 ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Alkyl phenols OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Hydroquinones OR SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Primary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine by DNA binding by OECD

Domain logical expression index: "h"

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

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Ester aminolysis OR Acylation >> Ester aminolysis >> Amides by Protein binding by OASIS v1.3

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "k"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.06

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of log Kow which is <= 1.8

Conclusions:
2-aminotoluene-4-sulphonic 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 2-aminotoluene-4-sulphonic 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. 2-aminotoluene-4-sulphonic 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 2-aminotoluene-4-sulphonic acid. The studies are as summarized 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 2-aminotoluene-4-sulphonic 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. 2-aminotoluene-4-sulphonic 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 2-aminotoluene-4-sulphonic acid. The study assumed the use of Chinese hamster ovary (CHO) cell line with and without S9 metabolic activation system. 2-aminotoluene-4-sulphonic 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 2-aminotoluene-4-sulphonic 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 for 2-aminotoluene-4-sulphonic acid is negative and hence the chemical is predicted to not classify as a gene mutant in vitro.

The predicted data is further supported by data from read across chemical.

The read across chemical 2-Amino- 1 -phenol-4-sulfonic acid (RA CAS no 98 -37 -3; IUPAC name: 3-amino-4-hydroxybenzenesulfonic acid) was studied by Zeiger et al (Environmental and Molecular Mutagenesis, 1988) to for its ability to induce mutations in strains of Salmonella typhimurium. The test was performed in a preincubation assay and the test chemical was dissolved in DMSO as the solvent and tested at concentration of 0, 33, 100, 333, 1000 or 2000 µg/plate using Salmonella typhimurium TA100, TA1535, TA97 and TA98 in the presence and absence of rat and hamster liver S9 metabolic activation system. Concurrent solvent and negative control chemicals were included in the study. 3-amino-4-hydroxybenzenesulphonic is not mutagenic to the Salmonella typhimurium strains TA100, TA1535, TA97 and TA98 in the presence and absence of rat and hamster liver S9 metabolic activation system.

 

Zeiger et al (Environmental and Molecular Mutagenesis, 1988) also studied the mutagenic activity of another 60 -70% structuraly similar read across chemical. m-Amino benzenesulfonic acid (RA CAS no 121 -47 -1; IUPAC name: 3-Aminobenzene sulphonic acid) was studied for its ability to induce mutations in strains of Salmonella typhimurium. The test compound was dissolved in DMSO and was tested at concentration of 0, 33, 100, 333, 1000 or 3333 µg/plate using Salmonella typhimurium TA100, TA1535, TA97 and TA98 in the presence and absence of 10 % and 30 % rat and hamster liver S9 metabolic activation system. Preincubation assay was performed with a preicubation for 20 mins. The plates were observed for histidine independence after 2 days incubation period. Concurrent solvent and positive controls were included in the study. m-Amino benzene sulfonic acidis not mutagenic to theSalmonella typhimurium TA100, TA1535, TA97 and TA98 in the presence and absence of rat and hamster liver S9 metabolic activation system and hence it is not likely to classify as a gene mutant in vitro.

Gene toxicity in vitro study was performed by Garner and Nutman (Mutation Research, 1977) on the Salmonella typhimurium TA1538 strain for the 50 -60% structrally and functionally simlar read across chemical 4-Amino-1-naphthalene sulphonic acid (RA CAS no 84 -86 -6). 4-Amino-1-naphthalene sulphonic acid was dissolved in DMSO and used at a concentration of 0, 50 and 100 µg/ plate in the presence and absence of S9 metabolic activation system. The plates were incubated for 48 hrs. Concurrent solvent and positive control chemicals were included in the study. All assays were performed in duplicate and the numbers of revertants on test plates greater than 30 was classified as being significantly mutagenic. The given test material 4-Amino-1-naphthalene sulphonic acid failed to induce mutation in Salmonella typhimurium TA1538 strain with and without 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, 2-aminotoluene-4-sulphonic acid does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant in vitro.

Justification for classification or non-classification

Based on the data available for the target chemical and its read across, 2-aminotoluene-4-sulphonic acid (CAS no 618 -03 -1) does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant in vitro.