4-amino-2,5-dimethoxy-N-phenylbenzenesulphonamide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed GLP and OECD guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

4-amino-2,5-dimethoxy-N-phenylbenzenesulphonamide

EC Number:

257-821-4

EC Name:

4-amino-2,5-dimethoxy-N-phenylbenzenesulphonamide

Cas Number:

52298-44-9

Molecular formula:

C14H16N2O4S

IUPAC Name:

4-amino-2,5-dimethoxy-N-phenylbenzene-1-sulfonamide

Details on test material:

- Name of test material (as cited in study report): Chinonbasesulfanilide TTR

Method

Species / strain

Species / strain / cell type:

other: TA 1535, TA 1537, TA 98, TA 100, WP2 uvrA

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital/ß-Naphthoflavone induced rat liver S9

Test concentrations with justification for top dose:

pre-experiment/experiment I: 3, 10, 33, 100, 333, 1000, 2500, 5000 µg/plate
experiment II: 33, 100, 333, 1000, 2500, 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties and its relative non-toxicity to the bacteria.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: sodium azide, 4-nitro-o-phenylene- diamine, methyl methane sulfonate, and 2- aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation;

DURATION
- Preincubation period: 1 hour
- Exposure duration: After solidification the plates were incubated upside down for at least 48 hours

NUMBER OF REPLICATIONS: 3 plates

Evaluation criteria:

A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and WP2 uvrA) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed (3).

A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration (2).

An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.

A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.

Statistics:

According to OECD 471, a statistical analysis of the data is not mandatory.

Results and discussion

Test results

Species / strain:

other: TA 1535, TA 1537, TA 98, TA 100, WP2 uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: experiment I: no toxic effects, experiment II: toxic effects at 5000 µg/plate in strain TA 1535 with metabolic activation and in strain TA 1537 with and without metabolic activation.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Precipitation of the test item was observed in the test tubes and on the agar plates from 2500 up to 5000 µg/plate in experiment I. In experiment II, precipitation was observed at 2500 and 5000 µg/plate in the test tubes and from 1000 up to 5000 on the agar plates. The undissolved particles had no influence on the data recording.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test item Chinonbasesulfanilide TTR was found to be not mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.

Executive summary:

This study was performed to investigate the potential of Chinonbasesulfanilide TTR to induce gene mutations in the plate incorporation test (experiment I) and the pre-incubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

The assay was performed in two independent experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations:

Pre-Experiment/Experiment I: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate

Experiment II: 33; 100; 333; 1000; 2500; and 5000 µg/plate

The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without metabolic activation in both independent experiments.

No toxic effects, evident as a reduction in the number of revertants (below the indication factor of 0.5), occurred in the test groups with and without metabolic activation in experiment I. In experiment II, toxic effects were observed at 5000 µg/plate in strain TA 1535 with metabolic activation and in strain TA 1537 with and without metabolic activation.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with Chinonbasesulfanilide TTR at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.