6-methoxy-m-toluidine

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well performed research study

Data source

Reference

Reference Type:

publication

Title:

Reproducibility of Microbial Mutagenicity Assays

Author:

V.C. Dunkel, E.Zeiger, D. Brunsick, E. McCoy, D. McGregor, K.Mortelmans, H.S. Rosenkranz, V.F. Simmon

Year:

1985

Bibliographic source:

Environm. Mutag, Volume 7, Suppl. 5: 1-248 (1985)

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Dunkel et al, Tests with Salmonella typhimurium and Escherichia coli using a standardized protocol, Environm. Mutag. 6 (Suppl. 2): 1 - 251

Deviations:

not specified

Principles of method if other than guideline:

four-laboratory study, plate-incorporation procedure

GLP compliance:

not specified

Type of assay:

bacterial gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

6-methoxy-m-toluidine

EC Number:

204-419-1

EC Name:

6-methoxy-m-toluidine

Cas Number:

120-71-8

Molecular formula:

C8H11NO

IUPAC Name:

2-methoxy-5-methylaniline

Details on test material:

- Name of test material (as cited in study report): p-Cresidine
- Analytical purity: 98.9 %

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Species / strain 3

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9-Mix of hamster-, mouse and rat liver with and without Aroclor 1254 induction

Test concentrations with justification for top dose:

Dose ranges tested based on the solubility and toxicity of the test chemicals, but did not exceed 10.0 mg/plate. Individual doses tested were from 0.3 to 10000 µg/plate.

Vehicle / solvent:

DMSO (dimethyl sulfoxide) or ethanol (95% ethanol)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO (dimethyl sulfoxide) or ethanol (95% ethanol)

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-nitrofluorene, 2-aminoanthracene, sodium azide, 9-aminoacridine, N-methyl-N'-nttro-N-nitrosoguanidine, 2-2(furyl)-3-(5-nitro-2-furyl) acrylamide

Details on test system and experimental conditions:

The chemical was tested in a four-laboratory study by the plate-incorporation procedure without and with metabolic activation using uninduced or Aroclor 1254-induced S-9's from rats, mice, and hamsters. All plates were prepared in triplicate, and concurrent positive and negative controls were run at all times.

Evaluation criteria:

A positive response was defined as a dose-related increase with at least two doses being greater than, or equal to, twofold background, unless the background was less than ten, in which case a threefold increase was required. A borderline response was defined as a test in which only a single dose was equal to or greater than twofold (or threefold) background. Low-level, non-dose-related increases were scored as negative, as were single doses whose increase was the result of widely divergent replicate plate counts.

Statistics:

Due to study design a maximum 4 results (4 laboratories) are available without metabolic activation and 24 results with metabolic activation (4 laboratories x 3 animal species x 2 types of metabolic activation)

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 1 of 4 positive, with metabolic activation: 20 of 24 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 1 of 4 positive, with metabolic activation: 13 of 24 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 0 of 3 positive, with metabolic activation: 0 of 24 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 1 of 4 positive, with metabolic activation: 10 of 22 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 1 of 4 positive, with metabolic activation: 21 of 24 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Test results 6

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

other: without metabolic activation: 0 of 4 positive, with metabolic activation: 2 of 24 positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive with metabolic activation

The test item is mutagenic when tested with metabolic activation in this test system.

Executive summary:

p-cresidine was tested for mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535, TA1537, and TA1538, and Escherichia coli WP2 uvrA in a four-laboratory study. The chemical was tested by the plate-incorporation procedure. The doses were ordered in half-log increments. Chemicals were tested without and with metabolic activation using uninduced and Aroclor-1254-induced S-9's from rats, mice, and hamsters. All plates were prepared in triplicate, and concurrent positive and negative controls were run at all times. The concentration did not exceed 10.0 mg/plate.

Without metabolic activation negative results were found, except one laoratory which generated positive results in all tester strains. With metabolic activation results for TA 98, 100, 1538 were predominantly positive and for TA 1535, 1537, WP2uvrA predominantly negative.