4-Methyl-3-amino-2-(methoxycarbonyl)-4,5-dihydrothiophene

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08/01/1997-18/04/1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EEC Directive 92/69, L 383 A, Annex B 14

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

methyl 3-amino-4-methyl-4,5-dihydrothiophene-2-carboxylate

EC Number:

603-030-8

Cas Number:

125089-02-3

Molecular formula:

C7H11NO2S

IUPAC Name:

methyl 3-amino-4-methyl-4,5-dihydrothiophene-2-carboxylate

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- batch No.of test material: 369/96
- Expiration date of the lot/batch: 30/04/1997

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: darkness at approximately 5°C in a refrigerator
- Solubility and stability of the test substance in the vehicle: confirmed over 4 hours

Method

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Vehicle / solvent:

Suspended in double-distilled water.

Controls

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

other: 2-aminoanthracene for all strains, with metabolic activation

Details on test system and experimental conditions:

Two indipendent mutagenicity studies were conducted, each in the absence and in the presence of a metabolizing system derived from a rat liver homogenate. For both studies, the compound was suspended in double-distilled water and each bacterial strain was exposed to 6 dose levels. Doses for both studies ranged from 4 to 5000 ug/plate.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1537

Remarks:

In the first exp. at conc. of 4 to 20 mg/kg

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Test results 2

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Additional information on results:

Toxicity was not observed either with or without metabolic activation.
Treatment of the cells with the substance resulted in relevant and dose-dependent increases in the number of revertant colonies with the Salmonella strain TA 100. In the first exp. only in the absence of S9-mix with the strain TA 1537 the number of revertant colonies was increased at the concentrations of 4 and 20 ug/plate, but this effect is caused of the low spontaneous number of the revertant exp. and is therefore of no biological relevance.

Remarks on result:

other: of no biological relevance

Remarks:

caused of the low spontaneous no. of the revertant colonies of the corresponding control group and was not reproduced.

Applicant's summary and conclusion

Conclusions:

The test compound proved to be not toxic to the bacterial strains.
No toxicity was found in the toxicity test with a dilution of tester strain TA 100 (designated TA 100 D), which was performed in parallel with the secnd mutation experiment, either in the absence or in the presence of metabolic activation.
All positive controls produced significant increases in the number of revertant colonies. Thus the sensitivity of the assay and the efficacy of the exogenous metabolic activation system were demonstrated.
The results lead to the conclusion that the substance is mutagenic in these bacterial test systems with and without an exogenous metabolizing system.