Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
4 June 1981 - 1 July 1981
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981
Report date:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
1,3-dihydro-5-methoxy-2H-benzimidazole-2-thione
EC Number:
253-326-2
EC Name:
1,3-dihydro-5-methoxy-2H-benzimidazole-2-thione
Cas Number:
37052-78-1
Molecular formula:
C8H8N2OS
IUPAC Name:
5-methoxy-1,3-dihydro-2H-benzimidazole-2-thione
Specific details on test material used for the study:
Tan-grey powder

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Metabolic activation:
with and without
Metabolic activation system:
Liver S9, exogenous metabolic activation system of mammalian microsomal enzymes derived from Aroclor-induced rat (male Sprague-Dawley rats) liver.
Test concentrations with justification for top dose:
1,0 µg to 5000 µg per plate.
A preliminary toxicity study was conducted with doses 1.22 µg to 10,000.00 µg per plate and the bacteria (TA-100) exhibited aproximately 92% toxicity at 5000 µg.
Vehicle / solvent:
Solvent: DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide

Results and discussion

Test results
Species / strain:
other: as listed above
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
The test material did not exhibit genetic activity in any of the assays conducted in this evaluation and was considered not mutagenic under these test conditions.