Registration Dossier

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
Study period:
18.04. - 26.07.2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The accordance of the study with its protocol, the OECD Guideline and the Principles of Good Laboratory Practice (GLP) is guaranteed.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
TA97a: hisD6610, TA 98: hisD3052; TA 100 and TA 1535 hisG46, TA102: hisG428
Species / strain
Species / strain / cell type:
other: TA 1535, TA 97a, TA 98, TA 100 und TA 102
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
other: TA97a, TA98 and TA100: uvrB; TA100 & 102: pKM 101
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
5 mg/ dish
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
Migrated to IUCLID6: additional: Sodiumazide, 4-Nitro-2-phenylendiamin

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
-
Cytotoxicity / choice of top concentrations:
not determined
Remarks:
-
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'. Remarks: -

Any other information on results incl. tables

no additional remarks

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Thiotiamin can be considered as not mutagenic in the Ames test under the described experimental conditions.
Executive summary:

Thiotiamin was evaluated for mutagenic activity in the Ames test. A standard plate incorporation and a preincubation modification assay in absence and in presence of an exogenous metabolic activation system (S9) were performed. Five Salmonella typhimurium

tester strains (TA1535, TA97, TA98, TA100, and TA102) were employed. The activity of the S9 -mix and the responsiveness of the tester strains were verified by including appropriate controls into each experiment. The substance was dissolved in dimethylsulfoxide (DMSO). As concentration 5 mg/plate was chosen for the main experiment.

No significant increase in the number of revertant colonies was apparent in all five tester strains (TA1535, TA97, TA98, TA100, and TA102) using both methods, after treatment with Thiotiamin.

Based on these data Thiotiamin can be considered as not mutagenic in the Ames test under the described experimental conditions.