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:
other information
Study period:
January 96
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1996
Report Date:
1996

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
- Justification why the confirmation of the negative result is not considered necessary is not provided.
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
Histidine gene locus
Species / strain
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Additional strain characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbital/beta-Naphthoflavone induced male rat liver S9 mix
Test concentrations with justification for top dose:
10.0, 33.3, 100.0, 333.3, 1000.0, 2500.0 and 5000.0 µg/plate








Vehicle:
DMF
Controls
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: without metabolic activation: Sodium azide, 4-Nitro-o-phenylenediamine, Methyl methane sulfonate; with metabolic activation: 2-Aminoanthracene
Details on test system and conditions:
plate incorporation assay

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
yes
Remarks:
Moderate toxic effects in strain TA 1535 at 2500 and 5000 µg/plate (+ S9); in strain 1537 at 1000 µg/plate and above (+ S9)
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Additional information on results:
No precipitation of the test article occurred up to the maximal applied dose.

Any other information on results incl. tables

Moderate toxic effeets, evident as a reduction in the number of revertants, occurred in the presence of metabolic activation in strain TA 1535 at 2500 and 5000 µg/plate and in strain TA 1537 at 1000 µg/plate and above.

The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without S9 mix in all strains used.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test subsatnce at any concentration 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.

Applicant's summary and conclusion

Executive summary:

The mutagenic potential of the test substance was evaluated in a Salmonella/microsome test with the S. typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 in the presence and absence of S9 mix according to OECD TG 471. Evidence of mutagenic activity was not seen up to the maximum recommended dose level of 5000 µg/plate. No substantial increases in revertant colony numbers of any of the five tester strains were observed at any dose level in the presence and absence of metabolic activation. There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance. Therefore, the test substance was considered to be non-mutagenic in the Salmonella typhimurium reverse mutation assay.