Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP compliant guideline study, available as unpublished report, restriction in design (no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix), but adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
, no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix.
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MBDA
- Storage: room temperature

Method

Target gene:
His-locus
Species / strain
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S9 mix
Test concentrations with justification for top dose:
- Experiment 1: 20, 100, 500, 2500, 5000 µg/plate
- Experiment 2: 15, 50, 150, 500, 1500 µg/plate
Vehicle:
- Vehicle used: DMSO
Controlsopen allclose all
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
10 µg/plate
Positive control substance:
other: 2-aminoanthracene
Remarks:
all strains with metabolic activation
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
5 µg/plate
Positive control substance:
other: N-methyl-N'-nitro-N-nitrosoguanidine
Remarks:
TA 100, TA 1535; without metabolic activation
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
10 µg/plate
Positive control substance:
other: 4-nitro-o-phenylendiamine
Remarks:
TA 98; without metabolic activation
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Remarks:
100 µg/plate
Positive control substance:
9-aminoacridine
Remarks:
TA 1537; without metabolic activation
Details on test system and conditions:
EXPERIMENT 1
- METHOD OF APPLICATION: in agar (plate incorporation)
- DURATION: Exposure duration: 48 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Method: reduced his- background growth, decrease in the number of his + revertants

EXPERIMENT 2
- METHOD OF APPLICATION: preincubation
- DURATION: Preincubation period: 20 min; Exposure duration: 48 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Method: reduced his- background growth, decrease in the number of his + revertants
Evaluation criteria:
In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility

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
Cytotoxicity:
yes
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:
TEST-SPECIFIC CONFOUNDING FACTORS
- Solvent solubility: Complete solubility of the test substance in DMSO

ADDITIONAL INFORMATION ON CYTOTOXICITY:
A bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) was observed depending on the strain and test conditions in the standard plate test at dose ≥ 2500 µg/plate and in the preincubation test at 1500 µg/plate.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

It is concluded that there is no evidence of induction of gene mutations by the test substance in the absence and presence of a metabolic activation system in the four S. typhimurium strains used in this study.
Executive summary:

In an OECD 471 guideline study, the substance was tested for its mutagenic potential based on the ability to induce point mutation in selected loci of several strains of Salmonella typhimurium (TA 1535, TA 100, TA 1537, TA98) in a reverse mutation assay. Bacteria were exposed to 20 -5000 µg test substance/plate in a standard plate test and in a preincubation test in the presence and absence of a metabolizing system (rat liver S-9 mix). A bacteriotoxic effect was observed depending on the strain and test conditions at doses ≥2500 µg/plate (standard plate test) and at 1500 µg/plate (preincubation test). An increase in the number of his+ revertants was not observed in the standard plate test or in the preincubation test either without S9 mix or after the addition of a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.