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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Screening study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
GLP compliance:
no
Remarks:
Screening-test
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
Histidine gene
Species / strain
Species / strain / cell type:
other: TA 1513, TA 100, TA 1537, TA 98, TA 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9-Mix
Test concentrations with justification for top dose:
0, 16, 50, 160, 500, 1600, 5000 µg/plate with and without S9-Mix - Plate incorporation screen
0, 100, 200, 400, 800, 1600, 3200 µg/tube Preincubation test with and without S9-Mix
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
Positive controls:
yes
Positive control substance:
other: other: sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine, cumene hydroperoxide, 2-aminoanthracene

Results and discussion

Test results
Species / strain:
other:
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: without metabolic activation 5000 mg/tube, with metabolc activation 3200 mg/tube preincubation test
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'.

Any other information on results incl. tables

No indication of a bacteriotoxic effect of the test substance at doses of up to and including 1600 µg/plate. The total bacteria counts consistently produced results comparable to the negative controls, or differed only insignificantly. No inhibition of growth was noted as well. Higher doses had a strain-specific bacteriotoxic effect. Therefore they could only partly be used for assessment purposes.

In the plate incorporation screen a dose-related and biologically relevant increase in mutant counts over those of the negative controls (with and without S9 -mix) could not be detected. Results were confirmed by the results of the preincubation screen.

Summary of results

S9 -mix       TA 1535       TA 100       TA 1537       TA 98       TA 102

without        neg.                neg.        neg.              neg.            neg.

with             neg                 neg.        neg.              neg.            neg.

The positive controls increased mutant counts to well over those of the negative controls, demonstrated the system´s sensitivity and the activity of the S9 mix.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative non-mutagenic

The test substance was considered to be non-mutagenic without and with S9-mix in the plate incorporation as well as in the preincubation modification of the Salmonella/mircosome test.
Executive summary:

The test subtance was screened with one plate per dose using Salomonella/microsome plate incorporation test for point mutagenic effects in doses of up to and including 5000 µg/plate (strains: TA 1535, TA 100, TA 1537, TA 98, TA 102). The independent repeat was performed as preincubation for 20 minutes at 37 °C and doses up to and including 3200 µg per tube. Doses up to and including 1600 µg per plate did not cause any bacteriotoxic effects: Total bacteria counts remained unchanged and no inhibition of growth was observed. At higher doses the substance had a strain-specific bacteriotoxic effect, so that this range could only be used to a limited extent.

Evidence of mutagenic activity of the test substance was not seen. No biologically relevant increase in the mutant count, in comparison with the negative controls, was observed.

The positive controls had a marked mutagenic effect, as was seen by a biologically relevant increase in mutant colonies compared to the corresponding negative controls.

Therefore the test substance was considered to be non-mutagenic without and with S9-Mix in the plate incorporation as well as in the preincubation modification of the Salomonella/microsome test.