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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD Guideline Study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Remarks:
Centre International de Toxicologie, France
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): D-(+)-Isobutyllactat
- Physical state: liquid
- Analytical purity: 99.5%
- Isomers composition: D/(D+L) = 99.4%
- Lot/batch No.: PR 596
- Storage condition of test material: 4°C

Method

Target gene:
his
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:
Aroclor induced rat liver S9-mix
Test concentrations with justification for top dose:
0, 100, 500, 1000, 2500, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9-mix for TA100 and TA1535
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
without S9-mix for 1537
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
without S9-mix for TA98 and TA1535
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-anthramine
Remarks:
with S9-mix for all used strains
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 to 72 hours
- Expression time (cells in growth medium): up to 72 hours


DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
- a test substance is considered as mutagenic it, for each test, it induces a doubling in the number of revertants when compared to that in the negative and/or solvent controls, for at least one of the tested strains and at one or more of the tested concentrations. In this case, a statistically significant dose relationship is investigated, using a linear regression analysis, and considered as signiticant if p ≤ 0.05 (for n = 18 values, the correlation coefficient r must be ≥ 0.47).
- a test substance is considered as non-mutagenic if the above two criteria are not fully met.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
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

The number of revertants obtained in the presence of the test substance with and without S9 mix for the 5 strains was equivalent to that of the negative and/or solvent controls. During the second assay, a doubling of the number of revertants when compared to that of the solvent was obtained at 2500 µg/plate concerning the TA 1537 strain. No statistically significant dose-effect relationship was observed (Y = 9.8 x + 11 r = 0.40) and this result was not noted in the first assay. Consequently, it was considered as non-significant.

Applicant's summary and conclusion