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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Ethyl lactate
EC Number:
202-598-0
EC Name:
Ethyl lactate
Cas Number:
97-64-3
Molecular formula:
C5H10O3
IUPAC Name:
ethyl 2-hydroxypropanoate
Test material form:
liquid
Remarks:
colorless transparent liquid

Method

Target gene:
TA97a: 4997D, TA98: 5011D, TA100: 4996D, TA102: 4982D, TA1535: 5012D
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA97a, TA98, TA100, TA102 and TA1535
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
The following nominal concentrations were prepared for the first experiment:
5 µL/plate, 1.5 µL/plate, 0.5 µL/plate, 0.15 µL/plate and 0.05 µL/plate

The following nominal concentrations were prepared for the second experiment:
5 µL/plate, 2.5 µL/plate, 1.25 µL/plate, 0.63 µL/plate, 0.31 µL/plate and 0.16 µL/plate
Vehicle / solvent:
ddH2O was used as solvent to dissolve the test substance.
Controls
Untreated negative controls:
yes
Remarks:
ddH2O and DMSO were used
Positive controls:
yes
Positive control substance:
sodium azide
benzo(a)pyrene
other: 4-Nitro-1,2-phenylene diamine, 2-Amino anthracene
Details on test system and experimental conditions:
All Salmonella typhimurium strains were obtained from TRINOVA BioChem GmbH (batch: TA97a: 4997D, TA98: 5011D, TA100: 4996D, TA102: 4982D, TA1535: 5012D) and were stored as lyophilizates in the refrigerator at 2-8 °C.
The lyophilizates were used to prepare permanent cultures which were filled into vials and stored at < - 75 °C.

Eight hours before the start of each experiment, an aliquot of a permanent culture per strain to be used was taken from the deep freezer to inoculate a culture vessel containing nutrient broth. After incubation overnight for eight hours at 37 ± 1 °C, the cultures were used in the experiment. During the test, the cultures were stored at room temperature as to prevent changes in the titre.

All vessels used are made of glass or sterilizable plastic. They were sterilized before use by autoclaving.
The following vessels were used:
• Schott-bottles, glass vials, and culture flasks for solutions and media
• Plastic petri plates
• test tubes for top-agar-bacteria-substance mix
Evaluation criteria:
All strains met the criterion of at least 109 bacteria/mL, and no inconsistencies were found in the sterility control. All determined values for the spontaneous revertants of the negative controls were in the normal range of the test laboratory. All positive controls (diagnostic mutagens) showed mutagenic effects with and without metabolic activation and were within the historical control data ranges.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium 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 1535
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 97
Remarks:
TA97a
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 98
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 102
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

Applicant's summary and conclusion

Conclusions:
Based on the results of this study it is concluded that Ethyl lactate is not mutagenic in the Salmonella typhimurium strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.