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Toxicological information

Genetic toxicity: in vitro

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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: GLP-compliant guideline study, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-ethoxy-2-methylpropane
EC Number:
211-309-7
EC Name:
2-ethoxy-2-methylpropane
Cas Number:
637-92-3
Molecular formula:
C6H14O
IUPAC Name:
2-ethoxy-2-methylpropane
Details on test material:
- Name of test material (as cited in study report): ETBE
- Physical state: colourless liquid
- Analytical purity: 95.8%
- Lot/batch No.: 93050601

Method

Target gene:
his
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA98, TA 100
Metabolic activation:
with and without
Metabolic activation system:
 Arochlor 1254-induced rat S9 fraction
Test concentrations with justification for top dose:
First test: 8, 40, 200, 1000 and 5000 ug/plate;
Second test: 313, 625, 1250, 2500 and 5000 ug/plate
Vehicle / solvent:
ethanol
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Nitrofluorene, 9-aminoacridine, sodium  azide, 2-aminoanthracene
Details on test system and experimental conditions:
Commercially-available freeze-dried S9 fraction (MOLTOX Inc) from Arochlor 1254-induced rats was used in these studies. Absolute ethanol was used as carrier solvent, and added at a final volume of 0.05 ml/plate. Each dose was tested in triplicate, with independent repeat. 2-Nitrofluorene (TA 98 and TA 1538), 9-aminoacridine (TA 1537) and sodium azide (TA 1535 and TA 100) were used as positive control substances in the absence of S9 mix, and 2-aminoanthracene (all strains) as positive  control in the presence of S9.

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION:
- Exposure duration: 48 hours (minimum)
- Temperature: 37 +- 1 oC
Evaluation criteria:
Results were considered positive if a suitable response had been obtained with the negative and positive control substances, and the number of revertants in the presence of ETBE was at least twice that of the negative control, with a dose-response correlation.
Statistics:
After completion of scoring, mean of revertant colonies and standard deviation for each dose are determined.

Results and discussion

Test results
Species / strain:
other: Salmonella typhimurium TA 1535, TA 1537, TA 1538, TA98, TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Results from a preliminary test using TA 100 (without S9) revealed no toxicity at doses up to 5000 ug/plate. All data met the acceptability criteria established for the test. No increase in the number of revertants was seen with any of the tester stains, both in the absence and presence of S9 fraction, in either the first or second study. A satisfactory response was obtained with the negative and positive controls.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion