3-(1-ethoxyethyl)-5-methyl-oxazolidin-2-one

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames Test: negative

Link to relevant study records

Reference

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

S9 mix from male Wistar rats livers

Test concentrations with justification for top dose:

0; 33; 100; 333; 1000; 2600 and 5200 μg/plate (with and without S9 mix): (SPT and PIT)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: good solubility of the test substance

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

other: 2-aminoanthracene, N-methyl-N`-nitro-N-nitrosoguanidine, 4-nitro-o-phenylenediamine

Details on test system and experimental conditions:

Standard plate test:
The experimental procedure of the standard plate test (plate incorporation method) was based on the method of Ames et al. (1, 2).
Salmonella typhimurium:
Test tubes containing 2-mL portions of soft agar (overlay agar), which consists of 100 mL agar (0.8% [w/v] agar + 0.6% [w/v] NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM histidine + 0.5 mM biotin) were kept in a water bath at about 42 - 45°C, and the remaining components were added in the following order: 0.1 mL test solution or vehicle (negative control), 0.1 mL fresh bacterial culture, 0.5 mL S9 mix (with metabolic activation) or 0.5 mL phosphate buffer (without metabolic activation).
After mixing, the samples were poured onto Minimal glucose agar plates (Moltox Molecular Toxicology, Inc.; Boone, NC 28607; USA) within approx. 30 seconds. After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies (his+ revertants) were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perceptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hinders the counting using the Image Analysis System.
Escherichia coli:
Test tubes containing 2-mL portions of soft agar (overlay agar), which consists of 100 mL agar (0.8% [w/v] agar + 0.6% [w/v] NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM tryptophan) were kept in a water bath at about 42 - 45°C, and the remaining components were added in the following order: 0.1 mL test solution or vehicle (negative control), 0.1 mL fresh bacterial culture, 0.5 mL S9 mix (with metabolic activation) or 0.5 mL phosphate buffer (without metabolic activation).
After mixing, the samples were poured onto Minimal glucose agar plates (Moltox Molecular Toxicology, Inc.; Boone, NC 28607; USA) within approx. 30 seconds. After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies (trp+ revertants) were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perceptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hinders the counting using the Image Analysis System.
Preincubation Test
The experimental procedure was based on the method described by Yahagi et al. and Matsushima et al.. 0.1 mL test solution or vehicle, 0.1 mL bacterial suspension and 0.5 mL S9 mix (with metabolic activation) or phosphate buffer (without metabolic activation) were incubated at 37°C for the duration of about 20 minutes using a shaker. Subsequently, 2 mL of soft agar was added and, after mixing, the samples were poured onto the agar plates within approx. 30 seconds.
After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perceptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hindered the counting using the Image Analysis System.

Evaluation criteria:

The test substance was considered positive in this assay if the following criteria were met: A dose-related and reproducible increase in the number of revertant colonies, i.e. at least doubling (bacteria strains with high spontaneous mutation rate, like TA 98, TA 100 and E.coli WP2 uvrA) or tripling (bacteria strains with low spontaneous mutation rate, like TA 1535 and TA 1537) of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.

Species / strain:

other: TA 1535, TA 100, TA 1537, TA 98 and E.coliWP2 uvrA

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

SOLUBILITY: No precipitation of the test substance was found with and without S9 mix.

TOXICITY: No bacteriotoxic effect was observed under all test conditions.

MUTAGENICITY: A relevant increase in the number of his+ or trp+ revertants (factor ≥ 2: TA 100, TA 98 and E.coli WP2 uvrA or factor ≥ 3: TA 1535 and TA 1537) was not observed in the standard plate test or in the preincubation test without S9 mix or after the addition of a metabolizing system.

Conclusions:

Under the experimental conditions chosen here, it is concluded that 3-(1-Ethoxyethyl)-5- methyloxazolidin-2-on is not a mutagenic test substance in the bacterial reverse mutation test in the absence and the presence of metabolic activation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The test substance 3-(1-Ethoxyethyl)-5-methyloxazolidin-2-on was tested for its mutagenic potential based on the ability to induce point mutations in selected loci of several bacterial strains, i.e. Salmonella typhimurium and Escherichia coli, in a reverse mutation assay. Test Strains are TA 1535, TA 100, TA 1537, TA 98 and E. coli WP2 uvrA and dose range 33 μg - 5200 μg/plate (SPT) and 33 μg - 5200 μg/plate (PIT). Standard plate test (SPT) and preincubation test (PIT) both with and without metabolic activation (liver S9 mix from induced rats). No precipitation of the test substance was found with and without S9 mix. No bacteriotoxic effect was observed under all test conditions. A relevant increase in the number of his+ or trp+ revertants (factor ≥ 2: TA 100, TA 98 and E.coli WP2 uvrA or factor ≥ 3: TA 1535 and TA 1537) was not observed in the standard plate test or in the preincubation test without S9 mix or after the addition of a metabolizing system. Under the experimental conditions of this study, the test substance 3-(1-Ethoxyethyl)-5-methyloxazolidin-2-on is not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay in the absence and the presence of metabolic activation.

Justification for classification or non-classification

Based on the results, the test item is no subject to classification and labelling according to Regulation (EC) No 1272/2008 (CLP).