Trimethyl orthoacetate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Near guideline studies, published in peer-reviewed literature, adequate for assessment

Data source

Reference

Reference Type:

publication

Title:

A compilation of two decades of mutagenicity test results with the Ames Salmonella typhimurium and L5178Y mouse lymphoma cell mutation assays

Author:

Seifried HE, Seifried RM, Clarke JJ, Junghans TB and San RHC.

Year:

2006

Bibliographic source:

Chem. Res. Toxicol. 19: 627-644

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Acetic anhydride

EC Number:

203-564-8

EC Name:

Acetic anhydride

Cas Number:

108-24-7

Molecular formula:

C4H6O3

IUPAC Name:

acetic anhydride

Details on test material:

- Name of test material (as cited in study report): acetic anhydride
- No further details reported

Method

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

- Type and identity of media: Cells grown in Fischer's medium supplemented with 10% horse serum and 0.02% pluronic F-68
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: no data
- Periodically "cleansed" against high spontaneous background: yes, at approximately 3 month intervals

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced liver S9 from male Sprague-Dawley rats

Test concentrations with justification for top dose:

0.04-0.3 µg/mL

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

Migrated to IUCLID6: 4.7 x 10-6 M (or methyl methanesulfonate at 10-20 µg/mL)

Controls 2

Positive control substance:

3-methylcholanthrene

Remarks:

Migrated to IUCLID6: 1.86 x 10-5 M (or dimethylbenz[α]-anthracene at 0.5-4 µg/mL)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

- A total of 1.2 x 107 cells in duplicate cultures were exposed to the test chemical, positive control, and solvent control for 4 h at 37± 1°C, washed twice with growth medium, and maintained at 37± 1°C for 48 h in log phase growth to allow recovery and mutant expression.
- Cells in the cultures were adjusted to 3 x 105/mL at 24 h intervals.
- They were then cloned (1 x 106 cells/plate for mutant selection and 200 cells/plate for viable count determinations) in soft agar medium containing Fischer's medium, 20% horse serum, 2 mM sodium pyruvate, 0.02% pluronic F-68, and 0.23% granulated agar.
- Resistance to trifluorothymidine (TFT) was determined by adding TFT (final concentration, 3 µg/mL) to the cloning medium for mutant selection. The 100x stock solution of TFT in saline was stored at -70°C and was thawed immediately before use.
- Plates were incubated at 37±1°C in 5% CO2 in air for 10-12 days and then counted with an automated colony counter. Only colonies larger than -0.2 mm in diameter were counted. Mutant frequencies were expressed as mutants per 106 surviving cells.

Evaluation criteria:

Results were interpreted using a doubling of the mutant frequency over the concurrent solvent-treated control value as an indication of a positive effect, together with evidence of a dose-related increase. Only doses yielding total growth values of 10% were used in the analysis of induced mutant frequency. Doses yielding less than 10% total growth were used in determining dose response.

Results and discussion

Test results

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

other: Inconclusive. With and without S9

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

see remarks on results

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
other: Inconclusive. With and without metabolic activation

Acetic anhydride is considered to have no significant mutagenic activity in mammalian cells.

Executive summary:

Acetic anhydride has been examined for mutagenic activity in mammalian cells in vitro using the mouse lymphoma L5178Y assay. Although the data can be formally regarded as equivocal, they do not indicate any significant genotoxic activity for acetic anhydride in mammalian cells in vitro. This evaluation of the data reports the findings as inconclusive.

Acetic anhydride is considered to have no significant mutagenic activity in mammalian cells.