3,3,5,7,7-pentamethyl-1,2,4-trioxepane

Genetic toxicity: in vitro

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:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

liquid

Specific details on test material used for the study:

Clear colourless liquid, purity 96.5%.

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9-mix (Aroclor-1254 induced rat liver S9-mix)

Test concentrations with justification for top dose:

Dose range finding test conducted at 3, 10, 33, 100, 333, 1000, 3330 and 5000 ug/plate. In the dose range finding study, pentamethyl-trioxepane did not precipitate on the plates at this dose level. The bacterial background lawn was not reduced at any of the concentrations tested and no biologically relevant decrease in the number of revertants was observed. Mutation assay and follow up repeat study was conducted at 100, 333, 1000, 3330 and 5000 ug/plate.

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Remarks:

DMSO

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

methylmethanesulfonate

other: 2-aminoanthracene

Details on test system and experimental conditions:

All incubations were carried out in the dark at 37 +/- 1.5 oC for 48 hours.

In the dose range finding test TA100 adn WP2uvrA were exposed to eight different doses with and without 5% S9 mix in triplicate. In the mutation assay, 5 different doses were tested with and without 5% S9 mix in triplicate in each cell line. Frequency of dosing was once.

Evaluation criteria:

- the negative control data (number of spontaneous revertants per plate) should be within the laboratory historical range for each tester strain
- the positive control chemicals should produce responses in all tester strains, which are within the laboratory historical range for each positive control substance. The mean plate count should be at least three times the concurrent vehicle control group mean.
- The selected dose range should include a clearly toxic conc. or should exhibit limited solubility as demonstrated by the preliminary toxicity range finding test or should extend to 5 mg/plate.

Statistics:

Not applicable: negative result

Results and discussion

Test results

Test results 1

Key result

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

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

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

Test results 3

Key result

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

Test results 4

Key result

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

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

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

Additional information on results:

All bacterial strains showed negative responses over the entire dose range, i.e. no dose-related, two-fold, increase in the number of revertants in two independently repeated experiments.

Not cytotoxic in the dose range finding test or mutation assay, highest conc. 5 mg/plate

Not genotoxic effects in the dose range finding test or mutation assay, highest conc. 5 mg/plate

Pentamethyl-trioxepane precipitated in the top agar layer at conc of 3330 and 5000 μg/plate. At the start of the incubation period precipitation was seen in the 5000 μg/plate. At the end of the incubation period it was gone.

Any other information on results incl. tables

Additionally, the stability of pentamethyl-trioxepane in dimethyl sulfoxide (DMSO) was determined. Conclusion: a 4.22% solution of pentamethyl-trioxepane in dimethyl sulfoxide (DMSO) is completely stable at room temperature during at least 24 hours.

The negative and strain-specific positive control values were within our laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly. The selected dose range extended to 5mg/plate.

Applicant's summary and conclusion

Conclusions:

Pentamethyl-trioxepane is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay

Executive summary:

Pentamethyl-trioxepane is not mutagenic in theSalmonella typhimuriumreverse mutation assay and in theEscherichia colireverse mutation assay