1-Ethoxy-2,3-difluor-4-[4-(trans-4-propylcyclohexyl)-1-cyclohexen-1-yl]-benzene

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07.09.2007- 18.02.2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Principles of method if other than guideline:

None

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

1-ethoxy-2,3-difluoro-4-{4-[(1s,4r)-4-propylcyclohexyl]cyclohex-1-en-1-yl}benzene

EC Number:

603-006-7

Cas Number:

124728-62-7

Molecular formula:

C23H34F2O

IUPAC Name:

1-ethoxy-2,3-difluoro-4-{4-[(1s,4r)-4-propylcyclohexyl]cyclohex-1-en-1-yl}benzene

Test material form:

solid: crystalline

Method

Target gene:

HIS operon (S. thyphimurium), TRY operon (E. coli)

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535

Details on mammalian cell type (if applicable):

his G 46, uvrB, rfa

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1537

Details on mammalian cell type (if applicable):

his C 3076, uvrB, rfa

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 98

Details on mammalian cell type (if applicable):

his D 3052, uvrB, rfa + R-factor

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 100

Details on mammalian cell type (if applicable):

his G 46, uvrB, rfa + R-factor

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain 5

Species / strain / cell type:

S. typhimurium TA 102

Details on mammalian cell type (if applicable):

his G 428, rfa + R-factor

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain 6

Species / strain / cell type:

E. coli WP2

Details on mammalian cell type (if applicable):

his C 3076, uvrB, rfa

Additional strain / cell type characteristics:

other: mutations in the tryptophan operon

Metabolic activation:

with and without

Metabolic activation system:

rat liver homogenate (S9 mix) with standard co-factors with metabolic activation (Aroclor)

Test concentrations with justification for top dose:

In the pre-experiment the concentration range of the test item was 3 - 5000 μg/plate. The pre-experiment is reported as experiment 1. Since no relevant toxic effects were observed 5000 μg/plate were chosen as maximal concentration. Due to the observed precipitation eight concentrations were tested in experiment II. The concentration range included two logarithmic decades. The following concentrations were tested: 3, 10, 33, 100, 333, 1000, 2500 and 5000 μg/plate.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO (> 99 %)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 2-aminoanthracene, 4-nitro-o-phenylene-diamine

Evaluation criteria:

A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and TA 102) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed. A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range.

Statistics:

No statistical evaluation of the data is required.

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:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

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:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

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:

not examined

True negative controls validity:

not examined

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:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Key result

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:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 6

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:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Please refer to confidential file under "Attachments".

Applicant's summary and conclusion

Conclusions:

The test material was non-mutagenic in the Salmonella typhimurium and Escherichia coli reverse mutation assay.

Executive summary:

The information for this endpoint study record was obtained from an experimental study. The OECD GLP criteria were met and the methods applied are fully compliant with OECD 471. This study was performed to investigate the potential of the test material to induce gene mutations according to the plate incorporation test (experiment I) and the preincubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100, and TA 102. The assay was performed in two independent experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the concentrations of 3, 10, 33, 100, 333, 1000, 2500 and 5000 μg/plate in pre-experiment/experiment I and II. The plates incubated with the test item showed normal background growth up to 5000 μg/plate with and without S9 mix in all strains used. No toxic effects, evident as a reduction in the number of revertants (below the induction factor of 0.5), occurred in the test groups with and without metabolic activation. Only in strain TA 1537 a minor reduction in the number of revertants (below the induction factor of 0.5) was observed at 5000 μg/plate in exp. I with S9 mix and in exp. II without S9 mix. No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test item at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies. In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used. Therefore, the test material is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.