Propane, 1,1,1,3,3-pentafluoro-3-methoxy-2-(trifluoromethyl)-

Genetic toxicity: in vitro

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

Study period:

24 February 2005 to 28 April 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Guideline-conform study under GLP without deviations.

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 (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

1,1,1,3,3-pentafluoro-3-methoxy-2-(trifluoromethyl)propane

EC Number:

609-534-4

Cas Number:

382-26-3

Molecular formula:

C5H4F8O

IUPAC Name:

1,1,1,3,3-pentafluoro-3-methoxy-2-(trifluoromethyl)propane

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Octafluoroisobutyl methyl ether
- Substance type: pure substance
- Physical state: liquid
- Analytical purity: > 86%
- Impurities (identity and concentrations): not reported
- Composition of test material, percentage of components: not reported
- Isomers composition: not reported
- Purity test date: not reported
- Lot/batch No.: 20/01/04-161
- Expiration date of the lot/batch: 31 December 2006
- Stability under test conditions: not reported
- Storage condition of test material: 2°C -8°C

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9-Mix

Test concentrations with justification for top dose:

Experiment I (TA 98, TA 100): 3; 10; 33; 100; 333; 1000; 2500; 5000 microgram/plate
Experiment I (plate incorporation test): 33; 100; 333; 1000; 3500; 5000 microgram/plate
Experiment II (pre-incubation test): 10 ; 33; 100; 333; 1000; 2500; 5000 microgram/plate

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

Dimethyl Sulfoxide (DMSO)

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 2-aminoantracece; 4-nitro-o-phenylenediamina

Evaluation criteria:

A test item is considered as mutagen if a biologically relevant increase in the number of revertants exceeding the treshold of twice (strains TA 98, TA 100 and TA 102) or three times (strains TA 1535 and TA 1537) the colony count of the corrisponding solvent control is observed.

A dose dependent increase is considered biologically relevant if the treshold 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 of negative and solvent controls such an increase is not considered biologically relevant.

ACCEPTABILITY OF THE ASSAY
The Salmonella Typhimurium reverse mutation assay is considered acceptable if it meets the following criteria:
- regular background growth in the negative and solvent control
- the spontaneous reversion rates in the negative and solvent control are in the range of our historical data
- the positive control substances should produce a significant increase in mutant colony frequencies

Statistics:

Statistical analysis of data was not performed.

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

toxicity was observed at highest tested doses

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Experiment I (plate incorporation test)

Any other information on results incl. tables

In both experiments, reduced background growth was observed with and without S9 mix in all strains used.

Toxic effects, evident as a reduction in the number of revertants (below the indication factor of 0.5) were observed at the following concentrations (microgram/plate).

 

	EXPERIMENT I		EXPERIMENT II
Strain	without S9 mix	with S9 mix	without S9 mix	with S9 mix
TA 1535	5000	5000	2500	1000, 5000
TA 1537	333, 5000	5000	333, 1000	1000 - 5000
TA 98	//	//	1000 - 5000	2500
TA 100	5000	//	1000 - 5000	1000 - 5000
TA 102	2500, 5000	2500, 5000	1000 - 5000	1000 - 5000

 // = no toxic effects observed

 

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with 2-[difluoro(methoxy)methyl]-1,1,1,3,3,3-hexafluoropropane at any concentration level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged of biological relevance.

 

Appropriate reference mutagens were used as positive controls. They showed a distinct increase in 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.

Applicant's summary and conclusion

Conclusions:

2-[difluoro(methoxy)methyl]-1,1,1,3,3,3-hexafluoropropane is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.

Executive summary:

This study was performed to investigate the potential of 2-[difluoro(methoxy)methyl]-1,1,1,3,3,3-hexafluoropropane to induce gene mutations according to the plate incorporating test (experiment I) and the pre-incubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100, 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 eas tested at the following concentrations:

Experiment I (TA 98, TA 100): 3; 10; 33; 100; 333; 1000; 2500; 5000 microgram/plate

Experiment I : 33; 100; 333; 1000; 3500; 5000 microgram/plate

Experiment II : 10 ; 33; 100; 333; 1000; 2500; 5000 microgram/plate

In both experiments, reduced background growth was observed with and without S9 mix in all strains used.

Toxic effect, evident as a reduction in the number of revertants, were observed at higher concentrations with and without metabolic activation in nearly all strains used.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with 2-[difluoro(methoxy)methyl]-1,1,1,3,3,3-hexafluoropropane at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

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 of frameshifts in the genome of the strains used.

Therefore, 2-[difluoro(methoxy)methyl]-1,1,1,3,3,3-hexafluoropropane is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.