2,6-dimethyl-4-(2,2,3-trimethylcyclopent-3-en-1-yl)cyclohex-2-en-1-ol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

- Ames Test (OECD 471, GLP, K, rel. 2): non mutagenic up to the maximum concentrations in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 & E.coli WP2uvrA.

- Chromosome aberration test (OECD 473, GLP, K, rel. 2): non clastogenic up to cytotoxic concentrations.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 13 February to 16 April 2012.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

GLP study conducted in compliance with OECD Guideline No. 471 without any deviation. The substance is adequately identified, but some data on composition is missing. Therefore validation applies with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

21 July 1997.

Deviations:

yes

Remarks:

2-Aminoanthracene was used as the sole indicator of the efficacy of the S9-mix. No information on the characterisation of S9 with a mutagen that requires metabolic activation by microsomal enzymes has been included in the report.

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:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspected on 2011-10-19,20&21 / Signed on 2011-11-17.

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Physical state: colorless to pale yellow dense gel

Species / strain / cell type:

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

Details on mammalian cell type (if applicable):

not applicable

Additional strain / cell type characteristics:

not applicable

Cytokinesis block (if used):

not applicable

Metabolic activation:

with and without

Metabolic activation system:

10% v/v S9 fraction; rat liver microsome fraction (S9)

Test concentrations with justification for top dose:

Mutagenicity test:
Main test: 0.3, 0.8, 2.3, 6.9 and 20.6 μg/plate in TA 98, TA 100, TA 1535, TA 1537 and WP2(pKM101) with and without S9 under the direct plate incorporation method.
Confirmation test: 0.3, 0.8, 2.3, 6.9 and 20.6 μg/plate in TA 98, TA 100, TA 1535, TA 1537 and WP2(pKM101) with and without S9 under the pre-incubation method.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Ethanol
- Justification for choice of solvent/vehicle: the solubility of the test item was evaluated in a standard solvent panel (milliQ water, ethanol 96%, DMSO
and corn oil). Observation of precipitation by the naked eye indicated that the test item is not soluble.

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

Remarks:

without S9 mix

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-amino-anthracene

Remarks:

with S9 mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) and preincubation

DURATION
- Preincubation period: 20 min at 37 °C
- Exposure duration: 37 °C for 48 h

NUMBER OF REPLICATIONS: 3 plates/dose

DETERMINATION OF CYTOTOXICITY
- Method: A reduction in the number of colonies in a dose-dependent manner compared to negative control for any strain and condition might indicate cytotoxicity.

OTHER:
- After an incubation of about 48 hours at about 37 ºC, the number of colonies per plate was counted.
Data are presented as the number of colonies present per plate (mean ± standard deviation). The R ratio is calculated as follows:
R = Number of revertant colonies in the presence of the test item / Number of revertant colonies in the absence of the test item
- Sterility test: The sterility of the test item was assayed by adding of 5 mg/plate to a minimal agar plate and incubating at 37°C for 48h. No growth was observed in the minimal agar plate after incubation with the test item.
- Solubility test: Solubility was assessed as precipitation in the final mixture under the actual test conditions. Observation of precipitation by naked eye indicates insolubility.

Evaluation criteria:

Several criteria are used for determining a positive result: a dose-response in the range tested and / or a reproducible increase at one or more concentrations in the number of revertant colonies per plate in at least one strain with or without metabolic activation system.
Positive results from the bacterial reverse mutation test indicate that a test item induces point mutations or frame-shifts in the genome of the tested bacterial strains.
Negative results from the test indicate that under the test conditions, the test item neither mutagenic nor-pro-mutagenic in the tested experimental system.

Statistics:

None

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not applicable

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Water solubility: None
- Precipitation: None
- Other confounding effects: None

CYTOTOXICITY TEST:
A decrease in the number of revertant colonies >50% compared to solvent reference was observed, indicating cytotoxicity of the test item. The lowest cytotoxic concentration was 20.6 µg/plate and it was used as the highest formulation for Ames test.

MUTAGENICITY TEST:
- No concentration of the test item showed a biological significant increase (R ≥ 2.5) of the number of revertant either with or without S9 metabolic activation.
− No dose response was observed in any of the tested bacterial strains.

HISTORICAL CONTROL DATA
- Positive and negative controls showed absolute numbers of revertant colonies comparable to historical data of the test facility.

OTHERS:
- Sterility test showed no contamination during the study.

None

Conclusions:

Under the test condition, the test mateiral is not mutagenic in presence and absence of metabolic activation in S. typhimurium strains TA1535, TA1537, TA98 and TA100, and E.coli WP2uvrA.

Executive summary:

In a reverse gene mutation assay performed according to the OECD test guideline No. 471 and in compliance with GLP, strains of Salmonella typhimurium (TA 1535, TA 1537, TA 98 and TA 100) and Escherichia coli WP2(pKM101) were exposed to the test item diluted in ethanol at the following concentrations both in the presence and absence of metabolic activation system (10% v/v S9).

 

Main test: 0.3, 0.8, 2.3, 6.9 and 20.6 μg/plate in TA 98, TA 100, TA 1535, TA 1537 and WP2(pKM101) with and without S9 under the direct plate incorporation method.

Confirmation test: 0.3, 0.8, 2.3, 6.9 and 20.6 μg/plate in TA 98, TA 100, TA 1535, TA 1537 and WP2(pKM101) with and without S9 under the pre-incubation method.

 

Negative and positive control groups were also included in mutagenicity tests.

 

Positive and negative controls showed absolute numbers of revertant colonies comparable to historical data. All positive controls showed valid ratios (R) above 2.5.

 

Cytotoxic effect was observed at 20.6 µg/plate. No concentration of the test item showed a biological significant increase (R ≥ 2.5) of the number of revertant either with or without S9 metabolic activation. No dose response was observed in any of the tested bacterial strains.

 

Under the test condition, the test material is not mutagenic with and without metabolic activation in S. typhimurium strains TA1535, TA1537, TA98 and TA100, and E.coli WP2uvrA.

This study is considered as acceptable and satisfies the requirement for reverse gene mutation endpoint.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 19 March to 05 July 2019.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study conducted according to OECD TG 473 without any deviation. The substance is adequately identified, but some data on composition is missing. Therefore validation applies with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Version / remarks:

Adopted 29 July 2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: The Japanese Ministry of Health, Labour and Welfare (MHLW), Ministry of Economy Trade and Industry (METI), and Ministry of the Environmental (MOE).

Version / remarks:

Guidelines of 31 March 2011.

Deviations:

no

Principles of method if other than guideline:

Not applicable.

GLP compliance:

yes (incl. QA statement)

Remarks:

UK GLP Compliance Programme (Inspected on 2018-08-21 / Signed on 2018-11-19).

Type of assay:

in vitro mammalian chromosome aberration test

Specific details on test material used for the study:

- Physical state: Pale yellow extremely viscous liquid.
- Storage condition of test material: Room temperature in the dark.

Target gene:

Not applicable.

Species / strain / cell type:

lymphocytes: human

Details on mammalian cell type (if applicable):

For lymphocytes:
- Sex, age and number of blood donors:
Preliminary Toxicity Test: female, aged 28 years
Main Experiment (4(20)-hour without S9-mix): female, aged 35 years
Main Experiment (4(20)-hour with S9-mix): female, aged 24 years
Main Experiment (24-hour without S9-mix): male , aged 21 years

- Whether whole blood or separated lymphocytes were used: for each experiment, sufficient whole blood was drawn from the peripheral circulation of a non-smoking volunteer who had been previously screened for suitability.
- Whether blood from different donors were pooled or not: no, one donor for each experiment.
- Mitogen used for lymphocytes: phytohaemagglutinin (PHA).

MEDIA USED :
Cells (whole blood cultures) were grown in Eagle's minimal essential medium with HEPES buffer (MEM), supplemented “in-house” with L-glutamine, penicillin/streptomycin, amphotericin B and 10 % fetal bovine serum (FBS), at approximately 37 ºC with 5 % CO2 in humidified air.

Additional strain / cell type characteristics:

other: Not applicable.

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- source of S9 : Covance laboratory (Lot No. PB/βNF S9 31/08/18 and 28/10/18 ), stored at approximately -196 °C.
- method of preparation of S9 mix: S9 fraction was obtained from the liver homogenates of male rats treated with Phenobarbitone/Beta-naphthoflavone.
- concentration or volume of S9 mix and S9 in the final culture medium : the final concentration of S9, when dosed at a 10% volume of S9-mix into culture media, was 2%.

Test concentrations with justification for top dose:

- Preliminary Toxicity Test (Cell Growth Inhibition): 0, 7.81, 15.63, 31.25, 62.5, 125, 250, 500, 1000 and 2000 µg/mL, 4h exposure time with and without metabolic activation followed by a 20h recovery period (4(20)-hour with (2%) and without S9-mix), and a continuous exposure of 24h without metabolic activation (24-hour without S9-mix).
Justification: The maximum dose was the maximum recommended dose level.

- Main Experiment: 0, 8, 16, 32, 36, 40, 44 and 48 µg/mL, 4(20)-hour without S9-mix. 0, 8, 16, 32, 48, 64, 80, 112 and 128 µg/mL, 4(20)-hour with S9-mix (2%).
0, 2, 4, 8, 16, 32, 48, 56 and 64 µg/mL, 24-hour without S9-mix.
Justification: The maximum dose level selected for the main experiment was based on toxicity for all three exposure groups (preliminary toxicity study).

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: dimethyl sulphoxide (DMSO).
- Justification for choice of solvent/vehicle: the test item was immiscible in aqueous media at 20 mg/mL but was miscible in DMSO at 200 mg/mL in solubility checks performed in house.
- Formulation preparation: the test item was accurately weighed,formulated in DMSO and appropriate serial dilutions prepared. The test item was formulated within two hours of it being applied to the test system; the test item formulations were assumed to be stable for this duration. No analysis was conducted to determine the homogeneity, concentration or stability of the test item formulation because it is not a requirement of the guidelines.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

Without metabolic activation.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

With metabolic activation (2% S9-mix).

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: quadruplicate cultures for the control; duplicate culture per dose levels
- Number of independent experiments: 2

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: Exp. 1: 4 hours (± S9) / Exp. 2: 24 hours (-S9)
- Harvest time after the end of treatment (sampling/recovery times): 24 hours

FOR CHROMOSOME ABERRATION:
- Spindle inhibitor (cytogenetic assays): Mitotic activity was arrested by addition of demecolcine (Colcemid 0.1 μg/mL), two hours before the harvest time.
- Methods of slide preparation and staining technique used including the stain used (for cytogenetic assays): After incubation with demecolcine, the cells were centrifuged, the culture medium was drawn off and discarded, and the cells re-suspended in 0.075M hypotonic KCl. After approximately fourteen minutes (including centrifugation), most of the hypotonic solution was drawn off and discarded. The cells were re-suspended and then fixed by dropping the KCl cell suspension into fresh methanol/glacial acetic acid (3:1 v/v). The fixative was changed at least three times and the cells stored at approximately 4 ºC to ensure complete fixation prior to slide preparation.
The lymphocytes were re-suspended in several mL of fresh fixative before centrifugation and re-suspension in a small amount of fixative. Several drops of this suspension were dropped onto clean, wet microscope slides and left to air dry. Each slide was permanently labeled with the appropriate identification data.
When the slides were dry, they were stained in 5 % Giemsa for 5 minutes, rinsed, dried and a cover slip applied using mounting medium.
- Number of cells spread and analysed per concentration (number of replicate cultures and total number of cells scored): Where possible 1000 cells per culture were evaluated for the incidence of metaphase cells and expressed as the mitotic index and as a percentage of the vehicle control value.
- Criteria for scoring chromosome aberrations (selection of analysable cells and aberration identification): Where possible, 300 consecutive well-spread metaphases from each concentration were counted, 600 from the vehicle control (150 per replicate), where there were at least 15 cells with aberrations (excluding gaps), slide evaluation was terminated. If the cell had 44-48 chromosomes, any gaps, breaks or rearrangements were noted according to the simplified system of Savage (1976) recommended in the 1983 UKEMS guidelines for mutagenicity testing and the ISCN (1985). Cells with chromosome aberrations were reviewed as necessary by a senior cytogeneticist prior to decoding the slides
- Determination of polyploidy / endoreplication: cells with 69 chromosomes or more were scored as polyploid cells (including endoreduplicated cells) and the incidence of polyploid cells (%) reported. Many experiments with human lymphocytes have established a range of aberration frequencies acceptable for control cultures in normal volunteer donors.

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method: mitotic index (MI)

Rationale for test conditions:

Human peripheral blood lymphocytes are recognized in the OECD 473 guidelines as being a suitable cell line for the Mammalian Chromosome Aberration Test.

Evaluation criteria:

The following criteria were used to determine a valid assay:
• The frequency of cells with structural chromosome aberrations (excluding gaps) in the vehicle control cultures was within the laboratory historical control data range.
• Concurrent positive control chemicals should induce responses that are compatible with those generated in historical positive control data base and produce a statistically significant increase compared with the concurrent negative control.
• The study was performed using all three exposure conditions using a top concentration which meets the requirements of the current testing guideline.
• The required number of cells and concentrations were analyzed.

Statistics:

The frequency of cells with aberrations excluding gaps and the frequency of polyploid cells was compared, where necessary, with the concurrent vehicle control value using Fisher's Exact test. (Richardson et al. 1989).
A toxicologically significant response is recorded when the p value calculated from the statistical analysis of the frequency of cells with aberrations excluding gaps is less than 0.05 when compared to its concurrent control and there is a dose-related increase in the frequency of cells with aberrations which is reproducible. Incidences where marked statistically significant increases are observed only with gap-type aberrations will be assessed on a case by case basis.

Key result

Species / strain:

lymphocytes: human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Data of pH: No significant change in pH when the test item was added into media.
- Data of osmolality: Osmolality did not increase by more than 50 mOsm.
- Possibility of evaporation from medium: not expected (vapour pressure = TBC Pa)
- Water solubility: Insoluble at 20 mg/mL.

PRELIMINARY TOXICITY TEST (CELL GROWTH INHIBITION TEST):
- A precipitate of the test item was observed in the parallel blood-free cultures at the end of the exposure at and above 250 µg/mL in all three exposure groups.
- Hemolysis was observed following exposure to the test item at and above 31.25 µg/mL in the 4(20)-hour exposure groups and at and above 125 µg/mL in the 24-hour continuous exposure group. Hemolysis is an indication of a toxic response to the erythrocytes and not indicative of any genotoxic response to the lymphocytes.
- Microscopic assessment of the slides prepared from the exposed cultures showed that metaphase cells were present up to 31.25 µg/mL in the 4(20)-hour exposure in the absence of metabolic activation (S9), and up to 62.5 µg/mL in the presence of S9 and the 24 hour continuous exposure groups. The test item induced evidence of toxicity in all three exposure groups.
The selection of the maximum dose level was based on toxicity for all three exposure groups.

MAIN STUDY RESULTS
- Concurrent vehicle negative and positive control data: all of the vehicle control cultures had frequencies of cells with chromosome aberrations within the expected range.
All the positive control items induced statistically significant increases in the frequency of cells with aberrations indicating that the sensitivity of the assay and the efficacy of the S9-mix were validated.
- Results from cytotoxicity measurements:
- The qualitative assessment of the slides determined that the toxicity was similar to that observed in the Cell Growth Inhibition Test. There were metaphases suitable for scoring present up to 48 µg/mL in the absence of S9-mix and up to 80 µg/mL in the presence of S9.
- The results of the mitotic indices (MI) from the cultures after their respective exposures confirm the qualitative observations in that a dose-related inhibition of mitotic index was observed in all three exposure groups.
- In the 4(20)-hour exposure group in the absence of S9, a plateau of toxicity was observed where 48%, 41% and 58% mitotic inhibition was achieved at 36, 40 and 44 µg/mL, respectively due to the relatively narrow dose range employed for this experiment. Above this dose level, very few metaphases were present. As a consequence, the maximum dose level selected for metaphase analysis was 44 µg/mL because this dose level achieved optimum toxicity as defined by the OECD 473 Test Guideline (55±5%).
- In the presence of S9, 29%, 21% and 51% mitotic inhibition was achieved at 32, 48 and 64 µg/mL, respectively. Above this dose level, there were either too few or no metaphases available for analysis. Therefore, the maximum dose level selected for metaphase analysis was 64 µg/mL because this dose level achieved optimum toxicity as defined by the OECD 473 Test Guideline (55±5%).
- An inhibition of mitotic index of 25%, 51% and 77% was noted at 16, 32 and 48 µg/mL, respectively, in the 24-hour continuous exposure group. Above this dose level, there were no metaphases present for analysis. Therefore, the maximum dose level selected for metaphase analysis was 32 µg/mL because this dose level achieved optimum toxicity as defined by the OECD 473 Test Guideline (55±5%).

- Genotoxicity results:
- The test item did not induce any statistically significant increases in the frequency of cells with aberrations either in the absence or presence of metabolic activation.
- The test item did not induce a statistically significant increase in the numbers of polyploid cells at any dose level in either of the exposure groups. There was no indication of endoreduplication noted.

HISTORICAL CONTROL DATA (mean ± standard deviation)
- Positive historical control data:
cells with aberrations (-gaps):
4(20)-hour exposure without S9%: 25.13 ± 13.14
4(20)-hour exposure with S9 (2%): 16.22 ± 7.00
24-hour exposure without S9: 26.81 ± 12.28
% cells with polyploids:
4(20)-hour exposure without S9%: 0.01 ± 0.06
4(20)-hour exposure with S9 (2%): 0.03 ± 0.12
24-hour exposure without S9: 0.02 ± 0.11

- Negative (solvent/vehicle) historical control data:
cells with aberrations (-gaps):
4(20)-hour exposure without S9%: 0.48 ± 0.40
4(20)-hour exposure with S9 (2%): 0.54 ± 0.53
24-hour exposure without S9: 0.36 ± 0.43

% cells with polyploids:
4(20)-hour exposure without S9%: 0.04 ± 0.13
4(20)-hour exposure with S9 (2%): 0.03 ± 0.10
24-hour exposure without S9: 0.02 ± 0.07

None.

Conclusions:

Under the test conditions, test item did not induce any statistically significant increase in the frequency of cells with chromosome aberrations, in either the absence or presence of a liver enzyme metabolizing system. The test item was therefore considered to be non-clastogenic to human lymphocytes in vitro.

Executive summary:

In an in vitro chromosome aberration test performed according to OECD Guideline 473 and in compliance with GLP, cultured human lymphocytes were exposed to test item at the following concentrations:

 

Preliminary Toxicity Test (Cell Growth Inhibition Test)

0, 7.81, 15.63, 31.25, 62.5, 125, 250, 500, 1000 and 2000 µg/mL; 4 h exposure time with and without metabolic activation followed by a 20 h recovery period (4(20)-hour with and without S9-mix), and a continuous exposure of 24 h without metabolic activation (24-hour without S9-mix)

 

Main experiment

4(20)-hour without S9-mix: 0, 8, 16, 32, 36, 40, 44 and 48 μg/mL;

4(20)-hour with S9 (2%): 0, 8, 16, 32, 48, 64, 80, 112 and 128 μg/mL;

24-hour without S9-mix: 0, 2, 4, 8,16, 32, 48, 56, 64 μg/mL;

Mitotic activity was arrested by addition of colcemid at 0.1 μg/mL for each culture, two hours before the harvest. The cells were then treated with a hypotonic solution, fixed, stained and examined for mitotic indices and chromosomal aberrations. Vehicle and positive controls were also included in this test.

 

All vehicle (Acetone) controls had frequencies of cells with aberrations within the range expected for normal human lymphocytes. All the positive control items induced statistically significant increases in the frequency of cells with aberrations indicating that the sensitivity of the assay and the efficacy of the S9- mix were validated.

 

The test item was toxic to human lymphocytes but did not induce any statistically significant increases in the frequency of cells with aberrations, using a dose range that included a dose level that induced 55±5% mitotic inhibition.

Under the test conditions, the test item was considered to be non-clastogenic to human lymphocytes in vitro.

This study is considered as acceptable and satisfies the requirement for chromosome aberration endpoint.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

 

Table 7.6/1: Summary of genotoxicity tests

 

Test n°	Test / Guideline Reliability	Focus	Strains tested	Metabolic activation	Test concentration	Statement
1   VIVOTECNIA, 2012	Ames Test (OECD 471) K, rel. 2	Gene mutation	TA 1535, TA 1537, TA 98, TA 100, E. coli WP2	-S9 +S9	0.3, 0.8, 2.3, 6.9 and 20.6 µg/plate (in ethanol)	-S9: non mutagenic +S9: non mutagenic
2 COVANCE, 2019	CAT (OECD 473) K, rel.2	Chromosomal Aberration	Human lymphocytes	-S9 +S9	Up to cytotoxicity	-S9 : non clastogenic +S9 : non clastogenic

 

Gene mutation Assay (Test n°1):

A Bacterial Reverse mutation Assay (Ames test) was performed according to OECD guideline No. 471 with the substance(See Table 7.6/1). No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains under the test conditions, with any dose of the substance, either in the presence or absence of metabolic activation. The substance does not induce gene mutations in bacteria whereas all positive control chemicals (with and without metabolic activation) induced significant increase of colonies.The substance is therefore considered as non-mutagenic according to the Ames test.

 

Chromosomal aberration (Test n°2)

The clastogenic potential of the substance was determined using anin vitrochromosome aberration test in human lymphocytes (OECD 473), which measures the potential of a substance to increase the incidence the of structural chromosome aberrations in cultured human lymphocytes.

None of the dose levels up to the cytotoxicity limit with the substance, either in the presence or absence of metabolic activation, induced significant increases in the frequency of cells with aberrations in either of three experiments. The substance does not induce structural aberrations in the chromosomes of human lymphocytes under activation and non-activation conditions, whereas both positive control chemicals (with and without metabolic activation) induced significant increases in the frequency of aberrant cells.The substance is therefore considered as negative for inducing chromosomal mutations in human lymphocyte cells under activation and non-activation conditions used in this assay.

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification for human health according to the Regulation (EC) No. 1272/2008 (CLP).

 

Self classification:

Based on the available data, no additional classification is proposed regarding genetic toxicity according to the CLP and to the GHS.