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Genetic toxicity in vitro

Description of key information

The reverse mutation assay in bacteria (Ames test) according to OECD TG 471 was negative (reference 7.6.1 -1).

The in vitro mammalian gene mutation assay (MLA) according to OECD TG 476 was negative (reference 7.6.1 -2).

Based on a read-across approach including seven category substances it is concluded that chromosomal aberration when tested in vitro would be negative (7.6.1 -3).

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2006-03-20 to 2006-03-19
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian cell gene mutation tests using the thymidine kinase gene
Target gene:
TK gene
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
Growth media:
Three media, supplementing RPMI 1640-medium with Glutamax 1 with different serum concentrations were used:

- Exposure medium: RPMI- 5 (RPM 1640 with 5% heat inactivated horse serum) 470 mL RPMI 164025 mL horse serum (heat-inactivated horse serum) 5 mL penicillin/streptomycin

- Culture medium: RPMI-10 (RPMI 1640 with 10% heat-inactivated horse serum) 445 mL RPMI 164050 mL horse serum (heat-inactivated horse serum) 5 mL penicillin/streptomycin

- Survivor- and selection medium: RPMI-20 (RPMI 1640 with 20% heat-inactivated horse serum) 395 mL RPMI 1640100 mL horse serum (heat-inactivated horse serum) 5 mL penicillin/streptomycin
Metabolic activation:
with and without
Metabolic activation system:
10% rat liver homogenate (S9 mix) with standard co-factors
Vehicle / solvent:
Acetone
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO, acetone
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitroquinoline N-oxide
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
7,12-dimethylbenzanthracene
Details on test system and experimental conditions:
see below
Evaluation criteria:
The effects of the test material upon the mutation frequency are defined as

-"No effect" or "no increase" in the mutation frequency if the mean frequency of the parallel incubations of a given test material concentration is less than 2.0-fold above the mean of the actual negative controls or the mean mutation falls within the historical range of the negative controls.
-"Clear effect" or "clear increase" in the mutation frequency if the test material induces at least a 3.0-fold increase above the mean of the actual negative controls and the mean mutation frequency for a given test material concentration is at least 1.5-fold above the highest value of the historical negative controls.
-All other results are defined as a "weak effect" or a "weak increase" of the mutation frequency.

Test materials are assessed as negative or non-mutagenic in this test system if:
-the assay is considered valid and -no effect (no increase in the mutation frequency) occurs in the two experimental series performed or
-a weak effect (weak increase) occurs in one series and no effect (no increase) in the other series of experiments.

Test materials are assessed as positive or mutagenic in this test system if:
-the assay is considered valid and -a clear effect (clear increase in the mutation frequency) occurs at similar concentrations of the test material in the two experimental series performed, or
-a clear effect (clear increase) occurs in one series and a weak effect (weak increase) in the other series of experiments at identical concentrations, or
-weak effects (weak increases) occur dose-dependently (over at least two test material concentrations) and reproducibly at identical concentrations in the two experimental series performed.

In all other cases, further decisions for testing strategies should be made following the scientific evaluation of all existing data including those of non-toxicological investigations.
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at 2.81 and 28.1 µg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
True negative controls validity:
not examined
Positive controls validity:
valid
Conclusions:
It is concluded that the test item is non-mutagenic and non-clastogenic in this test system under conditions where the positive controls exerted potent mutagenic effects.
Executive summary:

The objective of this study was to evaluate the mutagenic activity of the test material by examining its ability to induce TK mutations in L5178Y cells in the absence and presence of a rat liver metabolizing system (S9 mix).

The test material was assayed for its ability to induce mutations at th TK locus (5-trifluorothymidine resistance) in L5178Y mouse lymphoma cells using a fluctuation protocol acording to OECD Guideline 476. The study consisted of two independent experimental series, each conducted in the absence and presence of an exogenous metabolizing system (S9 mix from livers of rats pretreated with Aroclor 1254). Acetone was used as the solvent. The exposure times were 3 and 24 hours in the absence and 3 hours in the presence of S9 mix, respectively. Negative (solvent) and positive control treatments were included in each mutation experiment in the absence and presence of S9 mix. Mutant frequencies in negative control cultures fell within normal ranges, and clear increases in mutation were induced by the positive control chemicals 4-nitroquinoline N-oxide (without S9 mix) and 7,12-dimethylbenz[a]anthracene (with S9 mix). Therefore, the study was accepted as valid. No relevant increases in mutant frequency were observed following treatment with the test item in the two experimental series in the absence and presence of metabolic activation.

Based on the results it is concluded that the test item is non-mutagenic and non-clastogenic in this test system under conditions where the positive controls exerted potent mutagenic effects.

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2000-10-31 to 2000-11-16
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Target gene:
HIS operon (S. thyphimurium)TRY operon (E. coli)
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 / 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 / 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 / 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 / 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 / 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:
The test material concentrations were used selected according to the EC and OECD guidelines for this test system and the requirements of the Labor Ministry of Japan:
1. Series: 1.58, 5.00, 15.8, 50, 158, 500, and 1580 µg/plate

2. Series: 1.58, 5.00, 15.8, 50.0, 158, 500, 1580, 2810, and 5000 µg/plate

3. Series: 1.58, 5.00, 15.8, 50.0, 158, 500, 1580, 2810, and 5000 µg/plate (TA102 and WP2 only)
Vehicle / solvent:
Acetone
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: daunomycine
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with S9
Details on test system and experimental conditions:
The assessment of test material-induced effects is dependent on the number of spontaneous revertants of each bacterial strain (solvent controls) and the in-crease in the number of revertants at the test material concentration which shows the highest number of colonies.
The following criteria, based upon the historical controls of the laboratory and statistical considerations, are established:

Mean Number of Colonies Maximal Mean Number of Colonies over the Actual
(Solvent Control) (Test Material)

<=10 <=9 >=30
<=30 <=19 >=40
<=80 <=29 >=80
<=200 <=49 >=120
<=500 <=79 >=200

Assessment No increase Clear increase


All further results, ranging between "no" and "clear", are assessed as "weak in-creases".
Evaluation criteria:
A test material is defined as non-mutagenic in this assay if "no" or "weak increases" occur in the first and second series of the main experiment. ("Weak increases" randomly occur due to experimental variation.)

A test material is defined as mutagenic in this assay if:
- a dose-related (over at least two test material concentrations) increase in the number of revertants is induced, the maximal effect is a "clear increase", and the effects are reproduced at similar concentration levels in the same test system;
- "clear increases" occur at least at one test material concentration, higher concentrations show strong precipitation or cytotoxicity, and the effects are reproduced at the same concentration level in the same test system.In all further cases, a third test series with the bacterial strain in question should be performed. If the criteria for a positive test result are not fulfilled in at least two out of the three series, the test material is defined as being non-mutagenic in this test system.
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
True negative controls validity:
not examined
Positive controls validity:
valid
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
True negative controls validity:
not examined
Positive controls validity:
valid
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
True negative controls validity:
not examined
Positive controls validity:
valid
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
True negative controls validity:
not examined
Positive controls validity:
valid
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:
valid
True negative controls validity:
not examined
Positive controls validity:
valid
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
True negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
Precipitation occured at 50 and 500 µg/plate.
Conclusions:
With and without addition of S9 mix as external metabolizing system, the test item was not mutagenic under the experimental conditions described.
Executive summary:

The purpose of this in vitro reverse gene mutation test was to identify agents that cause mutations in bacteria cells and thus providing information on possible health hazards for the test material and serve as a rational basis for risk assessment to the genotoxic potential of the test item in man.

The investigations for mutagenic potential were performed using Salmonella typhimurium tester strains TA 98, TA 100, TA 102, TA 1535 and TA 1537, and Escherichia coli WP2 uvrA pkM101 in accordance with OECD TG 471. The plate incorporation test with and without addition of liver S9 mix from Aroclor 1254-pretreated rats was used. Two independent experimental series were performed for all strains. A third experimental series was performed with TA 102 and WP2 uvrA pkM101. In the series with S9 mix, 10 % or 20 % S9 in the S9 mix were used in the 1st or 2nd and 3rd series, respectively.

The test material was dissolved in acetone and tested at concentrations ranging from 1.58 to 5000 pg/plate. Precipitation of the test material on the agar plates occurred at concentrations 50 or 500 µg/plate, depending upon the experimental condition tested. Toxicity to the bacteria was not observed. Daunomycin, N-ethyl-N'-nitro-N-nitroso-guanidine, 9-aminoacridine and cumene hydroperoxide served as strain specific positive control compounds in the absence of S9 mix. 2-Aminoanthracene and benzo[a]pyrene were used for testing the bacteria and the activity of the S9 mix. Each treatment with the substances used as positive controls led to a clear increase in revertant colonies, thus showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used.

With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under the experimental conditions described.

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Justification for type of information:
Please refer to read-across (category) justification attached.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
Key result
Species / strain:
other: Chinese hamster ovary cells or Chinese hamster lung fibrobasts (V79)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
True negative controls validity:
not examined
Positive controls validity:
valid

Please refer to the attached justification.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Ames Test

The purpose of this in vitro reverse gene mutation test was to identify agents that cause mutations in bacteria cells and thus providing information on possible health hazards for the test material and serve as a rational basis for risk assessment to the genotoxic potential of the test item in man. The investigations for mutagenic potential were performed using Salmonella typhimurium tester strains TA 98, TA 100, TA 102, TA 1535 and TA 1537, and Escherichia coli WP2 uvrA pkM101 in accordance with OECD TG 471. The plate incorporation test with and without addition of liver S9 mix from Aroclor 1254-pretreated rats was used. Two independent experimental series were performed for all strains. A third experimental series was performed with TA 102 and WP2 uvrA pkM101. In the series with S9 mix, 10 % or 20 % S9 in the S9 mix were used in the 1st or 2nd and 3rd series, respectively.

The test material was dissolved in acetone and tested at concentrations ranging from 1.58 to 5000 pg/plate. Precipitation of the test material on the agar plates occurred at concentrations 50 or 500 µg/plate, depending upon the experimental condition tested. Toxicity to the bacteria was not observed. Daunomycin, N-ethyl-N'-nitro-N-nitroso-guanidine, 9-aminoacridine and cumene hydroperoxide served as strain specific positive control compounds in the absence of S9 mix. 2-Aminoanthracene and benzo[a]pyrene were used for testing the bacteria and the activity of the S9 mix. Each treatment with the substances used as positive controls led to a clear increase in revertant colonies, thus showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used.

With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under the experimental conditions described.

MLA

The objective of this study was to evaluate the mutagenic activity of the test material by examining its ability to induce TK mutations in L5178Y cells in the absence and presence of a rat liver metabolizing system (S9 mix).

The test material was assayed for its ability to induce mutations at th TK locus (5-trifluorothymidine resistance) in L5178Y mouse lymphoma cells using a fluctuation protocol acording to OECD Guideline 476. The study consisted of two independent experimental series, each conducted in the absence and presence of an exogenous metabolizing system (S9 mix from livers of rats pretreated with Aroclor 1254). Acetone was used as the solvent. The exposure times were 3 and 24 hours in the absence and 3 hours in the presence of S9 mix, respectively. Negative (solvent) and positive control treatments were included in each mutation experiment in the absence and presence of S9 mix. Mutant frequencies in negative control cultures fell within normal ranges, and clear increases in mutation were induced by the positive control chemicals 4-nitroquinoline N-oxide (without S9 mix) and 7,12-dimethylbenz[a]anthracene (with S9 mix). Therefore, the study was accepted as valid. No relevant increases in mutant frequency were observed following treatment with the test item in the two experimental series in the absence and presence of metabolic activation.

Based on the results it is concluded that the test item is non-mutagenic and non-clastogenic in this test system under conditions where the positive controls exerted potent mutagenic effects.

Chromosome aberration in vitro

A read-across approach is applied based on seven category substances. Please refer to the category justification attached in IUCLID Section 7.6.1 (reference 7.6.1 -3). Based on the WoE of all substances in the category, chromosomal aberration in vitro can be regarded negative for the target substance.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008
The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. Based on available data on genotoxicity, the test item does not require classification according to Regulation (EC) No 1272/2008 (CLP), as amended for the twelfth time in Regulation (EU) 2019/521.