Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames assay:

The test chemical did not induce gene mutation in the genome of the Salmonella typhimurium strains in the presence and absence of S9 metabolic activation system and hence it is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

Link to relevant study records
Reference
Endpoint:
in vitro gene mutation study in bacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
Experimental data from various test chemicals
Justification for type of information:
Data for the target chemical is summarized based on the various test chemicals
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
WoE derived based on the experimental data of various test chemicals
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay
Target gene:
Histidine
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Remarks:
1
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
other:
Species / strain / cell type:
S. typhimurium, other: TA98 and TA100
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Cytokinesis block (if used):
No data
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced S9 metabolic activation system
Test concentrations with justification for top dose:
1. 0.0 (NC), 0.005, 0.016, 0.050, 0.158, 0.501 mg/plate
2. 0 (Negative control), 50 or 200 µg/plate
Vehicle / solvent:
1. - Vehicle(s)/solvent(s) used: RO water
- Justification for choice of solvent/vehicle: The test chemical was soluble in RO water

2. - Vehicle(s)/solvent(s) used: Water
- Justification for choice of solvent/vehicle: The test chemical was soluble in water
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
Remarks:
RO water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
sodium azide
methylmethanesulfonate
other: 4-Nitro-o-phenylenediamine (TA 1537, TA 98, without S9); 2-Aminoanthracene (TA 1535, TA 1537, TA 98, TA 100 and TA 102, with S9)
Remarks:
1
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
other: 1,6-dinitropyrene
Remarks:
2
Details on test system and experimental conditions:
1. METHOD OF APPLICATION: in agar (plate incorporation- Trial I); preincubation (Trial II)

DURATION
- Preincubation period: Trial I: Not applicable Trial II: 60 min
- Exposure duration: 48 hrs
- Expression time (cells in growth medium): 48 hrs
- Selection time (if incubation with a selection agent): No data
- Fixation time (start of exposure up to fixation or harvest of cells): No data

SELECTION AGENT (mutation assays): No data

SPINDLE INHIBITOR (cytogenetic assays): No data

STAIN (for cytogenetic assays): No data

NUMBER OF REPLICATIONS: Each concentration, including the negative, vehicle and positive controls was tested in triplicate in two independent experiments performed

METHODS OF SLIDE PREPARATION AND STAINING TECHNIQUE USED: Not applicable

NUMBER OF CELLS EVALUATED: No data

NUMBER OF METAPHASE SPREADS ANALYSED PER DOSE (if in vitro cytogenicity study in mammalian cells): No data

CRITERIA FOR MICRONUCLEUS IDENTIFICATION: No data

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data
- Any supplementary information relevant to cytotoxicity: No data

OTHER EXAMINATIONS:
- Determination of polyploidy: No data
- Determination of endoreplication: No data
- Methods, such as kinetochore antibody binding, to characterize whether micronuclei contain whole or fragmented chromosomes (if applicable): No data

- OTHER: No data

2. METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: Not applicable
- Exposure duration: No data
- Expression time (cells in growth medium): No data
- Selection time (if incubation with a selection agent): No data
- Fixation time (start of exposure up to fixation or harvest of cells): No data

SELECTION AGENT (mutation assays): No data
SPINDLE INHIBITOR (cytogenetic assays): No data
STAIN (for cytogenetic assays): No data

NUMBER OF REPLICATIONS: Duplicate

NUMBER OF CELLS EVALUATED: No data

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data

OTHER EXAMINATIONS:
- Determination of polyploidy: No data
- Determination of endoreplication: No data
- Other: No data

OTHER: No data
Rationale for test conditions:
No data
Evaluation criteria:
1. 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 vehicle/solvent control is observed.

2. A positive result in the Ames test was defined as a reproducible, dose-related, at least twofold increase in the number of revertants over background

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 of negative control and vehicle control such an increase is not considered biologically relevant.
Statistics:
No data
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102
Remarks:
1
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA98 and TA100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
1. TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: No data
- Effects of osmolality: No data
- Evaporation from medium: No data
- Water solubility: No data
- Precipitation: No precipitation was noted at a dose upto 5 mg/plate in the pre-experiment
- Definition of acceptable cells for analysis: No data
- Other confounding effects: No data

RANGE-FINDING/SCREENING STUDIES: To evaluate the toxicity of the test item, a pre-experiment was performed with strains TA 98 and TA 100. Eight concentrations (0.0 (NC), 0.002, 0.005, 0.016, 0.050, 0.158, 0.501, 1.582 and 5.0 mg/plate) were tested for toxicity and mutation induction with 3 plates each (triplicates). The experimental conditions in this pre-experiment were the same as described below for the Trial-I (Plate incorporation test). Toxicity of the test item results in a reduction in the number of spontaneous revertants or a clearing of the bacterial background lawn.

In the pre-experiment, the concentration range of the test item was 0.002 – 5 mg/plate based on the solubility and precipitation test. There was no reduction in colony count as well as in background lawn in treated concentrations 5 (T8) mg/plate – 0.002 (T1) mg/plate) both in absence and in the presence of metabolic activation. Based on the results of pre-experiment following doses were selected for the main study trials: 0.050, 0.158, 0.501, 1.582 and 5 mg/plate, both in the absence (-S9) as well as in the presence of metabolic activation (+S9).

CYTOKINESIS BLOCK (if used)
- Distribution of mono-, bi- and multi-nucleated cells: No data

NUMBER OF CELLS WITH MICRONUCLEI
- Number of cells for each treated and control culture: No data
- Indication whether binucleate or mononucleate where appropriate: No data

HISTORICAL CONTROL DATA (with ranges, means and standard deviation and confidence interval (e.g. 95%)
- Positive historical control data: No data
- Negative (solvent/vehicle) historical control data: No data

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- Measurement of cytotoxicity used: No data
- Other observations when applicable: No data

2. No data
Remarks on result:
other: No mutagenic potential
Conclusions:
The test chemical did not induce gene mutation in the genome of the Salmonella typhimurium strains in the presence and absence of S9 metabolic activation system and hence it is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.
Executive summary:

Data available for the test chemicals was reviewed to determine the mutagenic nature of the test chemical. The studies are as mentioned below:

Ames assay was performed to investigate the potential of the test chemical to induce gene mutations in comparison to negative control according to the plate incorporation test (Trial I) and the pre-incubation test (Trial 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 negative, positive controls was tested in triplicate. Based on the solubility and precipitation test results eight different concentrations viz., 0.0 (NC), 0.002, 0.005, 0.016, 0.050, 0.158, 0.501, 1.582 and 5.0 mg/plate were selected for pre-experiment. Based on the pre-experiment results, the test item was tested with the following concentrations 0.0 (NC), 0.005, 0.016, 0.050, 0.158, 0.501 mg/plate for main study, both in the presence of metabolic activation (+S9) and in the absence of metabolic activation (-S9). No substantial increase in revertant colony numbers in any of the tester strains were observed following treatment with the test chemical at any dose level in both the confirmatory trials, neither in the presence nor in the 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. The spontaneous reversion rates in the negative, positive controls are within the range of our historical data. The positive controls used for various strains showed a distinct increase in induced revertant colonies in both the methods i.e. Plate incorporation method and Pre-incubation method. In conclusion, it is stated that during the described mutagenicity test and under the experimental conditions reported, the test chemical did not induce gene mutations by base pair changes or frame shifts in the genome of the strains used.  

Gene mutation toxicity study was performed to determine the mutagenic nature of the test chemical. The study was performed using S. typhimurium strains TA98 and TA100 with and without S9 metabolic activation system. The test was performed as per the plate incorporation assay at dose level of 0 (negative control), 50 or 200µg/plate. The chemical was dissolved in water. The result was considered positive when a reproducible, dose-related, at least two-fold increase in the number of revertants over background was observed. Concurrent positive and negative control chemicals were also included in the study. The test chemical did not induce a doubling of revertant colonies over the negative control using S. typhimurium strains TA98 and TA100 in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.

Based on the observations made, the test chemical did not induce gene mutation in the genome of the Salmonella typhimurium strains in the presence and absence of S9 metabolic activation system and hence it is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

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

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Gene mutation in vitro:

Data available for the various test chemicals was reviewed to determine the mutagenic nature of the test chemical. The studies are as mentioned below:

Ames test:

Ames assay was performed to investigate the potential of the test chemical to induce gene mutations in comparison to negative control according to the plate incorporation test (Trial I) and the pre-incubation test (Trial II) using theSalmonella typhimuriumstrains 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 negative, positive controls was tested in triplicate. Based on the solubility and precipitation test results eight different concentrations viz., 0.0 (NC), 0.002, 0.005, 0.016, 0.050, 0.158, 0.501, 1.582 and 5.0 mg/plate were selected for pre-experiment. Based on the pre-experiment results, the test item was tested with the following concentrations 0.0 (NC), 0.005, 0.016, 0.050, 0.158, 0.501 mg/plate for main study, both in the presence of metabolic activation (+S9) and in the absence of metabolic activation (-S9). No substantial increase in revertant colony numbers in any of the tester strains were observed following treatment with the test chemical at any dose level in both the confirmatory trials, neither in the presence nor in the 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. The spontaneous reversion rates in the negative, positive controls are within the range of our historical data. The positive controls used for various strains showed a distinct increase in induced revertant colonies in both the methods i.e. Plate incorporation method and Pre-incubation method. In conclusion, it is stated that during the described mutagenicity test and under the experimental conditions reported, the test chemical did not induce gene mutations by base pair changes or frame shifts in the genome of the strains used.  

Gene mutation toxicity study was performed to determine the mutagenic nature of the test chemical. The study was performed using S. typhimurium strains TA98 and TA100 with and without S9 metabolic activation system. The test was performed as per the plate incorporation assay at dose level of 0 (negative control), 50 or 200µg/plate. The chemical was dissolved in water. The result was considered positive when a reproducible, dose-related, at least two-fold increase in the number of revertants over background was observed. Concurrent positive and negative control chemicals were also included in the study. The test chemical did not induce a doubling of revertant colonies over the negative control using S. typhimurium strains TA98 and TA100 in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.

Based on the observations made, the test chemical did not induce gene mutation in the genome of the Salmonella typhimurium strains in the presence and absence of S9 metabolic activation system and hence it is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

On the basis of data available for the various test chemicals and applying the weight of evidence apprach, the test chemicals does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

On the basis of data available for the various test chemicals and applying the weight of evidence apprach, the test chemicals does not exhibit gene mutation in vitro. Hence the test chemical is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.