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Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Ames assay:

The test chemical did not induce mutation in the Salmonella typhimurium and Escherichia coli strains both in the presence and absence of S9 metabolic activation system and hence is not likely to be mutagenic under the conditions of the study.

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:
read-across source
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
WoE for the target CAS is summarized based on data from various test chemicals.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay
Target gene:
2.Histidine for Salmonella typhimurium
3.Histidine for Salmonella typhimurium and tryptophan for Escherichia coli
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Remarks:
2
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
not specified
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Remarks:
3
Details on mammalian cell type (if applicable):
not specified
Additional strain / cell type characteristics:
not specified
Cytokinesis block (if used):
not specified
Metabolic activation:
with and without
Metabolic activation system:
2. the S9 mix, prepared from a liver post-mitochondrial fraction (S9 fraction) of rats induced with Aroclor 1254.
3. Aroclor-induced rat liver S-9 mix
Test concentrations with justification for top dose:
2. - First mutagenicity experiment with and without S9 mix: 0, 312.5, 625, 1250, 2500 and 5000 µg/plate
- Second mutagenicity experiment with and without S9 mix: 0, 625, 1250, 2500, 3750 and 5000 µg/plate
3. 20 pg- 5,000 pg/plate (2.0E-5 µg- 0.005 µg/plate)
Vehicle / solvent:
2. vehicle was used.
3. Not specified
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
Remarks:
not specified
True negative controls:
not specified
Positive controls:
yes
Remarks:
not specified
Positive control substance:
not specified
Remarks:
2
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
not specified
Positive control substance:
not specified
Remarks:
3
Details on test system and experimental conditions:
2. NUMBER OF REPLICATIONS:
- Number of cultures per concentration - triplicate
- Number of independent experiments - two independent experiments

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): No data
- Test substance added -1st experiment (+S9/-S9) and 2nd experiment (-S9): in agar (plate incorporation); 2nd experiment (+S9): preincubation method

TREATMENT AND HARVEST SCHEDULE:
- Preincubation period, if applicable: 60 minutes (only in second mutagenicity test with S9 mix)
- Exposure duration/duration of treatment: 48 to 72 hours
3. METHOD OF TREATMENT/ EXPOSURE: standard plate test or the preincubation test
Rationale for test conditions:
Not specified
Evaluation criteria:
2. The evaluation of the toxicity was performed based on the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn.
3. Plates were observed for an increase in the number of his+ or trp+ revertants.
Statistics:
Not Specified
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102 : Study 2
Remarks:
2
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
True negative controls validity:
not specified
Positive controls validity:
valid
Species / strain:
other: Salmonella typhimurium TA 1535, TA 100, TA 1537, TA 98 and E. coli WP2 uvrA.: study 3
Remarks:
3
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
not specified
True negative controls validity:
not specified
Positive controls validity:
not specified
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation and time of the determination: No precipitate was observed in the petri plates when scoring the revertants at all dose-levels.

RANGE-FINDING/SCREENING STUDIES (if applicable): A preliminary toxicity test was performed to define the dose-levels of test chemical to be used for the mutagenicity study.

Ames test:
- Signs of toxicity - No toxicity was noted towards all the strains used, both with and without S9 mix.
3. TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation and time of the determination: No precipitation of the test substance was found.
Ames test:
- Signs of toxicity - A weak bacteriotoxic effect was occasionally observed.
Remarks on result:
other: No mutagenic effects were observed
Conclusions:
The test chemical did not induce mutation in the Salmonella typhimurium and Escherichia coli strains both in the presence and absence of S9 metabolic activation system and hence is not likely to be mutagenic under the conditions of the study.
Executive summary:

In different studies, the given test chemical has been investigated for the mutagenic nature. The studies are as mentioned below:

 

In Genetic toxicity in vitro study, the given test chemical was evaluated for its mutagenic potential in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102 according to the OECD guideline 471 and the EU Method B13/14. A preliminary toxicity test was performed to define the dose-levels of test chemical to be used for the mutagenicity study. The test chemical was then tested in two independent experiments, both with and without a metabolic activation system, the S9 mix, prepared from a liver post-mitochondrial fraction (S9 fraction) of rats induced with Aroclor 1254. Both experiments were performed according to the direct plate incorporation method except for the second test with S9 mix, which was performed according to the preincubation method (60 minutes, 37 deg C). The five strains of bacteria Salmonella typhimurium: TA 1535, TA 1537, TA 98, TA 100 and TA 102 were exposed to the following dose levels of test chemical (three plates/dose-level): 312.5, 625, 1250, 2500 and 5000 ug/plate, for the first mutagenicity experiment with and without S9 mix; 625, 1250, 2500, 3750 and 5000 ug/mL for the second mutagenicity experiment with and without S9 mix. After 48 to 72 hours of incubation at 37 deg C, the revertant colonies were scored. The evaluation of the toxicity was performed based on the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn. The number of revertants for the vehicle and positive controls was as specified in the acceptance criteria. The study was therefore considered valid. No precipitate was observed in the petri plates when scoring the revertants at all dose-levels. No toxicity was noted towards all the strains used, both with and without S9 mix. The test chemical did not induce any significant increase in the number of revertants, both with or without S9 mix, in any of the five strains. Under these experimental conditions, the given test chemical did not show any mutagenic activity in the bacterial reverse mutation assay, thus, it was considered as non-mutagenic.

 

Another gene mutation toxicity study was performed for the given test chemical to determine its mutagenic potential based on the ability to induce point mutations in selected loci of several bacterial strains, i.e. Salmonella typhimurium and Escherichia coli, in a reverse mutation assay. The strains tested were TA 1535, TA 100, TA 1537, TA 98 and E. coli WP2 uvrA at the dose range of 20 pg- 5,000 pg/plate ( 2.0E-5 µg- 0.005 µg/plate), tested with and without metabolic activation (Aroclor-induced rat liver S-9 mix). No precipitation of the test substance was observed. A weak bacteriotoxic effect was occasionally observed. An increase in the number of his+ or trp+ revertants was not observed in the standard plate test or in the preincubation test either without S-9 mix or after the addition of a metabolizing system. According to the results of the present study, the test chemical was considered as not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay.

 

Thus, based on the above summarized studies on test chemical, it can be concluded that the given test chemical did not induce mutation in the Salmonella typhimurium and Escherichia coli strains both in the presence and absence of S9 metabolic activation system and hence is not likely to be mutagenic under the conditions of the study.

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

Genetic toxicity in vivo

Description of key information

Ames assay:

In different studies, the given test chemical has been investigated for the mutagenic nature. The studies are as mentioned below:

 

In Genetic toxicity in vitro study, the given test chemical was evaluated for its mutagenic potential in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102 according to the OECD guideline 471 and the EU Method B13/14. A preliminary toxicity test was performed to define the dose-levels of test chemical to be used for the mutagenicity study. The test chemical was then tested in two independent experiments, both with and without a metabolic activation system, the S9 mix, prepared from a liver post-mitochondrial fraction (S9 fraction) of rats induced with Aroclor 1254. Both experiments were performed according to the direct plate incorporation method except for the second test with S9 mix, which was performed according to the preincubation method (60 minutes, 37 deg C). The five strains of bacteria Salmonella typhimurium: TA 1535, TA 1537, TA 98, TA 100 and TA 102 were exposed to the following dose levels of test chemical (three plates/dose-level): 312.5, 625, 1250, 2500 and 5000 ug/plate, for the first mutagenicity experiment with and without S9 mix; 625, 1250, 2500, 3750 and 5000 ug/mL for the second mutagenicity experiment with and without S9 mix. After 48 to 72 hours of incubation at 37 deg C, the revertant colonies were scored. The evaluation of the toxicity was performed based on the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn. The number of revertants for the vehicle and positive controls was as specified in the acceptance criteria. The study was therefore considered valid. No precipitate was observed in the petri plates when scoring the revertants at all dose-levels. No toxicity was noted towards all the strains used, both with and without S9 mix. The test chemical did not induce any significant increase in the number of revertants, both with or without S9 mix, in any of the five strains. Under these experimental conditions, the given test chemical did not show any mutagenic activity in the bacterial reverse mutation assay, thus, it was considered as non-mutagenic.

 

Another gene mutation toxicity study was performed for the given test chemical to determine its mutagenic potential based on the ability to induce point mutations in selected loci of several bacterial strains, i.e. Salmonella typhimurium and Escherichia coli, in a reverse mutation assay. The strains tested were TA 1535, TA 100, TA 1537, TA 98 and E. coli WP2 uvrA at the dose range of 20 pg- 5,000 pg/plate ( 2.0E-5 µg- 0.005 µg/plate), tested with and without metabolic activation (Aroclor-induced rat liver S-9 mix). No precipitation of the test substance was observed. A weak bacteriotoxic effect was occasionally observed. An increase in the number of his+ or trp+ revertants was not observed in the standard plate test or in the preincubation test either without S-9 mix or after the addition of a metabolizing system. According to the results of the present study, the test chemical was considered as not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay.

 

Thus, based on the above summarized studies on test chemical, it can be concluded that the given test chemical did not induce mutation in the Salmonella typhimurium and Escherichia coli strains both in the presence and absence of S9 metabolic activation system and hence is not likely to be mutagenic under the conditions of the study.

 

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Justification for classification or non-classification

Based on the data available and applying weight of evidence approach, the given test chemical does not exhibit gene mutation in vitro by Ames assay. Hence, the test chemical is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.