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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test material was not genotoxic in an Bacterial Mutagenicity Assay (Ames test) with and without metabolic activation.

Link to relevant study records
Reference
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:
2000-12-07 to 2001-03-21
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was performed in compliance with the Good Laboratory Practice (GLP) regulations (revised in 1997, ENV/MC/CHEM(98)17).The method followed that described in the OECD Guidelines for Testing of Chemicals (Adopted: 4 April 1984) No 471 "Bacterial Reverse Mutation Test".
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Principles of method if other than guideline:
none
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay
Test material information:
Composition 1
Target gene:
HIS operon (S. thyphimurium)
TRP operon (E. coli)
Species / strain:
S. typhimurium TA 1535
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate (S9 mix) with standard co-factors with metabolic activation (Aroclor)
Species / strain:
S. typhimurium TA 1537
Details on mammalian cell lines (if applicable):
his C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 98
Details on mammalian cell lines (if applicable):
his D 3052, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 100
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 102
Details on mammalian cell lines (if applicable):
his G 428, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
E. coli WP2
Details on mammalian cell lines (if applicable):
his C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the tryptophan operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
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: 5.00, 15.8, 50.0, 158, 500, 1580 and 5000 µg/plate
2. Series: 50.0, 158, 500, 1580 and 5000 µg/plate
Vehicle:
Acetone
Negative controls:
yes
Solvent controls:
yes
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Positive controls:
yes
Positive control substance:
9-aminoacridine
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with S9
Positive controls:
yes
Positive control substance:
other: daunomycine
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with S9
Positive controls:
yes
Positive control substance:
cumene hydroperoxide
Details on test system and conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

Metabolic acticvation:
1st Series: 10% S9 mix
2nd Series: 30% S9 mix
Rationale for test conditions:
According to Guideline
Evaluation criteria:
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)
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".Interpretations: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.
Statistics:
No statistics has been applied
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Additional information on results:
Precipitation occured at 50 and 500 µg/plate.
Conclusions:
With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under the experimental conditions described.
Executive summary:

Purpose

The purpose of this in vitro reverse gene mutation test is to identify agents that cause mutations in bacteria cells 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.

Study Design

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. 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. In the series with S9 mix, 10 % or 20 % S9 in the S9 mix were used in the 1st or 2nd series, respectively.

Results

The test material was dissolved in acetone and tested at concentrations ranging from 5.00 to 5000 µg/plate. Precipitation of the test material on the agar plates occurred at concentrations >=500 or 1580 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.

Conclusions

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

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

Mode of Action Analysis / Human Relevance Framework

The in vitro study was GLP compliant and of high quality (Klimisch 1). Therefore, the results are applicable to humans.

Additional information

Justification for classification or non-classification

The test material must not be classified with regard to genetic toxicity.