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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information
OECD 471, GLP study: negative with and without metabolic activation (BASF, 2000)
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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S-9 mix
Test concentrations with justification for top dose:
0, 20, 100, 500, 2500, and 5000 µg/plate (Standard Plate Test)
0, 4, 20, 100, 500, and 2500 µg/plate (Preincubation Test)
Vehicle / solvent:
- Vehicle/solvent used: Acetone
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in water, acetone was selected as the vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical contral data are available.
Untreated negative controls:
yes
Remarks:
sterility control
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
other: 2-aminoanthracene, 4-nitro-o-phenylendiamine, N-methyl-N'-nitro-N-nitrosoguanidine
Remarks:
with metabolic activation: 2-aminoanthracene (all strains); without metabolic activation: N-methyl-N'-nitro-N-nitrosoguanidine (TA 1535, TA 100), 4-nitro-o-phenylendiamine (TA 98), 9-aminoacridine (TA 1537) and 4-nitroquinoline-N-oxide (E Coli WP2 uvrA)
Details on test system and experimental conditions:
METHOD OF APPLICATION:
- 1st Experiment (standard plate test with and without S-9 mix)
- 2nd Experiment: (preincubation test with and without S-9 mix)

DURATION
- Preincubation period: 20 min (preincubation test only)
- Exposure duration: 48 - 72 hours

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY: decrease in the number of revertants, reduced his or trp background growth and reduction in the titer.
Evaluation criteria:
Generally, the experiment is to be considered valid if the following criteria are met:
- The number of revertant colonies in the negative controls was within the normal range of the historleal control data for each tester strain.
- The sterility controls revealed no indleation of bacterial contamination.
- The positive control articles both with and without S-9 mix induced a significant increase in the number of revertant colonies within the range of the historical control data.
- The titer of viable bacteria was >1E9/mL.

The test chemical is considered positive in this assay if a dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S-9 mix or after adding a metabolizing system.

A test substance is generally considered nonmutagenic in this test if the number of revertants for all tester strains were within the historical negative control range under all experimental conditions in two experiments carried out independently of each other.
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
- A very weak bacteriotoxic effect (slight decrease in the number of revertants, slight reduction in the titer) was occasionally observed depending an the strain and test conditions at >2500 µg/plate.
- Precpitation of the test substance was found from about 500 µg/plate onward.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Conclusions:
Interpretation of results (migrated information):
negative
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

In vitro

A bacterial reverse mutation assay was conducted in accordance with OECD 471 and in compliance with GLP. Salmonella typhimurium strains TA 1535, 1537, 98, 100, and E. coli WP2 uvrA were exposed 0, 20, 100, 500, 2500, and 5000 µg/plate in a Standard Plate Test and to 0, 4, 20, 100, 500, and 2500 µg/plate in a Preincubation Test. The tests were conducted with and without metabolic activation (Aroclor-induced rat liver S-9 mix). A very weak bacteriotoxic effect (slight decrease in the number of revertants, slight reduction in the titer) was occasionally observed depending an the strain and test conditions at > 2500 µg/plate. Precpitation of the test substance was found from about 500 µg/plate onward. 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 S9 mix or after the addition of a metabolizing system. Therefore, under the condition of this study the test substance is considered not to be mutagenic (BASF, 2000)

 


Justification for selection of genetic toxicity endpoint
Only study available

Justification for classification or non-classification

Based on the available data, the substance does not have to be classified according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.