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Toxicological information

Genetic toxicity: in vitro

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Administrative data

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:
April 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
March 1996
Qualifier:
according to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Version / remarks:
March 1996
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
December 1992
GLP compliance:
yes (incl. certificate)
Remarks:
testing lab.
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strainopen allclose all
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-induced rat liver S9 mix
Test concentrations with justification for top dose:
20 - 5000 µg/plate
Vehicle / solvent:
water
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: With S9 mix: 2-aminoanthracene; without S-9 mix: N-methyl-N' -nitro-N-nitrosoguanidine, 4-nitro-o-phenylendiamine, 9-aminoacridine, N-ethyl-N'-nitro-N-nitrosoguanidine
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) with or without S9 mix
DURATION
- Preincubation period: 20 min in the pre- incubation test
- Exposure duration: 48- 72h at 37°C
SELECTION AGENT: 0.5 mM histidine+ 0.5 mM biotin (Sal. typh.); 0.5 mM tryptophan (E. coli)
NUMBER OF PLATES: 3 plates/ dose
DETERMINATION OF BACTERIOTOXICITY: Number of revertants, his- or trp- background growth, titer determination with and without S9 mix
Evaluation criteria:
The test chemical is considered positive in this assay if the following criteria are met:
• 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.

Results and discussion

Test resultsopen allclose all
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
Remarks:
weak bacteriotoxicity at 500- 2.500 µg/ plate onward depending on the tester strain in the standard plate test and the preincubation test
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
Remarks:
weak bacteriotoxicity at 2.500 µg/ plate onward without S9-mix in the preincubation test
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Solubility: No precipitation of the test substance was found.
Toxicity: A weak bacteriotoxic effect was occasionally observed depending on the strain and test conditions from about 500 - 2500 µg/plate onward.
Mutagenicity: 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.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion