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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
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
Qualifier:
according to
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
Deviations:
no
GLP compliance:
yes (incl. certificate)
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 pKM 101
Metabolic activation:
with and without
Metabolic activation system:
liver preparations (S9 mix) from rats treated with phenobarbital and 5,6-benzoflavone
Test concentrations with justification for top dose:
Test 1: 5, 15, 50, 150, 500, 1500, 5000 µg/plate
Test 2: 50, 150, 500, 1500, 5000 µg/plate
Vehicle / solvent:
- DMSO (test substance not stable in water)
Controls
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: BaP, AAN, 2NF, NaN3, AAC, NQO as appropriate
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) - 1st test; preincubation- 2nd test

DURATION
TEST 1: In agar (plate incorporation)
- Exposure duration: 72 hours at 37 ºC in petri dishes
TEST 2: Pre-incubation
- Preincubation period: 30 minutes at 37 ºC before the addition of the agar overlay.

NUMBER OF REPLICATIONS: 3
Evaluation criteria:
For a test to be considered valid, the mean of the vehicle control revertant colony numbers for each strain should lie within or close to the 99% confidence limits of the current historical control range; the positive control compounds must induce an increase in mean revertant colony numbers of at least twice (three times in the case of strains TA1535 and TA1537) the concurrent vehicle controls. To be considered positive, the test substance mustinduce an increase in mean revertant colony numbers of at least twice (three times in the case of strains TA1535 and TA1537) the concurrent vehicle controls
Statistics:
Not needed

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
All controls were within 99% of the historical range. All positive controls responded with a positive response.

Applicant's summary and conclusion

Conclusions:
OS1600 showed no evidence of mutagenic activity in this bacterial system under the test conditions employed.
Executive summary:

An in-vitro bacterial reverse assay (Ames test) was performed on OS1600 in accordance with OECD Guideline 471. Salmonella typhimurium, strains TA1535, TA1537, TA98 and TA100 and Escherichia coli, strain WP2 uvrA (pKM101), were exposed to OS1600 diluted in dimethyl sulphoxide (DMSO) up to 5000 µg/plate. DMSO was also used as a negative control. Two independent mutation tests were performed in the presence and absence of liver preparations (S9 mix) from rats treated with phenobarbital and 5,6-benzoflavone. The first test was a standard plate incorporation assay; the second included a pre-incubation stage. No signs of toxicity were observed towards the tester strains in either mutation test following exposure to OS1600. No evidence of mutagenic activity was seen at any concentration of OS1600 in either mutation test. It was concluded that OS1600 showed no evidence of mutagenic activity in this bacterial system under the test conditions employed.