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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Remarks:
Conducted according to guideline in effect at time of study conduct.
Qualifier:
according to
Guideline:
other: Health Effects Testing Guidelines of US EPA (40 CRF 798.5265)
Deviations:
no
Remarks:
The study was conducted according to guideline in effect at the time of study conduct.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: 99.68%

Method

Species / strainopen allclose all
Species / strain / cell type:
other: TA100, TA1535, TA97, TA98
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S9
Test concentrations with justification for top dose:
0, 10, 50, 100, 500, 1000, 2500, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Based on information supplied by the sponsor.
Controls
Untreated negative controls:
yes
Remarks:
DMSO
Negative solvent / vehicle controls:
yes
Remarks:
DMSO, water
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene(all strains +S9), 2-nitrofluorene (TA98 -S9), sodium azide (TA100 and TA1535 -S9), ICR-191 acridine (TA97 -S9), methyl methane sulfonate (WP2urvA -S9)
Details on test system and experimental conditions:
METHOD OF APPLICATION: The plate incorporation method was applied. Treatment without activation was conducted by adding 0.1 mL of overnight culture containing 1E8 bacteria to top agar supplemented with L-histidine, biotin (for Salmonella strains) or L-tryptophan (for E. coli). The components were mixed and poured onto a plate containing Davis minimal agar. Treatments with activation were conducted as those without activation except that S9 mix was added to the bacteria/top agar mixture before it was poured onto a Davis minimal agar plate. The plates were incubated at approximately 37°C for approximately 48 hours.

DURATION
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: 2 trials with 3 treatments per concentration
Evaluation criteria:
A test substance was classified as positive when (1) the average number of revertants in any strain at any test substance concentration studied is at least 2 times greater than the average number of revertants in the negative control AND (2) there is a positive dose-response relationship in that same strain. A test substance is classified as negative when (1) there are no test substance concentrations with an average number of revertants which is at least 2 times greater than the average number of revertants in the solvent control OR (2) there is no positive dose-response relationship. A test substance is classified as equivocal when the test substance is not clearly negative yet does not meet the criteria for a positive response.
Statistics:
Trials were evaluated independently. For each selected tester strain, the average number of revertants and the standard deviation at each concentration with and without S9 activation were calculated.

Results and discussion

Test resultsopen allclose all
Species / strain:
other: TA100, TA1535, TA97, TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A pKM 101
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:
ADDITIONAL INFORMATION ON CYTOTOXICITY: Background lawn was noticeably thinner and/or size of microcolonies slightly larger than controls in TA1535 at 2500 µg/plate (without activation) and TA98 at 5000 µg/plate (without activation). Background lawn was markedly thinner and/or microcolonies were markedly larger than controls in TA1535 at 5000 µg/plate(without activation).
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
The study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability). The test substance was negative when tested in Salmonella typhimurium strains TA100, TA1535, TA97, and TA98 and in Escherichia coli WP2uvrA (pKM101) in the absence and presence of S9 activation.
Executive summary:

The test substance was evaluated for mutagenicity in Salmonella typhimurium strains TA100, TA1535, TA97, and TA98 and in Escherichia coli WP2uvrA (pKM101) with and without an exogenous metabolic activation system (S9). The maximum concentration tested was 5000 µg/plate. No evidence of mutagenic activity was detected in either of two independent trials. In this study, the test substance was negative.