HPLL

Genetic toxicity: in vitro

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:

2005 - 2006

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Test material form:

semi-solid (amorphous): gel

Remarks:

migrated information: paste

Method

Target gene:

Base-pair substitution type and frameshift type

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbitone/beta-naphthoflavone actvated rat liver S9

Test concentrations with justification for top dose:

0.5, 1.5, 5, 15, 50, 150, 500, 1500, 5000 µg/plate

Vehicle / solvent:

Tetrahydrofurane as the test material was not soluble in dimethyl sulphoxide and only partially soluble in acetone.

Controls

Untreated negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

N-ethyl-N-nitro-N-nitrosoguanidine

benzo(a)pyrene

other: 2-aminoanthracene

Evaluation criteria:

Increase in the frequency of revertant colonies

Results and discussion

Any other information on results incl. tables

The individual plate counts, the mean number of revertant colonies and the standard deviations for the test material, postive and vehicle controls, both with and without the metabolic activation, were recorded.

The test material caused visible but intermittent reduction in the growth of the bacterial background lawn to all of the Salmonella strains, initially at 500 µg/plate. The test material generally exhibited greater toxicity in the absence of S9. No toxicity was noted to Escherichia coli strain WP2uvrA at any test material dose level in Experiments 1 or 2.

The sensitivity of the bacterial tester strains to the toxicity of the test material varied significantly between bacterial strain type, exposures with and without S9 and experiment number. The inconsistency toxicity zxhibited by the test material to the bacterial strains was due to the known volatility. The test material was therefore tested to either the maximum recommended dose level of 5000 µg/plate or the toxic limit. A yellow / brown globular precipitate was observed at 5000 µg/plate, this did not prevent the scoring of relevant colonies.

No significant increase in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation.

All the positive controls chemicals used in the test induced marked increases in the frequency of relevant colonies thus confirming the activity of the S9-mix an dthe sensitivity of the bacterial strains.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative No significant increase in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation.

The test material was considered to be non-mutagenic under the conditions of the test.
The vehicle used (tetrahydrofuran) control plates gave counts of revertant colonies within the normal range.
All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation. This the sensitivity of the assay and the efficacy of the S9-mix were validated.