Propanoic acid, 2-[4-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-3-hydroxyphenoxy]-, isooctyl ester

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian cell gene mutation test using the Hprt and xprt genes

Test material

Test material information

Constituent 1

Method

Target gene:

hprt

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital/-naphthoflavone induced rat liver S9

Test concentrations with justification for top dose:

3.9, 7.8, 15.6, 31.3, 62.5, 125 and 250 mg/L (experiment 1; 4h)7.8, 15.6, 31.3, 62.5, 125 and 250 mg/L (experiment 2; 24h, without S9)12, 25, 50, 75, 100, 125 mg/L (experiment 2; 4h, with S9)

Vehicle / solvent:

Tetrahydrofuran

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

7,12-dimethylbenzanthracene

ethylmethanesulphonate

Details on test system and experimental conditions:

METHOD OF APPLICATION: in mediumDURATION- Preincubation period: Two days (experiment I and experiment II with S9 mix) or three days (experiment II without S9 mix) after sub-cultivation stock cultures- Exposure duration: 4h or 24h- Expression time (cells in growth medium): 7 days- Selection time (if incubation with a selection agent): 8 days- Fixation time (start of exposure up to fixation or harvest of cells): 19 daysSELECTION AGENT (mutation assays): 6-thioguanineNUMBER OF REPLICATIONS: Population doubling time 12 - 14hNUMBER OF CELLS EVALUATED: not applicableDETERMINATION OF CYTOTOXICITY- Method: cloning efficiencyOTHER: The stained colonies with more than 50 cells were counted. In doubt the colony size was checked with a preparation microscope.

Evaluation criteria:

A test item is classified as positive if it induces either a concentration-related increase of the mutant frequency or a reproducible and positive response at one of the test points.A test item is classified as mutagenic if it reproducibly induces a mutation frequency that is three times above the spontaneous mutation frequency at least at one of the concentrations in the experiment.

Statistics:

A linear regression (least squares) was performed to assess a possible dose dependent increase of mutant frequencies. The number of mutant colonies obtained for the groups treated with the test item were compared to the solvent control groups. A trend is judged as significant whenever the p-value (probability value) is below 0.05.

Results and discussion

Test results

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

The maximum concentration of the test item was limited by the solubility of the test item in a suitable solvent or aqueous medium. No cytotoxicity was observed in the pre-experiment when tested up to concentrations far above the limit of solubility of the test item in culture medium (2666.6 mg/L).Precipitation of the test item was observed in the first experiment at 62.5 mg/L and above in the presence and absence of metabolic activation. In the second experiment precipitation was noted at 31.3 mg/L and above without and at 100.0 mg/L and above with metabolic activation.No relevant cytotoxic effects indicated by a relative cloning efficiency I or relative cell densitiy below 50% occurred. However, in the absence of S9 mix in both experiments the cell density was reduced to approximately 63 % in one culture at the highest applied concentration of 250.0 mg/L. This considerable variability of the cell density between parallel cultures is most likely based on precipitation of the test item leading to mechanical cell damage by shear forces.