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Four genetic toxicity studies are available: mammalian cell gene mutation assay (with CHO cells), mouse micronucleus test, Ames test and an UDS assay. In all tests the test substance was negative for genetic toxicity.

 

Genetic toxicity in vitro

In a GLP complaint OECD 476 guideline study, Decyloxirane was tested for its potential to induce gene mutations at the HPRT locus in Chinese hamster ovary (CHO) cells in vitro. Two independent experiments were carried out, both with and without the addition of liver S9 mix from phenobarbital- and ß-naphthoflavone induced rats. Following attachment of the cells for 20 - 24 hours, cells were treated with the test substance for 4 hours. All cells were exposed to 0, 1.56, 3.13, 5, 6.25, 12.5, 25, 50, and 100 µg/mL in the first experiment and in the second experiment to 0, 2.5, 5, 10, 20, 40, 60, and 80 µg/mL without metabolic activation and to 0, 5, 10, 20, 40, 60, 80, and 100 µg/mL with metabolic activation. After exposure cells were cultured for 6 - 8 days and then selected in 6-thioguanine-containing medium for another week. Finally, the colonies of each test group were fixed with methanol, stained with Giemsa and counted. In the 1st and 2nd Experiment, at least the highest concentrations tested for gene mutations were clearly cytotoxic in the absence and the presence of metabolic activation. An increase in mutant frequencies either without S9 mix or after the addition of a metabolizing system in the two experiments wat not observed. The test substance was therefore not considered to be mutagenic.

 

In a GLP compliant OECD 487 guideline study, Decyloxirane was assessed for its potential to induce micronuclei in V79 cells in vitro (clastogenic or aneugenic activity). Two independent experiments were carried out, both with and without the addition of liver S9 mix from induced rats. In the first experiment cells were exposed for 4 hours to 0, 3.1, 6.3, 12.5, 25, 50 and 100 µg/mL (harvest time: 24 hours). In the second experiment cells without metabolic activation were exposed for 24 hours to 0, 1.6, 3.1, 6.3, 12.5, 25 and 50 µg/mL (harvest time: 24 hours). Cells with metabolic activation were exposed for 4 hours in the second experiment to 0, 3.1, 6.3, 12.5, 25, 50 and 100 µg/mL (harvest time: 44 hours). A sample of at least 2000 cells for each test group were analyzed for micronuclei. The vehicle controls gave frequencies of micronucleated cells within our historical negative control data range for V79 cells. Both positive control substances, EMS and cyclophosphamide, led to the expected increase in the number of cells containing micronuclei. Cytotoxicity indicated by clearly reduced proliferation index (CBPI) or poor slide quality wasobserved at least at the highest evaluated test substance concentration in all experimentalparts of this study. No increase in the number of cells containing micronuclei without S9 mix or after adding a metabolizing system was observed. The test substance was therefore not considered to have a chromosome-damaging effect nor to induce numerical chromosomal aberrations.

 

Tetradecyloxirane was also tested for its mutagenic potential, based on the ability to induce point mutations in selected loci of several bacterial strains, i.e. Salmonella typhimurium (TA1535, TA 1537, TA 98, TA 100) in a reverse mutation assay. An increase in the number of his+ revertants was not observed in the standard plate test either without S9 mix or after the addition of a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.

 

Genetic toxicity in vivo

In an adopted UDS assay, five mice received a single topical dose (0, 0.5, 1, 2%) of Decyloxirane. The skin epidermis was extracted and the unscheduled DNA synthesis was assessed using (3H)dTHd as marker and a liquid scintillation counter as detector. No DNA synthesis was induced by the test item. The positive controls (DMBA, MNNG, BaP) were valid.


Short description of key information:
No indication for the induction of genotoxicity was observed in a reverse mutation assay, an in vitro mammalian cell gene mutation assay with CHO cells and an in vitro mouse micronucleus test in V79 cells. In addition, no genotoxicity was observed in an in vivo unscheduled DNA synthesis assay.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The test substances were not genetic toxic in the performed tests. Based on this classification for genetic toxicity is not warranted in accordance with EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008.