2-ethylhexyl 14-ethyl-6,6-dioctyl-4,8,11-trioxo-5,7,12-trioxa-6-stannaoctadeca-2,9-dienoate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

non mutagenic (Ames, mammalian cell gene mutation assay)

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

non-genotoxic and non-clastogenic (mammalian erythrocyte micronucleus test)

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

The mutagenicity potential of the substance was evaluated by taking into consideration data on two analogue substances. Justification for Read Across is given in Section 13 of IUCLID.

In Vitro Gene Mutation Study in Bacteria

The mutagenicity of Similar Substance 02 was assessed in a bacterial reverse mutation assay (Ames Test) in accordance with OECD guideline 471 and EU Method B.13/14. During the study, Salmonella typhimurium strains TA1535, TA1537, TA98, TA100 and Escherichia coli strain WP2uvrA were treated with the test material using both the plate incorporation and pre-incubation methods at five dose levels, in triplicate, both with and without metabolic activation. The dose range for the study was determined in a preliminary toxicity assay and was 50 to 5000 µg/plate. Under the conditions of the study, the vehicle control plates gave counts of revertant colonies generally within the normal range. All positive controls used in the test induced marked increases in the frequency of revertant colonies, both with and without metabolic activation. The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level and was therefore tested up to the maximum recommended dose level of 5000 µg/plate. A test material precipitate was noted at and above 1500 µg/plate, though this observation did not prevent the scoring of revertant colonies. No toxicologically significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material, either with or without metabolic activation or exposure method. Small, statistically significant increases in WP2uvrA revertant colony frequency were observed in the presence of S9-mix at 50 and 5000 µg/plate in Experiment 2. These increases were considered to be of no biological relevance because there was no evidence of a dose-response relationship or reproducibility. Furthermore, the individual revertant counts at 50 and 5000 µg/plate were within the in-house historical untreated/vehicle control range for the tester strain and the fold increase was only 1.3 times the concurrent vehicle control. Therefore, the test material was concluded to be non-mutagenic under the conditions of the test.

Supporting information is available on Similar Substance 01. The cultures were exposed to 0, 62, 185, 556, 1667 and 5000 µg/plate. Precipitation of the test material was observed at a number of the concentrations tested. In some of the plates, a slight dose-dependant increase in the number of revertants was noticed; however this was accompanied by an increased background lawn and precipitation. This was therefore not attributed to the mutagenic potential of the test material. Under the conditions of the study, the results obtained with the test material in Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100 and in the Escherichia coli strain WP2uvrA, in both the absence and presence of metabolic activation (S9-mix), the test material was not mutagenic.

 

In vitro Gene Mutation Study

The potential of Similar Substance 01 to cause gene mutation or clastogenic effects in mammalian cells was determined in accordance with OECD 476, EU Method B.17 and EPA OPPTS 870.5300. L5178Y TK+/- mouse lymphoma cells were treated in vitro both in the presence and absence of metabolic system (S9 mix). Large and small mutant colonies were scored for all cultures in each experiment. In Experiment 1, cells were treated with the test material at eight dose levels (3.5 to 112 µg/ml), in duplicate, together with vehicle and positive controls using 4-hour exposure groups both in the absence and presence of metabolic activation (2 % S9). In Experiment 2, the cells were treated with test material at up to eight dose levels using a 4-hour exposure group in the presence of metabolic activation (20 to 90 µg/ml) and a 24 hour exposure group in the absence (0.63 to 20 µg/ml) of metabolic activation. Due to a marked difference in toxicity in the 4-hour exposure groups in the presence of metabolic activation between Experiment 1 and 2, and an apparent maximum exposure being achieved at the penultimate dose level in Experiment 2, a confirmatory Experiment 3 was performed using a 4-hour exposure group at ten dose levels (20 -110 μg/ml) in the presence of metabolic activation (1 % S9) only).

Under the conditions of the test, the maximum dose levels used in the mutagenicity test were limited by test material-induced toxicity. Overall, precipitate of test material was observed at and above 28 µg/ml in the mutagenicity test. The vehicle controls had mutant frequency values that were considered acceptable for the L5178Y cell line at the TK+/- locus. The positive control items induced marked increases in the mutant frequency indicating the satisfactory performance of the test and of the activity of the metabolising system. The test material did not induce any toxicologically significant dose-related increases in the mutant frequency at any dose level, either with or without metabolic activation, in either the first, second or third experiment. The test material is therefore considered to be non-mutagenic to L5178Y cells under the conditions of this assay.

 

In vivo Cytogenicity Study

The potential genotoxicity and clastogenicity of Similar Substance 01 to the bone marrow cells of Swiss male mice was assessed in vivo in a study conducted in accordance with OECD 474 and to GLP. 10 male mice were orally administered the substance at 2000 mg/kg bw while 5 male mice were oraly single administered the substance at 1000 and 500 mg/kg bw. Negative and positive controls run in parallel. At oral doses up to 2000 mg/kg bw (the limit dose recommended by the guideline) no chromosomal damage or damage to the mitotic spindle apparatus was noted. Under the conditions of the study the test material was found to be non-genotoxic and non-clastogenic.

Justification for classification or non-classification

According to the CLP Regulation (EC) No. 1272/2008, Annex I: 3.5.2.2. Substances are allocated to one of two categories:

- Category 1: substances known to induce heritable mutations or to be regarded as if they induce heritable mutations in the germ cells of humans. Substances known to induce heritable mutations in the germ cells of humans.

The classification in Category 1A is based on positive evidence from human epidemiological studies. Substances to be regarded as if they induce heritable mutations in the germ cells of humans.

The classification in Category 1B is based on: positive result(s) from in vivo heritable germ cell mutagenicity tests in mammals; or positive result(s) from in vivo somatic cell mutagenicity tests in mammals, in combination with some evidence that the substance has potential to cause mutations to germ cells. It is possible to derive this supporting evidence from mutagenicity/genotoxicity tests in germ cells in vivo, or by demonstrating the ability of the substance or its metabolite(s) to interact with the genetic material of germ cells; or positive results from tests showing mutagenic effects in the germ cells of humans, without demonstration of transmission to progeny; for example, an increase in the frequency of aneuploidy in sperm cells of exposed people.

- Category 2: substances which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans. The classification in Category 2 is based on: positive evidence obtained from experiments in mammals and/or in some cases from in vitro experiments, obtained from: somatic cell mutagenicity tests in vivo, in mammals; or other in vivo somatic cell genotoxicity tests which are supported by positive results from in vitro mutagenicity assays. Note: Substances which are positive in in vitro mammalian mutagenicity assays, and which also show chemical structure activity relationship to known germ cell mutagens, shall be considered for classification as Category 2 mutagens.

The substance is negative in the in vitro gene mutation study in bacteria, the in vitro gene mutation study in mammalian cells and in the mammalian erythrocyte micronucleus test in vivo. The substance does not therefore meet the criteria of the CLP Regulation (EC) No. 1272/2008 for the classification as mutagenic.