Bis(ethyl acetoacetato-O1',O3)bis(propan-2-olato)titanium

Endpoint summary

Additional information

In vitro mutagenic activity of bis(ethylacetoacetato-O1’,O3”) bis(propan-2-olato)titanium has been evaluated in one study with bacterial cells and in two studies with mammalian cells. Chromosome aberration study and gene mutation study in mammalian cells are performed according to the current guidelines and in accordance with GLP. These studies are evaluated to be reliable without restrictions. In vitro gene mutation study in bacterial cells (Ames test) pre-dates GLP and current guidelines, but the method is comparable to OECD 471 study. Thus, it is justified to select all three studies as key studies.

Gene mutation in bacterial cells

A bacterial mutagenicity study by Sippel, M.E. (1978) is considered reliable with one restriction; TA102 bacterial strain was not used in the study. This study was conducted by using five strains of Salmonella typhimurium bacteria (TA1535, TA1537, TA1538, TA98 and TA100) with and without metabolic activation. Bis(ethylacetoacetato-O1’,O3”) bis(propan-2-olato)titanium was tested for its ability to induce mutations at the concentration 1 000, 3 000, 5 000, 7 000 and 10 000 µg test substance/plate. Test substance did not induce mutations under conditions of this study.

Cytogenicity in mammalian cells

The potential of bis(ethylacetoacetato-O1’, O3”) bis(propan-2-olato) titanium to induce chromosome aberration was assessed in cultured peripheral human lymphocytes by Verbaan I. A. J (2013) in an OECD 473 guideline study. Both in the absence and presence of S9-mix bis(ethylacetoacetato-O1’, O3’’) bis(propan-2-olato) titanium did not induce a statistically significant or biologically relevant increase in the number of cells with chromosome aberrations in two independent experiments. No effects of bis(ethylacetoacetato-O1’, O3’’) bis(propan-2-olato) titanium on the number of endoreduplicated chromosomes were observed both in the absence and presence of S9-mix. It was noted that the target substance increased the number of polyploid cells both in the absence of S9-mix in a dose dependent manner at prolonged exposure times. In addition, an increase in the number of polyploid cells above the historical control data range was observed in one duplicate culture at the highest concentration tested after 3 h exposure in the presence of S9-mix.

The preliminary information suggests the possibility of the target substance to cause aneugenicity. However, further studies are not considered necessary since the target substance hydrolyzes rapidly (half-life less than 10 minutes) releasing isopropyl alcohol, ethyl acetoacetate and TiO2. Currently, there is no data from these degradation products indicating any concern about aneugenicity.

Gene mutation in mammalian cells

The potential gene mutagenic activity of bis(ethylacetoacetato-O1’,O3”) bis(propan-2-olato)titanium has been evaluated in L5178Y mouse lymphoma cells in an OECD 476 guideline study (Verspeek-Rip, 2013). The test substance was tested in two independent experiments with modifications in the duration of treatment time, concentration of S9-mix and dose levels. No significant increase in the mutation frequency at the TK locus was observed after treatment with bis(ethylacetoacetato-O1’,O3’’) bis(propan-2-olato)titanium either in the absence or in the presence of S9-mix. The numbers of small and large colonies in the bis(ethylacetoacetato-O1’,O3’’) bis(propan-2-olato)titanium treated cultures were comparable to the numbers of small and large colonies of the solvent controls.

Justification for selection of genetic toxicity endpoint
Conclusion based on the following assays: Bacterial reverse mutation assay (Ames test), In vitro mammalian cell gene mutation assay, In vitro mammalian chromosome aberration test.

Short description of key information:
In vitro:
Gene mutation (reverse mutation assay/Ames test): negative in all tested bacterial strains with and without metabolic activation (equivalent to OECD TG 471).
Chromosome aberration study in mammalian cells: negative, with and without metabolic activation (OECD 473).
Gene mutation study in mammalian cells: negative, with and without metabolic activation (OECD 476).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the results of in vitro bacterial gene mutation study, in vitro mammalian chromosomal aberration and gene mutation studies bis(ethylacetoacetato-O1’,O3”) bis(propan-2-olato)titanium has no potential to cause mutagenicity and genotoxicity. So no classification is required according to the criteria of CLP regulation 1272/2008 and the EU directive 67/548/EEC.