Bis(ethyl acetoacetato-O1',O3)bis(2-methylpropan-1-olato)titanium

Endpoint summary

Additional information

As there are no studies available for the target substance, the weight of evidence approach is used to fulfill the data requirements for this endpoint. The target substance is hydrolytically unstable with half-life of < 10 minutes (Brekelmans, M. J. C, 2013). Thus, the intrinsic properties are related to the most hazardous decomposition products, 2-methylpropanol being the most relevant for CSA.Further evidence on genotoxicity of the target substance is derived from the in vitro genotoxicity studies done for titanium tetrabutanolate, the analogue category member.

Gene mutation in bacterial cells

There is one publication by Shimizu (1985) where the gene mutation potential of 2-methylpropanol was evaluated in Ames test. This study was conducted using strains of Salmonella typhimurium bacteria (TA1535, TA1537, TA1538, TA98 and TA100) and E. coli WP2 with and without metabolic activation. 2-methylpropanol was not mutagenic in this assay either in the presence or absence of a liver microsomal system.

Further evidence on the potential of the target substance to induce gene mutation in bacteria comes from the analogue category member of the target substance, titanium tetrabutanolate. All these titanates in this category behave similar way when in contact with water. However, 2-methylpropanol is released from the target substance and n-butanol is released from titanium tetrabutanolate when the substances are in contact with water. The category justification and the read-across justifications are presented in the Annexes of the CSR.

The analogue substance, titanium tetrabutanolate, was tested in a bacterial mutagenicity study by Verspeek-Rip C. M (2012a). The study was considered reliable without restrictions as the study was performed in compliance with GLP according to OECD guideline 471. This study was conducted by using four strains of Salmonella typhimurium bacteria (TA98, TA100, TA1535, and TA1537) and Escherichia coli (WP2uvrA) with and without metabolic activation. Titanium tetrabutanolate was tested for its ability to induce mutations at the concentration of 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate. The test substance did not induce mutations under conditions of this study.

Based on the results presented above this titanate has no potential to cause genotoxicity in bacterial cells.

Cytogenicity in mammalian cells

Kreja (2002) investigated the cytogenicity potential of 2-methylpropanol in mammalian cells. Chinese hamster lung fibroblasts (V79) were exposed to the test substance in the absence and presence of S9-mix. 2-methylpropanol did not induce a statistically significant or biologically relevant increase in the micronucleus frequency.

Further evidence on the potential of the target substance to induce cytogenicity in mammalian cells comes from the analogue category member of the target substance, titanium tetrabutanolate. The potential of titanium tetrabutanolate to induce chromosome aberration was assessed in cultured peripheral human lymphocytes by Verbaan (2012). This study is considered reliable without restrictions as the study was performed in compliance with GLP according to OECD guideline 473. Titanium tetrabutanolate was tested with and without metabolic activation in doses up to 1000 µg/ml. The compound was not clastogenic in human lymphocyte assay either in the presence or absence of metabolic activation, i. e., it did not increase the number of polyploid cells and cells with endoreduplicated chromosomes in the cells.

Based on the data from the most hazardous degradation product of the target substance and from the analogue category member, bis(ethylacetoacetato‐O1',O3")bis(2-methyl propan-1-olato)titanium has not potential to cause cytogenicity in mammalian cells.

Gene mutation in mammalian cells

In the publication by Kreja (2002) mutagenicity potential of 2-methylpropanol was investigated in Chinese hamster lung fibroblasts (V79). Both in the absence and presence of S9-mix, 2-methylpropanol did not induce mutagenicity in the mammalian cells.

Further evidence on the potential of the target substance to induce gene mutation in mammalian cells comes from the analogue category member of the target substance, titanium tetrabutanolate. The potential gene mutagenic activity of titanium tetrabutanolate has been evaluated in L5178Y mouse lymphoma cells by Verspeek-Rip (2012b). The test method was comparable to OECD guideline 476 and the test was conducted in compliance with GLP. The test substance was tested in two independent experiments with modifications in the duration of treatment time and in the concentration of the metabolic activation system (S9-mix). Titanium tetrabutanolate was not mutagenic, both in the presence and absence of S9-mix.

Based on the data above bis(ethylacetoacetato‐O1',O3")bis(2-methyl propan-1-olato)titanium has no potential to cause gene mutation in mammalian cells.

As conclusion, the results from the in vitro genotoxicity assays from the read-across substances of bis(ethylacetoacetato‐O1',O3")bis(2-methyl propan-1-olato)titanium are universally negative. In addition, neither of the two other decomposition products (ethyl acetoacetate and TiO2) of the target substance has classification entries for genotoxicity.

Justification for selection of genetic toxicity endpoint
No in vitro genotoxicity studies are conducted for the target substance. Conclusion is based on the following assays: Bacterial reverse mutation assay (Ames test), in vitro mammalian cell gene mutation assay and in vitro mammalian chromosome aberration test performed for the analogue category member and the most hazardous degradation product of this titanate.

Short description of key information:
in vitro:
Following studies are conducted for titanium tetrabutanolate, the analogue category member.
Gene mutation (reverse mutation assay/Ames test): negative in all tested bacterial strains with and without metabolic activation (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).

Following studies are conducted for 2-methylpropanol, the most hazardous degradation product of the target substance.
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 (equivalent to OECD 473).
Gene mutation study in mammalian cells: negative, with and without metabolic activation (equivalent to 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 this titanate has no potential to cause mutagenicity and genotoxicity. No classification is required according to the criteria of CLP regulation 1272/2008 and the EU directive 67/548/EEC.