Isononanoic acid, mixed esters with dipentaerythritol, heptanoic acid and pentaerythritol

Endpoint summary

Additional information

Justification for grouping of substances and read-across

There are no data available on the genetic toxicity of 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3) in mammalian cells. In order to fulfil the standard information requirements set out in Annex VII and VIII, 8.4, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity, the substances 3,5,5-trimethylhexanoic acid hexaester with dipentaerythritol (monoconstituent, CAS 844198-63-3), 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) and Dipentaerythritol ester of fatty acids C5 and C9iso (CAS 647028-25-9) are selected as source for risk assessment. 

In vitro gene mutation in bacteria

The registered substance 3,5,5 trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3) was tested for mutagenicity in S. typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 according to OECD Guideline 471 (Cathalot, 2006). Test substance concentrations of 312.5, 625, 1250, 2500 and 5000 µg/plate in ethanol were tested in triplicates in two independent experiments. The plate incorporation method with and without the addition of a rat liver homogenate metabolising system (S9-mix) was used in experiment 1 and the preincubation method was used in experiment 2 with metabolic activation.

No cytotoxicity was observed. No increase in the frequency of revertant colonies compared to concurrent negative controls were observed in all tested strains, neither in the presence nor in the absence of metabolic activation. Thus, the test substance did not induce gene mutations in five tested Salmonella strains under the given test conditions.

CAS 84418-63-3 (monoconstituent)

In an additional study the structural related substance 3,5,5-trimethylhexanoic acid hexaester with dipentaerythritol (monoconstituent, CAS 84418-63-3) was tested for mutagenicity in S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 and E.coli strains WP2 uvr A pKM 101 and WP2P (WP2 pKM101) according to OECD Guideline 471 (Croda, 1991). Test substances concentrations of 100, 200, 500, 1000, 2500 and 5000 µg/plate with and without metabolic activation.

The plate incorporation method with and without the addition of a rat liver homogenate metabolising system (S9-mix) was used in experiment 1 and in experiment 2 without metabolising system and the preincubation method was used in experiment 2 with metabolic activation. No cytotoxicity was observed. No increase in the frequency of revertant colonies compared to concurrent negative controls were observed in all tested strains, neither in the presence nor in the absence of metabolic activation. Thus, the test substance did not induce gene mutations in five tested Salmonella and E. coli strains under the given test conditions.

In summary, due to consistently negative results 3,5,5 -trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB) is expected not to be mutagenic to bacteria.

 

In vitro cytogenicity in mammalian cells

Since no studies investigating the in vitro cytogenicity in mammalian cells are available for 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3), in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across from the structurally related analogue substances 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) and Dipentaerythritol ester of fatty acids C5 and C9iso (CAS 647028-25-9) was conducted.

CAS 131459-39-7 

An in vitro mammalian chromosome aberration test was performed with 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) in primary human lymphocytes according to OECD Guideline 473 (Wright, 1999). Duplicate cultures of human lymphocytes were evaluated for chromosome aberrations in the presence and absence of metabolic activation (rat liver S9-mix).

In the first experiment test substance concentrations of 39.06, 78.13, 156.25, 312.5; 625; 1250; 2500 and 5000 µg/mL in acetone were used for 4 hours of exposure with and without metabolic activation. In the second experiment 39.06, 78.13, 156.25, 312.5, 625, 1250, 2500, and 5000 µg/mL were used for 24 hours exposure without S9 and 39.06, 78.13, 156.25, 312.5, 625, 1250, 2500 and 5000 µg/mL for 4 hours with S9. Ethylmethanesulphonate and cyclophosphamide were used as positive control substances. Evaluation of 200 cells from each culture for chromosomal aberrations revealed no increase in the frequency of chromosome aberrations at any dose level in comparison to the negative controls. The test material demonstrated showed no cytotoxicity. All vehicle (solvent) controls had frequencies of cells with aberrations within the range expected for normal human lymphocytes. All the positive control materials induced statistically significant increases in the frequency of cells with aberrations indicating the satisfactory performance of the test and of the activity of the metabolising system. The test material did not induce a statistically significant increase in the frequency of cells with chromosome aberrations in either the absence or presence of a liver enzyme metabolising system in either of two separate experiments. The test material was therefore considered to be non-clastogenic to human lymphocytes in vitro.

CAS 647028-25-9

An in vitro mammalian chromosome aberration test was conducted with Dipentaerythritol ester of fatty acids C5 and C9iso (CAS 647028-25-9) in accordance with OECD guideline 473 under GLP conditions (Wright, 2000).

The induction of structural chromosome aberrations was evaluated in human lymphocytes in vitro incubated for 4 h with and without metabolic activation system and 20 h without metabolic activation system (S9-mix from rats treated with Aroclor 1245). Concentrations of 39.06-5000 µg/mL (4 h incubation, with and without S9-mix) and 156.25-5000 µg/mL (20 h incubation, without S9-mix) of the test substance were applied. The vehicle used in the testing was acetone. Cytotoxicity was evaluated calculating the mitotic index of 2000 cells and polyploidy was checked.

There was a cloudy appearance of the test material at all concentrations in both treatment groups after 4 h exposure. The negative and positive controls showed the expected results and were within the range of historical control data. No cytotoxicity was observed up to the highest tested concentration. No increase in the incidence of chromosome aberrations was observed under the conditions of the study.Thus, the Dipentaerythritol ester of fatty acids C5 and C9iso did not show clastogenic activity in this chromosomal aberration test performed in human lymphocytes in vitro.

As no mutagenic potential was found in the studies above, the 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3) is not considered to have cytogenetic potential in mammalian cells in vitro.

In vitro gene mutation in mammalian cells

Since no studies investigating the in vitro mutagenicity in mammalian cells are available for 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3), in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across from the structurally related analogue substance 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate (CAS 15834-04-5) was conducted.

CAS 15834-04-5

An in vitro mammalian cell gene mutation assay was performed with 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate (CAS 15834-04-5) according to OECD Guideline 476 in L5178Y mouse lymphoma cells (Verspeek, 2010). In the first experiment, the test item was tested up to concentrations of 100 μg/mL in the absence and presence of 8% (v/v) S9-mix, respectively. The incubation time was 3 hours. In the second experiment, 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate was tested up to cytotoxic levels of 100 µg/mL and 250 µg/L in the presence and absence of 12% (v/v) S9-mix respectively. The incubation times were 24 hours and 3 hours for incubations in the absence and presence of S9-mix, respectively. In the test, no cytotoxicty was noticed. However, the test item was test up at or above the precipitating dose level of 100 µg/mL. The spontaneous mutation frequencies in the solvent-treated control cultures were between the minimum and maximum value of the historical control data range and within the acceptability criteria of this assay. Mutation frequencies in cultures treated with positive control chemicals were increased by 13- and 11-fold for methylmethansulphonate (MMS) in the absence of S9-mix, and by 13- and 11-fold for cyclophosphamide (CP) in the presence of S9-mix. In the absence and presence of S9-mix, 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate did not induce a significant increase in the mutation frequency. In the absence presence of S9-mix, the test substance did not induce a significant increase in the mutation frequency in the second experiment. It is concluded that 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate is not mutagenic in the mouse lymphoma L5178Y test system under the experimental conditions described.

In summary, 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3) is not expected to have mutagenic potential in mammalian cells in vitro.

 

Conclusion for genetic toxicity in vitro

There are only a partial set of data available for genetic toxicity repeated dose toxicity of 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB). One negative study is available to assess the mutagenic potential in bacteria in the registered substance 3,5,5-trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 844198-63-3). Another negative study is available to assess the mutagenic potential in bacteria from the structural related substance 3,5,5-trimethylhexanoic acid hexaester with dipentaerythritol (monoconstituent, CAS 844198-63-3). The target substance is therefore not considered to induce point mutations by base-pair changes or frame-shifts in the genome of the strains tested. In vitro cytogenicity data are available from structural related substances. Studies investigating cytogenicity using human lymphocytes with 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) and Dipentaerythritol ester of fatty acids C5 and C9iso (CAS 647028-25-9) were negative for induction of chromosomal aberrations. Equally, no gene mutation effects were found in mammalian L5178Y cells treated with 2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate (CAS 15834-04-5). Therefore, 3,5,5 -trimethylhexanoic acid, mixed esters with dipentaerythritol (UVCB, CAS 84418-63-3) is not considered to have cytogenetic potential in mammalian cells in vitro. 

Justification for selection of genetic toxicity endpoint
Hazard assessment is conducted by means of read-across based on an analogue approach. No study was selected since all available in vitro genetic toxicity studies were negative. All available studies are adequate and reliable based on the identified similarities in structure and intrinsic properties between source and target substance and overall quality assessment (refer to the endpoint discussion for further details).

Short description of key information:
Negative results in Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537, TA 102,and E.coli strain with and without metabolic activation (OECD 471, GLP, analogue approach).
Negative results in mammalian chromosomal aberration test with lymphocytes (OECD 473, GLP, analogue approach).
Negative results in mammalian cell gene mutation tests using mouse lymphoma cells, with and without metabolic activation (OECD 476, GLP, analogue approach).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on information received on read-across from structurally similar substances, the available data on genetic toxicity do not meet the classification criteria according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.