branched-nonyl 3,5,5 trimethylhexanoate

Endpoint summary

Additional information

Justification for grouping of substances and read-across

There are no data available on the genetic toxicity of isononyl isononanoate. 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.

Overview of genetic toxicity

CAS	Chemical name	Molecular weight	Genetic toxicity (mutagenicity) in vitro, bacteria	Genetic toxicity (cytogenicity) in vitro, mammalian cells	Genetic toxicity (mutagenicity) in vitro, mammalian cells
(previously 42131-25-9) (a)	Isononyl isononanoate	ca 285	RA: CAS 59219-71-5	RA: CAS 10233-13-3 RA: CAS 26399-02-0	RA: CAS 10233-13-3 RA: CAS 26399-02-0
10233-13-3 (b)	Isopropyl laurate	242.41	--	Experimental result: not clastogenic	Experimental result: not mutagenic
26399-02-0	2-ethylhexyl oleate	394.67	--	Experimental result: not clastogenic	Experimental result: not mutagenic
59219-71-5	3,5,5-trimethylhexyl 3,5,5 -trimethylhexanoate	284.48	Experimental result: not mutagenic	--	--

(a) The substance subject to registration is indicated in bold font.

(b) Reference (read-across) substances are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information is used to predict the same endpoints for isononyl isononanoate. A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

 

Discussion

Gene mutation in bacteria in vitro

CAS 59219-71-5

The potential mutagenicity of 3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate was investigated in a bacterial mutation assay (Ames test) according to OECD guideline 471 and under conditions of GLP (Sire, 2005). In two independent experiments, the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 were exposed to the test substance at concentrations of 312.5, 625, 1250, 2500 and 5000 µg/plate for a period of 48-72 h. The plate incorporation method was applied for the first experiment with and without metabolic activation, and for the second experiment without metabolic activation. The preincubation method was used for the second experiment with metabolic activation. In both experiments, no cytotoxicity was observed up to and including the limit dose of 5000 µg/plate, with and without metabolic activation. A moderate to marked emulsion was observed in the Petri dishes when scoring the revertants at dose levels ≥ 625 µg/plate without metabolic activation, and at dose levels ≥ 1250 µg/plate with metabolic activation. No increase in the mean number of revertants was observed in any tester strain at any concentration tested. The positive controls included in the assay showed the expected results and verified the efficiency of the assay. Based on the results of this experiment, the test substance was considered to be non-mutagenic in the selected strains of S. typhimurium (TA 1535, TA 1537, TA 98, TA 100 and TA 102) in the presence and absence of metabolic activation.

Cytogenicity in vitro

CAS 10233-13-3

An in vitro mammalian chromosome aberration test was performed with isopropyl laurate (CAS 10233-13-3) in primary human lymphocytes, according to OECD 473 (Buskens, 2010). In the first experiment cells were exposed for 3 hours to test substance concentrations of 10, 33 and 100 µg/mL in ethanol with and without metabolic activation (S9-mix). In the second experiment cells were exposed for 24 hours to 66, 150 and 250 µg/mL followed by 24 hours expression time, and exposed for 48 hours to 3, 125 and 150 µg/mL followed by 48 hours expression time. The second experiment was performed without metabolic activation. 250 µg/mL was chosen as maximum dose due to limited solubility. The positive and negative controls were valid. No increase in the frequency of chromosome aberrations and polyploid cells was observed at any dose level. Some cytotoxicity was noted at the highest dose level without metabolic activation. The test material was therefore non-clastogenic to human lymphocytes in vitro.

CAS 26399-02-0

The cytogenetic potential of 2-ethylhexyl oleate (CAS 26399-02-0) was assessed in an in vitro mammalian chromosome aberration test in primary human lymphocytes, performed according to OECD guideline 473 (Buskens, 2010). 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, cells were incubated with test substance concentrations of 3, 10 and 33 µg/mL in ethanol for 3 hours with and without metabolic activation. In the second experiment cells were incubated with 3, 10 and 33 µg/mL for 24 hours followed by 24 hours expression time and 48 hours following 48 hours expression time, all without metabolic activation. 33 µg/mL was chosen as maximum dose due to limited solubility of the test substance. Evaluation of 100 well-spread metaphase cells from each culture for structural chromosomal aberrations revealed no increase in the frequency of chromosome aberrations and polyploid cells at any dose level in comparison to the negative controls. The test material demonstrated only modest cytotoxicity. The vehicle (solvent) and positive controls were shown to be valid. The test material did not induce a statistically significant increase in the frequency of cells with chromosome aberrations with or without metabolic activation.

Gene mutation in mammalian cells in vitro

CAS 10233-13-3

An in vitro mammalian cell gene mutation assay performed according to OECD 476 was performed with isopropyl laurate (CAS 10233-13-3) in mouse lymphoma L5178Y cells (Verspeek-Rip, 2010). The test substance was applied to the cells at concentrations up to and including 10μg/mL, which was the precipitation level. The cells were treated for 3 and 24 hours without metabolic activation, for 3 hours with 8% (v/v) S9-mix, and for 3 hour with 12% (v/v) S9-mix, respectively. No toxicity was observed and all dose levels were evaluated in the absence and presence of S9-mix. The positive and negative controls were valid. No significant increase in mutation frequency occurred. Therefore, isopropyl laurate was not mutagenic in the mouse lymphoma L5178Y test system under the relevant experimental conditions.

CAS 26399-02-0

An in vitro mammalian cell gene mutation assay was performed with 2-ethylhexyl oleate (CAS 26399-02-0) according to OECD 476 (Verspeek-Rip, 2010). Two independent experiments (with 3 or 24 hours of exposure) were performed in mouse lymphoma L5178Y cells in the absence and presence of metabolic activation (S9-mix) with test substance concentrations up to 100μg/mL dissolved in ethanol. Precipitation was seen at 100 µg/mL and higher. The positive and negative controls were valid and within the range of historical control data. No significant increase in mutation frequency occurred in any of the test conditions.

Conclusions for genetic toxicity in vitro

There are no data available on the genotoxicity of isononyl isononanoate. However, read-across from several structural analogues showed that the results of all in vitro genetic toxicity studies performed in bacteria and mammalian cells with and without metabolic activation were negative (Sire, 2005; Buskens, 2010; Buskens, 2010; Verspeek-Rip, 2010; Verspeek-Rip, 2010). Based on the available data, isononyl isononanoate is not anticipated to have a genotoxic potential.

Justification for selection of genetic toxicity endpoint
Hazard assessment is conducted by means of read-across from structural analogues. 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:
In vitro:
Mutagenicity in bacteria (OECD TG 471) using S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102: negative (based on read-across from CAS 59219-71-5)
Cytogenicity in mammalian cells in a chromosome aberration test (OECD TG 473) using Chinese hamster lung fibroblasts (V79): negative (based on read-across from CAS 10233-13-3 and CAS 26399-02-0)
Mutagenicity in mammalian cells in a MLA assay (OECD TG 476): negative (based on read-across from CAS 10233-13-3 and CAS 26399-02-0)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on read-across from the 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.