Fatty acids, C18-unsatd., trimers, 2-ethylhexyl esters

Endpoint summary

Additional information

Justification for grouping of substances and read-across

There are no data available on the repeated dose toxicity of Fatty acids, C18 unsatd., trimers, 2-ethylhexyl esters (CAS 173832-46-7). 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	173832-46-7 (a)	61788-89-4 (b)
Chemical Name	Fatty acids, C18 unsatd., trimers, 2-ethylhexyl esters	Fatty acids, C18-unsatd., dimers
Molecular weight	973.62 1085.84 1184.02	556.87; 564.93
Genetic Toxicity in vitro: Gene mutation in bacteria	RA: CAS 61788-89-4	Experimental result: Negative
Genetic Toxicity in vitro: cytogenicity in mammalian cells	RA: CAS 61788-89-4	Experimental result: Negative
Genetic Toxicity in vitro: gene mutation in mammalian cells	RA: CAS 61788-89-4	Experimental result: Negative

(a) Category members subjected to the REACh  Phase-in registration deadline of 31 May 2013 are indicated in bold font.

Lack of data for a given endpoint is indicated by “--“.

(b) Surrogate substances are indicated in normal font and are precursors/breakdown products of the target substance (i.e. alcohol and fatty acid moieties). Available data on these substances are used for assessment of toxicological properties by read-across on the same basis of structural similarity and/or mechanistic reasoning as described for the present analogue approach.

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 Fatty acids, C18 unsatd., trimers, 2-ethylhexyl esters (CAS 173832-46-7).

A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

 

Discussion

Genetic toxicity (mutagenicity) in bacteria in vitro

CAS 61788-89-4

The potential mutagenicity of Fatty acids, C18-unsaturated, dimers was investigated in a bacterial mutation assay (Ames test) in the S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 according to EU Method B.13/14 and in compliance with GLP (Henderson, 1993). In a preliminary toxicity test with concentrations ranging from 0.5 to 5000 µg/plate, the test substance did not induce cytotoxicity in all tester strains up to concentrations of 500 µg/plate in the presence or absence of metabolic activation system (S9 mix). No cytotoxicity could be determined at the limit concentration of 5000 µg/plate, since precipitates obscured the bacterial lawn. However, this concentration was included in the mutagenicity test as it was assumed that the precipitate would not interfere with scoring of revertant colonies. In the main assay, all tester strains were exposed for a period of 3 days to test substance at concentrations of up to 5000 μg/plate (with and without 10 or 30% S9 mix) in two independent experiments using the plate incorporation method. No increase in the number of revertant colonies was observed in TA 1535 and TA 100 in either experiment in the presence or absence of S9 mix. In contrast, TA 1537 showed a significant increase in revertant colonies in the first experiment at 5000 µg/plate in the presence of 30% S9 only. A significant increase in revertant colonies was also seen in a fourth assay with TA 1537 at 2000 µg/plate with 30% S9. No increase in the mean number of revertants of TA 1537 was seen in the presence of 10% S9 or in the absence of S9. In the first assay with strain TA 98, a significant increase in the number of revertants was seen at 5000, 1500, and 500 µg/plate with 30% S9 and at 5000, 1500, 500 and 150 µg/plate with 10% S9. However, the positive results in TA 98 and TA 1537 were not reproducible in further assays and the effects were not dose-dependent. Furthermore, the precipitation at the higher doses may have interfered with scoring of revertant colonies and may thus falsify the results. The positive and negative controls included in the experiment showed the expected results, with the exception of 2-aminoanthracene, which did not show a positive result at 30% S9 mix due to excessive amount of S9. Based on the results of this study, the test substance did not induce mutagenicity in the selected strains of S. typhimurium (TA 1535, TA 1537, TA 98 and TA 100) in the presence and absence of metabolic activation

Genetic toxicity (cytogenicity) in mammalian cells in vitro

CAS 61788-89-4

The clastogenic potential of Fatty acids, C18-unsaturated, dimers was assessed in an in vitro mammalian chromosome aberration test in cultured human lymphocytes in compliance with OECD Guideline 473 and GLP (Akhurst, 1993). The cells were exposed to the test material both in the presence and absence of S9 mix in two independent experiments with concentrations up to 300 µg/mL, which was the limit of solubility for the test substance. Based on the cytotoxicity data of both experiments, concentrations for metaphase analysis were selected. In the first assay, the mitotic index was reduced to 65% of the vehicle control value at 300 µg/mL (18 h harvest) in the absence of S9 mix, whereas no cytotoxicity was observed in the presence of S9 mix. Therefore, concentrations selected for metaphase analysis, with and without metabolic activation, were 75, 150 and 300 µg/mL. In the second assay, no significant reductions in mitotic index were observed at 300 µg/mL in the presence (18 and 32 h harvest) and in the absence of S9 mix (18 h harvest). In the absence of S9 mix (32 h harvest), 150 µg/mL caused a decrease in mitotic index to 63% of the vehicle control value. Concentrations selected for metaphase analysis, with and without metabolic activation (18 h harvest), were 75, 150 and 300 µg/mL. For the 32 h harvest, 150 µg/mL (without S9 mix) and 300 µg/mL (with S9 mix) were selected. No statistically significant increases in the proportion of aberrant cells were observed at any concentration of test material analysed, in either the absence or presence of S9 mix. Both positive control compounds yielded the expected results in both assays. No increase in the number of cells with chromosomal aberrations was observed compared to controls in any of the experiments performed, neither in the presence nor in the absence of metabolic activation. Visible precipitation of the test substance was observed at concentrations ≥ 300 µg/mL, which however did not interfere with chromosomal analysis. The positive and negative controls included during short-term and continuous exposure showed the expected results and thus verified the sensitivity of the assay.

Under the conditions of this experiment, Fatty acids, C18-unsaturated, dimers was not considered to be clastogenic in cultured human lymphocytes in the presence or absence of metabolic activation.

Gene mutation in mammalian cells in vitro

CAS 61788-89-4

Fatty acids, C18-unsaturated, dimers were tested for its mutagenic potential in a vitro mammalian cell mutation assay following OECD Guideline 476 and in compliance with GLP (Adams et al., 1993). In two independent experiments, mouse lymphoma L5178Y cells were treated with the test substance at concentrations up to 300 µg/mL (limit of solubility) with and without metabolic activation (S9 mix) for a period of 3 h. After an expression time of 48 h in growth medium, cells were incubated for 12 days with trifluorothymidine as selection agent for forward mutation at the thymidine kinase locus. The test material was cytotoxic in both the absence and presence of S9 mix (at 300 and 150 µg/mL, respectively). A statistically significant increase in mutant frequency was observed at 250 µg/mL in one of the two experiments without S9 mix. However, this increase was small and not considered to be biologically significant. In the presence S9 mix, no statistically significant increases in mutant frequency were observed in any of the two experiments performed. The corresponding positive and negative control substances showed the expected results and thus verified the sensitivity of the assay.

Based on the results of this study, it was concluded that Fatty acids, C18-unsaturated, dimers does not have a mutagenic potential in mammalian cells in vitro.

Conclusion for genetic toxicity

In summary, no information on genetic toxicity is available for Fatty acids, C18 unsatd., trimers, 2-ethylhexyl esters, thus read across from the possible breakdown product was conducted The surrogate substance (CAS 61788-89-4) was used as read-across, because of its structural similarity to the formed hydrolysis product of the target substance. The bacterial mutagenicity study as well as the studies investigating cytogenicity and mutagenicity in mammalian cells were negative.

Therefore, no genetic toxicity is expected for Fatty acids, C18 unsatd., trimers, 2-ethylhexyl esters.

Justification for selection of genetic toxicity endpoint
Hazard assessment is conducted by means of read-across from a structural analogue. 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:
Based on read-across from Fatty acids, C18-unsatd., dimers (CAS 61788-89-4), which shares a strong structural similarity to one of the hydrolysis products of the target substance, no hazard was identified.
In none of these studies mutagenicity in bacteria could be observed.
In none of these studies clastogenic effects in mammalian cells could be observed.
In none of these studies mutagenicity in mammalian cells could be observed.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on read-across from structurally related 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.