Fatty acids, C16-18, 2-hydroxyethyl esters

Endpoint summary

Additional information

Justification for read-across

The mutagenic potential of Fatty acids, C16-18, 2-hydroxyethyl esters (CAS 97281-23-7) was tested in bacteria. No data on cytogenicity and mutagenicity in mammalian cells are available for Fatty acids, C16-18, 2-hydroxyethyl esters (CAS 97281-23-7). In accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5 read-across from appropriate substances is conducted to fulfill the standard information requirements set out in Regulation (EC) No 1907/2006, Annex VII-VIII, 8.4.

According to 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) “to avoid the need to test every substance for every endpoint”.

 

Fatty acids, C16-18, 2-hydroxyethyl esters is an UVCB substance comprised of mainly mono- and diesters of ethylene glycol conjugated with C16 and C18 fatty acids. Thus, the test substance represents a glycol ester, which in general is known to be stepwise hydrolysed by gastrointestinal enzymes into the free fatty acid components and the respective alcohol (Long, 1958; Lehninger, 1970; Mattson and Volpenhein, 1972). Considering the common metabolism, the read-across approach is based on the presence of common precursors and the likelihood of common breakdown products via biological processes that result in structurally similar chemicals, and on common functional groups, structural similarities and similar physico-chemical, toxicological and toxicokinetic behaviour. For further details on the read-across approach, please refer to the analogue justification in section 13 of the technical dossier.

 

As no reliable data are available on genetic toxicity, read-across to the analogue substances Fatty acids, C16-18, esters with ethylene glycol (CAS 91031-31-1) and Butylene glycol dicaprylate / dicaprate (CAS 853947-59-8) was conducted.

 

 

Genetic toxicity in bacteria (Ames)

CAS97281-23-7

The mutagenic potential of Fatty acids, C16-18, 2-hydroxyethyl esters was assessed in a bacterial reverse mutation assay (Ames test) according to GLP criteria and OECD guideline 471 (Verbaan, 2016). The mutagenic potential of the test substance was assessed in S. typhimurium tester strains TA 1535, TA 1537, TA 98 and TA 100, and E. coli WP2 uvr A in a plate incorporation test with and without metabolic activation. In the first experiment, the test substance was tested at concentrations ranging from 1.7 – 5000 µg/plate and in the second experiment in the concentration range 154 - 1568 µg/plate. Precipitates were visible at 1600 µg/plate with and without S9 mix in the first and at 878 µg/plate (with the exception of tester strain TA 1537 and TA 100 (without S9-mix)) and 1568 µg/plate in all tester strains with and without S9 mix in the second experiment. The test substance did not induce an increase in reversions in any of the S. typhimurium strains with or without metabolic activation. Cytotoxicity was observed at 1600 µg/mL in TA 1535 and TA 1537 with and without metabolic activation in the first experiment, and starting at 878 µg/mL in TA 1535 with S9 mix and at 1568 µg/mL in TA 98 with S9 mix in the second experiment. The vehicle and positive controls were valid and the results fell within the range of historical control data. Based on the results of the conducted study, Fatty acids, C16-18, 2-hydroxyethyl esters is not expected to exhibit mutagenic properties in bacterial cells.

 

 

Genetic toxicity (cytogenicity) in mammalian cells in-vitro

CAS 853947-59-8

An in vitro mammalian chromosome aberration test was conducted with C8-C10-1,3-Butandiolester in accordance with OECD guideline 473 under GLP conditions (Dechert, 1997). The induction of structural chromosome aberrations was evaluated in vitro in Chinese hamster lung fibroblasts (V79) cells, incubated for 18 and 28 h with and without a metabolic activation system (S9-mix from rats treated with Aroclor 1245). Concentrations of 10-100 µg/mL (18 h incubation) and 80 and 100 µg/mL (28 h incubation) of the test substance in the vehicle ethanol were applied. The solubility limit of the test substance in the vehicle ethanol in the culture medium was determined to be 100 µg/mL. In the first experiment without metabolic activation, the negative controls exhibited a mitotic index of 2.0% only and the experiment was therefore repeated. Thereafter, the negative as well as the positive controls showed the expected results and were within the range of historical control data. The frequency of polyploidy cells with and without metabolic activation was within the expected range (< 10%). In the experiments both with and without metabolic activation, a systematic influence of the test substance was observed, which led to a reduction in the mitotic index. No statistically or biologically significant increase in the incidence of chromosome aberrations was observed.

Therefore, under the conditions of the study, C8-C10-1,3-Butandiolester did not show clastogenic activity in this chromosomal aberration test with and without metabolic activation performed in Chinese hamster lung fibroblasts in vitro.

 

Genetic toxicity (mutagenicity) in mammalian cells in-vitro

CAS 91031-31-1

Mutagenic properties of Fatty acids, C16-18, esters with ethylene glycol were characterized in an in vitro mammalian cell gene mutation study according to OECD guideline 476 under GLP conditions (Verspeek-Rip, 2010). Gene mutations in the thymidine kinase locus were investigated in L5178Y mouse lymphoma cells in the presence and absence of a metabolic activation system (Phenobarbital/β-naphtoflavone-induced rat liver S9). In the first experiment, cells were exposed for 3 h to test substance at concentrations of 0.1-333 µg/mL (in DMSO) with and without metabolic activation. Concentrations of the second experiment without metabolic activation for an exposure time of 24 h ranged from 3-175 µg/mL and with metabolic activation (3 h; 12% S9-mix) from 0.1-333 µg/mL. The vehicle and positive controls in the study showed the expected results and were within the range of historical control data. No cytotoxicity was observed up to the precipitating concentration of 100 µg/mL and up to 333 µg/mL, respectively. There was no significant increase in the number of forward mutations at the thymidine kinase locus of L5178Y mouse lymphoma cells treated with the test material, neither in the presence nor in the absence of a metabolic activation system. Under the conditions of the study, Fatty acids, C16-18, esters with ethylene glycol did not show gene mutation activity in this test performed in L5178Y mouse lymphoma cells in vitro.

 

Conclusion on genetic toxicity

The available data do not provide evidence that the target or source substances exhibit mutagenic or clastogenic properties in bacteria or mammalian cells. Therefore, no properties for genetic toxicity are expected for Fatty acids, C16-18, 2-hydroxyethyl esters (CAS 97281-23-7).

 

References

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within the CSR.

Justification for selection of genetic toxicity endpoint
Hazard assessment is conducted by means of read-across from structural analogues. 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 substances and overall quality assessment (refer to the endpoint discussion for further details).

Short description of key information:
Genetic toxicity in vitro:
Ames test (OECD 471): negative with and without metabolic activation in S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2 uvr A
Chromosome aberration (OECD 473): negative in Chinese hamster lung fibroblasts (V79) cells with and without metabolic activation
Gene mutation (OECD 476): negative in L5178Y mouse lymphoma cells with and without metabolic activation

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available data on the genetic properties of target substance and structural analogues, the available data on genetic toxicity do not meet the classification criteria according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.