Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters

Endpoint summary

Description of key information

RDT oral (OECD 408), rat NOAEL = 125 mg/kg bw/day (RA CAS 104-76-7), corresponding NAEL = 757.5 mg/kg bw/day for Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters
RDT oral (OECD 408), rat NOAEL = 741/855 mg/kg bw/day (males/females) (RA CAS 61788-89-4), corresponding NAEL = 1037.4/1197 mg/kg bw/day (males/females) for Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

125 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

The available information comprises adequate, reliable (Klimisch score 2) and consistent studies from a reference substance with similar structure and intrinsic properties. Read-across is justified based on structural similarity between the source and target substances, the source substance being a product of the hydrolysis of the target substance.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Justification for grouping of substances and read-across

There are only limited data available on repeated dose toxicity of Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2). In order to fulfil the standard information requirements set out in Annex VIII, 8.6, 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 repeated dose toxicity:

CAS	Chemical name	Molecular weight [g/mol]	Repeated dose toxicity Oral	Repeated dose toxicity Inhalation	Repeated dose toxicity Dermal
68440-06-2 (a)	Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters	789	RA: CAS 61788 -89-4 RA: CAS 104-76-7	--	--
104-76-7 (b)	2-ethylhexanol	130	Experimental result: NOAEL = 125 mg/kg bw/day (rat)	Experimental result: NOAEC = 638.4 mg/m³ air (rat)	--
61788-89-4 (b)	Fatty acids, C18-unsaturated, dimers	564	Experimental result: NOAEL = 855/741 (females/males) mg/kg bw/day (rat)	--	--

(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 the possible hydrolysis products of Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2). The available endpoint information is used to predict the same endpoints for Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2). A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Discussion

Repeated dose toxicity oral

No data on repeated dose toxicity is available with Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2). Therefore, read across from the possible theoretical hydrolysis products 2-ethylhexanol (CAS 104-76-7) and Fatty acids, C18-unsaturated, dimers (CAS 61788-89 -4) was applied.

CAS 104-76-7

A reliable key repeated dose toxicity (90-day) study with 2-ethylhexanol (CAS 104-76-7) is available and was performed equivalent or similar to OECD TG 408 (Astill, 1996). Groups of 10 Fischer 344 rats of each sex were administered the test material at doses of 0, 25, 125, 250, and 500 mg/kg bw/day via oral gavage for 90 days on 5 consecutive days per week. Animals were observed for mortalities and clinical signs at least twice daily or once daily on non-treatment days, and detailed clinical observations were performed daily. Body weights and food consumption were recorded weekly. Haematology parameters such as Hb, Hct, RBC, blood clotting and different leucocyte counts were evaluated on days 29 and 84. Clinical chemistry included aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, glucose, urea, creatinine, albumin, cholesterol, total protein, total bilirubin, Na, K, Ca and Cl and were evaluated on days 29 and 84. No urinalysis as well as neurobehavioural and Ophthalmoscopic examination were performed. One female rat administered with at 250 mg/kg bw/day died during the course of the study. There were no other mortalities or clinical findings differing from controls in rats at any treatment level during the course of the study. A decreased body weight gain in male and female rats at 500 mg/kg was recorded, starting at Week 4 in males and Week 11 in females, amounting to weight losses of 7% in males and 6% in females by Week 13. There were no differences from controls at any treatment level in food consumption in rats. There was a 25% increase in reticulocyte numbers in male and female rats at 500 mg/kg bw/day. Differences in clinical chemistry parameters from controls in treated rats were seen mostly at 84 days. Females at 250 and 500 mg/kg bw/day showed 30 and 36% decreases in serum ALT activities, respectively. Females at 500 mg/kg had a 16% decrease in serum cholesterol concentration and males at 500 mg/kg had 13% decreases in total protein and albumin concentrations. Significant organ weight differences from controls in rats were moderate and limited to the brain, kidneys, liver, stomach, and testes at 250 and 500 mg/kg. Male rat relative brain weights increased by 6% at 500 mg/kg, male kidney weights by 8% at 250 and 16% at 500 mg/kg, male liver weights by 8% at 250 and 29% at 500 mg/kg, male stomach weights by 11% at 500 mg/kg, and testis weights by 5.5% at 500 mg/kg. Female rat kidney weights increased by 5% at 250 and 6% at 500 mg/kg, female liver weights by 8% at 250 and 15% at 500 mg/kg, and female stomach weights by 6% at 250 and 16% at 500 mg/kg. Gross lesions differing from controls in both species were seen at 500 mg/kg only. In rats 2/10 males and 4/10 females exhibited single or multiple slightly elevated foci in the forestomach. There were no other gross findings in either species. Dose-related findings in histopathology were limited to the forestomach and liver at 500 mg/kg. There was a generalized acanthosis of the forestomach mucosa in 1/10 males with ballooning degeneration of the epithelial wall and acanthosis of the forestomach mucosa in 2/10 males and 5/10 females. There was a moderate decrease in hepatic peripheral lobular fatty infiltration in 4/10 males and 2/10 females and adrenal beta-cell hyperplasia in 3/10 female rats. Based on the results of the study a subchronic NOAEL value of 125 mg/kg bw/day was derived for 2-ethylhexanol (CAS 104-76-7) based on pathologic changes in the liver histology and organ weights, increase of reticulocytes and decrease of serum ALAT at higher doses. The molecular weight ratio of 2-ethylhexanol (MW 130.23 g/mol) and Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (MW 677.14 g/mol) is 5.19 (677.14/130.23). Thus, based on this molecular ratio factor the NAEL for Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2) was calculated to be 648 mg/kg bw/day (125 mg/kg bw/d x 5.19).

CAS 61788-89-4

A reliable supporting repeated dose toxicity (90-day) study with Fatty acids, C18-unsaturated, dimers (CAS 61788-89-4) is available and was performed equivalent or similar to OECD TG 408 and in compliance with GLP (Spurgeon and Hepburn, 1993).Three groups of 20 Sprague-Dawley rats of each sex were fed the test material at 0, 0.1, 1 and 5% (w/w) corresponding to 74.1, 740.9, 3591.2 mg/kg bw/day (males) and 90.5, 854.9, 4085.5 mg/kg bw/day (females) in purified diet for 90 consecutive days. The animals were observed for clinical signs up to two times per day. Food and water consumption was determined twice weekly. Body weights were determined weekly. Ophthalmoscopy was carried out before the start of the study and during the last week of the feeding period. Before necropsy, blood samples were taken for clinical pathology determinations. At necropsy, a full range of tissues were taken for histological examination. All tissues from the control and 5% groups were examined. Liver, adrenals, eyes, mesenteric lymph nodes, spleen and thyroids (females) from all groups were also examined. There were no decedents and no treatment-related clinical signs in rats fed the test substance for thirteen weeks. The lower food intake during the first four weeks of the study in rats fed the test material at 5% in diet may reflect an initial reluctance of the rats to eat the diet. Decreases in organ weight and/or relative organ weight of spleen, kidney and liver were observed, mainly after feeding the test material at 1.0% and 5.0%, but bore no relation to any effect which might have been expected on the basis of the histopathology findings. Plasma alkaline phosphatase activity (ALP) was increased in males and females fed the test material at 1.0% or 5.0%. An increase in plasma ALP activity may reflect induction (increased synthesis) in liver cells rather than increased release from damaged cells. Another plasma enzyme derived from the liver in the rat, alanine aminotransferase (ALT) was also increased in male and female rats fed at 5.0%. In addition to increases in plasma ALP level derived from the liver, treatment-related effects were observed on microscopic examination of that organ. Histological examination of liver from animals in the 5.0% treatment group revealed an increase in biliary hyperplasia. Interference in bile flow could be related to the observed increase in ALP, which is a sensitive indicator of cholestasis. Changes in ALP develop before there are any detectable increases in plasma bilirubin levels. It should be noted that while a very small increase in plasma bilirubin was observed in male rats fed the test material at 5.0% or 1.0%, the levels measured were below the sensitivity of the method and must be viewed with caution. Although the bile duct proliferation and sclerosis recorded in the liver may correlate with the increase in ALP, it should be noted only very minor biliary changes were seen in a few female rats. A small reduction in plasma calcium was observed in male and female rats fed the test material at 5.0%. Small reductions in both total serum protein and albumin were also observed in male and female rats in the 5.0% groups. It is possible the calcium and serum protein changes may be connected. However, reduction in plasma calcium was not always accompanied by a parallel reduction in plasma albumin. The changes in plasma calcium and serum proteins are small, probably representing a physiological rather than a pathological response to treatment with the test material. The plasma lipids cholesterol and triglyceride were reduced in male and female rats in the 5.0% and 1.0% treatment groups. It is possible that the test material blocks the absorption of lipid and other nutrients from the gut. Such activity could also explain changes in plasma electrolytes and intermediate metabolites. The reduction in periportal hepatocyte vacuolation seen on histological examination of the liver could correlate with the reduced plasma lipids, indicating some alteration in lipid metabolism, another possible explanation for the plasma lipid, serum protein and calcium changes. The pigment present in the macrophages in the mesenteric lymph nodes and spleen did not stain with Perls' stain for haemosiderin or aldehyde fuchsin for lipofuscin, but did stain with Schmorl's stain for lipofuscin. Lipofuscin is derived from oxidation of unsaturated lipids or lipoproteins. The test material is composed of a mixture of monomers, dimers and trimers of various fatty acids. It is likely that the pigment represents either lipofuscin produced by oxidation of some component of the test material, or that the test material itself stains positively. There was no evidence of any degenerative effect associated with pigmented macrophages. It is probable that they represent a physiological response to dietary administration of lipid materials such as the test material. Accumulations of macrophages in the mesenteric lymph nodes commonly occur as a result of ageing, or following administration of pigmented or lipid substances in the diet. Although the pigment appeared darker in the spleen than in the mesenteric lymph node, this may reflect a difference in density. The pigment was present alongside normal levels of haemosiderin which appeared tinctorially distinct. The coloured nature of the compound is also likely to have been responsible for the alteration in the colour of the caecal contents that was observed at necropsy. Increased cortical vacuolation in the adrenals, coupled with decreased cytoplasmic rarefaction probably indicates altered steroidogenesis. This was not accompanied by any evidence of degenerative change. The significance of the reduced extramedullar haemopoiesis in the adrenals is uncertain, but may possibly correlate with the reduction in neutrophil count in females fed the test material at 5.0% and 1.0%. All of the changes in the adrenal are minor in nature and of limited importance. In summary, based on clinical chemistry parameters and histopathological findings a NOAEL for 1% (w/w) test material in diet can be derived, corresponding to a dose of 741 and 855 mg/kg bw/day for males and females, respectively.The molecular weight ratio of Fatty acids, C18-unsaturated, dimers (MW 564.93 g/mol) and Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (MW 677.14 g/mol) is 1.12 (677.14/564.93). Thus, based on this molecular ratio factor the NAEL for Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters (CAS 68440-06-2) was calculated to be 829.92 and 957.6 mg/kg bw/day for males and females, respectively (741 mg/kg bw/d x 1.12; 855 mg/kg bw/d x 1.12).

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
Hazard assessment is conducted by means of read-across from structural surrogates (hydrolysis products). All available studies are adequate and reliable based on the common hydrolysis products between source and target substances and overall quality assessment.

Justification for classification or non-classification

The available data on repeated dose toxicity of Fatty acids, C18-unsatd., dimers, hydrogenated, 2-ethylhexyl esters do not meet the criteria for classification according to Regulation (EC) 1272/2008 and are therefore conclusive but not sufficient for classification.