Registration Dossier

Administrative data

Description of key information

Based on expert judgment,  there is no evidence that members of the SCAE C2-8 cause carcinogenicity.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

According to Article 13 of Regulation (EC) No. 1907/2006 "General Requirements for Generation of Information on Intrinsic Properties of substances", information on intrinsic properties of substances may be generated by means other than tests e.g. from information from structurally related substances (grouping or read-across), provided that conditions set out in Annex XI are met.

Annex XI, "General rules for adaptation of this standard testing regime set out in Annexes VII to X” states that “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or ‘category’ of substances. This avoids the need to test every substance for every endpoint".

Since the group concept is applied to the members of the SCAE C2 -8 category, data will be generated from representative reference substance(s) within the category to avoid unnecessary animal testing. Additionally, once the group concept is applied, substances will be classified and labeled on this basis.

The available data on carcinogenicity is conclusive but not sufficient for classification.

Additional information

The Short Chain Alcohol Esters (SCAE C2-C8) category covers esters from a fatty acid (C8-C29) and a C2-C8 alcohol (ethanol, isopropanol, butanol, isobutanol, pentanol, iso-pentanol, hexanol, 2-ethylhexanol or octanol). This category includes both well-defined mono-constituent substances as well as related UVCB substances with varying fatty acid chain lengths.

Fatty acid esters are generally produced by chemical reaction of an alcohol (e.g. isopropanol) with an organic acid (e.g. stearic acid) in the presence of an acid catalyst (Radzi et al., 2005). The esterification reaction is started by a transfer of a proton from the acid catalyst to the acid to form an alkyloxonium ion. The carboxylic acid is protonated on its carbonyl oxygen followed by a nucleophilic addition of a molecule of the alcohol to a carbonyl carbon of acid. An intermediate product is formed. This intermediate product loses a water molecule and proton to give an ester (Liu et al, 2006; Lilja et al., 2005; Gubicza et al., 2000; Zhao, 2000). Monoesters are the final product of esterification.  

The rationale for grouping the substances in the SCAE C2-C8 category is based on similarities in physicochemical, ecotoxicological and toxicological properties.

 

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, 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).

 

In this particular case, the similarity of the SCAE C2-C8 category members is justified, in accordance with the specifications listed in Regulation (EC) No. 1907/2006 Annex XI, 1.5

Grouping of substances and read across, based on representative molecular structure, physico-chemical properties, tox-, ecotoxicological profiles, supported by a robust set of experimental data and QSAR calculations. There is no convincing evidence that any one of these chemicals might lie out of the overall profile of this category, respectively.

 

Grouping of substances into this category is based on:

 

• Similar/overlapping structural features or functional groups: All category members are esters of primary alcohols (C2-C8) and fatty acids (C8-C29), with 13 to 32 carbons in total.

• Common precursors and the likelihood of common breakdown products via biological processes: All category members are subject to enzymatic hydrolysis by pancreatic lipases (Mattson and Volpenhein, 1972; and references therein). The resulting free fatty acids and alcohols are absorbed from the intestine into the blood stream. Fatty acids are either metabolised via the beta-oxidation pathway in order to generate energy for the cell or reconstituted into glyceride esters and stored in the fat depots in the body. The alcohols are metabolised primarily in the liver through a series of oxidative steps, finally yielding carbon dioxide (Berg et al., 2002).

• Similar physico-chemical properties: The log Kow and log Koc values of all category members are high (log Kow > 4, log Koc > 3), increasing with the size of the molecule. The substances are poorly soluble in water and have low vapour pressure. 

• Common properties for environmental fate & eco-toxicological: Based on experimental data , all substances are readily biodegradable and do not show toxic effects up to the limit of water solubility.

• Common levels and mode of human health related effects:All available experimental data indicate that the members of the SCAE C2-C18 category are not acutely toxic, are not irritating to the skin or to the eyes and do not have sensitizing properties. Repeated dose toxicity was shown to be low for all substances. None of the substances showed mutagenic effects, and toxicity to reproduction was low throughout the category.

 

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 considered as a category 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 listed below are allocated to the category of SCAE C2-C8.

 

 

Table 1: Members of the SCAE C2-C8 Category:

EC No.

CAS No.

Chemical name

Alcohol Carbon No.

Fatty acid Carbon No.

Total Carbon

MW

208-868-4

544-35-4

ethyl linoleate or ethyl octadeca-9,12-dienoate

2

18

20

308.50

203-889-5

111-62-6

Ethyl oleate

2

18

20

310.52

293-054-1

91051-05-7

Fatty acids, essential, ethyl esters

2

14 - 22

16 - 24

252.39-368.64

233-560-1

10233-13-3

Isopropyl laurate

3

12

15

242.41

203-751-4

110-27-0

Isopropyl Myristate

3

14

17

270.46

205-571-1

142-91-6

Isopropyl palmitate

3

16

19

298.51

269-023-3

68171-33-5

Isopropyl isostearate

3

18

21

326.56

203-935-4

112-11-8

Isopropyl oleate

3

18

21

324.55

292-962-5

91031-58-2

Fatty acids, C16-18, isopropyl esters

3

16 - 18

19 - 21

312.54-326.57

264-119-1

63393-93-1

Fatty acids, lanolin, isopropyl esters

3

10 - 29

13 - 32

214.34-480.85

204-666-5

123-95-5

butyl stearate

4

22

22

340.59

267-028-5

67762-63-4

Fatty acids, tall-oil, butyl esters

4

18

22

423.72

287-039-9

85408-76-0

Fatty acids, C16-18, Bu esters

4

16 - 18

20 - 22

312.53-340.58

284-863-0

84988-74-9

Fatty acids, C16-18 and C18-unsatd., Bu esters

4

16 - 18

20 - 22

312.53- 340.58

 

163961-32-8

Fatty acids, C16-18 and C18 unsatd. branched and linear, butyl esters

4

16 - 18

20 - 22

312.54- 340.58

211-466-1

646-13-9

Isobutyl stearate

4

18

22

340.59

288-668-1

85865-69-6

Fatty acids, C16-18, iso-Bu esters

4

16 - 18

20 - 22

312.54- 340.60

84988-79-4

84988-79-4

Fatty acids, C16-18 and C18-unsatd., iso-Bu esters

4

16 - 18

20 - 22

312.54- 340.60

228-626-1

6309-51-9

Isopentyl laurate

5

12

17

270.46

694-886-1

1365095-43-7

Fatty acids, C8-10, 3-methylbutyl esters

5

8 - 10

13 - 15

214.344- 242.40

251-932-1

34316-64-8

Dodecanoic acid, hexyl ester

6

12

18

284.49

218-980-5

2306-88-9

octyl octanoate

8

8

16

256.42

 

84713-06-4

Dodecanoic acid, isooctyl ester

8

12

20

312.53

243-697-9

20292-08-4

2-Ethylhexyl laurate

8

12

20

312.53

692-946-1

649747-80-8

Fatty acids, C8-10, 2-ethylhexyl esters

8

8 - 10

16 - 18

256.42-284.48

603-931-6

135800-37-2

Fatty acids, C8-16, 2-ethylhexyl esters

8

12 - 14

20 - 22

256.42-368.65

249-862-1

29806-73-3

2-ethylhexyl palmitate

8

16

24

368.64

 

22047-49-0

2-Ethyl hexyl Stearate

8

18

26

396.69

295-366-3

92044-87-6

Fatty acids, coco, 2-ethylhexyl esters

8

12 - 18

20 - 26

312.53-340.60

292-951-5

91031-48-0

Fatty acids, C16-18, 2-ethylhexyl esters

8

16 - 18

24 - 26

368.65-396.70

285-207-6

85049-37-2

Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters

8

16 - 18

24 - 26

368.65-396.70

247-655-0

26399-02-0

2-Ethylhexyl oleate

8

18

26

394.67

 

In order to avoid the need to test every substance for every endpoint, the category concept is applied for the assessment of environmental fate and environmental and human health hazards. Thus where applicable, environmental and human health effects are predicted from adequate and reliable data for source substance(s) within the group by interpolation to the target substances in the group (read-across approach) applying the group concept in accordance with Annex XI, Item 1.5, of Regulation (EC) No 1907/2006. In particular, for each specific endpoint the source substance(s) structurally closest to the target substance is/are chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substance are the basis of read-across.

A detailed justification for the grouping of chemicals and read-across is provided in the technical dossier (see IUCLID Section 13).

For the Short Chain Alcohol Esters (SCAE C2-C8) category are no data available for carcinogenicity.

According to the Reach regulation (1907/2006/EC), a carcinogenicity study may be proposed by the registrant or may be required by the Agency in accordance with Articles 40 or 41 if the substance has a widespread dispersive use or there is evidence of frequent or long-term human exposure, and the substance is classified as mutagen category 3 or there is evidence from repeated dose studies that the substance is able to induce hyperplasia and/or pre-neoplastic lesions.

There is no evidence that members of the SCAE C2 -8 cause carcinogenicity by a direct genotoxic mechanism, as the results of all genotoxicity studies were negative. Furthermore, in repeated dose toxicity studies and developmental studies, no evidence for hyperplasia or preneoplastic lesions was seen.

Thus, the proposal for a carcinogenicity study would be scientifically unjustified.

References:

*Berg, J.M., Tymoczko, J.L. and Stryer, L., 2002, Biochemistry, 5thedition, W.H. Freeman and Company

*Gubicza, L., Kabiri-Badr, A., Keoves, E., Belafi-Bako, K. (2000): Large-scale enzymatic production of natural flavour esters in organic solvent with continuous water removal. Journal of Biotechnology 84(2): 193-196

*Lilja, J. et al. (2005). Esterification of propanoic acid with ethanol, 1-propanol and butanol over a heterogeneous fiber catalyst. Chemical Engineering Journal, 115(1-2): 1-12.

*Liu, Y. et al. (2006). A comparison of the esterification of acetic acid with methanol using heterogeneous versus homogeneous acid catalysis. Journal of Catalysis 242: 278-286.

*Mattson, F.H. and Volpenheim, R.A. (1972): Relative rates of hydrolysis by rat pancreatic lipase of esters of C2-C18 fatty acids with C1-C18 primary n-alcohols,Journal of Lipid Research, 10, 1969

*Radzi, S.M. et al.(2005). High performance enzymatic synthesis of oleyl oleate using immobilised lipase from Candida antartica. Electronic Journal of Biotechnology 8: 292-298.

*Tocher, D.R. (2003):Metabolism and function of lipids and fatty acids in teleost fish,Reviews of Fisheries Science, 11 (2), 197

*Zhao, Z. (2000). Synthesis of butyl propionate using novel aluminophosphate molecular sieve as catalyst. Journal of Molecular Catalysis 154(1-2): 131-135.