Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

Toxicokinetics:

A registration dossier shall contain information on the human health hazard assessment (regulation 1907/2006, Art.10). However, it is considered that the information requirements for tall oil as laid down in annex VII to IX can be fulfilled by adaptation of the standard testing regime according to Annex XI, points 1.2. and 1.3. as presented in the following:

According to Regulation (EC) No 1907/2006 Annex V substances obtained from natural sources and not modified such as vegetable fats and oils as well as fatty acids from C6 to C24 and their potassium, sodium, calcium and magnesium salts are excluded from the obligation to register.

The substance subjected to registration is a mixture of different saturated and unsaturated C16 -C18 fatty acids. Based on this, the following endpoint is covered by publicly available data on fatty acids with the same or similar structure.

According to the HERA document on fatty acid salts (2002)“fatty acids are an endogenous part of every living cell and are an essential dietary requirement. They are absorbed, digested, and transported in animals and humans. Proposed mechanisms for fatty acid uptake by different tissues range from passive diffusion to facilitated diffusion or a combination of both (Abumrad et al. 1984; Harris et al., 1980). Radioactivity from labelled fatty acids administered orally, intravenously, intraperitoneally, and intraduodenally has been found in various tissues and in blood and lymph (CIR, 1987)” (HERA, 2002).

“Fatty acids taken up by the tissues can either be stored in the form of triglycerides (98 % of which occurs in adipose tissue depots) or they can be oxidised for energy via the β-oxidation and tricarboxylic acid cycle pathways of catabolism (Masoro, 1977). The β-oxidation of fatty acids occurs in most vertebrate tissues utilising an enzyme complex for the series of oxidation and hydration reactions resulting in the cleavage of acetate groups as acetyl CoA. β-oxidation essentially reduces the alkyl chain length by 2 carbon atoms with the release of acetic acid. This leaves another carboxyl group on the shortened alkyl chain for subsequent further β-oxidation. An additional isomerisation reaction is required for the complete catabolism of oleic acid. Alternate oxidation pathways can be found in the liver (ω-oxidation) and the brain (α-oxidation) (CIR, 1987).

Long chain, saturated fatty acids are less readily absorbed than unsaturated or short chain acids. Stearic acid is the most poorly absorbed of the common fatty acids (Clayton & Clayton, 1982; Opdyke, 1979). Several investigators have also found increasing fatty acid chain length slightly decreased their digestibility (CIR, 1987).

Howes (1975) examined the turnover of [14C] surfactants in the rat and found that at 6h after administration, the C10 and C12 soaps were readily metabolised and the main route of excretion was as14CO2. The C14 soap was readily incorporated into the body and the14C excretion was slow. The C16 and C18 soaps showed some metabolism with subsequent14CO2excretion but most of the14C was recovered in the carcass at 6 hours” (HERA; 2002).

“Pinto Correia et al. (1963) studied the absorption of oleic acid in 15 healthy human volunteers. The test subjects received a test meal containing 30 µCi139I-C1-labelled oleic acid suspended in an emulsion of 90 mL milk and 10 mL olive oil, followed by 150 mL milk. Blood samples were collected 1, 2, 4, 6, 12 and 24 h after ingestion and stools for up to 120 h. Radioactivity in blood samples reached a maximal mean value of 2.8% of applied activity per litre of blood 4 h after treatment. Data on radioactivity excreted via faeces indicated that 3.1% (range: 0.03–8.6%) of applied radioactivity was detected in the faeces” (EFSA NDA Panel, 2017).

Overall, it is concluded by the EFSA NDA Panel that “caprylic-, capric-, oleic-, lauric-, palmitic-, myristic- or stearic acid like other fatty acids were readily and extensively absorbed from the gastrointestinal tract. After absorption, fatty acids were either metabolised or incorporated into chylomicrons, which enter the systemic circulation. Ultimately, fatty acids, either incorporated into glycerides and phospholipids, were catabolised via the β-oxidation pathway and the tricarboxylic acid cycle to carbon dioxide which is finally excreted via exhalation” (EFSA NDA Panel, 2017).

Dermal penetration:

It has been shown that the greatest skin penetration of the human epidermis was with C10 and C12 soaps and the rate of percutaneous absorption of sodium laurate is greater than that of most other anionic surfactants. (Prottey and Ferguson, 1975; Madsen et al., 2001; Howes, 1975).

Howes (1975) studied the percutaneous absorption of some anionic surfactants and showed that sodium decanoate was reportedly poorly absorbed through the skin of rats when in uncovered contact for 15 minutes. Penetration through excised human skin proceeded at a rate similar to that for excised rat skin for up to 6 hours; thereafter absorption through human skin was slightly quicker. Also, for the three soaps which penetrated the skin (C10, C12 and C14) there was a lag time of 1 hour before any measurable penetration occurred, but after this the rate of penetration steadily increased. Howes also calculated from human epidermal studies in vitro that only small amounts of the C10, C12 and C14 soaps would be likely to penetrate the skin from a 15 minute wash and rinse in vivo. The low penetration rates of the C16 and C18 soaps suggests that little or none of these would penetrate from a 15 minute wash and rinse in vivo.

 

References

Abumrad, N.A., Park, J.H. and Park, C.R. (1984) Permeation of long-chain fatty acids into adipocytes. Kinetics, specificity and evidence for involvement off a membrane protein. J. Biol. Chem. 259(14): 8945-8953.

CIR (1987) Final report of the safety assessment for oleic acid, lauric acid, palmitic acid, myristic acid, stearic acid. Prepared by the Expert Panel of the Cosmetic Ingredient Review, Washington D.C.

Clayton, G.D. and Clayton, F.E. (1982) Patty’s Industrial Hygiene and Toxicology. Volume 2C: Toxicology. 3rd Revised Edition. John Wiley & Sons: New York.

EFSA ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food), Mortensen A, Aguilar F, Crebelli R, Di Domenico A, Dusemund B, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Leblanc J-C, Lindtner O, Moldeus P, Mosesso P, Parent-Massin D, Oskarsson A, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Wright M, Younes M, Boon P, Chrysafidis D, G€urtler R, Tobback P, Gergelova P, Rincon AM and Lambre C, 2017. Scientific Opinion on the re-evaluation of fatty acids (E 570) as a food additive. EFSA Journal 2017;15(5):4785, 48 pp.

Harris, P., Gloster, J.A. and Ward, B.J. (1980) Transport of fatty acids in the heart. Arch. Mal. Coeur 73(6): 595-598.

Howes, D. (1975) The percutaneous absorption of some anionic surfactants. J. Soc. Cosmet. Chem. 26: 47-63.

Human & Environmental Risk Assessment (HERA) on ingredients of European household cleaning products- Fatty Acid Salts, Draft for Public Comment, June 2002

Madsen, T., Buchardt Boyd, H., Nylén, D., Rathmann Pedersen, A., Petersen, G.I., and Simonsen, F. (2001) Environmental and Health Assessment of Substances in Household Detergents and Cosmetic Detergent Products. Environment Project No. 615, MiljØprojekt, MiljØstyrelsen.

Opdyke, D.L. (Editor) (1979) Monographs on fragrance raw materials. Stearic acid. Food Cosmet. Toxicol. 117(4): 383-8.

Pinto Correia J, Sousa Coelho C, Godinho F, Barros F and Mendes Magalhaes M, 1963. Use of labelled triolein and oleic acid in the study of intestinal absorption. American Journal of Digestive Diseases, 8, 649–665.

Prottey, C. and Ferguson, T. (1975) Factors which determine the skin irritation potential of soaps and detergents.J Soc Cosmet Chem.26: 29-46.

Masoro, E.J. (1977) Lipids and lipid metabolism. Ann. Rev. Physiol. 39: 301-321.