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EC number: 500-148-0
CAS number: 61788-89-4
Justification for read-across from fatty acids, tall-oil (CAS
In accordance with the specifications listed in Regulation (EC)
No. 1907/2006 Annex XI, 1.5 Grouping of substances and read across, the
similarity of category members has been shown to be justified based on
the scope of variability and overlapping of composition, representative
molecular structure, physico-chemical properties, tox-, ecotoxicological
profiles and supporting Information by various validated QSAR methods.
This information is given in further detail within the category
justification for the grouping of chemicals and read-across (see IUCLID
Section 13) for the dimerised fatty acids and its derivatives, and once
more within the endpoint summary and discussion for Toxicokinetics.
For assessment of human health hazards of the category members,
trends and similarities in toxicokinetic behaviour are most relevant. In
particular, the molecular weight-dependent decrease in oral and dermal
absorption and common metabolic and pathways, which are explained by
trends in molecular structure and common functional groups (monomers,
dimers and trimers of similar long-chain fatty acids). This justifies
the assumption that the toxicological profile of all category members is
similar and effects or the lack of effects observed in toxicological
studies of one ore more substances can also be expected and explained
for the other substances in the category.
For the endpoint skin sensitisation, within
the chemical categoryDimerised Fatty Acids and its
Derivatives, limited information is
available for fatty acids, C18-unsaturated, trimers (CAS No. 68937-90-6)
and isooctadecanoic acid (CAS No. 30399-89-4). This information is
discussed further below. Additionally, available information on pure
C16-C18 monomeric fatty acids was also taken into account for assessment.
Furthermore, a skin sensitisation study (Guinea Pig Maximisation
Test) with fatty acids, tall-oil(CAS
No. 61790-12-3),is available.
On the basis of Annex XI, Item 1.5, of Regulation (EC) No
1907/2006, whereby human health effects may be predicted from data for a
reference substance, provided that the physicochemical, toxicological
and ecotoxicological properties of the reference and target substances
are likely to be similar as a result of structural similarity,read-across
from the surrogate substance fatty acids, tall-oil (CAS No. 61790-12-3)
is conducted and the aforementioned study is selected as a key study for
assessment of potential skin sensitising effects of the members of the
category Dimerised Fatty Acids and its Derivates.
The similarities between fatty acids,
tall-oil and the category members are based on the following
The Dimerised Fatty Acids and its Derivates
category includes the following members:
61788-89-4 Fatty acids, C18-unsaturated,
68937-90-6 Fatty acids, C18-unsaturated,
68783-41-5 Fatty acids, C18-unsaturated,
dimers, hydrogenated, “Hydrogenated dimer”
71808-39-4 Fatty acids, C16-18 and C18
unsaturated, dimerized, “Crude dimer”
68955-98-6 Fatty acids, C16-18 and
C18-unsaturated, branched and linear, “Monomer acid”
68201-37-6 Octadecanoic acid, branched and
linear, “Hydrogenated monomer acid”
30399-84-9 Isooctadecanoic acid
All the members of this category of
substances are derived from unsaturated fatty acids, for example from
fatty acids, tall-oil, which contains predominantly C18 unsaturated and
saturated fatty acids.
Natural fatty acids, tall-oil has the
Chemical name: Fatty acids, tall-oil
Chemical formula: not available - UVCB
EC No.: 263-107-3
CAS Name: Fatty acids, tall-oil
CAS number: 61790-12-3
logKow: determined range 4.9 – 7.6 (Lightbody
et al., 2002)
Solubility in water (mg/L, at 20 °C): 12.6
(The quoted value represents the sum solubility of all the components of
the test material) (Dinwoodie,
Biodegradation at 28 days: 56-84% (Madsen,
1993; Aniol, 1999; Sewell, 1994)
The HPV report final submission for fatty
acids, tall-oil and related substances; CAS No. 61790-12-3 CAS No.
65997-03-7 CAS No. 68955-98-6 CAS No. 68201-37-6 CAS No. 61790-44-1 CAS
No. 61790-45-2 Submitted to the US EPA August 2004 was screened by the
US EPA and a screening level hazard characterisation report was
published in 2007 (U. S. Environmental Protection Agency, 2007). This
report prepared by the High Production Volume Chemicals Branch indicated
that fatty acids, tall-oil are non-toxic following acute oral exposure
(LD50 (rat) > 10000 mg/kg bw) and following a 90-day test in rats the No
Observed Effect Level (NOEL) was 5% (approximately 2500 mg/kg bw/day).
Fatty acids, tall-oil were negative in an Ames test with 5 S.
typhimurium strains and in an in vitro chromosomal aberration assay with
Chinese Hamster Ovary cells. In a Two-Generation Reproduction Toxicity
study in rats, the NOEL for reproduction and systemic toxicity was 10%
in diet (ca. 5000 mg/kg bw/day). Furthermore, fatty acids, tall-oil were
not acute toxic in fish (96 h NOELr 1000 mg/L), daphnia (48 h NOELr 1000
mg/L) and algae (72 h NOELr 845 mg/L).
Given their chemical nature, fatty acids,
tall-oil are expected to be absorbed, metabolised and excreted following
the same well-known pathways of dietary fatty acids.
In conclusion, the physicochemical,
toxicological and ecotoxicological properties of fatty acids, tall-oil
and the members of the category Dimerised Fatty Acids and its Derivates
are considered to be similar, and similarity is based on common
functional groups (long-chain fatty acids, saturated and unsaturated)
and the likelihood of common breakdown products via the metabolism of
fatty acids. It is therefore considered appropriate that the skin
sensitisation data of fatty acids, tall-oil is used for read-across
purposes to this category.
The selected study fulfils the requirements laid down in Annex XI,
Item 1.5, of Regulation (EC) No 1907/2006 for read-across, i.e. the
results are adequate for the purpose of classification and labelling
and/or risk assessment; have adequate and reliable coverage of the key
parameters addressed in the corresponding test method referred to in
Article 13(3); cover an exposure duration comparable to or longer than
the corresponding test method referred to in Article 13(3); and adequate
and reliable documentation of the applied method is provided.
The skin sensitising potential of fatty
acids, tall-oil (CAS No. 61790-12-3) was studied in a Guinea Pig
Maximisation Test according to OECD Guideline 406 and in compliance with
GLP. The study was performed on 30 Dunkin-Hartley guinea pigs divided
into a negative control group of 10 animals and a test group of 20
animals. The test comprised induction and challenge phases.
Induction was carried out by intradermal
injection of the test material at 6.25% (w/w) in coconut oil and by
closed patch topical application at 25% (w/w) in coconut oil for 48 h
one week apart. The negative control group was treated with coconut oil.
All animals were challenged 3 weeks after the
intradermal induction by closed patch topical application of the test
material at 12.5% (w/w) in coconut oil for 24 h on the left flank. The
skin reactions were evaluated 24 and 48 h after termination of the
No skin reactions were observed 24 and 48 h
after the challenge procedure.
A positive control test was also performed
using undiluted hexyl cinnamic aldehyde for induction and at 12.5% (w/w)
in ethanol/diethylphthalate 1:1 (w/w) for challenge, under experimental
conditions similar to those described above. Evidence of delayed contact
hypersensitivity was seen in 6 out of 10 animals (60%).
Under the experimental conditions described,
it was concluded that no evidence of delayed contact hypersensitivity
reaction was seen after treatment with fatty acids, tall-oil (Bollen,
The skin sensitising potential of fatty
acids, C18-unsaturated, trimers (CAS No. 68937-90-6) was assessed in two
independent Buehler Tests. Both studies involved the treatment of guinea
pigs (20 animals per concentration) using two procedures: the potential
induction of an immune response and a challenge of that response. Three
inductions with the undiluted test substance were performed. Animals
were challenged with the test substance at 0, 50 and 75% w/v in corn
oil. The sensitisation response of the animals was determined 1 and 2
days after challenge, by assessing the degree of erythema.
In one study, all animals treated with the
50% dilution showed no effects, while in 2/20 (10%) animals in the 75%
group mild sensitising effects were observed at both the 24 and 48 h
reading time points. In the other study, the test substance induced no
effects in any animal at any time (Johnson, 2000a, b).
Isooctadecanoic acid (CAS No. 30399-84-9) as
well as palmitic (C16), oleic and stearic (both C18) acids have been
assessed with respect to their safety as cosmetic ingredients, and
tested for skin sensitisation in a number of clinical studies.
Isooctadecanoic acid was neither irritating nor sensitising when applied
at concentrations of 10 and 35% in mineral oil to the skin of 103 and
168 subjects respectively. No evidence of contact sensitisation was
observed in 333 subjects tested in repeated insult patch tests using
product formulations containing 2.5-2.85% isooctadecanoic acid (CIR,
1983). In clinical repeated insult patch tests (occlusive,
semi-occlusive and open), maximisation tests as well as prophetic patch
tests using cosmetic product formulations containing palmitic, stearic
and oleic acids at concentrations between < 1
and 13%, no primary or cumulative irritation or sensitisation was
reported. Less than 5% of the ca. 4000 subjects tested reacted to a few,
isolated induction patches. Slight, if any, reactions were noted after
challenge patching at the original or adjacent applications sites of
some subjects (< 2%). The intensity of the observed reactions was not
directly related to the fatty acid concentrations in the product
formulations (CIR, 1987).
In addition, the skin sensitising potential
of isooctadecanoic acid was estimated by means of QSAR analysis.
Structural alerts were examined by means of the OECD QSAR Application
Toolbox databases. Alternatively, the record of the substance in the
Danish EPA QSAR Database was examined. The model applied for skin
sensitisation was MULTICASE model A33. No structural alerts were
detected in the molecule of the substance, hence the result was
negative. The result of the Multicase model was negative as well. Based
on the absence of relevant structural alerts, and the result recorded in
the QSAR database, the chemical is considered not sensitising.
Taken together, the information available on
structurally related substances indicates that fatty acids,
C18-unsaturated, dimers are unlikely to induce skin sensitisation.
on read-across from a supporting substance (surrogate fatty acids,
tall-oil) and information on further structurally related substances,
the available information on the skin sensitising potential of
fatty acids, C18-unsaturated, dimers is conclusive but not sufficient
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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