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EC number: 205-582-1
CAS number: 143-07-7
Irritation / corrosion:- skin: not irritating (OECD 404)- eyes: irreversible effects (OECD 405)
Skin irritation was analyzed in a study performed under GLP
according to OECD guideline 404, where 3 New Zealand White rabbits
received an application of 0.5 g lauric acid to the shaved skin for 4
hours under semi-occlusive conditions (Daamen, 1989). The resulting mean
scores for erythema and edema after 24 to 72 hours were 0.4 and 0,
respectively. Thus, lauric acid was found to be not irritating to the
In another study performed in accordance with OECD guideline 404,
4 “Kleinrussen” rabbits received an application of 0.5 g lauric acid to
the shaved skin for 4 hours under occlusive conditions (Kästner, 1988).
The resulting mean scores for erythema and edema after 24 to 72 hours
were 3.1 and 2, respectively. The observed erythema and edema
disappeared within 10 days, while scaling was observed until day 17
after the application. Based on the result, the study found lauric acid
to be irritating to skin. However, since lauric acid was applied under
occlusive condition, the result could not be taken into account for
In addition to the in vivo studies, an in vitro skin corrosivity
test with lauric acid is available, which was conducted under GLP
according to a method described by Oliver, Pemberton & Rhodes (1986 &
1988). Freshly clipped skin of Wistar rats was sealed to tubes and
suspended to physiological solution (Whittle, 1994). 150 µL of lauric
acid was the applied to the epidermal surface for 24 hours. After the
exposure the test substance was removed and any deterioration in the
skin was assessed by measuring the transcutaneous electrical resistance.
As a result, a mean resistance of 154 +/- 1.6 kOhm/skin disc was
measured indicating that lauric acid did not display properties
characteristic of those substances which may be corrosive to animal skin
In addition to studies with animals two studies with human
volunteers were available for assessment (Matthies, 1988). In the first
study, 10µL lauric acid at concentration of 50 % was applied to the back
of 20 subjects for 24 hours using a Large Finn Chamber on Scanpor
(Herma). The reactions were evaluated 1, 6, 24, 48, 72 and 14 hours
later. Although erythema, edema and scaling were reported, no single
score of these reactions were provided. In the second study with
volunteers, lauric acid at 80% was applied to the forearm of 10
volunteers, which was repeated every 30 seconds for 30 minutes
(Matthies, 1988). The reactions were scored 1 and 24 hours after the
last application until disappearance of the symptoms. As result, 3/10
subjects showed erythema with the lowest score after 30 min, which
disappeared after 30-35 min. The other subjects did not show any
Together the results of the human studies show, that lauric acid
can act as an irritant to skin when applied under occlusive condition.
However, under open conditions, no clear irritating properties were
demonstrated. In conclusion, lauric acid can be regarded as not
irritating to skin taking into account the data of studies with human
and animal data obtained in tests performed according to OECD guidelines.
Eye irritation was evaluated in a study performed under GLP
according to OECD guideline 405, where 52.45 +/- 0.45 mg of lauric acid
was instilled into the eyes of 3 New Zealand White rabbits (Daamen,
1989). The result mean scores for corneal opacity, iris, and
conjunctival erythema and chemosis after 24 – 72 h were 0.9, 0.8, 2.9
and 1.6, respectively. While the effect on the iris and the edema
disappeared within 7 and 21 days, respectively, corneal opacity and
erythema were still present at the end of the 21 day observation period.
In addition, neovacularisation starting from day 7 until day 21 was
found. Thus, lauric acid was found to cause serious damage to eyes.
The same result was found in another study conducted according to
OECD guideline 405, where only one “Kleinrussen” rabbit was used
(Kästner, 1988). As a result of the instillation of lauric acid, the
mean scores for corneal opacity, iris, and conjunctival erythema and
chemosis after 24 – 72 h were found to be 1, 0.3, 0.7, and 1,
respectively. However, corneal opacity was still present at the end of
the 21 day observation period indicating the irritating properties of
Lauric acid was found to be irritating to eyes in the study
perfomed according to national guidelines since corneal opacity and
moderate conjunctivitis were noted which did not subside within 72 hours
In addition, a study with the analogue fatty acids C12-14 is used
for the hazard assessment, since lauric acid is a main constituent of
fatty acids C12-14 and both substances belong to the same category due
to similar structural and toxicological properties. Thus, a read-across
is performed based on a category approach (for details refer to IUCLID
Fatty acids C12-14 containing 70% lauric acid was found to be not
irritating to eyes, when it was tested in a study performed according to
GLP and OECD guideline 405 where 0.1 g was instilled into the eyes of
three New Zealand White rabbits (Stelter, 2010). While neither mortality
nor significant clinical signs of toxicity were observed until 21 days
after the test item application, the resulting mean scores (24 – 48 – 72
hours) for corneal opacity, iris, conjunctival erythema and chemosis
were 0, 0, 0.78, and 0.67, respectively. Thus, lauric acid at a
concentration of 70% was not found to be irritation to eyes.
According to DSD (67/548/EEC) or CLP (1272/2008/EC) classification
criteria for irritation/corrosion, lauric acid has to be classified as
irritant to eye (R41; Eye Cat. 1) at concentration higher than and
including 70%. Thus, SCL of 70% for R41 and eye damage Cat.1 is assigned
to this substance.
No classification for skin irritation is required since the
criteria for classification is not fullfiled and thus a
non-classification is warranted.
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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