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EC number: 212-110-8
CAS number: 763-32-6
LLNA: Not sensitising, (mouse, GLP study according to OECD 429,
- No deaths occurred during the study
- No symptoms of local irritation at the
ears of the animals and no signs of systemic toxicity were observed
during the study period.
- The body weight of the animals, recorded prior
to the first application and prior to treatment with ³HTdR,
was within the range commonly recorded for animals of this strain and
- A relevant increase in ear weights was not
- A statistically significant increase in
lymph node weights was observed in the groups treated with 50 and 100%
test item concentration in comparison to the vehicle control group
Table of Lymph Node
Lymph Node Weights after Necropsy
Lymph Node Weight (mg per animal)
Mean Lymph Node Weight (mg per animal)
statistically significant increase vs. control group (p=0.027)
Skin sensitization potential of the main constituent
3-methylbut-3 -en-1-ol (CAS 763-32-6).
In the key study for skin sensitization according to OECD 429 and
GLP, i.e. a Local Lymph Node Assay according to OECD 429 and GLP, 3
-methylbut-3 -en-1 -ol was assessed for its possible contact allergenic
potential (Harlan CCR 2010). 3 -methylbut-3 -en-1 –ol was dissolved in
acetone:olive oil (4+1) and female mice were treated with the test item
concentrations of 25, 50, and 100%. The animals did not show any signs
of systemic toxicity or local irritation during the course of the study
and no cases of mortality were observed. Stimulation Indices (S.I.) of
1.48, 1.67, and 2.28 were determined with the test item at
concentrations of 25, 50, and 100% in acetone:olive oil (4+1),
respectively. A relevant increase in ear weights was not observed. A
statistically significant increase in lymph node weights was observed in
the groups treated with 50 and 100% test item concentration in
comparison to the vehicle control group (p=0.027). However, none of the
S.I.s determined for these concentrations exceeded the threshold of 3.
Skin sensitization potential of the impurity formaldehyde (CAS
The impurity formaldehyde is found to be present at concentrations
up to 0.999% in the substance to be registered (3-methylbut-3 -en-1-ol
There is sufficient evidence for skin sensitizing properties of
formaldehyde in guinea pig maximization tests (GPMT), in a Buehler test
in guinea pigs and in mouse local lymph node assays (LLNA). Furthermore,
formaldehyde is also identified as a dermal allergen in humans.
Accordingly, formaldehyde is listed Annex VI to the CLP Regulation with
the harmonized classification as a skin sensitizer Cat.1. Various skin
sensitization data in the GPMT (see. e.g. Kimber 1991), Bühler test (see
e.g. Hilton 1996), or LLNA (see e.g Hilton 1998) provide evidence of a
strong skin sensitizing potential of formaldehyde. Quantitative
estimates such as the EC3 values of the LLNA ranged between 0.33% and
According to current knowledge and application of the criteria
given in Annex I of Regulation (EC) No. 1272/2008, the classification
Skin Sens 1A, exceeding the classification given in Regulation (EC) No.
1272/2008, Annex VI, Table 3.1 is required.
- Kimber et. al. 1991. The murine local lymph node assay: results
of an inter-laboratory trial. Toxicol Lett 55: 203-213.
- Hilton et. al. 1996. Experimental assessment of the sensitizing
properties of formaldehyde. Fd Chem Toxicol 34: 571-578.
- Hilton et. al. 1998. Estimation of relative skin sensitizing
potency using the local lymph node assay: a comparison of formaldehyde
with glutaraldehyde. Am J Contact Dermat 9(1):29-33.
Overall, the skins sensitization data for the impurity
formaldehyde trigger a classification for the registered substance
(3-methylbut-3-en-1-ol or Isoprenol) as a skin sensitizer Cat 1 (H317:
May cause an allergic skin reaction).
In contrast, Isoprenol, was not a skin sensitiser under the test
conditions of the performed Local Lymph Node Assay. Accordingly, the
alternative grade is not to be classified as a skin sensitizer Cat.1,
due to its intrinsic properties and the absence of relevant levels of
the impurity formaldehyde.
No data available, however, no clear
substance related effects were seen in the acute inhalation toxicity
The present data on dermal sensitization for the main
constituent 3-methylbut-3 -en-1-ol (Isoprenol) do not fulfill the
criteria laid down in 1272/2008/EEC, and therefore, a
non-classification is warranted. However, the skin sensitization data
for the impurity formaldehyde (up to 0.999%) trigger a classification
for the registered substance as a skin sensitizer Cat 1 (H317: May
cause an allergic skin reaction).
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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