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EC number: 250-342-1 | CAS number: 30798-32-4
The test substance was not considered to be sensitizing to the skin in an OECD 442C study and an OECD 442D study. Based on the current data-set, there are no indications that the test substance has skin sensitising properties. Therefore it is concluded that it is scientifically not necessary to conduct further testing for skin sensitizing properties and that the test substance is not classified for this endpoint.
Skin sensitisation in vitro
In a GLP compliant study according to OECD 442D the ability of the test substance to activate the antioxidant/electrophile responsive element (ARE)-dependent pathway in the KeratinoSens assay was evaluated. Batch 207459-01 of the test item was a clear yellow liquid. A correction factor of 1.49 was used to correct for the purity. The test item was dissolved in dimethyl sulfoxide at 200 mM. From this stock 11 spike solutions in DMSO were prepared. The stock and spike solutions were diluted 100-fold in the assay resulting in test concentrations of 0.977 – 2000 µM (2-fold dilution series). Two independent experiments were performed. Both experiments passed the acceptance criteria: 1) The luciferase activity induction obtained with the positive control, Ethylene dimethacrylate glycol, was above the threshold of 1.5-fold in at least one concentration. 2) The EC1.5 of the positive control was between 5 and 125 μM (58.1 μM and 80.3 μM in experiment 1 and 2, respectively). A dose response was observed and the induction at 250 μM was higher than 2-fold (3.71-fold and 2.50-fold in experiment 1 and 2, respectively). 3) Finally, the average coefficient of variation of the luminescence reading for the negative (solvent) control DMSO was below 20% (12.8% and 12.9% in experiment 1 and 2, respectively). The average coefficient of variation of the luminescence reading for the negative (solvent) control DMEM was also below 20% (10.9% and 8.5% in experiment 1 and 2, respectively). Overall it is concluded that the test conditions were adequate and that the test system functioned properly. The test item showed no toxicity (no IC30 and IC50 value) and no biologically relevant induction of the luciferase activity (no EC1.5 value) was measured at any of the test concentrations in both experiments. The maximum luciferase activity induction (Imax) was 1.41-fold and 1.29-fold in experiment 1 and 2 respectively. The test item is classified as negative in the KeratinoSensTM assay since negative results (<1.5-fold induction) were observed at test concentrations of ≥1000 µM with a cell viability of >70% compared to the vehicle control.
Skin sensitisation in chemico
The reactivity of the test substance towards model synthetic peptides containing either cysteine (SPCC) or lysine (SPCL) was determined in a GLP compliant in chemico study according to OECD 442C. After incubation of the test substance with either SPCC or SPCL, the relative peptide concentration was determined by High-Performance Liquid Chromatography (HPLC) with gradient elution and photodiode array (PDA) detection at 220 nm and 258 nm. SPCC and SPCL Percent Depletion Values were calculated and used in a prediction model which allows assigning the test chemical to one of four reactivity classes used to support the discrimination between sensitizers and non-sensitizers. MQ/ACN (1:1, v/v) was found to be an appropriate solvent to dissolve the test substance and was therefore used in this Direct Peptide Reactivity Assay (DPRA) study. The validation parameters, i.e. calibration curve, mean concentration of Reference Control, the Coefficient of Variation for Reference Control samples, the mean percent peptide depletion values for the positive control with its standard deviation value and the standard deviation value of the peptide depletion for the test substance, were all within the acceptability criteria for the DPRA. No co-elution of the test item with SPPC or SPCL was observed. In the cysteine reactivity assay the test item showed 0.4% SPCC depletion while in the lysine reactivity assay test item showed 0.0% SPCL depletion. The mean of the SPCC and SPCL depletion was 0.2%. As a result the test substance was negative in the DPRA and classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model. In conclusion, since all acceptability criteria were met this DPRA is considered to be valid. The test substance was negative in the DPRA and was classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.
A Weight of Evidence evaluation was prepared to reach an overall conclusion on the endpoint skin sensitization based on all available relevant information (see attached document for the comprehensive Weight of Evidence evaluation).
A DPRA assay and KeratinoSensTM assay were performed in accordance with the strategy presented in ECHA Guidance on information requirements and chemical safety assessment Chapter R.7a. The test substance was negative in the DPRA and classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model. Furthermore, the test substance gave a negative result in the KeratinoSensTM assay (no activation of the antioxidant/electrophile responsive element (ARE)-dependent pathway in keratinocytes).
Based on the current data-set there are no indications that the test substance has skin sensitizing properties. Therefore it is concluded that it is scientifically not necessary to conduct further testing for skin sensitizing properties and that the test substance is not classified for this endpoint.
Based on the available information classification for skin sensitisation is not warranted in accordance with EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008.
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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