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Skin sensitisation

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skin sensitisation: in vitro
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
read-across: supporting information

Data source

Reference Type:
study report

Materials and methods

Test guideline
according to guideline
OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method)
GLP compliance:
yes (incl. QA statement)
Type of study:
activation of keratinocytes
Justification for non-LLNA method:
Skin sensitisers have been reported to induce genes that are regulated by the antioxidant response element (ARE). The KeratinoSensTM test is a method for which validation studies have been completed followed by an independent peer review conducted by the European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM). The KeratinoSensTM test method was considered scientifically valid to be used as part of an IATA (Integrated Approach to Testing and Assessment), to support the discrimination between skin sensitisers and non-sensitisers for the purpose of hazard classification and labelling. The method cannot be used on its own, neither to sub-categorise skin sensitisers into subcategories 1A and 1B as defined by the UN GHS, for authorities implementing these two optional subcategories, nor to predict potency for safety assessment decisions. However, depending on the regulatory framework a positive result may be used on its own to classify a chemical into UN GHS category 1.

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Test material form:
Details on test material:
Chemical Name Lauryl betaine
Physical State liquid - The sample was dried under a nitrogen purge to remove water prior to analysis.
CAS # 683-10-3
EU # 211-669-5
Manufacturer Colonial Chemical
Batch/lot # 53715J16
Received on November 22, 2016
Tested on January 31, 2017
Specific details on test material used for the study:
Test Item Name
ColaTeric LAB-70UP; (1-Dodecanaminium, N-(carboxymethyl)-N,N-dimethyl-, inner salt)
Supplier Code:Not provided
Supplier batch/lot number: 55880C17
CAS number: 683-10-3
Purity: 33.7%
Active Expiry Date: 10 Mar 2019 (from Cofa)
Physical sate: Liquid, clear
Storage Conditions: Standard (10-49˚C, closed container)
Solvent: 1% DMSO in cell culture medium Administration method
In cell culture medium
Concentrations tested (μg/ml)
200, 100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0.78, 0.39, 0.20, 0.10

Results and discussion

In vitro / in chemico

Key result
other: EC1.5 value
Luciferase measurements and MTT viability testing were performed. The sensitisation potential of ColaTeric LAB-70UP; was quantified by calculating 2 parameters known as the EC1.5 and the IMAX value.
Vehicle controls validity:
Negative controls validity:
Positive controls validity:
Remarks on result:
positive indication of skin sensitisation

Any other information on results incl. tables

The human skin sensitisation potential of ColaTeric LAB-70UP; (Lauryl betaine (C12)) was assessed using validated in vitro method: the KeratinoSensTM test to determine keratinocyte activation. The method was adapted to animal product-free conditions by XCELLR8 and reference chemicals described in the guideline and in the performance standards were used to confirm the reliability, accuracy, sensitivity and specificity values. The adapted method showed full concordance with the Validated Reference Method (VRM) – the KeratinoSensTM standard protocol. Clarification from the European Chemicals Agency (ECHA) says that data using the adapted method may be used in REACH submissions, provided that the Performance Standards data, demonstrating equivalence with the VRM, is included in the dossier.

In this study, ColaTeric LAB-70UP; (Lauryl betaine (C12) was classified as a sensitiser to human skin.

The sensitisation potential of was quantified by calculating 2 parameters known as the EC1.5 and the IMAX value.

Lauryl betaine caused luciferase induction >1.5 in all 3 repetitions. The respective EC1.5 value were calculated as 31.72μg/ml for repetition 1; 61.87 μg/ml for repetition 2 and 9.09μg/ml for repetition 3. Therefore, ColaTeric LAB-70UP; (Lauryl betaine (C12)) was classified as a sensitiser.

Applicant's summary and conclusion

Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Cetyl betaine is essentially the same molecule as lauryl betaine but with an extra C4 in the alkyl chain so it is likely that the toxicology of the two species will be very similar. Hence, it is assessed that the skin sensitisation response for cetyl would be similar to lauryl.