Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

In vitro studies covering three key steps of the adverse outcome pathway for skin sensitization as identified by the OECD (OECD Publication No.168; ENV/JM/MONO(2012)10) were performed. These study types have undergone in-house validation using 54 substances (Bauch et al., 2012 Regul Toxicol Pharmacol. 63: 489-504) and methods for keratinocyte activation and dendritic cell activation are in the final stages of validation at ECVAM (http://ihcp.jrc.ec.europa.eu/our_labs/eurl-ecvam/validation-regulatory-acceptance/topical-toxicity/skin-sensitisation). The ECVAM opinion on the direct peptide binding assay has been published on Dec 13, 2013. Based on the results of the in house validation (Bauch et al., 2012 Regul Toxicol Pharmacol. 63: 489-504) the predictive capacity of the evaluation scheme using DPRA (peptide reactivity), LuSens/KeratinoSens™ (keratinocyte activation) and h-CLAT (dendritic cell activation) is comparable to that of the local lymph node assay. When compared to the sensitization potential of the substances in humans, the classification based on an evaluation scheme using results obtained from theDPRA, LuSens and h-CLAT had a sensitivity of 93%, a specificity of 95% and an accuracy of 94%. This publication was also referenced by the OECD in the AOP guidance document. Furthermore, it is also in line with the recently published strategy by ECVAM (EURL ECVAM, JRC79446, doi:10.2788/84214; 2013).

 

In the evaluation scheme used here any two of the three test results determine the overall classification, i.e. any two positive test results drive the prediction of a sensitizer, while any two negative test results drive the prediction of a test substance to be a non-sensitizer (Bauchet al. 2012; Table 1). If two assays (DPRA ,LuSens or KeratinoSens, h-CLAT) yield concordant results, the result of the third assay is not necessarily required to determine the overall outcome of the evaluation scheme.

 

Table 1: Decision matrix for combinations of DPRA,LuSens/KeratinoSensand MUSST/ h-CLAT assays.

DPRA

LuSens/

KeratinoSensTM

MUSST/

h-CLAT

Test battery evaluation

positive

positive

positive

sensitizer

positive

positive

negative

sensitizer

positive

negative

positive

sensitizer

positive

negative

negative

non-sensitizer

negative

positive

positive

sensitizer

negative

positive

negative

non-sensitizer

negative

negative

positive

non-sensitizer

negative

negative

negative

non-sensitizer

Each individual assay was performed under GLP and the cell based assays LuSens and h-CLAT consisted of at least two independent experiments. Positive and negative controls were included in each experiment and confirmed the functionality and validity of the individual assays.

 

The test battery applicability is limited when testing substances insoluble in the commonly used vehicles and highly volatile substances. Substances susceptible to base-catalyzed hydrolysis cannot be evaluated reliably for binding to lysine as the incubation is performed at pH 10.2. Also substances that interfere with the experimental measurements (e.g., co-elution with the peptide in the DPRA-assay) are not or only partially suitable for testing using in vitro methods. The substance under evaluation did not have any of the above mentioned limitations and the outcome of this assay is therefore considered adequate for hazard identification for the endpoint of skin sensitization.

Based on the results obtained in these three assays and applying the evaluation criteria described in the robust study summaries, the test item is not peptide reactive, activates keratinocytes and activates dendritic cells. Applying the evaluation criteria described in table 1 the test material is predicted to be a skin sensitizer.

Migrated from Short description of key information:
Sensitization involves a number of key steps in order to take place, and can be described in terms of an adverse outcome pathway (AOP). These include reactivity with skin proteins (peptide reactivity), activation of skin cells (keratinocyte activation) and immune cells (dendritic cell activation). The studies carried out for this substance address these three key steps. The results are then used in a predefined evaluation scheme to determine hazard classification as a sensitizer by a weight-of-evidence approach.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is considered to be classified for skin sensitization under Directive 67/548/EEC, as amended for the 31sttime in Directive 2009/2/EG.

 

Classification,Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is considered to be classified for skin sensitization under Regulation (EC) No. 1272/2008, as amended for the third time in Directive (EC 618/2012).