Registration Dossier

Administrative data

Description of key information

Under the conditions of the key study, the test material was considered a skin sensitizer. However it was not possible to determine sub-categorisation based on this protocol and regime, and lack of dose response. However two structurally similar substances have been adequately tested in vivo (LLNA and GPMT) and both showed no responses sufficient for classification in any category. Therefore having considered these results and chemistry similarities, and also having some QSAR analysis completed for the skin sensitisation potential, it was concluded that the notification substance could be classified as Category 1B. Full details of the rationale and data are provided in the CSR, in the additional information section below, and also attached report.

Key value for chemical safety assessment

Skin sensitisation

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

The result of the Buehler study on EC#264-637-8 was that the substance is a possible sensitiser and using the ECHA guidance for CLP it may be concluded that Category 1B is the appropriate classification for this substance, however as stated Category 1A cannot be ruled out. In addition, there are some quality issues with the study as conducted which introduced doubt as to the potency, however even allowing for the issues, it was considered that the substance was likely to be a positive and that this result was credible, and that repeating the test would be contrary to animal welfare considerations. Thus a Category 1 was agreed.

Two analogue substances have also been tested in vivo, one producing only a very weak response in guinea pigs which did not warrant any classification, the other producing a negative result in an LLNA test where none of the test concentrations were above the threshold for classification (although tested at lower concentration). Therefore, with two structurally similar UVCBs producing negative classification results in animal studies, we would not expect the notification substance to have a high potency, indeed it might be reasonable to suggest a negative classification for the notification substance, despite its apparent positive in the Buehler (when taking into account all of the study issues). However, given the uncertainty the study issues introduced and also the additional nitrogen functional groups in the notification substance which may be active for this endpoint, it is considered appropriate and precautionary to adopt a Category 1B classification for skin sensitisation for EC#264-637-8.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does require classification with respect to skin sensitization. However it can be classified as Category 1B based on the in vivo data for the substance itself plus read-across to two other structurally similar substances and some QSAR evaluations. please see attached rationale document.