Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

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Endpoint:
skin sensitisation: in vitro
Data waiving:
study technically not feasible
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
2-BTP is highly volatile at room temperature and boils slightly below body temperature (e.g. 37°C, c.f. 2-BTP boiling temperature = 34.4°C; refer to dossier section 4.3 for details). Of the three key events in skin sensitisation described by REACH Annex VII Section 8.3.1, two of these events (specifically 8.3.1(b) inflammatory response in keratinocytes and 8.3.1(c) activation of dendritic cells) would be expected to be assessed by in-vitro studies:
EC test method B.60 (also OECD Test Guideline 442D), analysed by the KeratinoSens method involves a 48-hour incubation at 37°C; as the entire incubation step would take place above the boiling temperature of the test material it is highly likely that the test material would predominantly evaporate or otherwise volatilise out of solution and as such the study is not technically feasible.
Analysis of Activation of Dendritic cells as described in OECD Test Guideline 442E similarly describes a number of in-vitro tests, all of which involve incubation of the test substance at 37°C; for the reason described above these tests would similarly not be technically feasible.

It is noted that the in-chemico assessment of Molecular Interaction with Proteins (EC method B.59) is conducted typically at room temperature (c.a. 21°C) and it may be technically possible to conduct this study on 2-BTP. On the basis that at least two out of the three key events listed under Annex VII Section 8.3.1 must be assessed to be positive before a conclusion about Skin Sensitisation may be drawn, this assessment would not provide sufficient information in isolation from the other assessment of key events, and is therefore considered not to be scientifically justified.

According to REACH Annex XI Section 2, in-vitro testing for Skin Sensitisation is waived on the basis that testing is not technically possible.
Endpoint:
skin sensitisation: in vivo (LLNA)
Data waiving:
study technically not feasible
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
2-Bromo-3,3,3-trifluoropropene is highly volatile and boils just below body temperature (recorded boiling point = 34.4°C; refer to dossier section 4.3); it was considered that it would not be possible to maintain a sufficient amount of the test material in contact with the test animals' skin for long enough to ensure that an adequate measure of the sensitisation potential of the substance could be determined. On this basis the study was considered not technically feasible. Note that this experimental concern applies to both the LLNA and to Guinea Pig tests.

According to REACH Annex XI Section 2, in-vivo testing for skin sensitisation for 2-BTP is waived on the basis that testing is not technically possible.
Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

2-BTP has a high vapour pressure and a boiling temperature below 37°C (experimental value = 34.4°C, refer to dossier section 4.3). With respect to in-vitro testing as described in REACH Annex VII Section 8.3.1, two of the three key events leading to skin sensitisation are assessed by in-vitro tests conducted at 37°C: under the test conditions the test material would either be gas / vapour, or would evaporate rapidly; as such contact between the test material and the test system could not be ensured throughout the exposure period required by the studies. On this basis testing is not technically feasible.

It is noted that one of the key events leading to skin sensitisation named in REACH Annex VII Section 8.3.1 (specifically molecular interaction with proteins) may be assessed by an in-chemico study involving incubation at ambient temperature (c.a. 21°C) and it would theoretically be possible to conduct this assessment; however a comprehensive assessment of skin sensitisation potential requires at least two (and possibly three) of the key events to be assessed, therefore it would not be possible to make a conclusive assessment of the classification for skin sensitisation based on this result alone. On this basis the in-chemico assessment of molecular interaction with proteins is not scientifically justified.

With respect to in-vivo testing, both the murine Local Lymph Node Assay (LLNA) and earlier guinea pig tests require application of the test material to skin. As noted above the test material would be expected to evaporate rapidly upon application to skin and therefore satisfactory contact between the test material and the test subjects' skin for the required exposure duration could not be guaranteed. On this basis the assessment of skin sensitisation potential by available in-vivo methods is not technically possible.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

No relevant data are available regarding skin sensitisation. In practice it is considered unlikely that significant dermal contact will occur.