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:

The Local Lymph Node Assay (LLNA) was conducted to assess the potential of6,6'-[[3,3',5,5'-tetrakis(1,1-dimethylethyl)-[1,1'- biphenyl]-2,2'-diyl] bis(oxy)]bis-dibenzo[d,f][1,3,2]-dioxaphosphepinto cause contact sensitization by measuring lymphocyte proliferative responses from auricular lymph nodes following topical application of the test material to the mouse ear.

Screening Study: Three daily topical applications of 1%, 5%, 10%, or 25% of the test material were given to one animal at each dose level. Erythema was absent and body weights were unaffected in all dose groups. Results from this study were used to determine the dosing concentrations for the test material in the LLNA. LLNA: Six female mice/group received 1%, 5%, or 25% of the test material or vehicle (dimethylformamide; (DMF)) or 30% α-hexylcinnamaldehyde (HCA; positive control) on days 1-3. On day 6, uptake of 3Hthymidine into the auricular lymph nodes draining the site of chemical application was measured five hours post administration. Proper conduct of the LLNA was confirmed via a positive response using 30% α- hexylcinnamaldehyde (HCA), a moderate contact sensitizer, which elicited proliferation that was 11.4 times greater than vehicle-treated mice. Erythema was absent and body weights were unaffected in all dose groups. Mice treated with 1%, 5% and 25% of the test material elicited proliferative responses with stimulation indices (SI) that were respectively 1.4, 1.0, and 3.1 in comparison to vehicle-treated mice. The concentration that would cause a 3-fold increase in proliferation (EC3) was calculated to be 24.1% which is consistent with weak dermal sensitization potential as described by an expert ECETOC panel (Technical Report No. 87, 2003).

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

6,6'-[[3,3',5,5'-tetrakis(1,1-dimethylethyl)-[1,1'- biphenyl]-2,2'-diyl] bis(oxy)]bis-dibenzo[d,f][1,3,2]-dioxaphosphepin has an estimated EC3 of 24.1%, which is consistent with weak dermal sensitization potential, and is classified as a Skin sensitiser 1B.