Ammonium difluoro[1,1,2,2-tetrafluoro-2-(pentafluoroethoxy)ethoxy]acetate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The skin sensitising properties of EEA-NH4 were determined in a GLP study according OECD guideline 429 (Local Lymph Node Assay (LLNA)) and EU method B.42 (TNO Quality of Life, 2008). For this purpose, three groups of 5 animals each were treated with increasing concentrations of EEA-NH4 (10%, 25% and 50% in vehicle (w/v), respectively) applied on the dorsum of both ears (25 µL per ear) for three consecutive days. Three days after the last treatment, all animals received an intravenous injection of³H‑thymidine. Five hours later, the³H-thymidine incorporation in the draining auricular lymph nodes was determined. The results were compared with those of a control group which was treated with the vehicle (acetone/olive oil, 4:1 v/v). A positive control group treated with Hexyl Cinnamic Aldehyde (a 25% HCA solution in vehicle) was included in the study as a reliability check.

No signs of irritation were observed after application of a 10%, 25% and 50% concentration of EEA-NH4.

³H-thymidine incorporation in the auricular lymph nodes in animals treated with a 10% concentration EEA-NH4 was similar to that in vehicle control animals, whereas³H-thymidineincorporation was statistically significantly enhanced at 25% and 50% concentrations. Stimulation indices (SI’s) of 1.1, 2.2 and 1.9 were calculated in response to a 10%, 25% and 50% EEA-NH4 concentration respectively. Since the SI’s were lower than 3 at all concentrations the results indicted that EEA-NH4 should not be considered a skin sensitiser (a SI of 3 is the limiting value required for classification as a skin sensitiser).

No signs of irritation were observed after three consecutive applications of a 25% concentration of HCAin all animals.³H-thymidine incorporation in the auricular lymph nodes was statistically significantly enhanced in comparison with the vehicle controls. The calculated stimulation index of 4.0 supported this observation and demonstrated the sensitivity of the test system and validity of the model.

Migrated from Short description of key information:
The substance was not a skin sensitiser in a local lymph node assay in the mouse.

Justification for classification or non-classification

Under the experimental conditions of the available LLNA, stimulation indices of 1.1, 2.2 and 1.9 were observed for the³H-thymidine incorporation in the auricular lymph nodes of animals treated with 10, 25 and 50% concentrations of EEA-NH4 (w/v), respectively. Although the two highest concentrations reached statistically significant values compared to the control, the stimulation indices were all below a 3-fold increase in³H-thymidine incorporation, the limiting value required for classification as a skin sensitiser. Therefore EEA-NH4 is considered not to have skin sensitising activity when applied at concentrations up to the highest feasible concentration of 50%.