Acetic acid, 2-cyano-2-[3-[(3-methoxypropyl)amino]-2-cyclohexen-1-ylidene]-, 2-ethoxyethyl ester, (2Z)-

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In the chosen key study acc. to OECD TG 442B and GLP, the skin sensitising potential of 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) in female CBA/J mice was evaluated using the non-radioactive local lymph node assay (Ina Research Inc. (2012), 58V0473111X188), which assess BrdU incorporation as a measure of lymphocyte proliferation. In a screening test, test item formulations in DMF at concentrations of 10, 25 or 50 % (w/v) were administered once per day to both ear auricles (25 µL/ear) of each 2 mice/group on days 1-3. The animals were then observed for a further 3-day period (days 4-6). No clinical signs and no appreciable changes in body weights or auricular thickness were noted. In the main test the test item was accordingly applied at concentrations of 10, 25 and 50 % (w/v, dissolved in DMF) to 5 female mice/concentration. Concurrent vehicle (DMF) and positive control items (25 % (v/v) α‑Hexyl cinnamic aldehyde (HCA) in DMF) were applied in the same manner. On day 5, Bromodeoxyuridine (BrdU) was administered intraperitoneally (i.p.) to all animals at a dose level of 5 mg/animal. Clinical signs and body weights were determined. Ears were observed and scored for erythema and/or edema and ear punch biopsies were conducted for weight determination (assessment of irritation). Then the auricular lymph nodes were excised for lymph node weight determination and for subsequent assessment of BrdU incorporation by means of flow cytometry.

No clinical signs, including skin irritation at the application area, were observed in any animal in the test item-treated or vehicle control group. No appreciable body weight changes were observed. Very slight erythema was observed in the ear auricles in the positive control (PC) group at approximately 1 hour after application on days 2 and 3 only. An increased mean ear weight was present in the PC group only, as compared to the negative control (NC) group.

No relevant increases were observed in the mean auricular lymph node weights in the test item treated groups, as compared to the NC group. No statistically significant changes were noted in the lymphocyte count or in the ratio or count of BrdU-positive lymphocyte cells in any treated group as compared to the vehicle control group. The SI values were 1.1, 1.0 and 1.0 in the low, mid and high dose groups (10, 25 and 50 % (w/v)), respectively. Toxicologically relevant increases in the ratio and count of BrdU-positive lymphocyte cells were noted in the PC group as compared to the NC group. The SI value in the PC group was 7.4, indicating a positive response and an adequate sensitivity of the test system.

Based on the study results, 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) was considered not to possess any skin sensitising potential under the experimental conditions employed. Therefore, 2-ethoxyethyl (2Z)-2-cyano-2-[3-(3-methoxypropylamino)cyclohex-2-en-1-ylidene]acetate (C-1701 B_C_3) not considered to be a skin sensitiser.

Migrated from Short description of key information:
The test item (CAS 1419401-88-9) did not indicate a skin sensitising effect in the non-radioactive murine local lymph node assay (LLNA) as assessed by BrdU incorporation.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The present data on dermal sensitization do not fulfill the criteria laid down in 67/548/EEC and regulation (EU) 1272/2008, and therefore, a non-classification is warranted.