[No public or meaningful name is available]

Endpoint summary

Description of key information

Local Lymph Node Assay (OECD TG 429): skin sensitizer (BASF 2021; 58V0281/20B075)

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Additional information:

In the key study for skin sensitization, Santalol Oil was assessed using the radioactive Local Lymph Node Assay according to OECD TG 429 and GLP (BASF 2021; 58V0281/20B075). Groups of 5 female CBA/CaOlaHsd mice each were treated with 2.5%, 10% and 25% (w/w) preparations of Santalol Oil in ethanol or with the vehicle alone. Each test animal was treated with 25μL per ear of the appropriate test-substance preparation or the vehicle alone, applied to the dorsal surfaces of both ears on three consecutive days. Three days after the last application, ca. 20μCi3H-thymidine in 250μL sterile saline were injected into the tail vein of the mice. About 5 hours after the3H-thymidine injection, the mice were sacrificed, and the auricular lymph nodes were removed. Lymph node response was evaluated measuring3H-thymidine incorporation and the cell count and weight of each animal’s pooled lymph nodes were also determined. In addition, a 0.8 cm diameter sample was punched out of the apical part of each ear, and for each animal, the weight of the pooled punches was determined to obtain an indication of possible skin irritation.

No signs of systemic toxicity were noticed in all animals during general observation.

When applied as 10% and 25%, Santalol Oil induced biologically relevant (SI ≥ 3), statistically significant and concentration-dependent increases of3H-thymidine incorporation into the cells from the auricular lymph nodes. The increase of the 2.5% concentration was statistically significant but failed to reach the cutoff.

Concomitantly, the 10% and 25% concentrations induced biologically relevant and statistically significant responses (SI ≥ 1.5) in the auricular lymph node cell counts. The SI of the 2.5% concentration was statistically significant but failed to reach the cutoff.

In addition, statistically significant increases in lymph node weights were noted at all concentrations.

The test-substance concentrations did not cause relevant increases (SI ≥ 1.25) in ear weights, demonstrating the absence of excessive ear skin irritation. However, the SI (1.24) at the 25% concentration lies at the border of the cutoff value and was statistically significant.

In conclusion, Santalol Oil exhibits a skin sensitizing potential in the Local Lymph Node Assay under the test conditions chosen. The threshold concentration for sensitization induction was >2.5% <10%. The EC 3 for 3H-thymidine incorporation and the EC 1.5 for cell count was calculated by linear regression from the results of these concentrations to be 8.1% and 4.5%, respectively.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The present data on dermal sensitization fulfill the criteria laid down in regulation (EU) 1272/2008, and therefore, a classification with "Skin sensitisation" (Category 1B) is warranted.