Reaction mass of 4-isopropylidene-1-methylcyclohexene and 1-isopropyl-4-methyl-7-oxabicyclo[2.2.1]heptane and 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In a local lymph node assay performed according to OECD Guideline 429 and in compliance with GLP, groups of CBA/J mice (4 females/dose)

were exposed to 25 µL of Terpinolene multiconstituentin Acetone/Olive oil (4/1, v/v)at concentrations of 0 (vehicle control), 1, 2.5, 5, 10, and 25 % (v/v) to the dorsal surface of both ears for three consecutive days. On Day 6, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and measured for radioactivity expressed as number of disintegrations per minute (DPM) and stimulation index.The test concentrations for the main study were determined from a preliminary study where erythema and dryness of the skin were observed in right ear treated at 100% of both females. Dryness of the skin was noted in left ear treated at 50% of these females. In addition, an increase in ear thickness was recorded at the concentrations of 50% and 100%, showing the irritant potential of the test item at these concentrations. The highest concentration retained for the main test was therefore 25%.

No clinical signs and no mortality were observed during the main test. No local reactions and no notable increase in ear thickness were observed at any of the concentrations. Stimulation index for 1, 2.5, 5, 10, and 25 % were 0.35, 1.18, 0.77, 0.77 and 3.10, respectively. The calculated effective concentration inducing an SI of 3 (EC3) was 24 %. Positive control (α-hexylcinnamaldehyde) exhibited evidence of sensitisation (SI = 6.27).

A significant lymphoproliferation (SI > 3) was noted at the concentration of 25% and above. In the absence of local irritation, the significant lymphoproliferative responses observed were attributed to delayed contact hypersensitivity.

Migrated from Short description of key information:
In a LLNA, Terpinolene multiconstituent induced skin sensitisation with an EC3=24%.

Justification for selection of skin sensitisation endpoint:
Only one study available for this endpoint

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Terpinolene multiconstituent induced positive response in LLNA with an EC3=24% therefore it is classified "R43: May cause sensitisation by skin contact" according to the Annex VI of the Directive 67/548/EEC and skin sensitiser Category 1B according to the Regulation (EC) N° 1272-2008 (CLP).