3-ethoxy-1,1,5-trimethylcyclohexane

Endpoint summary

Description of key information

In vivo skin sensitisation - LLNA (OECD 429, GLP, K, Rel.1): skin sensitizer Cat.1B

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

An old in vivo study was performed similarely to a GPMT with major deviations (Potokar, 1979, Rel.4). 15/20 positive reactions were noted and the test substance was likely to be potentially a skin sensitiser. However, no details on the purity of the test material were available.

Regarding to the number of deviations in this study, a new LLNA study was performed according to the OECD test guideline No. 429 and in compliance with GLP (Sanders, 2016).

Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 100%, three treated groups, each comprising four mice receiving test item at concentrations of 25, 50% or 100% v/v in the vehicle 4:1 acetone:olive oil (AOO). Similarly constituted group received the vehicle 4:1 v/v acetone:olive oil (negative controls). No positive controls (with 25% v/v hexyl cinnamic aldehyde) were used in this study but historical control data was given in annex. Mice were treated by daily application of 25mL of the appropriate concentration or control, to the dorsal surface of both ears for three consecutive days.The proliferative response of the lymph node cells (LNC) from the draining auricular lymph nodes was assessed five days following the initial application, by measurement of the incorporation of 3H-methyl Thymidine (3HTdR) by β-scintillation counting of LNC suspensions. The response was expressed as radioactive disintegrations per minute per lymph node (dpm/node) and as the ratio of 3HTdR incorporation into LNC of test nodes relative to that recorded for control nodes (test/control ratio), termed as Stimulation Index (SI). The disintegrations per minute/node were obtanied by dividing the total pooled disintegrations per minute value by 8 (total number of lymph nodes).

The SI obtained for 25, 50 and 100% v/v were 0.91, 2.09 and 3.27, respectively, which indicates that test item showed the potential to induce skin sensitization. The EC3 value was calculated to be 89%. No sign of systemic toxicity or excessive local skin irritation were noted at the concentrations of 25, 50 and 100 % v/v.

The SI for the historical positive control substance hexyl cinnamic aldehyde was 6.08, which demonstrates the validity of this study.

 

Under the test conditions, test material is classified as a skin sensitizer.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

No data available on respiratory sensitisation, no method in animals and no guideline available to assess the respiratory sensitising potential of the substance.

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification according to the Regulation (EC) No. 1272/2008 and to the GHS.

Self-classification:

Based on the available data, the substance is classified as Skin Sens. 1B, H317 (May cause an allergic skin reaction) according to the Regulation (EC) No. 1272/2008 (CLP) and to the GHS, since EC3 is > 2% (89%).

No direct scientific data are available on the substance to address respiratory sensitisation.