3,7,11,15-tetramethylhexadecane-1,2,3-triol

Endpoint summary

Description of key information

The skin sensitisation potential of the test substance was assessed according to OECD Test Guideline 406 using a guinea pig maximisation test. There was a positive response incidence of 40% at the 24 and / or 48 h examination. The test substance is classified as a category 1B skin sensitizer; classification into sub-category 1B is appropriate based on the following criteria for the guinea pig maximisation test: ≥ 30% responding at > 1% intradermal induction dose.

An additional test performed using an open epicutaneous method indicated that sensitisation responses were detected at concentration of 3% or higher.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitisation potential of the test substance was assessed according to OECD Test Guideline 406 using a guinea pig maximisation test. The maximum non-irritant concentration was 25%.

Following the challenge application, 8 out of the 20 test guinea pigs reacted positively to 25% v/v test article at the 24 and/or the 48 hour observation, resulting in a response incidence of 40%. One of test animals exhibited a weak positive response (erythema score of 1) to the vehicle, ethanol, at the 24 hour examination only. None of the remaining test animals reacted positively to challenge with the vehicle at any examination.

None of the control animals reacted positively to challenge with either 25% v/v test article or the vehicle (ethanol) at any examination, resulting in a response incidence of 0%.

As no positive responses were exhibited by any of the control animals, the single isolated weak positive response by one animal in the test group to ethanol may have been due to non-specific irritation.

 

The test substance was also assessed for skin sensitisation potential according to OECD Test Guideline 406 using an open epicutaneous test.

Sensitisation responses were detected after both challenges at the application sites exposed to the test article in the concentration of 3% or higher. However, when applying the test substance at the concentration of 1% or lower during the challenges 1 and 2, no skin sensitisation responses as such were observed in the experiment.

The study concluded that concentrations ≥ 3% can induce cutaneous sensitisation in the guinea pig. However, cutaneous exposure to the test substance at lower concentrations (≤ 1%) did not result in sensitisation responses in the guinea pig.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

A skin sensitiser is defined as a substance that will lead to an allergic response following skin contact. Sensitisation includes two phases: The first phase is induction of specialised immunological memory in an individual by exposure to an allergen. The second phase is elicitation; the production of a cell-mediated or antibody-mediated allergic response by exposure to a sensitised individual to an allergen. Usually, lower levels are necessary for elicitation than are required for induction. 

Substances are classified as skin sensitisers (Category 1), if there is evidence in humans that the substance can lead to sensitisation by skin contact in a substantial number of persons, or if there are positive results from an appropriate animal test.

When an adjuvant type guinea pig test is used, a response in at least 30% of the animals is considered as positive. For non-adjuvant guinea pig tests, a response of at least 15% of the animals is considered positive.

The test substance was assessed in two animal studies using an open epicutaneous method and a guinea pig maximisation method.

The open epicutaneous method indicated that cutaneous sensitisation was induced by the test substance at concentrations ≥ 3%.

The guinea pig maximisation test is an adjuvant-type method. Following the challenge application, 8 out of the 20 animals reacted positively to the test substance at 25 % v/v. The response was positive for sensitisation in 40 % of the animals tested. This is above the threshold of 30% for the adjuvant type tests and the substance is therefore classified for skin sensitisation (Category 1).

Classification into sub-category 1B is appropriate based on the following criteria for the guinea pig maximisation test: ≥ 30% responding at >1% intradermal induction dose.