(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Endpoint summary

Description of key information

In an EpiDerm™ Corrosivity-Test and a HET-CAM in vitro corrosion test it is concluded that the test substance is not corrosive to either skin and eye. In vivo studies for skin and eye irritation with a structural analogue showed no potential for eye or skin irritation.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion

The corrosive potential was determined in an EpiDerm™ Corrosivity-Test in vitro. Two EpiDerm™ tissue samples were incubated with the test substance for 3 minutes and 1 hour, each (BASF 2003). Tissue viability was determined after exposure to the test substance. There was no decrease in tissue viability observed after 3 minute or 1 hour exposure. Based on these results the test substance was considered to be non-corrosive.

The potential of the structural analogue 4-tert-Butyl-3-hydroxy-2,6-xylylacetonitrile to cause acute dermal irritation or corrosion was assessed in a OECD 404 guideline study (compiant with GLP), by a single topical application of an amount of 0.5 g of the test substance for 4 hours to the intact skin of three White New Zealand rabbits, using a patch of 2.5 cm x 2.5 cm covered with semiocclusive dressing (BASF 2008). After removal of the patch, the application area was washed off. The cutaneous reactions were assessed immediately after removal of the patch and approximately 1, 24, 48, and 72 hours after removal. Slight or moderate erythema was observed in all animals up to 1 hour after removal of the patch. The cutaneous reactions were reversible in all animals within 24 hours after removal. The average score (24 to 72 hours) for irritation was calculated to be 0 for erythema and for edema. It was concluded that the test substance was not irritating to the skin.

Eye irritation

The potential to cause serious eye damage was determined in a HET-CAM in-vitro corrosion test (alternative method to study the potential of serious damage to the eyes/mucous membranes in incubated hen eggs) (BASF 2003). Three hen eggs were exposed to the test substance for 180 seconds. The test substance produced no coagulation, lysis or heamorrhagia effects within a relevant time period after application.

In an OECD 405 guideline study performed in accordance with GLP, the potential of the the structural analogue 4-tert-Butyl-3-hydroxy-2,6-xylylacetonitrile to cause damage to the conjunctiva, iris or cornea was assessed by a single ocular application of 0.1 mL bulk volume (about 37 mg) of the test substance to one eye of three White New Zealand rabbits (BASF 2008). About 24 hours after application the eye was rinsed with tap water. The ocular reactions were assessed approximately 1, 24, 48 and 72 hours after application. The average score (24 to 72 hours) for irritation was calculated to be 0 for corneal opacity, iris, chemosis, and 0.4 for conjunctival redness (in which three animals had a score of 0.7, 0.3 and 0.3 respectively). The findings were reversible within 72 hours after application. It was concluded that the test substance was not irritating to the eye.

Justification for selection of skin irritation / corrosion endpoint:
One skin corrosion in vitro study and one in vivo skin irritation study with an structural analogue are available. These studies are adequate for covering the endpoint.

Justification for selection of eye irritation endpoint:
One in vitro study on eye damage and one study on in vivo eye irritation of an structural analogue are available. These studies are adequate for covering the endpoint.

Justification for classification or non-classification

Based on the findings in the skin and eye corrosion study, the test substance is considered to be not corrosive. According to these results and negative in vivo skin and eye irritation studies with the structural analogue 4-tert-Butyl-3-hydroxy-2,6-xylylacetonitrile, classification according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and the Directive 67/548/EEC (DSD) is not warranted.