Tetrahydro-4-methyl-2-(2-methylprop-1-enyl)pyran

Endpoint summary

Description of key information

Skin irritation (OECD TG 404, GLP): irritating (BASF 2007; BASF18H0624/072134)
Eye irritation (weight of evidence rose oxide, dehydrorose oxide, dihydrorose oxide): irritating (IFF 1963; BASF 11H0576/072121; BASF 83/186)

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin irritation

In the key primary dermal irritation study according to OECD TG 404 and GLP, young adult white rabbits (3 males) were dermally exposed (semiocclusive) to unchanged rose oxide for 4 hours (BASF 2007; BASF18H0624/072134). Mean scores (24 -72 hours) for each animal were 3.0, 3.0 and 3.3 for erythema respectively. Mean scores (24 -72 hours) for edema were 1.0 for each animal.

Erythema were not reversible in all animals within 14 days after removal of the patch.

Under the conditions of the study, rose oxide was found to have a skin irritation potential.

Eye irritation

In the primary eye irritation study according to Draize, eye irritation was evaluated in 3 albino rabbits (IFF 1963). A 0.1 ml aliquot of 1.25% rose oxide in alcohol SDA 39C was instilled into the right eye of each rabbit. No adverse effects on cornea and iris were observed. Mean conjunctival redness scores (24, 48 and 72 hour observation timepoint) were 2.3, 2.3 and 2 for each animal respectively. Findings were not fully reversible within the observation time, i.e. 7 days. Mean chemosis scores (24, 48 and 72 hour observation timepoint) were 1.3, 1.6 and 0.6 for each animal respectively, showing an overall full reversibility within 7 days. No information was given on vehicle controls in order to rule out eye irritating effects of alcohol SDA 39C. Although rose oxide was tested as solution at low concentration and information on the eye irritating potential of the solvent used is not available, an indication of eye irritating properties of rose oxide exist based on the findings cited above.

Further eye irritation studies using substances with high structural similarities but varying in the numbers of double bonds as putative reactive structural feature (dehydro-rose oxide (CAS 60857-05-8) containing 2 double bonds or dihydro-rose oxide (CAS 13477-62-8) lacking any double bond) have been included for assessment:

Dihydro-rose oxide has been tested in 3 Vienna white rabbits according to OECD TG 405 (BASF 1983; 83/186). Unchanged dihydrorose oxide was instilled into the right eye of each rabbit (0.1 mL). No effects in terms of corneal opacity and iritis have been observed. Chemosis with a score of 1 for each animal was observed at the 1 hour reading only. Mean scores of 1 for conjunctival redness (24, 48 and 72 hour observation time point) was observed for each animal but was fully reversible within 8 days.

Dehydrorose oxide has been tested in 3 New Zealand white rabbits according to OECD TG 405 and GLP (BASF 2008; 11H0576/072121). Unchanged dehydrorose oxide was instilled into the right eye of each rabbit (0.1 mL). Mean scores (24, 48 and 72 hour observation time point) were 0.7, 1 and 0.7 for corneal opacity, 0.3, 0.3 and 0 for iritis, 2.3, 2 and 2 for conjunctival redness and 0.7, 0.7 and 1.3 for chemosis for each animal respectively.  All findings were overall fully reversible within 7 days.

Overall, eye irritating potential has been observed in a strucutally similar substance containing 2 double bonds whereas a structure lacking such double bonds showed only little eye irritating potential. Based on the fact that rose oxide contains a single double bond, a study with 1.25% rose oxide led to evident eye irritation (mean conjunctival redness scores >=2 and <2.5 without reversibility), and data with dehydrorose oxide containing 2 double bonds do not justify a classification for serious eve damage, rose oxide is to be classified as irritating to the eye according to regulation (EU) 1272/2008 in a weight of evidence.

Justification for classification or non-classification

The present data fulfill the criteria laid down in 67/548/EEC and regulation (EU) 1272/2008, and a classification "irritating to skin" (R38) and "skin irritant" (category 2) is warranted.

The present data on eye irritation do not fulfill the criteria laid down in 67/548/EEC. According to regulation (EU) 1272/2008, a classification as "irritating to eyes" (Category 2) is warranted. According to UN-GHS, a classification as " irritating to eyes" (Category 2A) is warranted.