1-isopropyl-2,2-dimethyltrimethylene diisobutyrate

Endpoint summary

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 adverse effect observed (not irritating)

Additional information

Skin irritation

 

The potential for 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate to cause skin corrosion/irritation is well understood. In a primary dermal irritation/corrosion study conducted according to OECD Guidelines, no erythema or edema was observed in three New Zealand White Rabbits at any time during the study when 0.5 mL of the undiluted test material was applied to intact shaved skin under semi-occlusive patch for 4 hours. In addition, two dermal toxicity studies were available for review. In one study conducted according to OECD Guideline 402, groups of 5 male and 5 female New Zealand White Rabbits were exposed to 2000 mg/kg bw of undiluted test material on shaved intact skin under semi-occlusive wrap for 24 hours. At the 24-hour observation, 3 animals were normal while the rest had very slight to slight erythema and/or edema. All males and 3/5 females were normal on Days 7 and 14. The two remaining females exhibited very slight erythema (Grade 1) at the 24-hour observation, severe erythema (Grade 4) with flaking skin on Day 7, and were normal on Day 14. In a non-guideline study in which three guinea pigs were exposed to 5, 10 or 20 mL/kg bw of the undiluted test material on shaved intact skin under occlusive wrap for 24-hours, slight to moderate edema, erythema and some hemorrhage were noted at the 24/48-hour examination but only desquamation was noted at the Day 7 and 14 examinations. 

 

Eye Irritation

 

The potential for 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate to cause eye burns/irritation is well understood. In an eye irritation study conducted according to OECD Guideline 405, the only irritant response was slight redness in 1/3 unwashed eyes and 3/3 washed eyes at the 1-hour examination following instillation of 0.1 mL of the test substance into the conjunctival sac of the eye. There was no staining in unwashed or washed eyes when tested with fluorescein dye 24 hours after test substance administration and there were no abnormal systemic signs noted during the 72-hour observation period.

 

Respiratory Tract Irritation

 

The potential for 1-isopropyl-2,2-dimethyltrimethylene diisobutyrate to cause respiratory tract irritation is well understood. In a non-guideline acute inhalation study in which rats were exposed to 0.12 mg/L (10 ppm) or 5.3 mg/L (453 ppm) of the test substance for 6 hours, no clinical signs suggestive of respiratory tract irritation were observed. The latter concentration could only be generated by heating the test material to 100°C.

Justification for classification or non-classification

No erythema or edema was observed in a primary dermal irritation/corrosion study conducted according to OECD Guidelines. In addition, the test conditions used in two dermal toxicity studies were significantly more severe, i.e., 24-hour exposure and much higher dose levels than current OECD guideline specifications for a skin irritation/corrosion study. Based on a weight-of-the-evidence assessment, 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate may cause slight, transient skin irritation but is not classified for “Skin irritation/corrosion” according to EU CLP.

The only clinical sign in rabbit eyes following instillation of 0.1 mL of test material into the conjunctival sac of the eye was slight redness at the 1-hr observation period. In addition, 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate is not classified under EU CLP for either skin corrosivity or irritation following 4 -hour semi-occluded contact with intact skin. Based on a weight-of-evidence assessment, 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate is not classified for eye irritation according to EU CLP.

There were no clinical signs indicative of respiratory tract irritation in rats following acute exposure to the highest airborne concentration of 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate that could be generated by heating the test material to 100°C. In addition, 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate is not classified as a skin irritant according to EU CLP. Based on a weight-of-the evidence assessment, 1 -isopropyl-2,2 -dimethyltrimethylene diisobutyrate is not classified for respiratory tract irritation according to EU CLP.