Butane, 2-ethoxy-2-methyl-

Endpoint summary

Description of key information

TAEE is considered irritating to the skin and eyes and not irritating to the respiratory tract. 

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)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

The skin irritation potential of TAEE was investigated in one in vivo and in one in vitro study.

Using a validated in vitro method under GLP (EPISKIN reconstituted human epidermis model from SkinEthic Laboratories; validated by ECVAM, April 2007) including appropriate negative (PBS) and positive (5% SDS) controls, TAEE was assessed as not irritating in this in vitro study (Harlan Laboratories Ltd, 2009a).

 

In vivo, the skin irritation potential was evaluated in a GLP-compliant guideline study (method B4 of Directive 2004/73/EC) using 2 male New Zealand White rabbits (Harlan Laboratories Ltd, 2009b). The test sample (0.5 ml) was applied undiluted to an area of clipped dorsal skin and covered with a semi-occlusive dressing for 4 hour. The wrappings were then removed, the test skin wiped clean with cotton wool moistened with distilled water and skin reactions recorded (Draize criteria) at 1, 24, 48 and 72 hour after patch removal. Well defined erythema (grade 2) and slight or very slight oedema (initially grade 2, decreasing to grade 1) were present from 24 hr to 72 hour at the test site, followed by crust formation at day 7 and slight desquamation at day 14. No corrosive effects were noted. The test substance was irritating to rabbit skin under the conditions of the study.

 

Eye irritation

The eye irritation potential of TAEE was investigated in two in vitro studies. In a GLP-compliant rabbit enucleated eye test (Harlan Laboratories Ltd, 2009c), TAEE was not an eye irritant under the conditions of the test. The test material was applied undiluted for 10 seconds, rinsed with saline solution and the corneal surface assessed for opacity, fluorescein uptake and swelling for up to 4 hour post-treatment. The assay has undergone inter-laboratory validation and shown to detect test materials that are negligible or moderate to severe ocular irritants.

 

Using a validated in vitro method (SKINETHIC reconstituted human corneal epithelium model from SkinEthic Laboratories; validated by ECVAM, April 2007), TAEE was assessed as an eye irritating substance (Harlan Laboratories Ltd, 2009d). The study was GLP compliant and included appropriate negative (PBS) and positive (5% SDS) controls. Results were presented as the mean % tissue viability of incubations containing the test or positive control samples relative to the negative controls. Interpretative criteria applied to the method indicated that incubations where the relative mean tissue viability was 60% or less should be considered irritant; those where mean viability exceeded 60% were non-irritant. The relative mean viability of the TAEE-treated incubations was 29.3% of control while relative mean viability for the positive control incubations was 49.2%.

 

Respiratory tract irritation

Signs of respiratory tract irritation, i.e.,bradypnoea and dyspnoea, were reported in the available acute inhalation toxicity study with rats (Covance Laboratories Ltd., 2009c; see Acute toxicity section for further details). However, these signs were only reported at a very high concentration of 23000 mg/m³and are therefore considered to be irrelevant for human risk assessment.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: irritating

Justification for classification or non-classification

Based on the available in vivo skin irritation study, TAEE should be classified for skin irritation in accordance to Directive 67/548/EEC (Xi; R38) and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 (Cat. 2; H315).

 

Regarding eye irritation, based on the results of the available in vitro studies, TAEE should be classified for eye irritation in accordance to Directive 67/548/EEC (Xi; R36) and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 (Cat. 2; H319).

Regarding respiratory tract irritation, signs of respiratory irritation have been reported in the available acute toxicity study, however, they were only observed at very concentration levels. Therefore classification of TAEE is not warranted in accordance to Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.