Registration Dossier

Administrative data

Description of key information

Respiratory irritation is expected. The reason is the strong irritating/corrosive effect of this substance and related primary, secondary and tertiary aliphatic amines with a similar pKa value.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin irritation/corrosion

Skin irritation and corrosion was tested in a study that was conducted similar to OECD 405 and under GLP conditions. 0.5 mL of DMBA was applied to two clipped skin sites on each of three Newzealand White rabbits. One site was covered for 3 minutes, while the second site covered (occlusive) for one hour. Following each exposure, the test sites were wiped and immediately graded for dermal reactions. Further readings were made at 1, 24, 48, 72 hours and 7 days post treatment. The findings were scored according the table contained in OECD 405.

 

N,N-dimethyl-n-butylamine produced high-grade erythema (score 4) and necrosis at one hour postdose at the three minute and 1-h exposure sites. The dermal responses progressed to eschar at all sites by 24 hours and persisted to test termination on study day 7. Very slight to moderate swelling (score 1 - 2) was observed at exposure sites during the first 24 hours postdose. This diminished by test termination. Due to the severe effects no further animals were used. Under the conditions of this test, N,N-dimethyl-n-butylamine produced skin corrosion at the three minute and one hour exposure sites (Siglin, 1989). The study is considered to be valid and suitable for assessment.

Eye irirtation/corrosion

N,N-dimethylbutylamine was considered to be a severe eye irritant, based on the results of a study that was conducted essentially similar to OECD 405. The eye reactions of rabbits were recorded up to 14 days after the application of 0.1 mL of the test substance into the conjunctival sac of rabbits, either for 24 hours (Group 1, 6 animals) or 15 seconds (Group 2, 3 animals; eye washed with water). The eye reactions of Group 1 animals indicated marked reactions of the cornea and conjunctivae, whereas the iris was not affected. The conjunctival reactions were largely reversible by day 13, whereas the corneal lesions persisted until the end of the observation period. (Cox and Botta, 1979). The study is considered to be valid with minor restrictions.


Justification for selection of skin irritation / corrosion endpoint:
Skin corrosion could have been predicted from the pKa value of the free base, and no testing would have been required. The prediction is in line with an existing valid in-vivo study which was selected because it demonstrated corrosion within 3 minutes.

Justification for selection of eye irritation endpoint:
The existing in-vivo study was selected. The same effct level could have been predicted from teh pKa value of the free base.

Effects on skin irritation/corrosion: highly corrosive

Effects on eye irritation: corrosive

Effects on respiratory irritation: irritating

Justification for classification or non-classification

Proposed classification: Cat 1A