Registration Dossier

Administrative data

Description of key information

Skin: Fluhr (2005): 1 % DMA in distilled water on human skin (paravertebral mid back). No significant irritation, but barrier disruption of the stratum corneum.
Skin and eyes: BASF, Gewebetoxikologische Grundprüfung, 1980, 40 % DMA in aqueous solution, in that concentration irritation of the skin and the eye.
Respiratory tract: DMA is an essentially irritant for the upper airways of rodents. (Gagnaire, 1989)

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:
adverse effect observed (irritating)

Additional information

Skin corrosion

A BASF AG internal procedure for skin irritation was used as in following described: two animals were treated with a 40 % DMA solution for 3 min and 4 animals for 4 hours using occlusive conditions. An application site of 2x2 cm was covered with the liquid test substance. After the application the skin was washed with Lutrol (50%). The animals were observed for 8 days and skin changes were recorded daily. On days 1 to 8 the exposure sites were examined and scored for erythema and edema on a graded scale of 0 to 2 or 4 respectively. The test substance was irritating to the skin of rabbits. The report describes findings after 24 hours and at the end of the observation period (8 days). The 3 min exposure caused in every animal severe erythema and slight edema. The 4 h exposure caused severe erythema and severe edema.

Skin irritation

In the study performed by Fluhr et al, 2005, it was shown that biogenic amines (1 %) cause disruption of the permeability barrier. The biogenic amines without the combination with SLS (AA/ AA, DMA/DMA, TMA/TMA) did not induce a significant irritation measured by Chromameter a* values. The values assessed with the visual score were overall very low. However, the application of each of the three biogenic amines did not reveal a significant irritation or increase in SC pH. Sequential application of SLS further enhanced the barrier disruption induced by the biogenic amines. The only exception was the irritation parameter Chroma a*, where no significant increase of redness could be observed. The TMA/SLS irritation and barrier disruption was slightly more prominent than those induced by AM/SLS and DMA/SLS, which can be explained by the higher concentration (1.5 vs. 1.0%). Since these results are detectable in all analyzed parameters, they assume that the described features may be consistent properties of biogenic amines. This dichotomy of usually related parameters of barrier disruption and induction of irritation might be based on the fact that the amines disturbed the intercellular barrier-lipid processing but did not induce a pH change and a subsequent increase in pH.

They assume that the mechanism by which the biogenic amines induce a barrier disruption and inflammatory reaction are different from that of SLS. The contact with both classes of irritants however did not show over additive effects. So the skin represents a better barrier for DMA induced alterations than all the mucosal membrane investigated.

Eye corrosion

For eye irritation a Draize test was performed on 3 rabbits (Vienna White) by BASF (1980). One single application was done with 100 µL, the eyes were not washed out afterwards. The untreated eye served as control. The test duration was 14 days. Scoring of ocular lesions was done according to the method of Draize et al. (1944). The application of the test substance caused an irreversible cornea and conjunctivae disturbance of a score of 4 of 4 and the animals did not recover within 8 days after treatment.

According to the authors, the test substance was classified as irritating to the rabbit eyes when applied without rinsing.

Respiratory irritation

In nasal irritation and pulmonary toxicity study of 20 aliphatic amines in mice, Gagnaire et al. exposed mice to airborne DMA to determine the RD50 value (Gagnaire et al., 1989). This value indicates 50% decrease in the respiratory rate and considered to be successfully used to predict safe industrial exposure. The onset of action of DMA was very rapid, ca. 30 sec. to 1 min. 70 ppm of DMA was determined as RD50 in mice. At the end of a 15 -min exposure period, the recovery of respiratory frequencies to the pre-exposure values was also rapid, ca.1 min. Due to the rapid recovery of respiratory frequency in mice, dimethylamine is considered to be moderately irritating to the upper respiratory and lower respiratory tract. This indictaes that DMA is more irritating as MMA and less irritating than TMA. The predicted safe levels to prevent upper airway irritation should not exceed 15 ppm for DMA. The effects of DMA were reversible in non-cannulated mice, but irreversible in tracheally cannulated mice (effects on the lower airways, can culminate in pulmonary congestion).

Conclusions:

Irritation/Corrosivity

The test substance was irritating to the skin of rabbits (BASF, 1980). Every animal showed severe erythema and slight to severe edema of the skin. Dimethylamine was also highly irritating to the eyes of rabbits (BASF, 1980) and the animals did not recover within 8 days after treatment. Additionally Gagnaire et al, 1989 proved that DMA is also highly irritating to the epithelium in the upper and lower respiratory tract. A concentration of 70 ppm DMA reduced the breathing frequency to 50 %. This indicates that DMA is more irritating as MMA and less irritating than TMA. The predicted safe levels to prevent upper airway irritation should not exceed 15 ppm for DMA. The effects of DMA were reversible in non-cannulated mice, but irreversible in tracheally cannulated mice (effects on the lower airways, can culminate in pulmonary congestion). Fluhr et al, 2005, showed that biogenic amines cause disruption of the permeability barrier. The biogenic amines without the combination with SLS (AA/ AA, DMA/DMA, TMA/TMA) did not induce a significant irritation measured by Chromameter a* values. The values assessed with the visual score were overall very low. So the skin represents a better barrier for DMA induced alterations than all the mucosal membrane investigated.

In the skin irritation studies, DMA was highly irritating to the skin. In the eye irritation study, DMA caused severe signs of irritation and they were not reversible within 8 days. So this substance is corrosive under the conditions used.


Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Effects on respiratory irritation: irritating

Justification for classification or non-classification

Classification is needed according to DSD and GHS:

DMA has been classified according to DSD as: (aqueous): C, R34, Corrosive, causes burns, (gaseous): Xi, R41 Irritant, Risk of serious damage to eyes; Xi, R 37/38 Irritant, Irritating to respiratory system and skin.

DMA has been classified according to GSH: (aqueous): Skin Corr. 1B. H314: Causes severe skin burns and eye damage; STOT Single Exp. 3, H335: May cause respiratory irritation; (gaseous): Skin Irrit. 2 H315: Causes skin irritation.

The distinction made for aqueous solution and gas are necessary, because in the solution the concentration of DMA might vary. Concerning the gas the concentration of it is always alike. Therefore different classifications for the both states are made.