N,N-dimethylacrylamide

Endpoint summary

Description of key information

N,N-dimethylacrylamide was found to be not irritating to the skin. From the results of in vitro eye irritation tests, and an in vivo test, it can be concluded that N,N-dimethylacrylamide causes serious eye damage.

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:

adverse effect observed (irritating)

Additional information

Skin irritation

In a skin irritation test comparable to OECD guideline 404, 0.5 mL N,N-dimethylacrylamide was applied undiluted to the skin of 6 rabbits for 24 hours under occlusive conditions (USEPA, 1992). Observations took place until 72 hours post-treatment. No signs of erythema or edema were observed in this study. The substance was not irritating to the skin of rabbits.

Eye irritation

N,N-dimethylacrylamide was tested using the in vitro Bovine Corneal Opacity and Permeability Test (BASF SE, 2012) according to OECD Guideline 437 under GLP. The potential of N,N-dimethylacrylamide to cause serious damage to the eyes was assessed by a single topical application of 750 μL of the test-substance preparation to the epithelial surface of isolated bovine corneas.

Three corneas were treated with the test-substance preparation for an exposure period of 10 minutes. Corneal opacity was measured quantitatively as the amount of light transmission through the cornea. Permeability was measured quantitatively as the amount of sodium fluorescein dye that passes across the full thickness of the cornea. Both measurements were used to calculate an In Vitro Irritancy Score of the test substance relative to the control corneas.

The mean opacity value was 38.8, the mean permeability value was 1.354 and the In Vitro Irritancy Score was 59.1. The negative control values were 0.75, 0.002 and 0.75 and the positive control values were 84.0, 3.615 and 138.2, respectively.

Based on the observed results and applying the evaluation criteria it is concluded, that N,N-dimethylacrylamide causes serious eye damage in the Bovine Corneal Opacity and Permeability Test (BCOP Test) under the test conditions chosen.

In an eye irritation test comparable to OECD guideline 405, 0.1 mL of the test substance was applied to the conjunctival sac of the eyes of 2 rabbits (USEPA, 1992). Scoring for cornea, conjunctivae, chemosis and iris were performed at 24, 48 and 72 hours after application. The mean (24, 48 and 72 hours) cornea score was 1, the mean (24, 48 and 72 hours) conjunctivae score was 1.2 and the mean (24, 48 and 72 hours) chemosis score was 2.4. The effects remained throughout the 72 hours observation period and were not reversible. The mean (24, 48 and 72 hours) iris score was 0.17 (fully reversible within 72 hours). N,N-dimethylacrylamide was judged to be potentially causing the risk of serious damage to the eyes.

 

N,N-dimethylacrylamide was also tested using the in vitro EpiOcular™ Test (BASF SE, 2012) under GLP. The potential of N,N-dimethylacrylamide to cause ocular irritation was assessed by a single topical application of 50 μL of the test substance to a reconstructed three dimensional human cornea model (EpiOcular™). Two EpiOcular™ tissue samples were incubated with the test substance for 30 minutes followed by a 2-hours post-incubation period.

Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with MTT was chosen as endpoint. The formazan production of the test substance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability.

The test substance is not able to reduce MTT directly.

The mean viability of the test-substance treated tissues was 5%.

Based on the observed results and applying the evaluation criteria it is concluded, that N,N-dimethylacrylamide shows an eye irritation potential in the EpiOcular™ eye irritation test under the test conditions chosen.

Effects on eye irritation: corrosive

Justification for classification or non-classification

Based on the available in vivo and in vitro data, N,N-dimethylacrylamide has to be classified for eye damage. According to Directive 67/548/EEC, classification with Xi, R41 is warranted. According to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, the classification is H318, Cat 1.

Based on the result of the skin irritation test, the substance does not need to be classified according to Directive 67/548/EEC and according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.