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Description of key information

Skin and eye irritation studies have been conducted on Laurylimidazole.  The results of the studies are:
Skin Irritation: Mildly irritating, not CLP classified
Eye Irritation: Possible eye irritant, not corrosive to eyes (Irritating to eyes (GHS Category 2A) in a study performed according to OECD 437.

Key value for chemical safety assessment

Additional information

The primary skin irritation potential of the test article (slightly yellow liquid, purity 99% CASRN 4303-67-7, batch 0001) was evaluated in New Zealand White rabbits. The procedure was based on the method prescribed by the CPSC of the US in 16 CFR 1500.41. The hair was clipped from the dorsal skin of six female rabbits. Immediately prior to test article application, a 2.5 cm square area of the right side of the spine was abraded with the tip of a scalpel blade. A similar site on the left side of each animal remained intact. A 0.5 mL aliquot of the test article was applied under a 2.5 cm square gauze pad to one abraded and one intact site per animal. The sites were occluded with elastic dressing for 24 hours and at the end of exposure the sites were wiped to remove any residual test article. Observations for skin irritation (erythema and edema) were recorded at 24 and 72 hours after exposure. For intact skin, the means of the 24- and 72 -hour scores for erythema for the six animals were 2, 2, 2, 2, 4 (with necrosis), and 2. For intact skin, the means of the 24- and 72 -hour scores for edema for the six animals were 2.5, 2, 2, 2.5, 2, and 2.5. Blanching was observed in all animals at 24 hours post-exposure. Hyperkeratinization was observed in all animals at 72 hours after exposure. The Primary Irritation Index (PII) including intact and abraded scores was 4.7. Based on the results of this study, the test article is a mild dermal irritant and is not classified for skin irritation according to CLP criteria.


The ocular corrosion potential of MTDID 13999 (clear yellowish liquid, Purity 99.0% CASRN 4303-67-7, Batch 529783) was tested in the Bovine Corneal Opacity and Permeability test (BCOP test). The study was performed in compliance with OECD GLP (98) 17 (1997). The test method was based on OECD no. 437 (2013), EC No. 440/2008 B. 47 (2010), OTWG- ICCVAM-NICEATM (2006), INVITTOX 127 (2006), and Gautheron, P. et al. 18: 442-449 (1992). Corneas were prepared in cell culture medium and incubated at 32 C for at least 1 hour prior to exposure. Corneas (3/group) were treated with 0.75 mL of undiluted MTDID 13999 test material and incubated in a horizontal position for 10 minutes at 32 C. A positive control (10% w/v Benzalkonium Chloride) and a negative control (physiological saline) were tested in parallel with the test material. At the end of the exposure period, the corneas were rinsed and incubated in fresh cell culture medium for 120 +/- 10 minutes at 32 C. Opacity was evaluated using an opacitometer after the 2 hour post-exposure incubation. Following opacity readings, the cell culture medium was replaced with Na-fluorescein medium and incubated for approximately 90 minutes at 32 C. Following the 90 minute Na-fluorescein exposure, permeability was measured. The mean in vitro irritation score (IVIS) was calculated and the scores were classified according to OECD 437 (2013). For MTDID 13999, the mean IVIS = 12 after 10 minutes. The mean opacity score was 7 (range 6-7) and the mean permeability score was 0.300 (range 0.252-0.376). The pH of the rinsing medium was not altered by the test substance. Based on the results of the test and OECD 437 (2013), MTDID 13999 is a possible eye irritant, but is not corrosive to eyes (IVIS = 12.0).

Justification for classification or non-classification

The test article does not meet the CLP classification criteria for skin irritation.


The test article is classified as irritating to the eyes (Category 2A) according to CLP criteria.