3-methyl-1-vinyl-1H-imidazolium methyl sulphate

Endpoint summary

Description of key information

in vitro skin irriation/corrosion test Epiderm (OECD 431 and 439, BASF SE, 2012): not irritating
in vivo eye irritation (OECD 405, BASF SE, 2012): no irritating

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:

no adverse effect observed (not irritating)

Additional information

Skin irritation:

The potential of 3-Methyl-1-vinyl-1 H-imidazolium methyl sulfate to cause dermal corrosion/irritation was assessed by a single topical application of the test substance to a reconstructed three dimensional human epidermis model (EpiDerm™) based on OECD guidelines 431 and 439 and GLP. For the corrosion test two EpiDerm™ tissue samples were incubated with the undiluted test substance for 3 minutes and 1 hour, respectively. The irritation test was performed with three EpiDerm™ tissue samples, which were incubated with the undiluted test substance for 1 hour followed by a 42-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 a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability. The EpiDerm™ skin corrosivity/irritation test showed the following results: The test substance is not able to reduce MTT directly. Corrosion test: The mean viability of the test-substance treated tissues determined after an exposure period of 3 minutes was 97%, and it was 102% after an exposure period of 1 hour. Irritation test: The mean viability of the test-substance treated tissues determined after an exposure period of 1 hour with about 42 hours post-incubation was 118%. Based on the observed results and applying the evaluation criteria it was concluded, that 3-Methyl-1-vinyl-1 H-imidazolium methyl sulfate does not show a skin irritation potential in the EpiDerm™ skin corrosion/irritation test under the test conditions chosen.

Eye irritation/corrosion:

The potential of3-Methyl-1-vinyl-1H-imidazolium methyl sulfateto cause damage to the conjunctiva, iris or cornea was assessed, in a GLP compliant eye irritation study (Bioassay 2012) tested according to OECD guideline 405, by a single ocular application of 0.1 mL of the test item to one eye of three White New Zealand rabbits (stepwise procedure starting with one animal and supplementing two additional animals). About 24 hours after application the eye was rinsed with tap water. The ocular reactions were assessed approximately 1, 24, 48 and 72 hours after application and in weekly intervals until day 7. The following test item-related clinical observations were recorded during the course of the study: Moderate iritis (grade 1), Slight conjunctival redness (grade 1), Slight or moderate conjunctival chemosis (grade 1 or 2), Slight or obvious discharge (grade 1 or 2), and additional findings like injected scleral vessels in a circumscribed or circular area were noted in the animals during the observation period. In all three animals the ocular reactions were reversible within 7 days after application. Mean scores calculated for each animal over 24, 48 and 72 hours were 0.0, 0.0 and 0.0 for corneal opacity, 0.0, 0.0 and 0.0 for iris lesions, 1.0, 1.0 and 1.0 for redness of the conjunctiva and 0.3, 0.0 and 0.0 for chemosis. Considering the described ocular reactions as well as the average score for irritation, 3-Methyl-1-vinyl-1H-imidazolium methyl sulfate does not show an eye irritating potential under the test conditions chosen. This study was performed to clarify the borderline results observed in the in vitro EpiOcular assay.

The potential of 3-Methyl-1-vinyl-1 H-imidazolium methyl sulfate to cause serious damage to the eyes was assessed by a single topical application of 750 μL of a 20% test-substance preparation to the epithelial surface of isolated bovine corneas according to OECD 437 guideline and GLP. Three corneas were treated with the test-substance preparation for an exposure period of 4 hours. 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 BCOP test showed the following results: IVIS of the test substance was 17.9, negative control had a value of 12.7 and the positive control resulted in an strongly increased IVIS of 102. Based on the observed results it was concluded, that 3-Methyl-1-vinyl-1 H-imidazolium methyl sulfate does not cause serious eye damage in the Bovine Corneal Opacity and Permeability Test (BCOP Test) under the test conditions chosen.

To furthermore test the potential of 3 -Methyl-1 -vinyl-1 H-imidazolium methyl sulfate to cause ocular irritation, a single topical application of the undiluted test substance to a reconstructed three dimensional human cornea model (EpiOcular™) was performed. Two EpiOcular™ tissue samples per test run were incubated with the test substance for 90 minutes followed by a 18-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 a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability. The EpiOcular™ eye irritation test showed the following results: The mean viability of the test-substance treated tissues was 59% in the 1st test run. In order to clarify this borderline result a 2nd test run was performed. The mean viability of the testsubstance treated tissues was 29% in the 2nd test run. The mean viability of both test runs was calculated to be 44%. Due to these borderline results, an in vivo eye irritation study was performed to clarify if the test substance is irritating to the eye in vivo or not.

Justification for classification or non-classification

Based on the available in vitro skin irritation test and the in vivo eye irriation test, no classification according to EU Directive 67/548/EEC and EU classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No 1272/2008 is warranted for skin and eye irritation.