2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridine carboxylate; imazapyr (ISO)

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Key Study (BASF SE, 2012/1247227, guinea pig, 2013)

In a skin sensitisation study according to OECD 406, 20 guinea pigs (Dunkin-Hartley, females, 5 weeks old) were induced by 3 topical applications with the test item, which was applied diluted at 60% in liquid paraffin under occlusive dressing followed by a 13 -day rest phase. The challenge phase, under occlusive dressing for 6 hours, consisted of a single topical application of the test item diluted at 60% in liquid paraffin. No macroscopic cutaneous reactions attributable to allergy were recorded during the examination following the removal of the occlusive dressing (challenge phase) from the animals of the treated group with the test item at 60%. No cutaneous intolerance reaction was recorded in animals from the negative control group. In conclusion, in view of these results, under these experimental conditions, the test item is not a skin sensitiser.

 

Supporting Study (American Cyanamid Company, IZ-412-005, guinea pig, 1986)

In a skin sensitisation study equivalent to OECD 406, 3 groups of 12 young adult male albino guinea pigs (Hartley) were tested. The induction phase included 9 applications of 6 hours contact period each (0.4 g test item moistened with 0.4 mL of physiological saline) wrapped with plastic wrap and was followed by a 2 -week rest period. The challenge application was applied once for a contact period of 6 hours (0.4 g test item moistened with 0.4 mL of physiological saline). All animals appeared normal throughout the study and exhibited an acceptable weight gain. There was no erythema or oedema observed after any application of the test item. At the same time, erythema and oedema reactions were observed in animals given the positive control sensitization agent, thus demonstrating the animals used in this study were responsive to a proven sensitizing agent. In conclusion, the test item when tested as supplied is not a skin irritant, fatiguing agent or a skin sensitiser in the albino guinea pig.

 

Supporting Study (American Cyanamid Company, IZ-416-001, guinea pig, 1983)

In a skin sensitisation study equivalent to OECD 406, 2 groups of 10 young adult male albino guinea pigs were treated with 3 inductive and one challenge application with the test item (0.3 g test in physiological saline in Hill Top Chambers) for 6 hours per application. The inductive applications were given once per week for 3 weeks. Fourteen days after the last inductive applications was given, all animals received a challenge application. There was no erythema or oedema observed after any application of the test item. Erythema and oedema reactions were observed in animals given the positive control sensitization agent, thus demonstrating the animals used in this study were responsive to a proven sensitizing agent. No mortality or remarkable clinical signs were noted during the study except for yellow-staining at the site of application of the positive control test material. Evaluation of body weight data indicated no significant differences. It is concluded that under the conditions of this study, the test item is not a skin sensitiser.

 

CONCLUSION

In all sensitisation studies, the test item revealed to be not skin sensitising whereas the positive control induced the appropriate responses.