Propanoic acid, 2-cyano-2-methyl-, methyl ester

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In order to study a possible skin sensitisation potential of 2-cyano-2-methyl-propanoic acidmethyl ester, three groups each of five female mice were treated once daily with the test item at concentrations of 25, 50% (w/w) and 100% in acetone:olive oil (4+1 v/v) by topical application to the dorsum of each ear for three consecutive days. The appropriateness of the used concentrations was previously assessed by a pre-experiment. A control group of five mice was treated with the vehicle (acetone:olive oil (4+1 v/v)) only. The treated animals did not show any signs of systemic toxicity or local skin irritation during the course of the study and no cases of mortality were observed. A statistically significant increase in ear weights was not observed in any test item treated group in comparison to the vehicle control group. The cutoff-value for a positive response regarding the ear weight index of 1.1 reported for BALB/c mice was also not exceeded in any dose group. A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentration resulted in 3-fold or greater increase in incorporation of 3HTdR compared with concurrent controls, as indicated by the Stimulation Index (S.I.). The estimated concentration of test item required to produce a S.I. of 3 is referred to as the EC3 value. In this study Stimulation Indices (S.I.) of 1.00, 0.88, and 0.63 were determined with the test item at concentrations of 25, 50% (w/w) and 100% in acetone:olive oil (4+1 v/v), respectively. A statistically significant or biologically relevant increase in DPM value or in lymph node weight and cell count was not observed in any of the tested dose groups in comparison to the vehicle control group. The cutoff-value for a positive response regarding the lymph node cell count index of 1.55 reported for BALB/c mice was also not exceeded in any dose group. [BASF, 2012]

Migrated from Short description of key information:
The test item 2-cyano-2-methyl-propanoic acid-methyl ester was not a skin sensitiser under the test conditions of the LLNA (OECD 429).

Justification for classification or non-classification

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