Ethyl 2-cyanoacrylate

Endpoint summary

Description of key information

Ethyl 2-cyanoacrylate (ECA) rapidly polymerises in the presence of moisture. Study data demonstrates that this polymerisation takes at maximum a few minutes to be completed, depending on the specific conditions of reaction (see 7.1.1. Basic toxikokinetics, study on polymerisation speed). Due to this high reactivity after contact to water, ECA cannot be tested in water-based test systems that are typically part of the current in vitro-test batteries. In animals, the skin would finally be exposed to the polymer or its degradation products but not to ethyl 2-cyanoacrylate. Hence, this study is waived according to REACH Annex XI, section 2. This is in accordance with the ECHA guidance (chapter R.5, version 2.1 of December 2011), in which in chapter R.5.2.2 the example of a substance having a high reactivity with water is explicitly mentioned as a case where testing might not be feasible for technical reasons.

Two comparable structural homologues, methyl 2 -cyanoacrylate and butyl 2 -cyanoacrylate, where tested in animals without inducing skin sensitisation. For the above mentioned reasons it is not possible to decide if this result reflects missing intrinsic potential of skin sensitiation, or if it is the consequence of rapid polymerisation of the structural homologues.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vitro

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

Test not performed because ethyl 2-cyanoacrylate is highly reactive to water resulting in fast polymerization process (in seconds) thus the nature of the substance does not allow to be tested for the endpoint Skin Sensitisation: in vitro.
The physico-chemical characteristics of ethyl 2-cyanoacrylate:
- dramatically limit or exclude testing of certain assays since its reactivity with water results immediately into a polymer;
- may also prevent administration of precise and consistent doses of the chemical for both in vitro studies and in vivo studies
as it is described in the Guidance on information requirements and chemical safety assessment Chapter R.5: Adaptation of information requirements chapter (R.5.2.2 Testing is technically not possible (page 28)) the waiver is herewith justified.
Conform Annex XI section 2 of REACH it is possible omit any required information under the justification that testing is technically not possible.

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

In a study by Parker & Turk (1983) the potential of, among others, methyl 2-cyanoacrylate (MCA) and butyl 2-cyanoacrylate (BUCA) to induce skin sensitization was assessed with the Polak method in Guinea pigs. In contrast to other acrylic compounds, MCA and BUCA did not induce skin sensitization. The authors concluded on the basis of 21 tested acrylate and methacrylate compounds, that those structures with substitution on carbon 2 (such as MCA and BUCA in their study, but which is also the case for ECA), were not able to induce skin sensitization.

Allergic reactions towards cyanoacrylate adhesives are described in literature. As the composition of the commercial products has not been described in most of the case reports, it could not be clarified which chemical substances were present and contributed to the adverse skin effects. However, considering the widespread industrial and domestic use of cyanoacrylates, sensitization seems to be rare, indicating that cyanoacrylates do not have to be considered as relevant skin sensitizers.

Tissue adhesives for humans containing cyanoacrylate are in medical use for approx. 20 years and are sold in various international markets. One example is Indermil®, which was granted the CE mark in accordance with the European Medical Device Directive (93/42/EEC) in 1995. The US FDA has approved this medical device in 2002.

 

It is concluded, based on the overall weight of evidence, that ethyl 2-cyanoacrylate is not sensitizing to the skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the data of an in vivo experiment with methyl 2-cyanoacrylate and butyl 2-cyanoacrylate, and in light of the long history of safe use of cyanoacrylates as tissue adhesives and instant glues, it is concluded that ECA is not sensitizing to the skin (see endpoint conclusion).