Butanoic acid, 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indenyl ester

Endpoint summary

Description of key information

Skin sensitisation: no skin sensitiser based on testing in OECD TG 406

Respiratory sensitisation: the substance is not considered a respiratory sensitiser in absence of human data and in absence of skin sensitisation in animals.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In addition to the GPMT test also a HRIPT test is available showing absence of effects at 100%.

A Guinea Pig Maximisation Test (GPMT) was performed according to OECD guideline 406 to determine the sensitisation potential of the substance. Intradermal induction was performed with 5% Cyclobutanate in arachis oil BP, epicutaneous induction with 100% test material and epicutaneous challenge with 100 and 75% concentrations.
After induction injection discrete/patchy moderate and confluent erythema was noted at the intradermal induction sites of test and control group animals. Discrete or patchy erythema was also noted after topical induction of test group animals on the induction sites. Bleeding from intradermal injection sites was noted in 9 test group animals after 1 hour. The control animals showed discrete or patchy erythema at topical induction site.
At challenge, 8 and 0 out of 20 test group animals (100% Cyclobutanate) showed a positive skin reaction at the 24 and 48 hour reading. For the control group, this was 1 and 0 out of 10. In the 75% Cyclobutanate group, 6 and 0 out of 20 animals responded positive. In the control group 2 and 0 positive skin reactions were observed.
Under the conditions of this study, a positive skin reaction was seen in 8 out of 20 guinea pigs 24 hours after challenge. These reactions were not considered sensitising, as they were not apparent after 48 hours (sensitisation rate: 0%).
Based on these results, Cyclobutanate is considered to be non-sensitising to the skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Respiratory sensitisation can be assessed using human data such as indicated in R7.3.5.2 of the ECHA guidance (2017) that indicate respiratory reactions e. g. from consumer experience or occupational exposure. In case no such data are available the respiratory sensitisation can be assessed using the integrated evaluation strategy for respiratory sensitisation data in the ECHA guidance (R7A, Fig. 7.3-4, 2017), which says that if the substance is not a skin sensitiser, it is unlikely to be a respiratory sensitiser.

Justification for classification or non-classification

The substance is not a skin sensitizer in the Guinea Pig Maximisation Test (OECD guideline 406) and therefore does not need to be classified for skin sensitisation according to EU CLP (EC No. 1272/2008 and its amendments). Consequently, Cyclobutanate is unlikely to be a respiratory sensitiser and it does not have to be classified as such.