2,2,5-trimethyl-5-pentylcyclopentan-1-one

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Existing human data (HRIPT, Biotest, 1978) concluded that the registered substance has no skin sensitization potential at 10% in White petrolatum. However, the reliability of those data on its own was not considered adequate to meet the REACH requirements and to make a conclusion on classification and labelling.

Therefore, a weight-of evidence approach using the HRIPT result, the GPMT result on the supporting substance (2-pentylcyclopentan-1-ol, see IUCLID section 13 for read-across justification), and two QSARs, which was considered sufficiently robust to conclude on the skin sensitisation potential of the substance.

The GPMT study on 2-pentylcyclopentan-1-ol (Toxicol, 1995, rel.2) was performed according to the OECD test guideline no. 406 and in compliance with GLP using the Guinea-Pig Maximisation Test method (20 treated animals + 10 controls).

The test material (in 1:1 mixture of Freund’s Complete Adjuvant and water) diluted in light liquid paraffin at 5% (v/v) was administered by injection for intradermal induction. As the substance was not a skin irritant, 24 hours prior to the topical application, the site was pre-treated with 10% w/w sodium lauryl sulphate in light liquid paraffin. Topical induction was performed with the test material as supplied, 7 days after intradermal injections. For the challenge, 21 days after study initiation, the test material was tested undiluted.

One test animal was killed in extremis on the day of patch removal following topical induction and was found to have a prolapsed uterus following a post-mortem examination.

Following challenge, none of the remaining 19 test animals responded positively at the 24 or 48 hour observations, resulting in a response incidence of 0 %. Similarly, none of the 19 animals responded positively to challenge with the vehicle.

The historical positive control, hexyl cinnamic aldehyde, produces evidence of skin sensitization in 8 of 10 animals at 50 %, resulting in a response incidence of 80 %. These results confirmed that hexyl cinnamic aldehyde is a sensitizer under the conditions of this study and the test system was therefore considered to be validated.

Under the test conditions, the supporting substance is not a skin sensitizer.

Both the OECD QSAR Toolbox and ToxTree did not show any alert for protein binding with the substance.

Based on the whole data, it can be concluded that the substance is not a skin sensitizer.

Migrated from Short description of key information:
Skin sensitisation: Not sensitising, WoE (GPMT data on a supporting substance, HRIPT, QSARs)

Justification for selection of skin sensitisation endpoint:
No key study was selected since all studies were used within a weight-of-evidence approach.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification according to the Regulation (EC) No 1272/2008.

Self-classification:

Based on the available information, no additional self-classification is proposed according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP.

No information is available regarding respiratory sensitisation.