3,4-dihydro-2H-pyran

Endpoint summary

Description of key information

The test item 3, 4-Dihydro-2H-pyrane was found to be a skin sensitiser in the Local Lymph Node Assay (OECD 429).

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In order to study a possible skin sensitisation potential of 3,4-Dihydro-2H-pyrane, three groups each of five female mice were treated once daily with the test item at concentrations of 25 and 50% (w/w) in acetone:olive oil (4+1 v/v) and 100% (undiluted test item) 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. Five days after the first topical application the mice were injected intravenously into a tail vein with radio-labelled thymidine (³H-methyl thymidine). Approximately five hours after intravenous injection, the mice were sacrificed, the draining auricular lymph nodes were excised, pooled per animal and immediately weighed. Single cell suspensions of lymph node cells were prepared from lymph nodes pooled per animal. An aliquot of each cell suspension was used for determination of lymph node cell count. The proliferative capacity of pooled lymph node cells was determined by the incorporation of³H-methyl thymidine measured in ab-scintillation counter. All treated animals survived the scheduled study period and no signs of systemic toxicity or local skin irritation were observed.

A test item is regarded as a sensitiser in the LLNA if exposure to one or more test item concentration results in a 3-fold or greater increase in incorporation of³HTdR compared with concurrent controls, as indicated by the Stimulation Index (S.I.). The estimated test item concentration required to produce a S.I. of 3 is referred to as the EC3 value. In this study Stimulation Indices (S.I.) of 1.37, 1.44, and 4.74 were determined with the test item at concentrations of 25 and 50% (w/w) in acetone:olive oil (4+1 v/v) and 100% (undiluted test item), respectively. A dose response was observed. An outlier was not identified in any of the tested groups. The EC3 value calculated was 73.6% (w/w). [BASF, 2012]

Justification for classification or non-classification

3,4 -Dihydro-2H-pyrane is considered to be skin sensitising (cat.1B, H317) according to the criteria of EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No 1272/2008.