2,5-dimethylhexane-2,5-diol

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 2,5-Dimethyl-2,5-hexanediol, three groups each of five female mice were treated once daily with the test item at concentrations of 5, 10, and 25% (w/w) in dimethylformamide by topical application to the dorsum of each ear for three consecutive days. The test item could be dissolved in the vehicle. The appropriateness of the used concentrations was previously assessed by a pre-experiment. A control group of five mice was treated with the vehicle (dimethylformamide) 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. All treated animals survived the scheduled study period and no signs of systemic toxicity or local skin irritation were observed. A statistically significant or biologically relevant increase in ear weights was not observed in any treated group in comparison to the vehicle control group. 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 0.82, 1.05, and 0.78 were determined with the test item at concentrations of 5, 10, and 25% (w/w) in dimethylformamide, respectively. An outlier was identified in the low dose group. However, an exclusion of the outlier did not change the overall test result and, therefore, the value in question was not excluded from calculation. A statistically significant or biologically relevant increase in DPM value and also in lymph node weight and cell count was not observed in any of the tested dose groups in comparison to the vehicle control group. An EC3 value could not be calculated, since none of the tested concentrations induced a S.I. greater than the threshold value of 3. [BASF, 2012]

Migrated from Short description of key information:
The test item 2,5-Dimethyl-2,5-hexanediol was not a skin sensitiser in the Local Lymph Node Assay.

Justification for classification or non-classification

Classification for sensitisation is not warranted according to the criteria of EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No 1272/2008.