4-oxovaleric acid

Endpoint summary

Description of key information

Skin sensitiser

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitisation potential of the substance was evaluated considering data from an in-vivo study as well data obtained from an in-vitro study on Similar Substance 01. Justification for Read Across is given in Section 13 of IUCLID.

The ability of the substance to induce skin sensitisation in the CBA/JN mouse, was evaluated using the Local Lymph Node Assay (LLNA: BrdU-ELISA method) according to the OECD Guideline 442b. In the main assay, the test item was topically administered at the concentrations of 25, 10 and 5 % (w/w), in acetone:olive oil 4:1 (v/v) for three consecutive days. After one day of no treatment, BrdU solution was injected inter-peritoneally. Twenty four hours after BrdU injection, the animals were killed and the auricular lymph nodes were rapidly excised, pooled on individual basis and individually collected. Cell suspensions were prepared for the evaluation of proliferation at lymph node. An increase in cell proliferation of draining lymph nodes was observed in the high, medium and low dose groups with SI of 2.05, 1.88 and 1.31 respectively, indicating that the test item may elicit a sensitisation response. Dunnett’s test showed a statistically significant difference between mid- and high dose groups, when compared to the negative control group. The substance is considered to be a skin sensitiser.

The in vitro intrinsic sensitizing potential of the similar substance was evaluated according to the human cell line activation test (h-CLAT) following the OECD Guideline 442E. THP-1 cell cultures were exposed to eight concentrations of the test item, ranging from 39.1 to 5000 μg/ml, for 24 hours. After exposure, the expression of two cell surface antigens, CD86 and CD54, was measured by flow cytometry method. Vehicle control (RPMI), negative control (LA) and positive controls (DNCB and NiSO4) run in parallel. The chemicals were tested in two independents experiments. RFI of CD54 was higher than 200 in two experiments at 5000 μg/ml concentration. Since the RFI of CD54 exceeded 200 % in two experiments the substance should be identified as a skin sensitizer.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the CLP Regulation (EC) No. 1272/2008:

Annex I: 3.4.2.2. Skin Sensitisers Annex I: 3.4.2.2.1. Hazard categories

Annex I: 3.4.2.2.1.1. Skin sensitisers shall be classified in Category 1 where data are not sufficient for sub-categorisation.

Annex I: 3.4.2.2.1.2. Where data are sufficient a refined evaluation according to section 3.4.2.2.1.3 allows the allocation of skin sensitisers into sub-category 1A, strong sensitisers, or sub-category 1B for other skin sensitisers.

Annex I: 3.4.2.2.1.3. Effects seen in either humans or animals will normally justify classification in a weight of evidence approach for skin sensitisers as described in section 3.4.2.2.2. Substances may be allocated to one of the two sub-categories 1A or 1B using a weight of evidence approach in accordance with the criteria given in Table 3.4.2 and on the basis of reliable and good quality evidence from human cases or epidemiological studies and/or observations from appropriate studies in experimental animals according to the guidance values provided in sections 3.4.2.2.2.1 and 3.4.2.2.3.2 for sub-category 1A and in sections 3.4.2.2.2.2 and 3.4.2.2.3.3 for sub-category 1B.

Data from the in-vitro OECD442E do not permit any subclassification. The results obtained in this study suggest that the substance is a skin sensitiser. Data from the in-vivo OECD 442E also do not permit any subclassification. The SI index obtained in all the three concentrations tested was above 1.6 and there was statistically significant difference between mid- and high dose groups, when compared to the negative control group. Considering data obtained from both studies, the substance is classified in Category 1 (H317) for skin sensitisation according to the CLP Regulation (EC) No.1272/2008.