C12-14 (even numbered) alkyl glycosides, oligomeric and C12-14 (even numbered) alkyl glycosides, oligomeric, carboxymethyl ethers, sodium salts

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

IN VIVO APPROACH

This approach consists of a LLNA test conducted according to the OECD TG 429, under GLP conditions (C0101673-0, 2001). In this study, three groups of four female CBA mice each were treated with the test item at concentrations of 10%, 25%, and 50% in bi-distilled water, by topical application to the dorsum of each ear lobe (left and right) on three consecutive days. A control group of four mice was treated with the vehicle (bi-distilled water) 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 excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes which were washed subsequently and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a beta-scintillation counter. A test item is regarded as a sensitizer in the LLNA if the exposure to at least one concentration of the test item results in an incorporation of 3HTdR at least 3 -fold or greater than that recorded in control mice, as indicated by the stimulation index (SI). In the present case, the stimulation index (SI) was 2.4, 2.2, and 2.9 for the test item at a concentration of 10, 25 and 50%, respectively. Thus, Plantapon LGC Sorb was found to be a non-sensitizer when tested in the LLNA. However, because of the boderline SI of 2.9 for th 50% formulation, it was decided to perform in vitro experiments and assess the enpoint in a weight of the evidence approach.

IN VITRO APPROACH

Due to the complexity of the skin sensitization process a single in vitro assay is not sufficient to adequately assess this toxicological endpoint. Therefore, a combination of several methods addressing two major steps of the sensitization process: protein reactivity and activation of dendritic cells has been proposed in a strategy to assess the sensitizing potential.

The myeloid U937 skin sensitization test (MUSST) is a dendritic cell activation test to predict skin sensitizing potential (BASF 65V0675/11A366, 2011). The test is performed using the human pro-monocytic cell line U937 as surrogate for dendritic cells, and as parameter the change in the expression of the cell membrane marker CD 86 measured by flow cytometry after 48 hours of test substance exposure is determined. Plantapon LGC Sorbwas tested in a concentration range of 25 to 402 µg/mL. No induction of the expression of CD 86 was observed at sufficiently non-cytotoxic (cell viability>70%) concentrations, which were >= 25 and < 401.2 µg/mL. From this it was concluded that the test item did not induce dendritic cell activation.

Plantapon LGC Sorb further was tested in the Direct Peptide Reactivity Assay (DPRA) (BASF 64V0675/11A365, 2012). In the Direct Peptide Reactivity Assay (DPRA) the reactivity of a test item towards synthetic cysteine (C)- or lysine (K)-containing peptides is evaluated. For this purpose the test item is incubated with synthetic peptides for 24 hours at room temperature and the remaining non-depleted peptide concentration is determined by high performance liquid chromatography (HPLC) with gradient elution and UV-detection at 220 nm. The peptides are custom material containing phenylalanine to facilitate UV-detection and either cysteine or lysine as the reactive centre. In the present case, the test item was solved at a 100 mM concentration in de-ionized water. Three samples of the test item preparation were incubated with each peptide in ratios of 1:10 (for C-peptide) or 1:50 (for K-peptide). Additionally triplicates of the concurrent vehicle control and a positive control substance (p-benzoquinone) were incubated with the peptides.Plantapon LGC Sorbshowed a reactivity of 0% towards the cysteine-peptide and 0% to lysine-peptide. Thus, the mean reactivity was 0% indicating minimal reactivity and therefore, the test item was considered to be a non-sensitizer in the present assay.

WEIGHT OF THE EVIDENCE

The LLNA showed a borderline negative result (SI of 2.9 for the 50% formulation). The in vitro assays showed that the test material does not react with proteins and does not activate dendritic cells. Hence, the overall conclusion is that the LLNA result is likely correct, i.e. the material should be considered a non-skin sensitizer.

Migrated from Short description of key information:
The results of an in vivo guideline LLNA test showed that the test item is a non-sensitizer to the skin. This was confirmed by two in vitro approaches (MUSST assay and DRPA assay).

Justification for selection of skin sensitisation endpoint:
In vivo guideline study conducted according to GLP confirmed by two in vitro assays.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available in vitro and in vivo data, the test item does not need to be classified according to the EU Directive 67/548/EEC and to the CLP Regulation (EC)/1272/2008.