Hexanedioic acid, polymer with 2,2'-oxybis[ethanol]

Endpoint summary

Description of key information

The test substance Hexanedioic acid oligomeric reaction products with 2,2'-oxybis[ethanol] was tested for irritation/corrosion in different test systems. The results showed no indication of eye or skin irritation.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The test substance Hexanedioic acid oligomeric reaction products with 2,2'-oxybis[ethanol] was tested for irritation/corrosion in different in vitro test systems:

1. Human skin model test (OECD 431): The test was performed according to GLP with the human skin model EpiDerm™ (Epi-200 tissue model, MatTek Corporation Ashland, USA). The tissues (surface 0.6 cm²) were treated with the test item (50 µl undiluted) and controls (deionised water as negative, 8 mol/l KOH as positive control), respectively. Corrosive potential of the test substance was predicted by assessing cytotoxicity, expressed by a decrease in mitochondrial dehydrogenase activity. This decrease was measured indirectly via spectrophotometrical determination of the blue colored formazan. After treatment with the test item, the relative absorbance values were 101.1 % of the negative controls after three minutes treatment, which is well above the threshold for corrosion potential (50%). It was concluded that the test substance is a non-corrosive.

2. Human skin model test (OECD 439): The test was performed according to GLP with the human skin model EpiDerm™ (Epi-200 tissue model, MatTek Corporation Ashland, USA). The tissues (surface 0.6 cm²) were treated with the test item and controls (PBS as negative, 5% SDS as positive control), respectively. Irritation potential of the test substance was predicted by assessing cytotoxicity, expressed by a decrease in mitochondrial dehydrogenase activity. This decrease was measured indirectly via spectrophotometrical determination of the blue colored formazan. After treatment with the test item, the relative absorbance values were 99% of the negative controls, which is well above the threshold for irritation potential (50%). It was concluded that the test substance is a non-irritant.

3. EpiOcular™ eye irritation test (no guideline):

The test was performed according to GLP using the EpiOcular™ OCL-200 kit. The test substance was applied to the tissues (two tissue samples per treatment group). Negative (de-ionized water) and positive controls (methyl acetate) were run concurrently. Formazan production after incubation with MTT was measured as indicator for cytotoxicity. The ratio of formazan production in the test substance-treated tissues and that in the negative control tissues indicates relative tissue viability. The test substance was not able to reduce MTT, and the mean viability of the test substance-treated tissues was 102%, which is well above the threshold for irritation potential (50%). It was concluded that the test substance does not show an eye irritation potential. No guideline is available for this assay. However, the EpiOcular™ assay has been validated in idependent studies (BASF in-house validation, Kolle et al., ATLA, 2011; Kaluhzny et al., ATLA, 2011), the results of which prove its high rate of correct predictivity. More specifically, the overall sensitivity of the assay was calculated to be 98.0% and 98.1%, depending on the study, indicating that practically no false negative predictions are made using this test system. Thus, it can be concluded that the test substance is not irritating to the eyes.

Based on the results of all performed studies, it can be concluded that the test substance is neither corrosive nor irritating to the skin and that it holds no eye irritation potential.

Justification for selection of eye irritation endpoint:
The EpiOcular eye irritation test has been validated using a number of known irritants and non-irritants (BASF in-house validation, Kolle et al., ATLA, 2011; Kaluhzny et al., ATLA, 2011). The overall sensitivity of the assay was calculated to be 98.1% (Kaluhzny et al.) and 98% (Kolle et al.), whereas the specificity of the test was 72.2% (Kaluzhny et al.) and 64% (Kolle et al.) under the presumption that a chemical can be regarded as an irritant (GHS Category 1 or 2) if the tissue viability is ≤ 60%, and as a non-irritant (GHS unclassified) if the viability is > 60%. The results indicate that the EpiOcular eye irritation test shows an extremely low rate of false negatives. In contrast, a recent ICCVAM validation has shown that alcohols tend to be overpredicted by the HET-CAM assay (ICCVAM Test Method Evaluation Report 2010: Current Validation Status of In Vitro Test Methods Proposed for Identifying Eye Injury Hazard Potential of Chemicals and Products (Appendix E – Background Review Document Current Status of In Vitro Test Methods for Identifying Mild/Moderate Ocular Irritants: The Hen's Egg Test–Chorioallantoic Membrane (HET-CAM) Test Method)). Since the HET-CAM assay is not applicable to the present test substance due to its high content of hydroxyl groups, and since the EpiOcular assay was negative for the test substance, it can be concluded that the test compound is a not irritating to eyes.

Justification for classification or non-classification

The conducted tests gave no indication of irritative/corrosive effects to the skin or irritative effects to the eyes, and as a result there is no need for classification according to GHS.