Nonanoic acid, esters with adipic acid and trimethylolpropane

Endpoint summary

Description of key information

Skin irritation (OECD 439, GLP read across): not irritant

Skin corrosion (OECD 431, GLP, read across): not corrosive

Eye irritation (OECD 405, GLP, read across): not irritant

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

Justification for read-across

There are no data available on skin irritation /corrosion and eye irritation of the target substance Nonanoic acid, esters with adipic acid and trimethylolpropane. Therefore, read-across from the appropriate structural analogue substances trimethylolpropane tripelargonate (CAS 126-57-8) and Fatty acids, C8-10, mixed esters with adipic acid and trimethylolpropane (CAS 95912-89-3) is conducted in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. in order to fulfil the standard information requirements defined in Regulation (EC) No 1907/2006, Annex VII, 8.1 and 8.2. Common functional groups and structural similarities combined with similar toxicokinetic properties of the source and target substances are the basis of read-across. A detailed justification for the analogue read-across approach is provided in the technical dossier (see IUCLID Section 13).

Skin irritation, in vitro

CAS 126-57-8

The skin corrosive properties of the source substance trimethylolpropane tripelargonate (CAS 126-57-8) were assessed according to OECD guideline 431 and GLP (Laus GmbH, 2012). Two tissues of the human skin model EpiDerm™ were treated with trimethylolpropane tripelargonate (CAS 126-57-8) for 3 min and 1 h, respectively. 50 μL of the liquid test item was applied to each tissue and spread to match the tissue size. Deionised water was used as negative control, 8M KOH was used as positive control. After treatment, the respective substance was rinsed from the tissue; and cell viability of the tissues was evaluated by addition of MTT, which can be reduced to a blue formazan. Formazan production was measured by measuring the optical density (OD) of the resulting solution. After treatment with the negative control, the absorbance values were well above the required acceptability criterion of mean OD > 0.8 for both treatment periods. The positive control showed clear corrosive effects for both treatment periods. After the 3-min treatment with the test item, the relative absorbance values were reduced to 98.1%. This value is well above the threshold for corrosion potential (50%). After the 1-h treatment, the relative absorbance values were reduced to 92.0 %. This value, too, is well above the threshold for corrosion potential (15%). The source substance is considered to meet the criteria as “non-corrosive to skin”.

CAS 95912-89-3

A GLP-conform in vitro skin irritation study according to OECD guideline 439 was performed with Fatty acids, C8-10, mixed esters with adipic acid and trimethylolpropane (CAS 95912-89-3) (Laus GmbH, 2012). In this study, a reconstructed three-dimensional human epidermis model was used to investigate the effects of the undiluted test substance on the viability of epidermal keratinocytes. After 60 min exposure to the test substance, the viability of human keratinocytes was 99.4% compared with the negative control PBS (100%). The positive control (5% SDS) significantly reduced the viability of cells compared with the negative control, fulfilling the criteria for the acceptability of the assay (relative viability ≤ 20%). Since the mean relative tissue viability was ≥ 50% after 60 minutes treatment, the test substance was considered to be non-irritant to human skin according to the criteria specified in OECD guideline 439.

Based on the results of both in vitro studies and applying the read across approach, the target substance is expected to be not irritant to the skin.

Eye irritation, in vivo

CAS 126-57-8

The eye irritation potential of trimethylolpropane tripelargonate (CAS 126-57-8) was investigated in a study performed according to OECD guideline 405 and GLP (Research Toxicology Center, 2014). A 0.1 mL aliquot of the test item was instilled into the right eye of a total of 3 rabbits. The eye irritation reaction was assessed and scored approximately 1, 24, 48, and 72 h after dosing. No significant irritation at either the conjunctivae, iris or cornea was recorded in any treated animal during the study. The scores were 0 for all the rabbits at every time point and for every parameter (chemosis, conjunctivae, iritis, corneal opacity). There were no signs of pain/distress after dosing. Changes in body weight were unremarkable. There was no indication of a systemic effect related to treatment. The test substance did not cause eye irritation in the rabbit.

Overall conclusion

The available data with the analogue substances trimethylolpropane tripelargonate (CAS 126-57-8) and Fatty acids, C8-10, mixed esters with adipic acid and trimethylolpropane (CAS 95912-89-3) revealed no irritant properties to the skin and to the eyes, respectively. Therefore applying the read-across approach similar results are expected for the target substance.

Justification for classification or non-classification

According to Article 13 of Regulation (EC) No. 1907/2006 "General Requirements for Generation of Information on Intrinsic Properties of substances", information on intrinsic properties of substances may be generated by means other than tests e.g. from information from structurally related substances (grouping or read-across), provided that conditions set out in Annex XI are met. Annex XI, "General rules for adaptation of this standard testing regime set out in Annexes VII to X” states that “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or ‘category’ of substances. This avoids the need to test every substance for every endpoint". Since the analogue concept is applied to Nonanoic acid, esters with adipic acid and trimethylolpropane, data will be generated from data for reference source substance(s) to avoid unnecessary animal testing. Additionally, once the analogue read-across concept is applied, substances will be classified and labelled on this basis.

Therefore, based on the analogue read-across approach, the available data on skin and eye irritation do not meet the classification criteria according to Regulation (EC) 1272/2008 and are therefore conclusive but not sufficient for classification.