Monoethanolamine oleate

Endpoint summary

Description of key information

The substance is not irritating to skin, but irritating to eyes.

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:

adverse effect observed (irritating)

Additional information

Skin irritation

The skin irritation potential of monoethanolamine oleate was studied in vitro in the GLP-compliant OECD Guideline 439, using Epiderm reconstructed skin membranes (TNO Triskelion B.V., 2011a). The EpiDerm™ skin membranes were topically exposed the test substance for 1 h. After culturing for 42 h the viability of the epidermal cells was assessed using the MTT test. The general principle for the detection of viability via the MTT test is the conversion of the yellow tetrazolium salt (MTT) to the purple coloured product formazan by mitochondrial enzymes. The formation of formazan was measured using a spectrophotometer. The results were interpreted according to the following scheme: if the mean tissue viability expressed as % of negative control was ≥ 50%, the substance was considered not irritating to skin (UN GHS No Category); if the mean tissue viability was < 50%, the substance was considered to be irritating; UN GHS Category 2. Phosphate-buffered saline (PBS) and 5% sodium dodecyl sulphate (SDS) were used as a positive and a negative controls, respectively. Three replicates were used for each substance.

Some chemicals are known to non-specifically reduce MTT, resulting in a blue precipitate. Therefore, prior to the start of the study, 30 μl of the test substance was incubated in 1 mL 1 mg/mL MTT solution for ca. 3 h at ca. 37ºC and 5% CO₂ and the formation of a blue formazan product was assessed visually. During incubation the test substance turned blue/purple and therefore it was concluded that it was necessary to include freeze-killed tissues (frozen controls) treated with PBS and the test substance in the main study.

The mean tissue viability was 93 ± 11% for monoethanolamine oleate, 100 ± 1% for PBS and 5 ± 1% for 5% SDS. The optical density of the frozen controls (FC) treated with the test substance was comparable to the optical density of frozen controls treated with the negative control (PBS). Therefore, it was not necessary to correct data for MTT reduction of the test substance. Based on the results of the study, the substance is not irritating to skin.

Eye irritation

The eye irritating potency of monoethanolamine oleate was studied in a GLP-compliant OECD Guideline 405 study, using three male New Zealand White rabbits (TNO Triskelion B.V., 2011b). The study was conducted because the non-GLP evaluation of eye irritation in vitro using the Isolated Chicken Eye Test (OECD 438) did not reveal signs of severe irritancy. 0.1 mL of the test substance was instilled in the conjunctival cul-de-sac of the right eye, with another eye serving as an untreated control. The effects were examined at 1, 24, 48, 72 hours and 7 days post-instillation. Monoethanolamine oleate caused slight or moderate corneal opacity (mean score at 24 + 48 + 72 hours 0.87 out of max. 4), slight iritis (mean score at 24 + 48 + 72 hours 0.77 out of max. 2), moderate redness (mean score at 24 + 48 + 72 hours 1.77 out of max. 3) and slight or moderate swelling of the conjunctivae (mean score at 24 + 48 + 72 hours 1.43 out of max. 4) and moderate ocular discharge (mean score 1.78 out of max. 3). At 7 days after treatment all eye effects had cleared completely.

The individual scores for corneal opacity at 24, 48 and 72 hours were 0.3, 1.0 and 1.3; for iritis, 0.3, 1.0 and 1.0, for the redness of conjunctivae, 1.3, 2.0 and 2.0, and for chemosis 0.3, 2.0 and 2.0. Based on these results, the substance fulfills the criteria of classification as irritating to eyes according to EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and EU Directive 67/548/EEC.

Effects on eye irritation: irritating

Justification for classification or non-classification

Based on the results of the in vitro skin irritation study with Epiderm reconstructed skin membranes, the substance does not need to be classified for skin irritation according to EU Directive 67/548 and EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

Based on the individual scores at 24 + 48 + 72 hours in two out of three animals of ≥ 1, but < 3 for corneal opacity, ≥ 1, but < 1.5 for iritis, ≥ 2 for redness of conjunctiva and ≥ 2 for chemosis, classification of the substance as Irritating to eyes (Category 2), H319 (causes serious eye irritation) is warranted according to EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008. This classification translates into Xi, R36 (irritating to eyes) according to EU Directive 67/548/EEC.