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Diss Factsheets

Administrative data

Description of key information

The calculated oral and dermal LD50 for monoethanolamine oleate are > 2000 mg/kg bw, based on the read-across with monoethanolamine. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
2 000 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
2 000 mg/kg bw

Additional information

No substance-specific data on the acute toxicity of monoethanolamine oleate are available. However, according to Article 13 of the REACH legislation, in case no appropriate animal studies are available for assessment, information should be generated whenever possible by means other than vertebrate animal tests, i. e. applying alternative methods such as in vitro tests, QSARs, grouping and read-across.

Monoethanolamine oleate is a salt of monoethanolamine and oleic acid and is expected to dissociated into the respective monoethanolammonium cation and oleate anion upon uptake by the body. Therefore it is considered to be acceptable to derive lacking information on toxicological properties of monoethanolamine oleate by read-across from its starting materials. Oleic acid is exempted from the registration under REACH according to Annex V of REACH legislation as a non-hazardous substances. Therefore toxicological properties of monoethanolamine oleate are expected to be governed solely by monoethanolamine.

In the oral acute toxicity study with rats, performed according to a protocol similar to OECD Guideline 401 (Union Carbide Corporation, 1988a), undiluted monoethanolamine was administered by gavage at dose levels of 0.25, 0.50, 1.0, 2.0, 4.0 mL/kg bw (equal to 254, 509, 1018, 2036, 4072 mg/kg bw based on a density of 1.018 g/ml) to groups of male and female rats (5/sex/dose at dose levels up to and including 2.0 mL/kg bw, and 2 males/dose at 4 mL/kg bw dose level). Animals were observed for 14 days and necropsied. All animals in the two highest dose groups died. There were no deaths in 0.25 mL/kg bw group; 1 death (male) in the 0.50 mL/kg bw group and 3 deaths (1 male, 2 females) in 1.0 mL/kg bw group. All deaths occurred relatively rapidly after dosing (within 2 days), except for one male rat that died after 12 days after a dose of 0.5 mL/kg. Both of the male rats receiving monoethanolamine at the maximum peroral dosage of 4.0 mL/kg died after 3 hours. One female in the 2.00 mL/kg group died after 4 hours. The clinical signs included sluggishness, piloerection, slight kyphosis, emaciation, unsteady gait, crust and staining of the fur and unkept appearance. Pathological findings revealed red lungs and distended stomach and intestines filled with red liquid in deceased. Mottled red kidneys were observed in the survivors of 1.0 mL/kg bw group; no remarkable findings were observed in survivors of 0.25 and 0.50 mL/kg bw groups. Based on the results of the study, LD50 in males and females were 1.19 (95% CI = 0.79 - 1.80) ml/kg and 1.07 (95% CI = 0.72 - 1.59) mL/kg. The recalculated LD50 for both sexes was 1089 mg/kg bw.

In the acute dermal toxicity study with rabbits, performed according to a protocol similar to OECD Guideline 402 (Union Carbide Corporation, 1988c)

, monoethanolamine was administered to groups of 5 male and 5 female rabbits under occlusive dressing for 24 hours at dose levels of 1.0, 2.0 or 4.0 mL/kg bw (equal to 1018, 2036 and 4072 mg/kg bw). Animals were observed for 14 days and then necropsied. No animals died in the lowest dose group. One male and one female animals died in the 2.0 mL/kg bw dose group and 9 animals (5 males, 4 females) died in the 4.0 mL/kg bw group. Erythema, edema, necrosis, scabs formation and ulceration were common skin reactions observed. Salmon-coloured to dark red lungs were observed in deceased animals together with stomach and intestines filled with liquid or gas. The LD50 was 2504 (95% CI = 1822 -3451) mg/kg bw for male and 2881 (95% CI= 1639 -5070) mg/kg day for female rabbits.

In the acute inhalation toxicity study with rats (Union Carbide Corporation, 1988b)

a group of 5 male and 5 female rats was exposed to the saturated vapour concentration of monoethanolamine, equal to 1.3 mg/L, for 6 hours. There were no deaths or signs of toxicity noted. Pathological findings were uneventful. Based on these findings, LD50 (6 h) for monoethanolamine was > 1.3 mg/L.

As the toxicity of monoethanolamine oleate is expected to be caused by the toxicity of monoethanolamine released upon dissociation, a correction for molecular weight is warranted. An equimolar amount of monoethanolamine is produced upon the intake of monoethanolamine oleate. Using the oral LD50 value of 1089 mg/kg bw and applying a correction factor of 343.31/61.08, corresponding to the ratio of molecular weights of monoethanolamine oleate and monoethanolamine, an LD50 of 6121 mg/kg bw is calculated for monoethanolmine oleate.

For acute dermal toxicity, using the lower value of 2504 mg/kg bw for male rabbits, a value of 2504 × 343.31/61.08 = 14974 mg/kg bw is obtained. These values exceed by far the maximum limit doses recommended by OECD Guidelines and are far above the classification limits of 2000 mg/kg bw for acute toxicity. As the calculated values are excessively high and may exceed the maximal tolerated physiological dose, the OECD guideline limit values of 2000 mg/kg bw will be taken forward for risk assessment.

No LC50 value can be derived for acute inhalation toxicity based on the available data. However, in accordance with Annex VIII of REACH, this information is not required, as data on two routes of exposure are available.

Justification for classification or non-classification

Based on the calculated LD50 values for acute oral and dermal toxicity for monoethanolamine oleate, classification is not not warranted in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and EU Directive 67/548/EEC.