2-[(1-methylpropyl)amino]ethanol

Endpoint summary

Description of key information

The data available on 2-[(1-methylpropyl)amino]ethanol and the estimations from its physico-chemical properties indicate a significant absorption by oral, dermal and inhalation routes of exposure, widespread distribution, rapid metabolism by oxidation and no bioaccumulation potential of parent and transformation products.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

100

Absorption rate - inhalation (%):

100

Additional information

There is no toxicokinetics, metabolism and distribution data available on 2-[(1-methylpropyl)amino]ethanol. Therefore, the assessment of the toxicokinetics of 2-[(1-methylpropyl)amino]ethanol is based on the available toxicological data and the physicochemical properties as suggested by the REACH Guidance Chapter R.7c:

Molecular weight: 117.19 g/mole

Water solubility: 544 g/L at 20°C ± 1°C

Partition coefficient log Kow = 0.4 

 

ABSORPTION

 

Oral route

 

According to the REACH Guidance, the physicochemical characteristics of 2-[(1-methylpropyl)amino]ethanol (log Pow 0.4) and the molecular mass (117.19 g/mol) are in a range suggestive of absorption as such from the gastro-intestinal tract subsequent to oral ingestion. This assumption of oral absorption is confirmed by the mortality observed at 2000 mg/kg bw in the acute oral toxicity study (Pelcot, 2010) and at 1000 mg/kg bw/d in the oral 2-week toxicity study (Spezia, 2011b).

 

Therefore, the oral absorption of 2-[(1-methylpropyl)amino]ethanol can be assumed to be 100% for risk assessment.

 

Inhalation route

 

According to the REACH Guidance, the physicochemical characteristics of 2-[(1-methylpropyl)amino]ethanol (log Pow 0.4) and the molecular mass (117.19 g/mol) are in a range suggestive of absorption as such from the respiratory subsequent to inhalation exposure. This assumption of absorption is confirmed by the clinical signs of toxicity observed at 0.76 mg/L in the acute inhalation toxicity study (Schuler, 2012). Therefore, the inhalation absorption can be assumed to be 100% for risk assessment.

 

Dermal absorption

 

According to the REACH Guidance, the n-Octanol/water partition coefficient ((log Pow), the water solubility and molecular weight of2-[(1-methylpropyl)amino]ethanol are in ranges which favour dermal absorption. In such circumstances, a default value of 100% skin absorption is generally used.

 

DISTRIBUTION and METABOLISM

 

According to the REACH Guidance, as a small molecule a wide distribution of 2-[(1-methylpropyl)amino]ethanol is expected.

 

The major routes of metabolism of secondary amines involve various oxidative processes, including N-oxidation and dealkylation followed by deamination and conjugation, and other enzyme-catalyzed reactions leading to detoxification and excretion. Additionally, N-acetylation (a genetically regulated process in humans) may occur, but represents only a very minor pathway in the metabolism of aliphatic amines.

 

In animals, aliphatic amines are metabolized to carboxylic acid and urea. For secondary amines, metabolic intermediates are the corresponding aldehyde and ammonia. Metabolic pathways involved include (1) monoamine oxidase deamination; (2) diamine oxidase deamination; (3) N-dealkylation by cytochrome-P450; N-oxidation by cytochrome P-450 to the nitrone; and (4) N-oxidation by microsomal flavin-containing monooxygenase (FMO).

 

ELIMINATION

 

According to the REACH Guidance, the n-Octanol/water partition coefficient (log Pow of 0.4) is not suggestive of accumulation of unchanged 2-[(1-methylpropyl)amino]ethanol in fatty tissues subsequent to absorption.