Cyclohexanaminium, N,N,N-trimethyl-, hydroxide (1:1)

Endpoint summary

Description of key information

Relevant physical-chemical information:

Molecular weight 159.27 g/mol

LogP(ow) = -2.19 at 23°C and pH 11.6

Water solubility – very high (aqueous solution), estimated at 1000 g/L (at 25°C) by EPIWIN

pKa unknown, probably quite high (compare triethylamine: pKa (in water) 10.72)

Vapour pressure: expected equal to water (23 hPa at 20°C)

 

 

Oral Absorption:

The test substance is highly hydrophilic with very good water solubility and a logPOW of -2.19. The molecular weight is below 500 g/mol, which suggests good absorption in the first place.

The test substance is a strong base with a pH > 11 measured for a 50% aqueous solution. No information on the pKa value is available, but it can be assumed to be quite high based on structurally related substances. For example, the pKa-value of triethylamine in water is 10.72. Based on this information, the test substance most likely reacts with the hydrochloric acid of the stomach to a chloride salt.

Due to its corrosive properties, no data on acute oral toxicity are available for the test substance itself. However, the sulfate salt was tested in acute oral toxicity and showed mortality and clinical signs, suggesting absorption of the ionized substance.

Hydrolization of the test substance in the stomach is unlikely and was not predicted by OECD QSAR Toolbox. Whether metabolization of the test substance by intestinal microbiota occurs in the lower GI tract is not known and cannot be excluded. From the data available, absorption in the GI tract is considered likely.

 

Respiratory absorption:

The test substance is present as 50% aqueous solution, therefore the vapour pressure of water is assumed. Given that the test substance is a liquid, particle size considerations do not apply. As mentioned above, the substance is very hydrophilic and LogPOW is -2.19. Absorption directly across the respiratory tract epithelium cannot be excluded.

 

Dermal absorption:

The test substance is a liquid with a molecular weight above 100 g/mol. Water solubility is very high and the logPOW is at -2.19, therefore the substance is very hydrophilic. According to ECHA Guidance document R.7c, substances with high affinity for aqueous compartments can be too hydrophilic to cross the strateum corneum. Vapour pressure is expected to be equal to that of water, since the substance is present as aqueous solution. According to ECHA Guidance document R.7c, the vapour pressure of 23 hPa at 20°C may limit dermal penetration. Surface activity can increase dermal penetration, but based on the chemical structure, surface activity of the test substance is not expected. The test substance was shown to be corrosive and can potentially damage the skin barrier, thereby increasing absorption.

Due to its corrosive properties, no data on dermal toxicity or sensitization are available for the test substance.  

 

Distribution:

The test substance has a molecular weight of 159.27 g/mol, is highly water soluble and has a logPOW of -2.19. Therefore, distribution to aqueous compartments is expected, distribution to fatty tissues expected to be low. Target organ toxicity or signs of toxicity were not observed in an OECD TG 422 study.

Based on its phys-chem properties, accumulation of the test substance is not expected.

 

Excretion:

Based on size and water solubility, excretion of the test substance via urine is expected. Based on structure and phys-chem properties, the test substance unlikely to be excreted to a significant extent via bile. Excretion via breast milk cannot be excluded but is not likely to occur to a significant extent due to the hydrophilic nature of the test substance. Excretion via exhaled air is expected minimal to non-existent. Similarly, excretion via saliva, sweat, hair, or nails is considered unlikely.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100