(hexadecylamidopropyl)trimethylammonium chloride

Endpoint summary

Description of key information

Experimental toxicokinetic studies are not available for C16 Alkylamidopropyltrimethylammonium Chloride.

The log Kow of 2.49 and the molecular weight of 391.07 g/mol are suggestive of oral absorption from gastro-intestinal tract, by dermal route or from the lungs.
It is generally thought that ionised substances do not readily diffuse across biological membranes. However, due to the lack of experimental data, 100% absorption by all routes is assumed as worst case default for chemical safety assessment.
Based on physicochemical properties, no potential for bioaccumulation is to be expected.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

Experimental toxicokinetic studies are not available for C16 Alkylamidopropyltrimethylammonium Chloride. Thus, the assessment of toxicokinetics is based on the physicochemical properties:

 

molecular weight: 391.07 g/mol

water solubility (critical micelle concentration): 203 mg/L at 20.1°C

log Kow: 2.49

 

The substance is a surfactant showing a complex solubility behaviour due to aggregation. The concentration reaches a limiting value at the critical micelle concentration (the limit above which virtually all additional surfactant molecules form micelles) remaining approximately constant when the total concentration is further increased.

Moreover, the substance is a quaternary ammonium ion. As it is generally thought that ionised substances do not readily diffuse across biological membranes, this will also be taken into account for the assessment of toxikokinetics.

 

Oral absorption

The physicochemical properties of C16 Alkylamidopropyltrimethylammonium Chloride (log Kow = 2.49) and the molecular weight of 391.07 g/mol are in a range suggestive of absorption from the gastro-intestinal tract subsequent to oral ingestion (molecular weight < 500 g/mol, log Kow between -1 and 4).

For chemical safety assessment an oral absorption rate of 50% is assumed as a worst case default value in the absence of other data

 

Dermal absorption

It is generally thought that ionised substances do not readily diffuse across biological membranes.

However, in the absence of detailed dermal penetration data it has to be assumed that dermal penetration may occur.

For chemical safety assessment a dermal absorption rate of 50% is assumed as a worst case default value (same absorption rate as via the oral route).

 

Inhalation absorption

For chemical safety assessment an inhalative absorption rate of 100% is assumed as a worst case default value in the absence of other data.

 

Distribution

As a small molecule a wide distribution can be expected. No information on potential target organs are available. However, as an ionised molecule, the substance is thought to not readily diffuse across biological membranes.

 

Metabolism

It is very difficult to predict the metabolic changes a substance may undergo on the basis of physico-chemical information alone.

Based on the structure, the substance is likely to undergo hydrolysis by amidases, which in general have a broad substrate specificity. Hydrolysis of C16 Alkylamidopropyltrimethylammonium Chloride would result in Palmitic acid and 3-Aminopropyltrimethylammonium chloride.

Palmitic acid is likely to enter the normal fatty acid metabolism and may be broken down to carbon dioxide or two carbon fragments, or be re-esterified to triacylglycerols and either metabolised for energy or stored in adipose tissue.

In general, lower primary aliphatic amines are metabolised to the corresponding carboxylic acid and urea.

The quaternary site would not be expected to undergo metabolism, but to remain unchanged.

 

Elimination

The major routes of excretion for substances from the systemic circulation are the urine and/or the faeces.

Palmitic acid as one metabolite would enter the regular fatty acid metabolism and be indistinguishable from Palmitic acid from other sources. Thus, further considerations are not considered necessary.

The amine metabolite is likely to be excreted via the urine. Favourable physicochemical properties for urinary excretion are good water-solubility and low molecular weight (< 300 g/mol; mostly anionic and cationic compounds). 

 

Bioaccumulation

Based on the log Kow <3 (2.49) the substance is unlikely to accumulate with the repeated intermittent exposure patterns normally encountered in the workplace.