Reaction products of C16-18 (even numbered), C18 unsaturated alkylamines with C10-13 alkylbenzenesulfonic acid

Endpoint summary

Key value for chemical safety assessment

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

No experimental toxicokinetic study is available on the registered substance. However, as per REACH guidance document R7.C, information on absorption, distribution, metabolism and excretion may be deduced from the physicochemical properties.

 

ABSORPTION
The registered substance is a reaction products of C16-18 (even numbered), C18 unsaturated alkylamines with C10-13 alkylbenzenesulfonic acid.
Considering its composition, the substance is expected to be available as its individual constituents following absorption.

 

Oral absorption
The physicochemical characteristics of Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. suggest absorption of this fraction following an exposure via the oral route, since it has a molecular weight below 500 and a Log Kow between -1 and 4. This is supported by experimental data on this fraction. Considering that the partition coefficient of the amine is above 4, despite its favourable molecular weight, it could limit the absorption of this fraction following an oral exposure. However, this value represents a worst-case scenario based on information on similar substances.
Most adverse effects observed following an exposure to the registered substance via the oral route could be the consequence of stress, local effects with subsequent inflammatory reaction, or poor general condition of the animals. Macroscopic and microscopic findings in the lungs may be indicative of an oral absorption of the fractions of the registered substance.
In the absence of experimental data on the absorption of the registered substance, it is considered that oral absorption in the rat was 50% less effective than the human absorption by inhalation in accordance with ECHA Guidance.

 

Inhalation absorption
The registered substance was found to have a vapour pressure of 0.000096Pa, and is therefore not volatile.
100% of inhalation absorption in taken into account for risk assessment in accordance with the ECHA Guidance.
There is no study available on the toxicity of the registered substance following an exposure via inhalation.

 

Dermal absorption
Considering the higher water solubility and Log Kow < 4 of Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs., this fraction of the registered substance could be expected to be better absorbed than the amine fraction.
Since the skin sensitisation study provided a positive result, it is indicative that some uptake occurred.
There is no additional study available on the toxicity of the registered substance following a dermal exposure.

 

DISTRIBUTION
Both fractions of the registered substance have a molecular weight below 500 and a Kog Kow > 0, and can therefore be expected to distribute into cells and the intracellular concentration may be higher than extracellular concentration particularly in fatty tissues.
According to the EU Risk Assessment on Primary Alkyl Amines, bioavailable amount of the amine fraction should be rapidly distributed into the lungs, brain, heart, spleen, kidneys and liver. Findings in lungs during a repeated-dose toxicity study conducted via the oral route with the registered might therefore be a consequence of the distribution of the amine fraction.

METABOLISM
Sulfophenyl butanoic and sulfophenyl pentatonic acid were identified as metabolites of benzenesulfonic acid, C10-13-alkyl derivs.
According to the EU Risk Assessment on Primary Alkyl Amines, the amine fraction should be oxidatively deaminated by monoaminooxidases with concomitant formation of ammonia and the corresponding alkylamine aldehyde. Subsequently, the aldehydes are oxidised by aldehydedehydrogenases to the corresponding carboxylic acids, which, in turn, are further metabolised by ß-oxidation.

ELIMINATION
The urinary route was identified as the main route of excretion for Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs.
According to the EU Risk Assessment on Primary Alkyl Amines, metabolised amine fraction should be eliminated mainly via inhalation, with urinary excretion being only a minor route.