Reaction mass of sodium hydrogen N-(1-oxooctadecyl)-L-glutamate and sodium hydrogen N-(1-oxohexadecyl)-L-glutamate

Endpoint summary

Description of key information

The substance Sodium Stearoyl-L-Glutamate is a multi-constituent organic substance composed by sodium hydrogen N-(1-oxooctadecyl)-L-glutamate (main component – ca. 64%) and sodium hydrogen N-(1-oxohexadecyl)-L-glutamate (ca. 33%), with a molecular weight ranging between 419 and 429. 
Based on the organic nature of the components within the substance, complete oral absorption for the substance as a whole might be expected. Complete (100%) oral absorption will be used for risk assessment.
In the absence of quantitative information, for the purposes of risk assessment estimation of mammalian dermal absorption is made in accordance with principles adopted by the EFSA guidance on estimating dermal absorption of pesticide active substances (EFSA, 2012).  On this basis, dermal absorption for the substance is assumed at 25%.
In the absence of quantitative information, complete absorption (100%) following inhalation is assumed for the purposes of risk assessment.

Key value for chemical safety assessment

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

25

Absorption rate - inhalation (%):

100

Additional information

The substance is a multi-constituent organic substance consisting of a major component at ca. 64% and a minor component at ca. 33%, with a molecular weight ranging between 419 and 429. It is an off-white solid powder under ambient conditions, with 77.1% of particles being less than 100 µm in size. Its water solubility was found to be related to the loading rate of the test material, with the major component being generally more water soluble than the minor component. It has surfactant properties so that it was not possible to determine an octanol-water partition coefficient. The substance is readily biodegradable.

 

Absorption

Nothing can be inferred from the acute oral toxicity study, because no clinical sign was observed following oral administration at the limit dose of 2000 mg/kg bw. The molecular weight not exceeding 500g/mol, and the nature of components suggest good oral absorption, with the process starting already in the stomach where peptidases are likely to cleave the peptide bond giving rise to fatty acids and glutamate. In addition,the surface-active properties could enhance intestinal absorption by affecting cell membrane, although metabolism from the intestinal flora can be expected to occur, as supported by readily biodegradability. 

Based on the organic nature of the components within the substance,complete oral absorption for the substance as a whole might be expected. Complete (100%) oral absorption will be used for risk assessment.

 

No adverse effects, either local or systemic, were recorded in the acute dermal toxicity, the skin irritation or the skin sensitisation studies conducted with the substance, and nothing can be inferred about the dermal penetration properties of the substance from these studies.

In the absence ofquantitative information, for the purposes of risk assessment estimation of mammalian dermal absorption is made in accordance with principles adopted by the EFSA guidance on estimating dermal absorption of pesticide active substances (EFSA, 2012). On this basis, dermal absorption for the substance is assumed at 25%.

 

In the absence ofquantitative information, complete absorption (100%) following inhalation is assumed for the purposes of risk assessment.

 

Distribution

It can be expected that once absorbed the components of the substance will be widely distributed within the body. It is anticipated that the substance will be metabolised to substrates of endogenous metabolism. The acyl residues will be distributed via chylomicrons, while sodium will become part of the large physiological pool for this electrolyte existing within the body. Glutamic acid will reach the liver, and there subjected to metabolism or re-used for other metabolic processes.

 

Metabolism

The acyl residues and glutamate will be used as a source of energy within the citric acid cycle; in case of glutamate, it will be also used for the synthesis of peptides or other amino acids, or excreted in the form of urea.

 

Elimination

Most of the components deriving from metabolism/degradation of the parent compound will be re-used for other metabolic processes within the body; sodium will be eventually excreted in the urine as will be urea, resulting from the catabolism of glutamate.