Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts

Endpoint summary

Description of key information

Absorption:

Systemic bioavailability of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts is considered likely after oral uptake and an absorption along the gastrointestinal tract is favoured. Systemic bioavailability was confirmed in several oral acute and repeated dose toxicity studies. Due to its solid state, the moderate molecular weight in the range of 287.4 – 427.6 g/mol and the ionic nature, only limited dermal penetration is expected. Based on the respirable size of the particles, Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts may potentially be inhaled and reach the thoracic region. The use of the substance is not anticipated to result in the formation of aerosols, but in case of operational exposure to dusts, respiratory exposure may potentially occur.

 

Distribution and accumulation:

Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts has a log Pow od -0.44 – 0.54 and is considered to distribute within the body and to enter preferentially fatty tissues to some extent.

Metabolism and excretion:

Structure related considerations suggest enzymatic degradation in analogy to accepted metabolic pathways for amide hydrolysis and fatty acid ß-oxidation. The metabolism will not generate metabolites of toxicological concern. Excretion of postulated metabolites is considered fast and complete.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

There are no experimental studies available investigating the toxicokinetic properties of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts. Therefore, whenever possible, toxicokinetic behavior was assessed taking into account the available information on physico-chemical and toxicological characteristics of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts according to the “Guidance on information and chemical safety assessment Chapter R.7c: Endpoint specific guidance (ECHA, 2017)”.

 

Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts is a UVCB substance and has a molecular weight of 287.4 -427.6 g/mol. It is a white solid powder with a moderate to high water solubility (0.23 – 250 g/L), a vapour pressure of < 1 Pa (4.7E-5 Pa at 25°C) and a log Pow of -0.44 - 0.54.

 

Absorption

Absorption is a function of the potential for a substance to diffuse across biological membranes. The most useful parameters providing information on this potential are the molecular weight, the octanol/water partition coefficient (log Pow) value and the water solubility. The log Pow value provides information on the relative solubility of the substance in water and lipids (ECHA, 2017).

 

Oral:

The molecular weight (287.4 -427.6 g/mol), the water solubility ((0.23 – 250 g/L) and the moderate log Pow value (-0.44 - 0.54) favour an absorption along the gastrointestinal tract.

 

The acute oral toxicity study of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts and also of the read-across substance Sodium 2-[methyloleoylamino]ethane-1-sulphonate  has been investigated in rats (Clariant, 1987a and 1987b). The LD₅₀ from these studies was determined to be > 2000 mg/kg bw for male and female animals, respectively. As a number of clinical signs of toxicity were observed following dose administration, it can be assumed that a certain amount of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts must have been absorbed. Similar observations were made in a sub-acute and a sub-chronic oral toxicity study in rats (Covance 2021a and Covance 2021b) in male and female Wistar rats. Although no adverse effects were observed, clinical signs of toxicity, alterations in haematology and clinical chemistry parameters as well as changes in hormone levels confirmed the uptake of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts after oral exposure.

 

Dermal:

Regarding the water solubility (0.23 - 250 g/L) and the lipophilic properties of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts (log Pow -0.44 - 0.54), dermal absorption is anticipated to be generally possible. However, due to its solid state and the moderate molecular weight of 287.4 – 427.6 g/mol, dermal uptake is overall considered to be low. This result is underpinned by a Dermwin v2.0 QSAR modelling assessment which estimated a dermal permeability constant of Kp 9.38E- 006 cm/h for Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts. The maximum flux Imax (Imax = Kp [cm/h] x water solubility [mg/cm³]) was calculated, resulting in dermal absorption of 0.002 and 2.345 µg substance/cm²/h.

If a substance shows skin irritating or corrosive properties, damage to the skin surface may enhance penetration. If the substance has been identified as a skin sensitizer then some uptake must have occurred although it may only have been a small fraction of the applied dose (ECHA, 2017).

The available data on skin irritation in vitro and skin sensitisation in guinea pigs did not show any irritating or sensitising effects, therefore no enhanced penetration of the substance due to skin damage is expected (Croda, 2013a and 2013b and Clariant, 1994).

Overall, taking all available information into account, the dermal absorption potential of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts is considered to be low.

 

Inhalation:

The particle size determination of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts revealed percentile values of D10: 3.87 µm, D50: 16.58 µm and D90: 59.97 µm. Particles with and aerodynamic diameter below 100 µm have the potential to be inhaled and may reach the thoracic region of the respiratory tract if they are < 50 µm and the alveolar region if they are < 15 µm (ECHA, 2017). Therefore, inhalation of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts is generally possible. However, since the substance is a solid with a very low vapour pressure (4.7E-5 Pa at 25°C), it is probably not available for inhalation as vapour. Furthermore, the use of the substance is not anticipated to result in the formation of aerosols, particles or droplets of inhalable size. In case of operational exposure to dusts, respiratory exposure may potentially occur.

 

 

 

Distribution

Distribution within the body depends on the molecular weight, the lipophilic character and water solubility of a substance. In general, the smaller the molecule, the wider is the distribution. If the molecule is lipophilic, it is likely to distribute into cells and the intracellular concentration may be higher than extracellular concentration particularly in fatty tissues (ECHA, 2017). With a molecular weight of 287.4 - 427.6 g/mol and the slight lipophilic character (log Pow > 0), Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts is considered to distribute within the body and to enter preferentially fatty tissues to some (limited) extent.

 

Metabolism and Excretion

Following the accepted metabolic pathways for alkylamides, the amide linkage of Ethanesulfonic acid, 2-(methylamino)-, N-coco acyl derivs., sodium salts will initially be hydrolysed to generate sodium N-methyl taurine and fatty acids by fatty acid amide hydrolase, the principal catabolic enzyme for fatty acid amides having both, esterase and amidase activity (EPA, 2009). This metabolism step was also observed after modelling of potential metabolites with the hydrolysis simulator of the OECD toolbox Vs. 3.2. The resulting anionic sulfonate may be either directly excreted in the urine or converted to a dianionic salt with glucuronic acid that is excreted. The fatty acid moiety is metabolised in a second step via the ß-oxidation pathway (Stryer, 1996). This metabolic behaviour was also demonstrated for sodium N-oleoyl-N-methyltaurine in Pseudomonas alcaligenes (Denger et al. 2008).

 

 

References:

Denger, K., Mayer, J., Hollemeyer, K., Cook, A.M. (2008), FEMS Microbiol. Lett. 288: 112- 117

 

ECHA (2017). Guidance on information requirements and chemical safety assessment, Chapter R.7c: Endpoint specific guidance. Version 3.0.

 

EPA (2009), Final Rule, Federal Register 74, 2009 [EPA-HQ-OPP-2008-0725; FRL-8426-8]

 

Stryer, L. (1996). Biochemie. 4. Auflage. Heidelberg Berlin Oxford: Spektrum Akademischer Verlag