Dodecyl(2-hydroxy-3-sulphonatopropyl)dimethylammonium

Endpoint summary

Description of key information

There is no requirement to generate experimental toxicokinetic data under REACH. No toxicokinetic data are identified; however a theoretical assessment of the toxicokinetic properties of the substance is made, based on existing toxicity data, (Q)SAR, and taking into account the (physico)chemical properties of the substance. 

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

BETADET S-20

The substance BETADET S-20 (CAS 13197 -76-7) is a UVCB.  A theoretical toxicokinetic assessment is made for the major component (lauryl hydroxysultaine; dodecyl(2-hydroxy-3-sulphonatopropyl)dimethylammonium (~75%).

Absorption

The major component (lauryl hydroxysultaine) is predicted to be bioavailable according to Lipinski’s rules (Oasis). The estimated Log Kow value (-1.3) does not favour oral absorption; however the molecular weight and high water solubility means that oral absorption is likely. Hydrolysis and/or microbial metabolism may occur in the gastrointestinal tract, leading to the absorption of lower molecular weight breakdown products. The substance is a solid, therefore significant inhalation exposure is not predicted. The water solubility of the substance favours absorption following inhalation exposure. The water solubility of the substance favours dermal absorption; however this may be limited by the relatively high molecular weight and low lipid solubility.

In the absence of specific data, dermal absorption is assumed to be equivalent to dermal absorption; inhalation absorption is assumed to be twice that of oral absorption.

Distribution

Information from the 90-day study reports elevated liver and kidney weights, indicating that the substance and/or its metabolites are distributed to the liver and kidneys. This finding therefore indicates systemic exposure. The 90-day rat study reports slight increases in liver and kidney weights at the highest dietary concentration of 0.5% (5000 ppm, equivalent to 380 and 440 mg/kg bw/d in males and females respectively); findings were not associated with histopathology and are not therefore considered to be adverse but can be taken to indicate systemic (post-hepatic) distribution. 

Metabolism

The mammalian metabolism of lauryl hydroxysultaine is predicted using OECD QSAR Toolbox (v.4). The rat liver S9 metabolism simulator predicts four oxidative metabolites. Three metabolites arise from sequential hydroxylation of the ω-carbon of the C12 sidechain to form the corresponding alcohol, aldehyde and carboxylic acid. A further metabolite is predicted to arise from hydroxylation of the (ω-1)-carbon of the C12 sidechain. The in vivo rat metabolism simulator predicts two metabolites, arising from hydroxylation of the (ω-2)- and (ω-3)- carbons on the C12 sidechain. The skin metabolism simulator predicts the oxidation of the hydroxyl group on the hydroxysultaine moiety of the intact molecule to generate an aldehyde. The molecule is predicted to be hydrolytically stable at neutral, acidic and basic pH; therefore hydrolysis in the gastrointestinal tract is not predicted. It is notable, however, that extensive microbial metabolism is predicted (>100 metabolites), indicating that metabolism by the gastrointestinal microflora may occur following oral exposure.

Excretion

Increased kidney weight in the absence of histopathological or clinical chemistry correlates in the 90-day rat study indicates an adaptive effect, possibly reflecting urinary excretion. Based on the likely extensive metabolism of the substance urinary excretion of metabolites is predicted.

Bioaccumulation

Bioaccumulation is not predicted, based on the likely metabolism and excretion of the substance.