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Description of key information

Key value for chemical safety assessment

Additional information

There are no in vivo data on the toxicokinetics of triacetoxyethylsilane. The following summary has therefore been prepared based on validated predictions of the physicochemical properties of the substance itself and its hydrolysis products.Triacetoxyethylsilane is a moisture-sensitive liquid that hydrolyses very rapidly in contact with water (half-life <0.2 minutes at pH 7; predicted), generating acetic acid and ethylsilanetriol. Human exposure can occur via the inhalation or dermal routes. Due to the very rapid hydrolysis, relevant dermal and inhalation exposure would be to the hydrolysis products.

Absorption

Oral: Significant oral exposure is not expected for this corrosive substance.

Dermal: The molecular weights of the hydrolysis products are favourable for absorption across the skin. The predicted water solubility (1E+06 mg/l, miscible) and predicted log Kow(-1.9) of ethylsilanetriol suggest that absorption across the skin is likely to be very low, as the substance is likely to be too hydrophilic to cross the lipid-rich environment of the stratum corneum. However, where contact with the skin occurs, corrosive effects will damage the skin and penetration of the skin might be enhanced. Skin irritation studies did not show any signs of systemic toxicity that could be differentiated from effects secondary to the extreme local effects.

Inhalation: The predicted log Kow and very high water solubility of the hydrolysis product, ethylsilanetriol is likely to lead to some of this hydrolysis product being retained in the mucous of the lungs. Absorption might be increased following corrosive effects on the respiratory epithelium. There are no inhalation data that could be reviewed for signs of systemic toxicity, and therefore absorption.

Distribution

All absorbed test substance is likely to be in the form of the hydrolysis products. Ethylsilanetriol is not likely to distribute into cells due to its very high water solubility and low log Kow.

Metabolism

There are no data regarding the metabolism of ethylsilanetriol. Genetic toxicity tests in vitro showed no observable differences in effects with and without metabolic activation for triacetoxyethylsilane.

Excretion

The low molecular weight and water solubility of ethylsilanetriol suggest that it is likely to be effectively eliminated via the kidneys in urine.