Mono- and/or di- and/or tri(1-phenylethyl)-m-cresol and p-cresol

Endpoint summary

Description of key information

Atlen SK is expected to undergo dermal and oral/GI absorption and to exhibit high bioaccumulation potential.

Key value for chemical safety assessment

Bioaccumulation potential:

high bioaccumulation potential

Additional information

Atlen SK was not specifically tested with respect to its toxicokinetics. Hence, information on its absorption, distribution, metabolism and excretion were derived from the relevant available information following the guidance document Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance. (version of May 2008).

 

Absorption

Physicochemical properties of Atlen SK indicate that its degree of absorption should decrease in the following order:

dermal ≥ oral/GI > respiratory (inhalation).

Main indicators of Atlen SK slightly higher potential for dermal absorption with respect to oral/GI absorption are the following facts: Alten SK is liquid, its constituents have relatively low molecular weights (ranging from 212 to 421), its water solubility is 10.3-16.7 mg/l (depending on pH) which indicates low to moderate absorption through skin, its log P is 4.45 which indicates high uptake into the stratum corneum, it has low vapour pressure and in skin sensitisation assay it gave positive response. Regarding the oral/GI absorption although molecular weight of Alten SK constituents is < 500 (which is favourable for oral/GI absorption), yet it is still > 200 which for water insoluble substances (and Atlen SK has low water solubility) excludes possibility for the substance to pass through aqueous pores or be carried through the epithelial barrier by the bulk passage of water. Its low water solubility also limits its absorption by passive diffusion. Also not all conditions favouring micellular solubilisation are met as log P is indeed > 4 but water solubility is not 1 mg/l or less.

Potential of Atlen SK for respiratory absorption is deemed as the lowest of all three routes due to its low volatility (its vapour pressure is 0.122 kPa which is < 0.5 kPa limit mentioned in the guidance) and low potential to form aerosols.

 

Distribution

From the point of view of evaluation of Atlen SK distribution, available data is very limited and does not allow for any conclusions to be drawn.

 

Accumulative potential

As Atlen SK has log P > 4 and no further data is available it has to be assumed that Atlen SK has potential to accumulate within the body. Potential to accumulate in adipose tissue and stratum corneum can be expected. For the purpose of Chemical Safety Assessment it was assumed that Atlen SK has high bioaccumulation potential.

 

Metabolism

Available data does not allow to draw any conclusion with respect to metabolism of Atlen SK.

 

Excretion

As Atlen SK has low water solubility its excretion with urine may be limited. The part of Atlen SK which after penetration of stratum corneum did not penetrate the viable epidermis may be sloughed off with skin. Available data does not allow to draw any further conclusions.