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Description of key information

Key value for chemical safety assessment

Additional information

Assessment of the toxicokinetic behavior of test substance:

There were no studies available in which the toxicokinetic properties of the test substance were investigated. The test substance is a reaction product with a molecular weight ranging from 756 to 2800 depending on the oligomerization status. The test article is a white powder with a calculated log Pow of 12.9 and a water solubility of < 0.0001 g/l. The vapor pressure was calculated at 4.45E-18 at 25°C.

Absorption

In an acute oral toxicity study in rats no substance-related mortality and no systemic findings were observed after oral administration of test substance. Therefore, no conclusion can be drawn regarding systemic availability. Generally, the smaller the molecule, the more easily it may be taken up. Molecular weights below 500 g/mol are favorable for absorption; molecular weights above 1000 g/mol do not favor absorption. The larger molecules present in the test material (dimers and higher, molecular weight above 1500) might be too large to be absorbed in the gastrointestinal tract. The monomer is in a weight range which is in favor of absorption. However, the water solubility of the test article is very low, thus not favoring the substance to be readily dissolved in gastrointestinal fluids. Furthermore, passive diffusion is also not very likely to happen because of the high log P (> 4) of the test substance. Based on these physico-chemical parameters, the potential for absorption through the gastrointestinal tract is considered to be low for all oligomers present in the test substance. In a subacute repeated dose toxicity study no toxicological relevant effects were reported up to the highest dose tested (1000 mg/kg). No indications of systemic availability could be obtained in this study. The bioaccumulation potential is therefore regarded as low.

Dermal uptake is favored for chemicals with a molecular weight < 100 dermal, while chemicals with a molecular weight > 500 have low potential to penetrate the skin (ECHA GD 7c, 2008). Based on the molecular size, the test article is therefore expected to possess a low dermal penetration potential. Highly lipophilic substances (log P 4-6) that come into contact with the skin can readily penetrate the lipid rich stratum corneum but are not well absorbed systemically. Although they may persist in the stratum corneum, they will eventually be cleared as the stratum corneum is sloughed off. In conclusion, systemic availability of the test article after dermal exposure is expected to be low. This is in line with a dermal acute toxicity study which did not show any effects after a dermal exposure to 2000 mg/kg body weight.

No data from acute or repeated dose toxicity studies by the inhalation route are available which could provide information about the systemic distribution of the test substance after inhalation. However, inhalative exposure to vapors is not of relevance as the substance has a very low vapor pressure.

Excretion

The excretion pathway is largely dependent on molecular size, polarity and water solubility. The parent compound is expected to be excreted mainly via feces. Potential metabolites are either excreted via feces or urine, depending on their molecular size and water solubility after phase II metabolism.