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Description of key information

With reference to its physical state (pasty solid), the Log Pow of 2.23, and the moderate water solubility the absorption of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate might be assumed to take place in low amounts. One of the characteristic and functional active centers of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate is the ester binding between the alcoholic compound and Phosphate. With reference to the occurrence of endogenous esterases which take part in the mammalian phase I metabolism it can be assumed that the substance can be hydrolysed.

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential

Additional information

Assessment of the Toxicokinetic Behaviour

 

Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate

 

There are no studies available in which the toxicokinetic properties of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate were investigated.

 

Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate is a pasty solid. The water solubility of this substance is 1.923 g/L (critical micelle concentration; see chapter 4.8). The octanol water partition coefficient (Log Pow) value was determined to be 2.23 (see chapter 4.7). Due to the moderate Log Powof 2.23 in combination with the water solubility and the assumed hydrolysis of the ester binding to form phosphoric acid and the alcohol components (see chapter 7.1.1) only a low potential of bioaccumulation is considered.

 

Absorption

With reference to its physical state (pasty solid), the Log Powof 2.23, and the moderate water solubility the absorption of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate might be assumed to take place in low amounts. In addition a passage through aqueous pores appears to be unlikely with reference to its molecular weight of 248 g/mol (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, Table R.7.12-1, p. 152). Furthermore, the substance contains hydroxyl functions which might be ionisable and is a salt which comprises ionic components. Ionisation does not contribute to a ready diffusion across biological membranes (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, p. 150). Therefore, a considerable absorption of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate can be excluded. This assumption is strengthened by the results of the acute oral toxicity studies in rats (LD502010 mg/kg bw) which resulted only in local respiratory effects (gastro-intestinal tract, lung, secretion from eyes and nose) that caused death. Gastric irritant changes were also observed in the repeated dose study.

 

Distribution

Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate does not have highly hydrophilic properties and contains relatively long branched carbon chains. Therefore, it is not likely that it will be distributed widely and will not tend to migrate via aqueous channels and pores (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, pp. 159-160).

 

Metabolism

One of the characteristic and functional active centers of Reaction mass of potassium ethyl octylphosphonate and diethyl octylphosphonate is the ester binding between the alcoholic compound and Phosphate. With reference to the occurrence of endogenous esterases which take part in the mammalian phase I metabolism it can be assumed that the substance can be hydrolysed. Studies on genotoxicity performed with Hordaphos MDGB (Ames-Test; Chromosome aberration test and HPRT test) were negative, i.e. there is no indication of a reactivity of the substance under the test conditions.

Excretion

With reference to the moderate Log Pow, the limited solubility and the molecular weight both excretion types via urine or feces are likely (please refer to Guidance on information requirements and chemical assessment, Chapter R.7c, p. 162).