Reaction mass of hexadecyl dihydrogen phosphate and dihexadecyl hydrogen phosphate

Endpoint summary

Description of key information

no study available

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Additional information

There are no studies available in which the toxicokinetic properties of Reaction mass of dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate were investigated.

 

Reaction mass of dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate is a solid. The water solubility of this substance is 26 m g/L (critical micelle concentration; see chapter 4.8). The octanol water partition coefficient (Log P_ow) value was determined to be 2.23 (see chapter 4.7). Due to the moderate Log P_owof 2.83 in combination with the water solubility and the assumed hydrolysis of the ester binding to form phosphoric acid and the alcohol components only a low potential of bioaccumulation is considered.

 

Absorption

With reference to its physical state (solid), the Log P_owof 2.83, and the limited water solubility the absorption of Reaction mass of dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate 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 322 g/mol in case of the mono ester (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. 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 dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate can be excluded. This assumption is strengthened by the result of the acute oral toxicity study in rats (LD₅₀> 1600 mg/kg bw) which resulted no clinical signs.

 

Distribution

Reaction mass of dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate 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 dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate 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 Reaction mass of dihexadecyl hydrogen phosphate and hexadecyl dihydrogen phosphate (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 P_ow, 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).