Polyphosphoric acids, esters with triethanolamine, sodium salts

Endpoint summary

Additional information

The substance is composed as described in Section 1.2. It is a pale yellow liquid and the molecular weight is >119.96 - < 521.02 g/mol. The low vapour pressure value (1.0 Pa at 25°C) and predicted negative explosive and oxidising properties shows that the substance is non volatile therefore inhalation is not a significant route of exposure. The substance has a low log octanol/water partition coefficient value (Log₁₀Pow -4.23) and high water solubility (miscible at 20°C). The available acute dermal and repeated dose reproductive screening studies showed limited evidence of absorption, metabolism and excretion (Sanders A, 2011c; Adamska M, 2012

The test item was non-mutagenic in bacteria (Bowles A, 2011) and non-clastogenic in mammalian cellsin vitro(Bohnenberger, 2011), however it is mutagenic in mammalian (CHO) cellsin vitroin the absence of an auxiliary metabolising system (Morris A, 2011).

The test item is not a skin sensitizer however it is considered a mild irritant (Arcelin, 2011; Sanders A, 2011c).

Absorption

Although the test item is lipophobic in nature the high water solubility (miscible at 20°C) and small molecular size of the substance could allow absorption through passive diffusion. This would suggest that the gastro-intestinal tract provides a route of absorption, following oral administration, before entering the circulatory system via the blood.

Limited absorption may also take place via the skin due to small molecular size and water solubility. Although the substance is not a skin sensitizer there is evidence of mild dermal irritation (Arcelin G, 2011; Sanders A, 2011c). Therefore damage to the skin surface may allow for increased penetration of the substance through the skin.

The low vapour pressure value (1.0 Pa at 25°C) shows that the substance is not available as a vapour therefore inhalation is not a significant route of exposure.

Distribution

Once absorbed, the substance may be distributed in serum due to the water solubility and may therefore be distributed systemically. The lack of evidence to suggest the test item is a sensitizer suggests that it does not bind to circulatory proteins. The high water solubility would also suggest that the test item does not accumulate in body fat.

Metabolism

The results of the repeated dose reproductive screening study did not show evidence to indicate any test item influenced hepatic metabolism. The results of the reverse mutation assay showed no evidence that genotoxicity is either enhanced or diminished in the presence of the S9 metabolising system (Bowles A, 2011). On the other hand in a mutagenicity study using mammalian (CHO) cellsin vitro(Morris A, 2011), the elimination of the mutagenic response by the addition of a rat S9 metabolising system suggests that the test substance may undergo hepatic metabolism in the intact animal.

Excretion

There is no evidence to indicate the route of excretion but high water-soluble products are not favorable for biliary excretion and therefore urinary excretion may well be a significant route for this material. Any test item that is not absorbed will be excreted in the faeces.

Summary

The available information suggests that absorption of the test substance from the gastrointestinal tract can take place. Some absorption may also take place via the skin. Once absorbed, the substance would be distributed in the serum and urine is the significant route of excretion. There is limited evidence suggesting that the test substance may be metabolised, however no studies have been conducted to identify metabolites.