Reaction mass of Ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate.

Endpoint summary

Additional information

Liquid form:

Oral absorption: In aqueous environments, such as the body the ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate is completely dissociated into the ammonium (NH4 +) and the phopshate (PO4 3-) ions. Phosphates are absorbed from the gastrointestinal tract as orthophosphate. The transport of phosphate from the lumen is an active, energy-dependent process, and there are factors that appear to modify the degree of its intestinal absorption. Vitamin D stimulates phosphate absorption, and this effect has been reported to precede the action of the vitamin on transport of calcium ion. In general, about two thirds of the ingested phosphate is absorbed from the gastrointestinal tract in adults. Absorbed phosphate is almost entirely excreted into the urine. After ingestion, ammonium ions can be absorbed by diffusion of the unionized ammonia or by active transport of ammonium ion. After intestinal absorption, ammonium ions are converted to urea by the liver, and subsequently excreted in urine. Based on low MW and high water solubility, high oral absorption is expected. Therefore, 100% absorption is taken for oral exposure.

Inhalation: Since the vapour pressure of the liquid form of the reaction mass of Ammonium dihydrogenorthophosphate and Diammonium hydrogenorthophosphate is low (assimilated to the vapour pressure of water), inhalation exposure to the liquid form of the reaction mass is not expected.

Dermal exposure: Ammonium dihydrogenorthophosphate and Diammonium hydrogenorthophosphate

ionize as soon as they dissolve and having water solubility above 10 g/L. Moreover, these substances may be too hydrophilic to cross the lipid rich environment of the stratum corneum. Therefore, 10% dermal absorption of the reaction mass is proposed.

Solid form:

Oral absorption: In aqueous environments, such as the body the ammonium dihydrogenorthophosphate and diammonium hydrogenorthophosphate is completely dissociated into the ammonium (NH4 +) and the phopshate (PO4 3-) ions. Phosphates are absorbed from the gastrointestinal tract as orthophosphate. The transport of phosphate from the lumen is an active, energy-dependent process, and there are factors that appear to modify the degree of its intestinal absorption. Vitamin D stimulates phosphate absorption, and this effect has been reported to precede the action of the vitamin on transport of calcium ion. In general, about two thirds of the ingested phosphate is absorbed from the gastrointestinal tract in adults. Absorbed phosphate is almost entirely excreted into the urine. After ingestion, ammonium ions can be absorbed by diffusion of the unionized ammonia or by active transport of ammonium ion. After intestinal absorption, ammonium ions are converted to urea by the liver, and subsequently excreted in urine. Based on low MW and high water solubility, high oral absorption is expected. Therefore, 100% absorption is taken for oral exposure.

Inhalation: Due to the aerodynamic diameter of the solid form of the reaction mass of Ammonium dihydrogenorthophosphate and Diammonium hydrogenorthophosphate (D50 = 3.25 mm and no particle lesser than 100 µm - see section 4.5 of the IUCLID on the reaction mass solid form particle size distribution) it is not expected that this substance will reach the nasopharyncheal region or subsequently the tracheobronchial or pulmonary region. Therefore, based on the high aerodynamic diameter of the reaction mass, inhalation exposure is not expected for the solid form.

Dermal exposure: Ammonium dihydrogenorthophosphate and Diammonium hydrogenorthophosphate ionize as soon as they dissolve and having water solubility above 10 g/L. Moreover, these substances may be too hydrophilic to cross the lipid rich environment of the stratum corneum. Therefore, 10% dermal absorption of the reaction mass is proposed.