Дигидрофосфат натрия двуводный (USP

Химические свойства

white crystalline solid

Использование

Sodium dihydrogen phosphate dihydrate acts as buffering capacity reagent in molecular biology, biochemistry and chromatography. It is used in the preparation of biological buffers. It is also used in the purification of antibodies, as a laxative and, in combination with other sodium phosphates.
Sodium phosphate monobasic dihydrate is a reagent with very high buffering capacity widely used in molecular biology, biochemistry and chromatography. Sodium phosphate dibasic is highly hygroscopic and water soluble.
Recommended chemicals for the preparation of phosphate buffers are sodium dihydrogen phosphate dihydrate，NaH2PO4.2H2O(mol. wt.156.0)，disodium hydrogen phosphate dihydrate，Na2HPO4.2H2O (mol. wt.178.0), and sodium hydroxide pellets.

Методы производства

Monobasic sodium phosphate is prepared by adding phosphoric acid to a hot, concentrated solution of disodium phosphate until the liquid ceases to form a precipitate with barium chloride. This solution is then concentrated and the monobasic sodium phosphate is crystallized.

Фармацевтические приложения

Monobasic sodium phosphate is used in a wide variety of pharmaceutical formulations as a buffering agent and as a sequestering agent. Therapeutically, monobasic sodium phosphate is used as a mild saline laxative and in the treatment of hypophosphatemia.
Monobasic sodium phosphate is also used in food products, for example, in baking powders, and as a dry acidulant and sequestrant.

Безопасность

Monobasic sodium phosphate is widely used as an excipient in parenteral, oral, and topical pharmaceutical formulations.
Phosphate occurs extensively in the body and is involved in many physiological processes since it is the principal anion of intracellular fluid. Most foods contain adequate amounts of phosphate, making hypophosphatemia virtually unknown except in certain disease states or in patients receiving total parenteral nutrition. Treatment is usually by the oral administration of up to 100 mmol of phosphate daily.
Approximately two-thirds of ingested phosphate is absorbed from the gastrointestinal tract, virtually all of it being excreted in the urine, and the remainder is excreted in the feces. Excessive administration of phosphate, particularly intravenously, rectally, or in patients with renal failure, can cause hyperphosphatemia that may lead to hypocalcemia or other severe electrolyte imbalances. Adverse effects occur less frequently following oral consumption, although phosphates act as mild saline laxatives when administered orally or rectally (2–4 g of monobasic sodium phosphate in an aqueous solution is used as a laxative). Consequently, gastrointestinal disturbances including diarrhea, nausea, and vomiting may occur following the use of monobasic sodium phosphate as an excipient in oral formulations. However, the level of monobasic sodium phosphate used as an excipient in a pharmaceutical formulation is not usually associated with adverse effects.
LD50 (rat, IM): 0.25 g/kg(10)
LD50 (rat, oral): 8.29 g/kg

хранилище

Monobasic sodium phosphate is chemically stable, although it is slightly deliquescent. On heating at 100°C, the dihydrate loses all of its water of crystallization. On further heating, it melts with decomposition at 205℃, forming sodium hydrogen pyrophosphate, Na2H2P2O7. At 250℃ it leaves a final residue of sodium metaphosphate, NaPO3.
Aqueous solutions are stable and may be sterilized by autoclaving.
Monobasic sodium phosphate should be stored in an airtight container in a cool, dry place.

Несовместимости

Monobasic sodium phosphate is an acid salt and is therefore generally incompatible with alkaline materials and carbonates; aqueous solutions of monobasic sodium phosphate are acidic and will cause carbonates to effervesce.
Monobasic sodium phosphate should not be administered concomitantly with aluminum, calcium, or magnesium salts since they bind phosphate and could impair its absorption from the gastrointestinal tract. Interaction between calcium and phosphate, leading to the formation of insoluble calcium phosphate precipitates, is possible in parenteral admixtures.

Регуляторный статус

GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (injections; infusions; ophthalmic, oral, topical, and vaginal preparations). Included in nonparenteral and parenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.