Disodium phosphate (DSP)

Disodium phosphate (DSP), or sodium hydrogen phosphate, or sodium phosphate dibasic, is the inorganic compound with the formula Na2HPO4. Potassium Phosphate, Dibasic is the dipotassium form of phosphoric acid, that can be used as an electrolyte replenisher and with radio-protective activity. Upon oral administration, potassium phosphate is able to block the uptake of the radioactive isotope phosphorus P 32 (P-32).

It is one of several sodium phosphates. The salt is known in anhydrous form as well as forms with 2, 7, 8, and 12 hydrates. All are water-soluble white powders; the anhydrous salt being hygroscopic.  It has a role as a buffer.

 

 Properties

Dipotassium phosphate (K2HPO4) is a highly water-soluble salt often used as a fertilizer and food additive as a source of phosphorus and potassium as well as a buffering agent.

 

Chemical formula	Na2HPO4
Molar mass	141.96 g/mol (anhydrous) 177.99 g/mol (dihydrate) 268.07 g/mol (heptahydrate)
Appearance	White crystalline solid
Odor	odorless
Density	1.7 g/cm3
Melting point	250 °C (482 °F; 523 K) decomposes
Solubility in water	7.7 g/100 ml (20 °C) 11.8 g/100 mL (25 °C, heptahydrate)
Solubility	insoluble in alcohol
structure

 

Production and reactions

It can be generated by neutralization of phosphoric acid with sodium hydroxide:

H3PO4 + 2 NaOH → HNa2PO4 + 2 H2O

Industrially It is prepared in a two-step process by treating dicalcium phosphate with sodium bisulfate, which precipitates calcium sulfate:[2]

CaHPO4 + NaHSO4 → NaH2PO4 + CaSO4

In the second step, the resulting solution of monosodium phosphate is partially neutralized:

NaH2PO4 + NaOH → HNa2PO4 + H2O

Uses

It is used in conjunction with trisodium phosphate in foods and water softening treatment.

In foods, it is used to adjust pH. Its presence prevents coagulation in the preparation of condensed milk. Similarly, it is used as an anti-caking additive in powdered products.[3] It is used in desserts and puddings, e.g. Cream of Wheat to quicken cook time, and Jell-O Instant Pudding for thickening. In water treatment, it retards calcium scale formation. It is also found in some detergents and cleaning agents.

Heating solid disodium phosphate gives the useful compound tetrasodium pyrophosphate:

2 HNa2PO4 → Na4P2O7 + H2O

Monobasic and dibasic sodium phosphate are used as a saline laxative to treat constipation or to clean the bowel before a colonoscopy.

Phosphorus is a naturally occurring substance that is important in every cell in the body. The majority of phosphorus in the body is found in the bones. The potassium and sodium salt forms of phosphorus are called phosphates.

Potassium phosphate and sodium phosphate is a combination medicine used to make the urine more acid to help prevent kidney stones.

Potassium phosphate and sodium phosphate may also be used for purposes not listed in this medication guide.

In mouthwash disodium phosphate acts as a buffering agent that helps maintain the pH or acidity of the product. When disodium phosphate is combined with fluoride and phosphoric acid to form an acidulated phosphate fluoride  solution as outlined in the FDA’s Anticaries monograph, that solution promotes remineralization and helps prevent enamel dissolution.

What are the alternatives?

For anticaries mouthwash products, with acidulated phosphate fluoride solution, disodium phosphate and phosphoric acid are required in conjunction with Sodium Fluoride per the Anticaries Drug Products for Over-the-Counter Human Use, Final Monograph.1 Tom’s offers both fluoride and fluoride free mouthwash options.

What are the side effects of Potassium And Sodium Phosphate ?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• severe or ongoing diarrhea;
• seizures (convulsion);
• shortness of breath; or
• signs of a kidney problem–little or no urinating; painful or difficult urination; swelling in your feet or ankles; feeling tired or short of breath.

Common side effects may include:

• nausea, vomiting, stomach pain, diarrhea;
• bone or joint pain;
• headache, dizziness, tired feeling;
• muscle pain or weakness;
• increased thirst; or
• numbness or tingly feeling.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.