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Phosphoric Acid

    Synonyms:Acid fosforico; acide phosphorique; acidum phosphorum concentratum; E338; hydrogen phosphate; syrupy phosphoric acid.

    Description: Concentrated phosphoric acid occurs as a colorless, odorless, syrupy liquid.

    Chemical Name: Orthophosphoric acid [

    • Phosphoric acid is widely used as an acidifying agent in a variety of pharmaceutical formulations.

    • It is used in pharmaceutical products as part of a buffer system when combined with a phosphate salt such as sodium phosphate, monobasic or dibasic.

    • It is also widely used in food preparations as an acidulant, flavor, and synergistic antioxidant (0.001–0.005%) and sequestrant.

    • Therapeutically, dilute phosphoric acid has been used welldiluted in preparations used in the treatment of nausea and vomiting.

    • Phosphoric acid 35% gel has also been used to etch tooth enamel and to enhance delivery of drugs through the nail.

    • Nanosized hydroxyapatite powder was made by combining phosphoric acid with egg shells.

    Phosphoric acid is a strong acid and reacts with alkaline substances. Mixtures with nitromethane are explosive.

    In the concentrated form, phosphoric acid is an extremely corrosive and harmful acid. However, when used in pharmaceutical formulations it is usually very diluted and is generally regarded as an essentially nontoxic and nonirritant material. 

    Observe normal precautions appropriate to the circumstances and quantity of material handled. Phosphoric acid is corrosive and can cause burns on contact with the skin, eyes and mucous membranes; contact should be avoided. Splashes should be washed with copious quantities of water. Protective clothing, gloves and eye protection are recommended.

    Dilute phosphoric acid.