Dibasic calcium phosphate dihydrate

• BPCalcium Hydrogen Phosphate Dihydrate
• JPDibasic Calcium Phosphate Hydrate
• Ph. Eur.Calcium Hydrogen Phosphate Dihydrate
• USP–NFDibasic Calcium Phosphate Dihydrate

calcium hydrogen orthophosphate dihydrate; calcium monohydrogen phosphate dihydrate; DCPD; Di-Cafos; dicalcium orthophosphate; DI-TAB; Emcompress; phosphoric acid calcium salt (1:1) dihydrate; E341(ii)

Calcium hydrogen phosphate dihydrate · [7789-77-7]

UNII O7TSZ97GEP · PubChem CID 104805

CaHPO4·2H2O · 172.09

Diluent (filler)

Typical concentrations: q.s. · Dosage forms: Solid

Widely used as a tablet and capsule diluent, in wet granulation and, in coarse granular grades, in direct compression, where it often makes up a large part of the tablet. It is also a source of calcium and phosphorus in nutritional supplements and a polishing agent in toothpastes.

A white, odourless, tasteless powder or crystalline solid. Coarse direct-compression grades consist of aggregates of fine crystals and flow well.

True density

about 2.3–2.4 g/cm³

Bulk density

high compared with organic fillers; granular grades typically above 0.8 g/cm³

pH

about 7.4 (20% w/w slurry)

Solubility

practically insoluble in water and ethanol; dissolves in dilute hydrochloric and nitric acids

Dehydration

loses its water of crystallisation on heating below 100 °C, especially in humid conditions

Non-hygroscopic and stable at room temperature. Under some combinations of temperature and humidity, for example during drying or film coating, it may lose water of crystallisation, which can affect tablet hardness and drug stability. Store in a well-closed container in a cool, dry place.

Should not be used with tetracycline antibiotics, whose absorption is reduced by calcium. Its slightly alkaline surface can degrade drugs that are unstable at neutral to alkaline pH, and calcium ions may interact with acidic drugs.

Prepared by reacting purified phosphoric acid with calcium hydroxide or calcium carbonate in aqueous suspension in stoichiometric proportions, under conditions that give the dihydrate, followed by filtering and drying at low temperature. Direct-compression grades are made by agglomeration and sieving.

Widely used in oral products and foods and regarded as non-toxic and non-irritant.

Observe normal precautions for the quantity handled. Avoid dust; eye protection, gloves and a dust mask are recommended.

GRAS listed. Accepted as a food additive in Europe (E341(ii)). Included in the FDA Inactive Ingredient Database (oral capsules and tablets) and in non-parenteral medicines licensed in Europe.

Dibasic calcium phosphate, anhydrous; tribasic calcium phosphate; calcium carbonate; calcium sulfate.

It consolidates mainly by brittle fracture, so tablet strength is relatively insensitive to lubricant level and mixing time, and it is often combined with plastically deforming microcrystalline cellulose. It is abrasive to tooling, and because it is insoluble a disintegrant is needed.