Calcium sulfate dihydrate

• BPCalcium Sulphate Dihydrate
• Ph. Eur.Calcium Sulfate Dihydrate
• USP–NFCalcium Sulfate

Calcii sulfas dihydricus; Compactrol; gypsum; light spar; mineral white; terra alba; E516

Calcium sulfate dihydrate · [10101-41-4]

UNII 4846Q921YM · PubChem CID 24928

CaSO4·2H2O · 172.17

Diluent (filler)

Typical concentrations: — · Dosage forms: Solid

Used as a diluent in tablets and capsules; granular grades are available for direct compression and the powder is also used in wet granulation. It is used in foods as a firming agent and calcium source, and in dental products.

A white or almost white, odourless and tasteless powder or fine crystalline granules.

Water of crystallisation

≈ 20.9% w/w (theoretical)

Solubility

slightly soluble in water (roughly 2–2.5 g/L at room temperature); practically insoluble in ethanol

Thermal behaviour

loses water on heating to form the hemihydrate (plaster of Paris) and, at higher temperatures, the anhydrous salt

True density

≈ 2.3 g/cm³

Chemically stable and does not lose its water of crystallisation at normal storage temperatures. Drying temperatures during granulation should be kept moderate to avoid partial dehydration, which changes the compaction properties. Store in a well-closed container in a cool, dry place.

Calcium salts reduce the absorption of tetracyclines and some other drugs that form calcium complexes.

Obtained by milling and purifying natural gypsum, or by precipitation from a solution of a calcium salt with a sulfate.

Used in oral pharmaceuticals and foods and regarded as non-toxic and non-irritant at the levels employed.

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

GRAS listed. Accepted as a food additive in Europe (E516). Included in the FDA Inactive Ingredient Database (oral capsules and tablets) and in non-parenteral medicines licensed in Europe.

Calcium sulfate anhydrous; calcium sulfate hemihydrate; calcium phosphate, dibasic; calcium carbonate.

The dihydrate must not be confused with the hemihydrate (plaster of Paris), which sets to a hard mass when mixed with water and is unsuitable as a diluent. Tablets made with calcium sulfate dihydrate are non-hygroscopic but, because the material is poorly soluble, may need a disintegrant.