Calcium Sulfate

Calcium Sulfate

Both calcium sulfate and calcium sulfate dihydrate are white or offwhite, fine, odorless, and tasteless powder or granules.

Nonproprietary Names

  • BP: Calcium Sulphate Dihydrate
  • PhEur: Calcium Sulphate Dihydrate
  • USP-NF: Calcium Sulfate
Calcium Sulfate


Calcium sulfate anhydrous anhydrite; anhydrous gypsum; anhydrous sulfate of lime; Destab; Drierite; E516; karstenite; muriacite; Snow White. Calcium sulfate dihydrate alabaster; calcii sulfas dihydricus; Cal-Tab; Compactrol; Destab; E516; gypsum; light spar; mineral white; native calcium sulfate; precipitated calcium sulfate; satinite; satin spar; selenite; terra alba; USG Terra Alba.


Chemical Name and CAS Registry Number

  • Calcium sulfate [7778-18-9]
  • Calcium sulfate dihydrate [10101-41-4]

Empirical Formula and Molecular Weight

  • CaSO4 136.14
  • CaSO4.2H2O 172.17

Functional Category: Desiccant; tablet and capsule diluent.

Applications in Pharmaceutical Formulation or Technology

Calcium sulfate dihydrate is used in the formulation of tablets and capsules. In granular form it has good compaction properties and moderate disintegration properties. Calcium sulfate hemihydrate, is used in the preparation of plaster of Paris bandage, which is used for the immobilization of limbs and fractures; it should not be used in the formulation of tablets or capsules.

Anhydrous calcium sulfate is hygroscopic and is used as a desiccant. The uptake of water can cause the tablets to become very hard and to fail to disintegrate on storage. Therefore, anhydrous calcium sulfate is not recommended for the formulation of tablets, capsules, or powders for oral administration. Therapeutically, calcium sulfate is used in dental and craniofacial surgical procedures.

Method of Manufacture

Anhydrous calcium sulfate occurs naturally as the mineral anhydrite. The naturally occurring rock gypsum may be crushed and ground for use as the dihydrate or calcined at 1508C to produce the hemihydrate. A purer variety of calcium sulfate may also be obtained chemically by reacting calcium carbonate with sulfuric acid or by precipitation from calcium chloride and a soluble sulfate.


Related Substances

Calcium phosphate, dibasic anhydrous; calcium phosphate, dibasic dihydrate; calcium phosphate, tribasic; calcium sulfate hemihydrate.


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