International Numbering System (INS) for Food Additives: 516
Food additives Europe numbers: E516
Functional Category
Desiccant; tablet and capsule diluent
Applications in Pharmaceutical Formulation
Calcium sulfate dihydrate is used in the formulation of tablets and capsules. In granular form it has good compaction properties and moderate disintegration properties.(1,2) Calcium sulfate hemihydrate (see Section 17), 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.(3,4)
Description
Both calcium sulfate and calcium sulfate dihydrate are white or offwhite, fine, odorless, and tast
Stability and Storage Conditions
Calcium sulfate is chemically stable. Anhydrous calcium sulfate is hygroscopic and may cake on storage. Store in a well-closed container in a dry place, avoiding heat
Incompatibilities
In the presence of moisture, calcium salts may be incompatible with amines, amino acids, peptides, and proteins, which may form complexes. Calcium salts will interfere with the bioavailability of tetracycline antibiotics.(5) It is also anticipated that calcium sulfate would be incompatible with indomethacin,(6) aspirin,(7) aspartame,(8) ampicillin,(9) cephalexin,(10) and erythromycin(11) since these materials are incompatible with other calcium salts. Calcium sulfate may react violently, at high temperatures, with phosphorus and aluminum powder; it can react violently with diazomethane
Safety
Calcium sulfate dihydrate is used as an excipient in oral capsule and tablet formulations. At the levels at which it is used as an excipient, it is generally regarded as nontoxic. However, ingestion of a sufficiently large quantity can result in obstruction of the upper intestinal tract after absorption of moisture. Owing to the limited intestinal absorption of calcium from its salts, hypercalcemia cannot be induced even after the ingestion of massive oral doses. Calcium salts are soluble in bronchial fluid. Pure salts do not induce pneumoconiosis