Calcium phosphate dibasic

Description

Anhydrous dibasic calcium phosphate is nonhygroscopic and stable at room temperature. It does not hydrate to form the dihydrate. Anhydrous dibasic calcium phosphate is used in toothpaste and dentifrice formulations for its abrasive properties. Anhydrous dibasic calcium phosphate is used both as an excipient and as a source of calcium in nutritional supplements. It is used particularly in the nutritional/health food sectors. It is also used in pharmaceutical products because of its compaction properties, and the good flow properties of the coarse-grade material.

Chemical properties

Anhydrous dibasic calcium phosphate is a white, odorless, tasteless powder or crystalline solid. It occurs as triclinic crystals.

Physical properties

White triclinic crystal; density 2.92 g/cm³ (anhydrous) and 2.31 g/cm³ (dihy drate); hardness 3.5 Mohs; decomposes on heating; inosluble in water and alcohol; KSP 2.7x10^-7; soluble in dilute mineral acid.

The Uses of Calcium phosphate dibasic

Dibasic calcium phosphate anhydrous is widely used in oral pharmaceutical products, food products, and toothpastes, and is generally regarded as a relatively nontoxic and nonirritant material. It is used as a feed additive for livestock and poultry. It can promote feed digestion, put on animal?s weight, raise laying rate or producing milk rate, cure diseases such as rickets, osteomalacia and anemia.

Production Methods

Calcium phosphates are usually prepared by reacting very pure phosphoric acid with calcium hydroxide, Ca(OH)₂ obtained from limestone, in stoichiometric ratio in aqueous suspension followed by drying at a temperature that will allow the correct hydration state to be achieved. After drying, the coarse-grade material is obtained by means of a classification unit; the fine particle-size material is obtained by milling. Dibasic calcium phosphate, anhydrous, may also be prepared by spray-drying.

Definition

ChEBI: Calcium hydrogenphosphate is a calcium phosphate.

Agricultural Uses

Dicalcium phosphate (CaHPO₄) is made from calcium carbonate and phosphoric acid. It contains 34% citrate- soluble phosphorus pentoxide (P₂O₅). It is not commonly used as a fertilizer, but is used as a supplement to animal feed.

Safety Profile

Skin and eye irritant. A nuisance dust.

Storage

Dibasic calcium phosphate anhydrous is a nonhygroscopic, relatively stable material. Under conditions of high humidity it does not hydrate to form the dihydrate.
The bulk material should be stored in a well-closed container in a dry place.

Incompatibilities

Dibasic calcium phosphate should not be used to formulate tetracyline antibiotics.
The surface of milled anhydrous dibasic calcium phosphate is alkaline and consequently it should not be used with drugs that are sensitive to alkaline pH. However, reports suggest there are differences in the surface alkalinity/acidity between the milled and unmilled grades of anhydrous dibasic calcium phosphate; the unmilled form has an acidic surface environment. This difference has important implications for drug stability, particularly when reformulating from, e.g. roller compaction to direct compression, when the particle size of the anhydrous dibasic calcium phosphate might be expected to change.
Dibasic calcium phosphate dihydrate has been reported to be incompatible with a number of drugs and excipients, and many of these incompatibilities are expected to occur with dibasic calcium phosphate, anhydrous; see Calcium phosphate, dibasic dihydrate.

Regulatory Status

GRAS listed. Accepted as a food additive in Europe. Included in the FDA Inactive Ingredients Database (oral capsules and tablets). Included in nonparenteral medicines licensed in Europe. Included in the Canadian List of Acceptable Non-medicinal Ingredients.