Magnesium carbonate

• BPHeavy Magnesium Carbonate; Light Magnesium Carbonate
• JPMagnesium Carbonate
• Ph. Eur.Magnesium Carbonate, Heavy; Magnesium Carbonate, Light
• USP–NFMagnesium Carbonate

Basic magnesium carbonate; heavy magnesium carbonate; light magnesium carbonate; hydromagnesite; magnesii subcarbonas; magnesium carbonate hydroxide; E504(i)

Hydrated basic magnesium carbonate (light and heavy forms) · [546-93-0]

UNII 0IHC698356 · PubChem CID 11029

(MgCO3)4·Mg(OH)2·5H2O (approximate) · ≈ 485 (basic); 84.31 (MgCO3)

Diluent (filler), Adsorbent

Typical concentrations: — · Dosage forms: Solid

Used as a tablet and capsule diluent, including in direct compression where levels of up to about 45% w/w have been used, and as an adsorbent for liquids such as flavour oils in powders. It is also used as an alkalising agent, an anticaking agent and colour-retention agent in foods, and therapeutically as an antacid and osmotic laxative.

A white, odourless powder or light, friable masses. The light form is very bulky; the heavy form is denser and granular. Commercial material is a basic hydrated carbonate rather than normal MgCO3.

Bulk density

light grade very low (bulky); heavy grade several times higher

Solubility

practically insoluble in water and ethanol; dissolves in dilute acids with effervescence

Aqueous suspension

alkaline

Thermal behaviour

loses water and carbon dioxide on heating, leaving magnesium oxide

Stable in dry air. Store in a well-closed container in a cool, dry place.

Reacts with acids, releasing carbon dioxide. It raises the microenvironmental pH, which can degrade base-sensitive drugs or alter dissolution, and magnesium ions can chelate drugs such as tetracyclines and fluoroquinolones, reducing their absorption.

Prepared by precipitation from solutions of a soluble magnesium salt with sodium carbonate; the temperature and concentration of the reaction determine whether the light or heavy form is obtained.

Regarded as non-toxic at excipient levels. Larger oral doses have a laxative effect and can cause hypermagnesaemia in patients with renal impairment. Release of carbon dioxide in the stomach can cause belching.

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

GRAS listed. Accepted as a food additive in Europe (E504). Included in the FDA Inactive Ingredient Database (oral capsules and tablets) and in non-parenteral medicines licensed in Europe.

Magnesium oxide; magnesium hydroxide; calcium carbonate; magnesium trisilicate.

Specify the light or heavy grade, as their bulk volumes and flow differ greatly. The light grade's high porosity makes it a good carrier for liquid ingredients, while the heavy grade is preferred where higher fill weights are needed.