General Description
Synonyms: Calcined magnesia; calcinated magnesite; Descote; E530; Magcal; Magchem 100; Maglite; magnesia; magnesia monoxide; magnesia usta; magnesii oxidum leve; magnesii oxidum ponderosum; Magnyox; Marmag; Oxymag; periclase.
Description: Both forms of magnesium oxide occur as fine, white, odorless powders. Magnesium oxide possesses a cubic crystal structure, though the BP 2009 and PhEur 6.4 describe the appearance of light magnesium oxide as an amorphous powder.
Chemical Name: Magnesium oxide
Uses
Magnesium oxide is used as an alkaline diluent in solid-dosage forms to modify the pH of tablets.
It can be added to solid-dosage forms to bind excess water and keep the granulation dry.
In combination with silica, magnesium oxide can be used as an auxiliary glidant.
It is also used as a food additive and as an antacid, either alone or in conjunction with aluminum hydroxide.
Magnesium oxide is additionally used as an osmotic laxative and a magnesium supplement to treat deficiency states.
Incompatibilities
Magnesium oxide is a basic compound and as such can react with acidic compounds in the solid state to form salts such as Mg(ibuprofen)2 or degrade alkaline-labile drugs. Adsorption of various drugs onto magnesium oxide has been reported, such as antihistamines, antibiotics (especially tetracyclines), salicylates, atropine sulfate, hyoscyamine hydrobromide, paracetamol, chloroquine; and anthranilic acid derivatives have been reported to adsorb onto the surface of magnesium oxide. Magnesium oxide can also complex with polymers, e.g. Eudragit RS, to retard drug release and can interact in the solid state with phenobarbitone sodium. Magnesium oxide can also reduce the bioavailability of phenytoin, trichlormethiazide, and antiarrhythmics. The presence of magnesium oxide can also have a negative impact on the solid-state chemical stability of drugs, such as diazepam. Magnesium oxide has been used as a stabilizer for omeprazole due to its strong waterproofing effect
Safety
Magnesium oxide is widely used in oral formulations as an excipient and as a therapeutic agent. Therapeutically, 250–500 mg is administered orally as an antacid and 2–5 g as an osmotic laxative. Magnesium oxide is generally regarded as a nontoxic material when employed as an excipient, although adverse effects, due to its laxative action, may occur if high doses are ingested orally
Handling Precautions
Observe normal precautions appropriate to the circumstances and quantity of material handled. Magnesium oxide may be harmful if inhaled, ingested, or absorbed through the skin in quantity, and is irritating to the eyes and respiratory system. Gloves, eye protection, and a dust mask or respirator are recommended