Pharmacopeial Specifications:
- Identification: Positive test for magnesium
- Assay (MgO): 96.0%–100.5%
- Loss on Ignition: NMT 10% (light); NMT 2% (heavy)
- Acid Insoluble Substances: NMT 0.05%
- Heavy Metals: NMT 20 ppm
- Microbial Limits: Generally not required due to its inorganic nature
Applications in Pharmaceutical Formulation:
- Antacid: Neutralizes excess gastric acid in oral suspensions or chewable tablets.
- Alkalizing agent: Used to adjust pH in formulations.
- Tablet diluent: Occasionally employed as an inert filler in tablets and capsules.
- Nutritional supplement: Provides magnesium in multivitamin or mineral formulations.
Comments:
Magnesium oxide reacts with gastric acid to form magnesium chloride and water, relieving indigestion. It has high acid-neutralizing capacity and is often combined with aluminum compounds for balanced GI effects. Its laxative effect may limit use in sensitive patients. Selection between light and heavy forms depends on bulk density needs in tablet or capsule manufacturing.
