Magnesium trisilicate is a fine, white to off-white, odorless, tasteless powder composed of magnesium oxide and silicon dioxide in varying proportions. It is insoluble in water but reacts with dilute acids, releasing magnesium ions and forming a gel-like silica matrix.
Chemical Name and CAS Registry Number:Magnesium trisilicate [14987-04-3]
Functional Category:Antacid; adsorbent; tablet diluent
Identification: Positive for magnesium and silicate
Assay (MgO content): 20.0%–30.0%
Loss on Drying: NMT 15%
Acid Consumption Capacity: Meets monograph limits (e.g., not less than 25 mL of 0.1 N HCl per gram)
pH (suspension): 7.0–9.0
Microbial Limits: Complies with pharmacopeial standards
Antacid: Used in oral suspensions and chewable tablets to neutralize gastric acid and relieve heartburn or indigestion.
Adsorbent: Incorporated to absorb toxins or other substances in the GI tract.
Tablet diluent: Occasionally used in solid dosage forms due to its inert nature and bulk.
Magnesium trisilicate is well-tolerated and provides prolonged antacid action due to its slow reactivity. It is often used in combination with other antacids like aluminum hydroxide. Its ability to adsorb bile salts and other substances enhances its use in gastrointestinal formulations.
