Magnesium Aluminum Silicate

Synonyms: Aluminii magnesii silicas; aluminosilicic acid, magnesium salt; aluminum magnesium silicate; Carrisorb; Gelsorb; Magnabrite; magnesium aluminosilicate; magnesium aluminum silicate, colloidal; magnesium aluminum silicate, complex colloidal; Neusilin; Pharmasorb; silicic acid, aluminum magnesium salt; Veegum.

Description: The PhEur 6.3 describes magnesium aluminum silicate (aluminium magnesium silicate) as a mixture of particles with colloidal particle size of montmorillonite and saponite, free from grit and nonswellable ore.

Chemical Name: Aluminum magnesium silicate 
Magnesium aluminum silicate

Adsorbent; stabilizing agent; suspending agent; tablet and capsule
disintegrant; tablet binder; viscosity-increasing agent.

• Magnesium aluminum silicate has been used for many years in the formulation of tablets, ointments, and creams.

• It is used in oral and topical formulations as a suspending and stabilizing agent either alone or in combination with other suspending agents.

• The viscosity of aqueous dispersions may be greatly increased by combination with other suspending agents, such as xanthan gum, owing to synergistic effects; see Xanthan Gum.

• In tablets, magnesium aluminum silicate is used as a binder and disintegrant in conventional or slow-release formulations.

• Magnesium aluminum silicate may cause bioavailability problems with certain drugs

Owing to its inert nature, magnesium aluminum silicate has few incompatibilities but is generally unsuitable for acidic solutions below pH 3.5. Magnesium aluminum silicate, as with other clays, may adsorb some drugs. This can result in low bioavailability if the drug is tightly bound or slowly desorbed, e.g. amfetamine sulfate, tolbutamide, warfarin sodium, diazepam, and diclofenac sodium.

Magnesium aluminum silicate is generally regarded as nontoxic and nonirritating at the levels employed as a pharmaceutical excipient. Subacute animal feeding studies in rats and dogs fed magnesium aluminum silicate at 10% of the diet, for 90 days, were negative, including autopsy and histopathological examinations.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended. Adequate ventilation should be provided and dust generation minimized.

Attapulgite; bentonite; kaolin; magnesium silicate; magnesium trisilicate; montmorillonite; saponite; talc.