International Numbering System (INS) for Food Additives: 553(i)
Food additives Europe numbers: E553a
Functional Category
Anticaking agent; glidant.
Applications in Pharmaceutical Formulation
Magnesium silicate is used in oral pharmaceutical formulations and food products as a glidant and an anticaking agent.
Description
Magnesium silicate occurs as an odorless and tasteless, fine, whitecolored powder that is free from grittiness.
Stability and Storage Conditions
Magnesium silicate should be stored in a well-closed container in a cool, dry place.
Incompatibilities
Magnesium silicate may decrease the oral bioavailability of drugs such as mebeverine hydrochloride,(1) sucralfate, and tetracycline, via chelation or binding, when they are taken together. The dissolution rate of folic acid,(2) erythromycin stearate,(3) paracetamol(4) and chloroquine phosphate(4) may be retarded by adsorption onto magnesium silicate. Antimicrobial preservatives, such as parabens, may be inactivated by the addition of magnesium silicate.(5) Magnesium silicate is readily decomposed by mineral acids.
Safety
Magnesium silicate is used in oral pharmaceutical formulations and is generally regarded as an essentially nontoxic and nonirritant material. Orally administered magnesium silicate is neutralized in the stomach to form magnesium chloride and silicon dioxide; some magnesium is absorbed. Caution should be used when greater than 50 mEq of magnesium is given daily to persons with impaired renal function, owing to the risk of hypermagnesemia. Reported adverse effects include the formation of bladder and renal calculi following the regular use, for many years, of magnesium silicate as an antacid.