Magnesium Hydroxide

Magnesium hydroxide is, after aluminium hydroxide, the most widely used antacid active. The compound is used in both suspension and powder formulations, usually in combination with aluminium hydroxide. It has a high acid-binding capacity and reacts rapidly to neutralize gastric acid.  The ingestion of pure magnesium hydroxide antacids leads to undesirably high pH values in the stomach, which can, in turn, stimulate acid production. For this reason it is recommended that magnesium hydroxide is combined with aluminium hydroxide in antacid formulations. Combination products also overcome the laxative effect of magnesium hydroxide as this is compensated for by the mild obstipative effect of aluminium hydroxide.

Magnesium Hydroxide Powders

GILUMAG® D 211 / D 212 / D 214

Magnesium hydroxide powders are used in the production of tablets, granules and powder mixtures, often in combination with ALUGEL® A 211 or ALUGEL® A 215. They differ with respect to particle size and bulk density.

TypeD 211D 212D 214
Mg(OH)2 -Assay95,0 – 100,5 %95,0 – 100,5 %95,0 – 100,5 %
Density (tapped)0,40 – 0,60 g/ml0,60 – 0,80 g/ml1,01 – 1,25 g/ml
d906 – 10 µm10 – 25 µm20 – 45 µm
PharmacopoeiaUSP, PhEurUSP, PhEurUSP, PhEur


GILUMAG® D 220 is an ultra-fine, low bulk density powder, with a particle size of less than 8 µm. The fine particle size makes GILUMAG® D 220 ideal for the formulation of soft tablets and candies as it can be easily mixed into the gel matrix of these types of products. 
GILUMAG® D 220 is readily mixed with water. The resulting suspensions, after homogenization, are stable, highly viscous, and have a smooth, non-gritty mouth feel. These characteristics make GILUMAG® D 220 particularly suitable for the formulation of antacid suspensions in combination with ALUGEL® pastes.

Assay95,0 – 100,5 %
Density (tapped)max. 0,41 g/ml
d504 – 8 µm
PharmacopoeiaUSP, PhEur

Magnesium Hydroxide Suspensions


GILUMAG® D 611 is a pumpable paste containing approx. 30% Mg(OH)2. It is ideally suited for  the production of single and double strength, free-flowing suspensions. Even after long periods of storage D 611 is readily stirred to a homogeneous suspension.

Assay 29,0 – 33,0 % Mg(OH)2
Viscosity  (Brookfield)min. 4000 mPa s (LV 3/12)


GILUMAG® D 661 is a highly viscous, thixotropic, paste containing approx. 30 % Mg(OH)2. The high viscosity guarantees excellent storage stability. Single strength or Milk of Magnesia type products can be formulated without the need for additional thickening agents.


Assay 29,0 – 33,0 % Mg(OH)2
Viscosity  (Brookfield) min. 1000 mPa s 
 (at 25 %, LV 3/12)