Chemical Properties
Almost white powder, granules or plates.
Uses
Used as an Antacid Raw material in a specific antacid formulations, Ceramics, Suspending Agent, Thickning agent etc.
Description
Aluminum magnesium silicate is a white powder, granules or plates. It can be used as an excipient, such as adsorbent, stabilizer, suspending agent, disintegrant for tablet and capsule, binder for tablet, thickener. Incorporation of MAS into the diclofenac sodium (DS) aqueous gels caused a statistical increase in viscosity and a shift from Newtonian flow to pseudoplastic flow with thixotropic property.
Production Methods
Magnesium aluminum silicate is obtained from silicate ores of the
montmorillonite group, which show high magnesium content. The
ore is blended with water to form a slurry to remove impurities and
separate out the colloidal fraction. The refined colloidal dispersion
is drum-dried to form a small flake, which is then micro-atomized to
form various powder grades.
Pharmaceutical Applications
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.
Safety
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.
LD50 (rat, oral): > 16 g/kg
storage
Magnesium aluminum silicate is stable indefinitely when stored
under dry conditions. It is stable over a wide pH range, has baseexchange
capacity, absorbs some organic substances, and is
compatible with organic solvents.
Magnesium aluminum silicate should be stored in a well-closed
container, in a cool, dry place.
Incompatibilities
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.
Regulatory Status
Included in the FDA Inactive Ingredients Database (oral granules,
solutions, suspensions and tablets; rectal; and topical preparations;
vaginal preparations). Included in nonparenteral medicines licensed
in the UK. Included in the Canadian List of Acceptable Nonmedicinal
Ingredients.