Magnesium aluminum silicate

• BPAluminium Magnesium Silicate
• Ph. Eur.Aluminium Magnesium Silicate
• USP–NFMagnesium Aluminum Silicate

Aluminium magnesium silicate; magnesium aluminium silicate; colloidal magnesium aluminium silicate; aluminii magnesii silicas; smectite clay; Veegum; Magnabite

Aluminium magnesium silicate (a purified blend of colloidal montmorillonite and saponite clays) · [1327-43-1]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Gelling agent, viscosity modifier, Adsorbent

Typical concentrations: — · Dosage forms: Liquid, Semi-solid

Used as a suspending agent, emulsion stabiliser, viscosity-increasing agent and adsorbent in oral and topical preparations, and as a binder and disintegrant in tablets. Typical concentrations: adsorbent 10–50%; emulsion stabiliser 1–5% (oral) or 2–5% (topical); suspending agent 0.5–2.5% (oral) or 1–10% (topical); tablet binder or disintegrant 2–10%; viscosity-increasing agent 2–10%.

Off-white to creamy white, odourless, tasteless, soft, slippery small flakes or a fine powder. The particles are thin platelets that swell in water to form colloidal dispersions.

pH

9.0–10.0 (5% w/v aqueous dispersion)

Moisture content

not more than 8% w/w

Viscosity

grade-dependent; 5% w/v dispersions range from low to high viscosity and are thixotropic

Solubility

practically insoluble in water, ethanol and organic solvents; swells in water

Stable indefinitely when stored dry. Aqueous dispersions are stable over a wide pH range (about 3.5–11) and their viscosity rises on standing or with heating; they may need a preservative. Store in a well-closed container in a cool, dry place.

Strongly acidic conditions (below pH 3.5) reduce the viscosity of dispersions. Being anionic, it can be flocculated by cationic materials and electrolytes, and it may adsorb some drugs (for example certain antibiotics and amines), reducing their availability.

Obtained from naturally occurring smectite clays, which are blended, dispersed in water to remove grit, then dried and milled or flaked.

Not absorbed after oral administration and regarded as non-toxic and non-irritant at excipient levels. Inhalation of the dust should be avoided.

Observe normal precautions for the quantity handled. Avoid generating dust; eye protection, gloves and a dust mask are recommended.

Included in the FDA Inactive Ingredient Database (oral suspensions and tablets; rectal and topical preparations) and in non-parenteral medicines licensed in Europe.

Attapulgite; bentonite; hectorite; kaolin; magnesium trisilicate; talc.

Dispersions are best prepared by adding the powder slowly to water with vigorous stirring; hydration is faster in warm water. It is often combined with xanthan gum or carboxymethylcellulose sodium, which gives synergistic viscosity and better suspension stability.