Magnesiumstearat

Magnesiumstearat, also known as magnesium distearate, is the magnesium salt of stearic acid. Its chemical formula is Mg(C18H35O2)2. It is a white to off-white, odorless powder that is highly hydrophobic and practically insoluble in water; it has limited solubility in hot organic solvents such as acetone or chloroform. It is typically used as a lubricant and flow aid in various formulations.

Production of magnesiumstearat involves the neutralization of stearic acid with a magnesium salt, such as magnesium oxide or magnesium hydroxide. The resulting compound forms a fine, inert powder that is easy to incorporate into powder blends.

In pharmaceutical manufacturing, magnesiumstearat is widely used as an excipient and processing aid. Its primary function is to act as a lubricant and anti-adherent to prevent tablet and capsule sticking to equipment during compression and ejection. It also serves as a glidant to improve powder flow, which helps ensure uniform tablet weight and content. In addition to pharmaceuticals, it is used in cosmetics as a lubricating and smoothing agent and in some foods as a processing aid or anti-caking agent, helping to improve texture and prevent clumping.

Safety and regulation are generally favorable; magnesiumstearat is regarded as relatively inert and of low toxicity. It is permitted for use in pharmaceuticals, cosmetics, and foods in many jurisdictions, though excessive inhalation of the dry powder can be irritating and formulation effects, such as altered dissolution of active ingredients, may occur at higher concentrations.