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Magnesium stearate

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Magnesium stearate
Names
IUPAC name
Magnesium octadecanoate
Identifiers
3D model (JSmol)
ECHA InfoCard 100.008.320 Edit this at Wikidata
E number E572 (acidity regulators, ...)
  • CCCCCCCCCCCCCCCCCC(=O)[O-].CCCCCCCCCCCCCCCCCC(=O)[O-].[Mg+2]
Properties
C36H70MgO4
Molar mass 591.27 g/mol
Melting point 88 °C (190 °F; 361 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Magnesium stearate, also called octadecanoic acid, magnesium salt, is a white substance which is solid at room temperature. It has the chemical formula Mg(C18H35O2)2. It is a salt containing two equivalents of stearate (the anion of stearic acid) and one magnesium cation (Mg2+). Magnesium stearate melts at about 88 °C, is not soluble in water, and is generally considered safe for human consumption. Because it is widely regarded as harmless, it is often used as a diluent[1] in the manufacture of medical tablets, capsules and powders.[2] In this regard, the substance is also useful because it has lubricating properties, preventing ingredients from sticking to manufacturing equipment during the compression of chemical powders into solid tablets; magnesium stearate is the most commonly used lubricant for tablets.[3] It is used to bind sugar in hard candies. It is also a common ingredient in baby formulas. In pure powder form, the substance can be a dust explosion hazard,[4] although this issue is effectively insignificant beyond the manufacturing plants using it.

When used as a filling agent in the manufacture of capsules and tablets, such as vitamins, the source of this ingredient is typically bovine.[citation needed] However, there is an increasing number of vegetarian options in which the product specifically indicates it contains magnesium stearate from vegetable sources.

Magnesium stearate is a major component of "bathtub rings". When produced by soap and hard water, magnesium stearate and calcium stearate both form a white solid insoluble in water, and are collectively known as "soap scum".

References

  1. ^ http://pubs.acs.org/cen/whatstuff/86/8601sci3.html
  2. ^ Sworbrick, James (1990). Encyclopedia of pharmaceutical technology. p. 2274. ISBN 0824728246, 9780824728243. {{cite book}}: Check |isbn= value: invalid character (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  3. ^ Weiner, Myra L. (1999). Excipient Toxicity and Safety. p. 10. ISBN 0824782100, 9780824782108. {{cite book}}: Check |isbn= value: invalid character (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  4. ^ International Chemical Safety Card 1403