Magnesium stearate

Magnesium stearate
IUPAC name	Magnesium octadecanoate
Identifiers
CAS number	557-04-0 Y
PubChem	11177
SMILES	CCCCCCCCCCCCCCCCCC(=O)[O-].CCCCCCCCCCCCCCCCCC(=O)[O-].[Mg+2]
Properties
Molecular formula	C36H70MgO4
Molar mass	591.27 g/mol
Appearance	light white powder
Odor	slight
Melting point	88 °C, 361 K, 190 °F
Solubility in water	negligible
Solubility	insoluble in ether slighty soluble in benzene
Hazards
MSDS	External MSDS
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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^{[citation needed]}. Because it is widely regarded as harmless, it is often used as a diluent^[1] in the manufacture of medical tablets, capsules and powders (E470b).^[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; James C. Boylan (1990). Encyclopedia of pharmaceutical technology. p. 2274. ISBN 0824728246, 9780824728243. 
3. ^ Weiner, Myra L.; Lois A. Kotkoskie (1999). Excipient Toxicity and Safety. p. 10. ISBN 0824782100, 9780824782108. 
4. ^ International Chemical Safety Card 1403