Stearic acid, stearate hydroxylation

Ester formation with hydroxyl-containing APIs has been observed for acid salts (e.g., succinic acid, citric acid, formic acid, acetic acid, etc.) as well as excipients (e.g., stearic acid, magnesium stearate). See Figure 85 for an example of the reaction of a hydroxyl group with succinic acid (124). 

The surface modification of the fillers used is implemented by the use of a variety of chemical compounds such as organosilanes, stearic acid, fatty acid, silicone oil, zinc stearate, magnesium stearate, and titanium stearate. In this case, the modifier functional groups interact with the hydroxyl groups of filler, while the carbon chains of the modifier are much shorter than the carbon chains of the used polymer that hinders the... 

The fatty acids have special names. The saturated Cjg acid is called stearic , and the compound listed is 2,3-dihydroxypropyl stearate. The alcohol residue is glycerol. Since only one hydroxyl is esterified this type of ester is called a monoglyceride and the compound may be named monoglyceryl stearate. It is valuable in food processing as an emulsifier. 

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