Excipient (pharmacologically inactive substance)
What is it?
Lecithin is used to stabilize emulsions. Lecithin is present in all living cells and is a significant constituent of nerve and brain cells. Egg lecithin is commonly used in the pharmaceutical and cosmetics industry. It is a purified mixture of phospholipids supplying phosphatidylcholine, but does not contain cholesterol or proteins. In the pharmaceutical industry, it is used as a wetting agent, dispersing agent, carrier, and emulsifier; it is often used for intravenous (IV) emulsions. Only a few emulsions are considered safe for IV use, including lecithin, polysorbate 80, and Poloxamer 188. In the cosmetics industry, it is used to oli in water emulsions for cosmetic compositions or pharmaceutical excipients. Commercial lecithin primarily comes from soybean oil. The FDA considers egg lecithin as generally regarded as safe. Lecithin is virtually non-toxic, as it can be fully metabolized, unlike its counterpart synthetic emulsions.
 Christoph Wabel. Dissertation. Influence of Lecithin on Structure and Stability of Parenteral Fat Emulsions. Accessed March 31, 2014. http://www2.chemie.uni-erlangen.de/services/dissonline/data/dissertation/Christoph_Wabel/html/Chapter1.html