It is also used along with sodium taurocholate for simulating fed- and fasted-state biorelevant media in dissolution studies of highly lipophilic drugs. However, lecithin extracts consist of a mixture of phosphatidylcholine and other compounds. Phosphatidylcholines are such a major component of lecithin that in some contexts the terms are sometimes used as synonyms. Gobley eventually completely described his lecithin from chemical structural point of view, in 1874. The name lecithin was derived from Greek λέκιθος, lekithos 'egg yolk' by Theodore Nicolas Gobley, a French chemist and pharmacist of the mid-19th century, who applied it to the egg yolk phosphatidylcholine that he identified in 1847. Purified phosphatidylcholine is produced commercially. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria, including Escherichia coli. lecithin) is a major component of pulmonary surfactant and is often used in the L/S ratio to calculate fetal lung maturity.

They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. Phosphatidylcholines ( PC) are a class of phospholipids that incorporate choline as a headgroup.

Pure pc phosphotyldcholine