Lecithins: A comprehensive review of their properties and their use in formulating microemulsions

Abstract

Lecithins are a phospholipid-rich mixture recovered from the degumming process of crude vegetable oils. Since the nineteenth century, this by-product of oil processing has been used as a food and pharmaceutical ingredient. Lecithins' popularity as an ingredient in the pharmaceutical and food industries arises from their particular properties, such as their hydrophilic-lipophilic balance, critical micellar concentration, and assembly properties. However, there is limited knowledge of the use of lecithins to formulate pharmaceutical-and food-grade microemulsions. Unlike conventional emulsions, microemulsions are thermodynamically stable systems that offer longterm stability. Besides, microemulsions show nano-sized droplets, transparency, ease of preparation and scale-up, and do not require expensive equipment. This review aims to provide a comprehensive overview of lecithins, their properties, and their use in formulating microemulsions, a promising method to incorporate, protect, and deliver bioactive compounds in pharmaceutical and food products. Practical applicationsLecithins are a phospholipid-rich mixture recovered from the degumming process of crude vegetable oils. Since the nineteenth century, this by-product of oil processing has been used as a food ingredient. Lecithin phospholipids are commonly used as emulsifier agents in the food and pharmaceutical industries because of their particular properties. However, there is limited knowledge of the use of lecithins to formulate pharmaceutical-or food-grade microemulsions. Unlike conventional emulsions, microemulsions are stable systems that offer long-term stability, nano-sized droplets, transparency, ease of preparation and scale-up, and do not require expensive equipment. This review aims to provide a comprehensive overview of lecithins, their properties, and their use in formulating microemulsions, a promising method to incorporate, protect, and deliver bioactive compounds such as vitamins, flavors, antioxidants, nutrients, colors, antimicrobials, and polyphenols.

Release of Tretinoin Solubilized in Microemulsion from Carbopol and Xanthan Gel: In Vitro versus Ex Vivo Permeation Study

“…Generally, phospholipids are recognized as chemical penetration enhancers since the contact of phospholipids with the skin might cause skin hydration, and subsequently an increase in the drug concentration in the tissue. Lecithin-based microemulsions have a natural affinity to the cell membrane, causing an enhancement in the dermal and transdermal absorption of several drugs [ 45 ].…”

Supramolecular gels – a panorama of low-molecular-weight gelators from ancient origins to next-generation technologies

“…70 More recently, soy-lecithin, extracted from soy beans, has become the dominant source of industrially-produced lecithin. 71 Lecithin is well-known for its properties as an emulsifier (surfactant) helping stabilise combinations of oil and water. It can be fully metabolised, is safe for food use, and is found in a huge range of products, such as chocolate, where it stabilises fats, and prevents phase separation.…”

Phosphorus sustainability: a case for phytic acid as a biorenewable platform

“…Plant and animal cell membranes contain a large amount of phosphorus in the form of phospholipids such as the phosphatidylcholines ( 9 ), one of the main constituents of the phospholipid mixture lecithin. Lecithin has a widespread application in the food industry 41 and is available cheaply (from soybean; ∼US$30 per 500 g), 42 whereas pure phosphatidylcholines are expensive (>US$139 per 100 mg). 43 Several lecithin processing techniques exist that modify the parent mixture to meet specific industrial demands, also enabling the isolation of specific phospholipids.…”