Sorbitan esters as nonionic surfactant and emulsifier in various micro- and nanoformulations: Recent progress and limitations

Surfactants mitigate the surface tension between liquids, facilitating the formation of emulsions and enhancing the dispersion of ingredients. There are four major types of surfactants, involving anionic, cationic, amphoteric, and nonionic surfactants. Sorbitan esters or Spans are nonionic surfactants, which have numerous applications in the preparation of creams, ointments, emulsions, and pharmaceutical products. For example, sorbitan trioleate or Span ۸۵ is a nonionic surfactant and emulsifier used in various industries. It's a pale yellow, viscous liquid at room temperature, formed by the esterification of sorbitan with oleic acid. Span ۸۵ is known for its ability to produce water-in-oil (W/O) emulsions as well as oil-in-water (O/W) emulsion stabilizer, making it appropriate in cosmetics, pharmaceuticals, and food processing. As important disadvantages, the application of Span ۸۵ in cosmetic products can be a skin and eye irritant. Furthermore, it can bind to proteins and divalent cations in the body, reducing its effectiveness. For overcoming these hindrances, other surfactants or emulsifiers are often preferred in pharmaceutical micro- and nanoformulations, which we have presented in this review.

کلیدواژه ها:

Water-in-oil (W/O) emulsions ، Cosmetics ، Pharmaceuticals ، Food processing