Sorbitan Monostearate (Span 60) is a lipophilic emulsifier that is a sorbitan fatty acid ester, being a sorbitol-derived analog of glycerol monostearate. It is a nonionic, oil-dispersible surface-active agent. It is used as a gloss enhancer in chocolate coatings; as a dispersant aid in coffee whiteners; to increase volume in cakes and icings; and often in combination with polysorbates.

Sorbitan monostearate (abbreviation SMS), or Span 60, is an emulsifier esterified from sorbitol and stearic acid with the European food additive number E491. This ingredient is mostly used in baking yeast by improving the activity of instant dry yeast when the yeast is rehydrated before use.

Bilayers prepared from sorbitan fatty acid esters (Span) have been frequently used for delivery of drugs including flavonoids. We applied molecular dynamics simulation to characterize the structure of a sorbitan monostearate (Span 60) bilayer in complex with three representative flavones, a subclass of flavonoids. At a low concentration, unsubstituted flavone, the most hydrophobic member, was able to flip over and cross the bilayer with a large diffusion coefficient. At a high concentration, it was accumulated at the bilayer center resulting in a phase separation.

SPAN 60 Sorbitane Monostearate