monoolein

Monoolein, also known as glyceryl monooleate, is the monoester of glycerol and oleic acid (cis-9-octadecenoic acid). It is a lipophilic, amphiphilic lipid that serves as an emulsifier, thickener, and stabilizer in a range of products. The compound has the chemical formula C21H40O4 and is typically a viscous, colorless to pale yellow oil at room temperature. It is produced by esterification of glycerol with oleic acid, or by glycerolysis of fats and oils, and is purified for commercial use.

In formulations, monoolein contributes surface-active properties that help stabilize emulsions and solubilize lipophilic actives. Beyond simple emulsification, it is valued for its ability to form lipid-based phases, including the lipidic cubic phase with water, which is used in some drug-delivery systems and in membrane protein crystallography. Because of its miscibility with oils and its relatively low polarity, it is also employed as a solvent or co-solvent for lipid-soluble compounds.

Regulatory and practical notes: Monoolein is widely used as a food additive under the designation E471, representing mono- and diglycerides of fatty acids. It is also used in cosmetics and pharmaceutical formulations as an emollient, thickener, or processing aid. Safety evaluations generally consider it suitable for these uses, though high concentrations can cause irritation in some contexts. Proper handling and storage are advised to minimize oxidation and degradation.

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