Food additives Europe numbers: E491
Functional Category
Dispersing agent; emulsifying agent; nonionic surfactant; solubilizing agent; suspending agent; wetting ag
Applications in Pharmaceutical Formulation
Sorbitan monoesters are a series of mixtures of partial esters of sorbitol and its mono- and dianhydrides with fatty acids. Sorbitan diesters are a series of mixtures of partial esters of sorbitol and its monoanhydride with fatty acids. Sorbitan esters are widely used in cosmetics, food products, and pharmaceutical formulations as lipophilic nonionic surfactants. They are mainly used in pharmaceutical formulations as emulsifying agents in the preparation of creams, emulsions, and ointments for topical application. When used alone, sorbitan esters produce stable water-in-oil emulsions and microemulsions, but are frequently used in combination with varying proportions of a polysorbate to produce water-in-oil or oil-in-water emulsions or creams of varying consistencies, and also in self-emulsifying drug delivery systems for poorly soluble compounds.(1) Sorbitan monolaurate, sorbitan monopalmitate and sorbitan trioleate have also been used at concentrations of 0.01–0.05% w/v in the preparation of an emulsion for intramuscular administration.
Description
Sorbitan esters occur as cream- to amber-colored liquids or solids with a distinctive odor and taste; see Table V
Stability and Storage Conditions
Gradual soap formation occurs with strong acids or bases; sorbitan esters are stable in weak acids or bases. Sorbitan esters should be stored in a well-closed container in a cool, dry place
Safety
Sorbitan esters are widely used in cosmetics, food products, and oral and topical pharmaceutical formulations, and are generally regarded as nontoxic and nonirritant materials. However, there have been occasional reports of hypersensitive skin reactions following the topical application of products containing sorbitan esters.(2–5) When heated to decomposition, the sorbitan esters emit