Polysorbates advantage

Emulsions of fatty- and petroleum-based substances, both oils and waxes, of the o/w type are made by using blends of sorbitan fatty esters and their poly(oxyethylene) derivatives. Mixtures of poly(oxyethylene(20)) sorbitan monostearate (Polysorbate 60) and sorbitan monostearate are typical examples of blends used for lotions and creams. Both sorbitan fatty acid esters and their poly(oxyethylene) derivatives are particularly advantageous in cosmetic uses because of their very low skin irritant properties. Sorbitan fatty ester emulsifiers for w/o emulsions of mineral oil are used in hair preparations of both the lotion and cream type. Poly(oxyethylene(20)) sorbitan monolaurate is useflil in shampoo formulations (see Hairpreparations). Poly(oxyethylene) sorbitan surfactants are also used for solubilization of essential oils in the preparation of colognes and after-shave lotions. 

Adsorption of a non-ionic polymer (gum or cellulosic) or surfactant (polysorbate 80) of sufficient chain length creates steric hindrance and prevents adjacent suspended particles from coming close enough to join each other. Steric stabilization has the advantage over electrostatic stabilization in that it is relatively insensitive to the presence of electrolyte in the aqueous vehicle. 

Polysorbate-20, 60, and SO. These have the same acceptable daily intake as sorbitan esters but are characterized by the property of enhancing the absorption of fat-soluble substances (38). This property can be an advantage or an adverse effect depending on the drug. Furthermore, poly-sorbates can also provoke hypersensitivity following topical application. They may disrupt normal membrane structures (39). 

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