A polymer and a mixture of phospholipids
are dissolved in water-miscible organic solvents such as acetone or
ethanol. The compound to be encapsulated or loaded is dissolved
in a lipophilic solvent and added to the organic solvent. The organic
solution is then added, via stirring, to an aqueous solution containing a surfactant. Addition to the aqueous solution causes the water-miscible solvent to rapidly diffuse into the aqueous phase, which results in the formation of lipophilic nanodroplets that contain the compound to be encapsulated. The water-insoluble polymer now migrates to the O/W interface where it adsorbs to form an interfacial membrane around the lipophilic core. The resultant suspension is then concentrated by evaporating the organic solvent and water under pressure