Patent ID: 8246868

Claim:
A method for producing a vesicle, which comprises the following steps (1) to (4): (1) a step of producing a W/O emulsion from an aqueous solution containing a substance to be entrapped in a vesicle in a dissolved or suspended state and a first oil phase containing an emulsifier; (2) a step of cooling the W/O emulsion to a temperature at which the aqueous solution becomes a frozen particle and the oil phase maintains a liquid state, and removing the first oil phase while retaining at least some of the emulsifier on the surface of the frozen particle; (3) a step of adding a second oil phase containing a vesicle constituent lipid to the frozen particle and then stirring the mixture, so as to substitute the emulsifier on the surface of the frozen particle with the vesicle constituent lipid, wherein a lipid bilayer membrane is formed on an outer surface of the frozen particle while maintaining an internal water phase in the particle; and (4) a step of adding an external water phase to the frozen particle coated with a lipid membrane, so as to hydrate the lipid membrane by the external water phase.