Process for the preparation of liposomes in aqueous solution

A process for the preparation of a solution or suspension of liposomes in an aqueous medium comprising the steps of dispersing a first aqueous liquid in an essentially water-insoluble solvent in the presence of a compound of the formula XY wherein X is a hydrophilic lipophobic group and Y is a lipophilic hydrophobic group to form a dispersion of liposome precursors in the solvent, the precursors consisting of small vesicles of the first aqueous liquid surrounded by a monomolecular film of compound XY, emulsifying the liposome precursors in a second aqueous medium in the presence of a compound of the formula ZW wherein Z is a hydrophilic group and W is a hydrophobic group to thereby form a solution or suspension of liposomes in the second aqueous medium, said liposomes consisting of the first aqueous liquid surrounded by a bimolecular film of the structure XY-WZ and removing the water-insoluble solvent prior to or after said emulsification.

A process for the preparation of a solution or suspension of liposomes in an aqueous medium comprising the steps of dispersing a liquid product to be encapsulated with the aid of sonic or ultrasonic vibration in an essentially water-insoluble solvent containing in solution an excess of a compound of the formula XY wherein X is a hydrophilic lipophobic group and Y is a hydrophobic lipophilic group to form a dispersion of liposome precursers in the solvent consisting of vesicles of the liquid product surrounded by a monomolecular film of the compound XY, emulsifying this dispersion of liposome precursors containing an excess of the XY compound in a second aqueous medium to form a solution or suspension of liposomes consisting of vesicles of the liquid product surrounded by a bimolecular film of structure XY-YX and thereafter removing the solvent by evaporation to provide a solvent-free solution or suspension of the liposomes in said aqueous medium.