CA1323568C — Multivesicular liposomes having a biologically active substance encapsulated therein in the presence of a hydrochloride

USPTO Abstract

Multivesicular Liposomes Having a Biologically Active Substance Encapsulated Therein In the Presence of a Hydrochloride Abstract of the Disclosure Disclosed are large multivesicular liposomes containing biologically active substances, the multivesicular liposomes having defined size distribution, adjustible average size, adjustible internal chamber size and number, and having substantially higher encapsulation efficiency and substantially slower leakage rate of the biologically active substance than in the previous art. The process comprises dissolving a lipid component in volatile organic solvents, adding an immiscible aqueous component containing a hydrochloride and one or more biologically active substances to be encapsulated, making a water-in-oil emulsion from the two components, immersing the emulsion into a second aqueous component, dividing the emulsion into small solvent spherules which contain even smaller aqueous chambers, and then evaporating the solvents to give an aqueous suspension of multivesicular liposomes encapsulating biologically active substances.