Patent ID: 7641917

Claim:
A method of encapsulating an active substance in a polymeric encapsulating material to make an encapsulated product in particulate form, the method comprising the steps of: forming a mixture of a supercritical fluid, a polymeric encapsulating material, and an active substance; causing or allowing the encapsulating material to encapsulate the active substance to form an encapsulated product; separating the encapsulated product from the supercritical fluid to obtain encapsulated product particles in which the active substance is encapsulated by the encapsulating material; wherein the supercritical fluid is carbon dioxide; wherein the encapsulated product comprises the active substance that has been encapsulated by an interpolymer complex; wherein at least two different complementary polymers of different species interact together by hydrogen bonding to form the interpolymer complex; wherein the forming of the mixture comprises the step of dissolving the supercritical fluid in the interpolymer complex to liquefy or plasticize the interpolymer complex; and wherein the polymers which form the interpolymer complex are selected from complementary members of the group consisting of poly(vinyl acetate)-crotonic acid copolymer, poly(vinyl pyrrolidone), poly(ethylene glycol), poly(vinyl pyrrolidone)-poly(vinyl acetate) copolymer and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)triblock copolymer.