Patent ID: 7897141
Filing Date: 2011-03-01
Classification: A61K,B01J,C08L,G01N

Abstract:
1. A method for producing an echogenic polymer microcapsules or nanocapsules comprising: (a) dissolving a non-water soluble sublimable substance in one or more volatile non-polar solvents to form a first mixture; (b) dissolving a non-water soluble polymer in said first mixture to form a second mixture which is an outer surface forming phase; (c) adding a core forming phase comprising water and a water soluble sublimable substance dissolved in water to the second mixture and emulsifying the second mixture to produce a water/oil emulsion; (d) mixing said water/oil emulsion with an aqueous phase comprising water and a surfactant in an amount sufficient to form a water/oil/water emulsion comprising a population of microcapsules or nanocapsules, wherein said microcapsules or nanocapsules have an outer surface consisting of (i) a solution of the non-water soluble sublimable substance, the non-polar solvent and the non-water soluble polymer and (ii) a core comprising a solution of water and the water-soluble sublimable substance; (e) hardening said outer surface of said population of microcapsules or nanocapsules by mixing said microcapsules or nanocapsules with a hardening agent and therefore forming a population of hardened microcapsules or nanocapsules having a hardened outer surface; (f) washing said population of hardened microcapsules and nanocapsules to remove the hardening agent and traces of the non-polar solvent; and (g) removing the non-water soluble sublimable agent from the hardened outer surface and removing water and the water soluble sublimable agent from the core and thereby forming hollow areas in the hardened outer surface and a hollow core surrounded by the hardened outer surface, and thereby obtaining said echogenic polymer microcapsules or nanocapsules.