New production of microparticles involves use of aqueous solution of purified amylopectin-based starch of reduced molecular weight

摘要

Production of microparticles involves preparation of an aqueous solution of purified amylopectin-based starch (at least 20 wt.%) of reduced molecular weight, combining the solution with biologically active substance to form an emulsion of starch droplets, gelling the droplets and drying gelled starch particles. Production of microparticles containing a biologically active substance involves: (a) preparing an aqueous starch solution comprising starch (at least 20, preferably more than 25 wt.%), which has an amylopectin content exceeding 85% by weight; (b) combining the biologically active substance with the starch solution to form a composition in the form of a solution, emulsion or suspension; (c) mixing the composition with an aqueous solution of a polymer (A), which forms a two-phase aqueous system, thus forming an emulsion of starch droplets containing the biologically active substance as an inner phase in an outer phase of the polymer solution; (d) gelling the starch droplets into starch particles through the natural capacity of the starch to solidify; (e) drying the starch particles (preferably after prior removal of the outer phase through washing); and (f) optionally applying a release-controlling shell of a biocompatible and biodegradable polymer (preferably by air suspension technology) to the dried starch particles. The molecular weight of the amylopectin is reduced such that at least 80 wt.% of the material is within 10-10000, and has an amino acid nitrogen content of less than 50 microg per g dry weight of starch. An Independent claim is also included for the microparticles.