Patent ID: 7105181

Claim:
A process for producing parenterally, administrable microparticles containing a biologically active substance, comprising: a) preparing an aqueous starch solution, comprising starch which (i) has an amylopectin content exceeding 85% by weight, in which the molecular weight of the amylopectin has been reduced such that at least 80% by weight of the amylopectin is within the range of 10-10,000 kDa; which (ii) has amino acid nitrogen content of less than 50 μg per gram dry weight of starch, the starch concentration of the solution being at least 20% by weight; and which (iii) essentially lacks covalently bonded hydroxyethyl groups; b) combining the biologically active substance with the starch solution under conditions such that a composition in a form selected from a solution, emulsion, or suspension of said substance the starch solution is produced; c) adding the composition obtained in step b) an aqueous solution of a polymer having the ability of forming a two-phase aqueous system, thereby forming an emulsion of starch droplets which contain the biologically active substance as an inner phase in an outer phase of said polymer solution, wherein the polymer solution is added to the composition in at least two steps, in which at least one of the additions occurs after the emulsion has begun to be created; d) causing or allowing the starch droplets obtained in step c) to gel into starch particles through the natural capacity of the starch to solidify; e) drying the starch particles after prior removal of said outer phase through washing, and f) optionally applying a release-controlling shell of a biocompatible and biodegradable polymer by air suspension technology to the dried starch particles.