A process for producing parenterally administrable microparticles, in which an at least 20% by weight aqueous solution of purified amylopectin-based starch of reduced molecular weight is prepared, the solution is combined with biologically active substance, an emulsion of starch droplets is formed in an outer phase of polymer solution, the starch droplets are made to gel, and the gelled starch particles are dried. A release-controlling shell is optionally also applied to the particles.Microparticles which essentially consist of said starch, have an amino acid content of less than 50 .mu.g and have no covalent chemical cross-linking.