The invention relates to a system for administering biologically active substances produced by foaming techniques using compressed gases or supercritical fluids. The invention relates to a porous system containing biologically active substances comprising a polymer matrix of poly(D,L-lactic-co-glycolic acid) or a polymer mixture containing poly(D,L-lactic-co-glycolic acid) of an inherent viscosity of less than 0.5 dL/g with other biodegradable synthetic or semisynthetic polyesters, a release-regulating component (starch and derivatives) and at least one biologically active substance, characterized in that it is a biodegradable matrix with a solid or semisolid consistency and a homogeneous appearance. The invention also relates to a method for producing said systems using foaming with compressed fluids, and to the use for the production of implants and scaffolds comprising said system. Optionally, a porogenic agent can be used for the formation of macropores by thermal decomposition.
