Abstract: The invention relates to a novel biologically active composition which comprises a biologically active agent composition which comprises a biologically active agent to be released therefrom, said biologically active agent being dissolved and/or dispersed in a supersaturated state within a carrier, which carrier comprises a liquid and/or solid non-crystalline ester and/or polyester matrix, and where the precipitation of said biologically active agent is substantially, or completely, inhibited therein. Said supersaturated states is obtainable by subjecting one or more carrier staring substances(s) to such chemical reaction(s) that an ester and/or polyester matrix is provided, the biologically active agent being added after said chemical reaction(s) has (have) been completed.