Abstract: The present invention relates to a basically spherical hyperbranched block copolymer having an internal hydrophobic block and an external hydrophilic block. Within the spherical copolymer, the hydrophobic block constitutes a hydrophobic layer, suitable to associate or encapsulate hydrophobic bioactive agents, while the hydrophilic block provides an outer layer, which is suitable to render the copolymer soluble or dispersible in aqueous solutions. Also claimed is a method for preparing the copolymer, which is suitable to encapsulate fragrances, flavours, drugs, agrochemicals, for example.