A process for preparing polymeric composite particles includes the steps of preparing an oil phase containing a biodegradable polymer and a water phase containing a hydrophilic compound or nanoparticle and emulsifying the oil phase in the water phase to form emulsions. Then solvent is removed from the emulsions to prepare the particles in the form of capsules and spheres in sizes from 0.01 μm (10 nm) to 50 μm.