CONTROLLED RELEASE FORMULATIONS

摘要

Active substances intended for topical application are incorporated in novel formulations in which they are retained as impregnants inside the pores of porous solid particles or microspheres. The pores form a continuous network open to the exterior of the particles, permitting outward diffusion of the impregnants at a controlled rate depending on the pore size. The impregnated particles are prepared by the polymerization of monomer droplets which contain the active substance mixed in with the monomers, or by impregnation of preformed particles with the active substance.