Ionic compositions comprise an active ingredient absorbed within a network of internal pores defined by a plurality of polymeric particles. The particles are preferably crosslinked polymeric beads having a diameter in the range from about 5 to 100 microns and a surface charge density from about...http://www.google.es/patents/US5840293?utm_source=gb-gplus-sharePatente US5840293 - Ionic beads for controlled release and adsorption
