There is no accepted international definition of a nanoparticle, but one given in the new PAS71 document developed in the UK is: "A particle having one or more dimensions of the order of 1000nm or less". Nanoencapsulation of drugs involves forming drug load particles with diameters ranging from 1 to 1000 nm. Nanoparticles are defined as solid, submicron-sized drug carriers that may or may not be biodegradable. nanoparticle variesinmanufacturing methods and in this paper we focus on polymeric nanoparticle particulary chitosan /Alginate nanoparticle and charactristic and advantage .