From the past 33 years, so many technologies for reduction of particle size are investigated to develop the drug delivery. Present a lot of latest techniques have been recognized in the pharmaceuticals. Polymeric nanoparticles (PNPs) are defined as particulate dispersions or solid particles with small size in the mean range of 10-1000nm, it protects the drug against in-vitro & in-vivo degradation it releases the drug in a controlled and sustained way and also gives the possibility of drug targeting. The uses of polymeric nanoparticles are a worldwide advance to enhance the poorly soluble drugs therapeutic performance in several administration routes. A number of procedures to make polymeric nanoparticles have been modified like nanoprecipitation technique, solvent evaporation technique, dialysis technique, supercritical fluid technology etc. In this review mainly focused on different preparation methods for PNPs, routes of nanoparticles administration and recent patents on PNPs.