The present study describes preparation and evaluation of nanoparticulate systems containing losartan potassium by using polymers eudragit RS100 and eudragit RSPO by sonication method (Probe sonicator) for the treatment of hypertension to increase the oral bioavailability. The prepared Nanoparticles were evaluated for Surface morphology, Drug entrapment efficiency, Differential scanning colorimetry, particle size, FTIR, in-vitro drug release and stability studies. The prepared Nanoparticles are smooth in surface and showing spherical shape and average particle size of the Nanoparticles were found in the range of 300 nm to 500 nm. The drug entrapment efficiency (EE) of prepared nanoparticles were found in the range of 78.14% to 91.64%. The in-vitro drug release data of all the formulations were found to be zero order and shown maximum release over a period of 24hrs. The FTIR Spectra of Nanoparticles formulation are compared with the spectra of pure drug of losartan and there is no much deviation in the spectra’s and not observed any drug and polymer interactions. The short-term stability of optimized formulation was conducted for drug entrapment efficiency and In-vitro drug release studies, where results shown that there is no significant change in the formulation.