In recent years, utilization of chitosan /tripolyphosphate nanoparticles has been considered greatly as protein delivery vehicles. Effects of a variety of factors on final characteristics of nanoparticles have been studied by many investigators. Although, the objective of this study was to achieve smaller chitosan nano carriers via changing fabrication parameters such as pH and temperature and to elucidate their effect on the size and polydispersity of nanoparticles. Nanoparticles were produced by ionic gellation method and particle’s morphology was shown by field emission scanning electron microscopy (FE-SEM). The results show that with increasing pH value from 4.5 to 6, either poly dispersity or hydrodynamic diameter decreased significantly in a linear trend (R2= 0.94 for size and 0.99 for pdI data). Results of this study could be used for preparing protein loaded chitosan nanoparticles with small sizes in the range of below 120 nanometers which is sympathetic for drug delivery applications. پرونده مقاله