Storage conditions seem to be important in the long-term stability of nanoparticles (NPs). This work studies the effects of surfactants and storage container on particle size distribution and zeta potential during long-term storage of acid hydrolyzed potato starch NPs. The NPs were prepared from potato starch using acid hydrolysis and high-intensity ultrasonication. During the ultrasonic treatment, the surfactants were added dropwise to the solutions to reduce the size and stabilize the formed NPs. Particle size distribution, zeta potential, and FE-SEM were used to characterize the ensuing NPs. Additionally, a 5-month stability study was performed to evaluate the maintenance of potato starch NPs over time at different storage conditions. Then, NPs from corn starch were produced by the same procedure and were used for preparing pH-responsive nanocarriers containing NaHCO3 for delivery of an anti-cancer drug, FTY720. These NPs were able to release the drug at pH 5.0 because of CO2 generated from NaHCO3 in acidic pH and released from the NPs by the production of pores, which accelerate drug release.