In this study, we synthesized and characterized a zwitterionic polymer based on the 4-vinylpyridine monomer (4-VP) and used it as a practical drug carrier for 5-fluorouracil (5-FU). Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), gel permeation chromatography (GPC) and zeta potential analysis were conducted to investigate the molecular interactions, morphology, molecular weight, and surface charge, respectively. The GPC findings showed the weight average molecular weight of 64.5 kDa for poly(4-VP). Using ethyl bromoacetate in a basic medium, the zwitterion poly(4-VP), abbreviated as ZVP, was obtained and showed a different morphology, medium weight average molecular weight, and increased negative surface charge (−17 mV) as compared to poly(4-VP). Moreover, the ZVP nanoparticles (NPs) illustrated a mean size of 76 nm, polydispersity index of 0.25 and ultimate 5-FU cumulative release of 55% with a first-order kinetic model. The in vivo results showed that the percentage of neutrophils over time in ZVP NPs was lower than 5-FU, indicating the reliable potential of the ZVP coating for the enhancement of the drug circulation time in blood with long-term stability for medical applications.