The study of the interactions of drugs with plasmatic proteins is of fundamental importance for the understanding of their biological applications and effects. The classical analytical techniques employed for the characterization of the degree of binding in such ligand/receptor systems are mainly based on separation method and spectroscopic characterizations. In the present study, we show that diffusion-based NMR spectroscopy is a useful tool for the fast and reliable determination of the quantitative binding between a polymer-drug bioconjugate and a model protein in aqueous solution. The dissociation constant (Kd) related to the binding event was calculated and compared with the results obtained from a classical fluorescence-based assessment, showing good match between these two methods.
