Abstract <p>The protein corona has a significant impact on the biodistribution, pharmacokinetics and therapeutic functionality of nanosystems, which determines the need for an in-depth study of the factors influencing its formation. The auxiliary substances included in the nanoparticles, in particular, polyvinyl alcohol, can affect their physico-chemical properties, thereby affecting the formation of a protein corona. In this work, nanoparticles based on a copolymer of lactic and glycolic acids loaded with paclitaxel were synthesized by single emulsification method using various concentrations of polyvinyl alcohol. The obtained nanoparticles were characterized by dynamic and electrophoretic light scattering methods. The adsorption models of Langmuir, Freundlich, Langmuir–Freundlich and Brunauer, Emmett and Teller were used to describe the process of protein adsorption on the surface of nanoparticles. The obtained data indicate that the concentration of adsorbed proteins decreases when the residual polyvinyl alcohol concentration on the particle surface is increased. The revealed relationship will allow optimizing the design of nanosystems based on a copolymer of lactic and glycolic acids in order to increase the effectiveness of therapy.</p>