Abstract—Biodegradable polymeric nanoparticles conjugated with targeting vector molecules have become
prospective agents to improve the effectiveness of chemotherapeutic cancer treatment. This approach reduces
the systemic toxicity of the drugs and increases the specificity of their uptake by cancer cells. A method has
been developed to obtain complex nanoparticles loaded with the antitumor drug paclitaxel and a Cterminal
fragment of recombinant oncofetal alphafetoprotein serving as a vector molecule, the in vitro cytotoxic
activity of complex nanoparticles for MCF7 human breast adenocarcinoma cells and resistant MDR1+ cells
of the MCF7Adr subline was shown to be higher than the cytotoxicity of the free drug and drugloaded nano
particles without the vector molecule. Moreover, the toxicity of complex paclitaxelloaded nanoparticles
against lymphocytes was low, which confirmed the selectivity of nanoparticle action. In summary, these
results demonstrate that the strategy of active targeting of nanoparticles can efficiently enhance the antitumor
activity of paclitaxel and it can solve the problem of reversing the multidrug resistance (MDR) of tumor cells.