Elimination of a Viscumin-Ferromagnetic Nanoparticles Conjugate from the Tumor Nodule in Mice

External magnetic field is characterized by low toxicity and existence of magnetic properties, which contributes to an interest in the development of products from ferromagnetic nanoparticles (FNP) for antitumor therapy. Previously we synthesized a conjugate of ferromagnetic magnetite nanoparticles and viscumin (mistletoe lectin I, MLI), which exhibits the antitumor activity. Studying the pharmacological properties of this conjugate (FNP-MLI) was directed to the evaluation of FNP-MLI elimination after intratumor injection in mice. The elimination rate of FNP-MLI was much lower than that of native plant MLI. The presence of FNP-MLI was not accompanied by undesired changes in the tumor tissue. The use of a FNP-MLI conjugate allowed us to prolong the time of MLI presence in tissues without increasing the dose of exogenous lectin. These features contribute to the prolongation of an immunomodulatory effect of MLI.