ABSTRACT
Pharmacokinetics of the doxorubicin (DOX) conjugates with magnetite nanoparticles of the core/ shell type in mice following i.v. injection in a dose of 12.5 microg Fe/g tissue w/w was studied using electron spin resonance technique (ESR). Conjugation of the DOX with magnetic nanoparticles was shown to considerably decrease DOX bioavailability in the heart and kidney tissues compared to the free DOX. A non-uniform stationary magnetic field B of 210 mT and [deltaB] of 200 mT/cm was found to be efficient in increasing DOX conjugate bioavailability in the target site. The magnetic field was also found to inhibit conjugate accumulation in the liver resulted in the increased bioavailability of the conjugates in the blood. The phenomenon can be associated with in vivo inhibition of the phagocytic activity of the immunocompetent cells upon application of magnetic fields. Morphometry data in agreement with pharmacokinetic data revealed a decrease in the conjugate concentration in the liver tissue and cells as well as the relative decrease in conjugate concentration in the Kupffer cells compared to hepatocytes upon application of magnetic fields.
