The particle size is one of critical parameters influencing the biodistribution of detonation nanodiamonds (DND) after their administration into the body. As DNDs are prone to aggregation, the difference between their sizes in aqueous and physiological solutions has to be taken into account. Radioactive I125-BSA molecules were covalently immobilized on DNDs divided in three fractions of different average size. The DND-BSAI125 conjugates were intravenously administrated into adult mice and the particle allocation in the animal's organs and blood was evaluated based on the radioactivity distribution. We conclude that most of the conjugates were taken from the bloodstream and trapped in the liver and spleen. The short-term distribution pattern for all DNDs was similar regardless of size and practically unchanged with time. No significant clearance of the particles was observed for 4 h, but the presence of DNDs was detected in the blood. It was found that the largest particles tend to accumulate more into the liver as compared to the smaller ones. However, the size effect was not well pronounced for the studied size range.

An experimental dosage form of rubomycin is developed: the drug is incorporated in absorbable polymeric (polyhydroxybutyrate) matrix in the form of microparticles. Antitumor efficiency of this rubomycin dosage form was studied in laboratory mice with transplanted Ehrlich ascitic carcinoma. Rubomycin deposited in polymeric microparticles exhibited pronounced antitumor activity, inhibited the proliferative activity of Ehrlich ascitic carcinoma, and improved survival of mice with tumors. This dosage form of the drug can be used for local injections.

Nanoparticles of antiferromagnetically ordered materials acquire the uncompensated magnetic moment caused by defects and surface effects. A bright example of such a nanoantiferromagnet is nanoferrihydrite consisting of particles 2−5 nm in size, the magnetic moment of which amounts to hundreds of Bohr magnetons per particle. We present a brief review of the studies on magnetic properties of ferrihydrite produced by bacteria. Special attention is focused on the aspects of possible biomedical applications of this material, i.e., the particle elimination, toxicity, and possible use for targeted drug delivery.

We studied antitumor properties of modified detonation nanodiamonds loaded with doxorubicin on in vivo model of Ehrlich ascites carcinoma. The type of tumor development and morphological characteristics of the liver, kidneys, and spleen were evaluated in experimental animals. Modified nanodiamonds injected intraperitoneally produced no antitumor effect on Ehrlich carcinoma. However, doxorubicin did not lose antitumor activity after sorption on modified nanodiamonds.