In vivo study on the biodistribution of silica particles in the bodies of rats.

Abstract

BACKGROUND: Biodegradable carrier materials with nontoxic degradation products are very valuable for delivering drugs and biologically active molecules. Many organic systems (such as liposomes, micelles and polymeric nanoparticles) and inorganic systems (metal oxides and silica) have been researched for delivering active substances to organs. Silica seems to be one of the most interesting and promising materials. OBJECTIVES: The aim of this study was to investigate the SiO2 elimination process from rats' organisms and to ascertain the distribution and prospective accumulation sites of the silica particles. MATERIAL AND METHODS: A suspension of silica particles (Ø 150 nm) in 0.9% NaCl solution was introduced into rats' circulatory system. The degradation of these particles over time and their accumulation in the heart, lungs, kidneys and liver were observed. RESULTS: It was found that 36% of the introduced silica particles were excreted with urine after four days. The remaining particles were accumulated in the kidneys and lungs, probably in the lung air sacs and kidney glomerulus. CONCLUSIONS: Silica seems to be promising carrier material. Silica particles dissolve in the rat's body and are eliminated in urine.