Distribution and resorption of polymeric microparticles in visceral organs of laboratory animals after intravenous injection.

Microparticles obtained by using (14)C-labeled resorbable hydroxyaminobutyric acid polymer were injected into the caudal vein of laboratory animals without negative aftereffects for their growth and development and without changes in the macro- and microstructure of organs and tissues. The distribution of microparticles in the viscera and the dynamics of accumulation of carbon-containing polymer degradation products in the viscera were studied. The main targets for the particles are liver tissues, as well as renal and splenic tissues. The polymeric matrix of the microparticles is most actively destroyed in the spleen and liver. The presence of high-molecular-weight polymeric matrix in organs indicates the integrity of microparticles and the possibility of long-term (up to 12 weeks) functioning of polymeric particles in vivo.