DISTRIBUTION AND ELIMINATION OF POLY(METHYL-2-C-14-METHACRYLATE) NANOPARTICLE RADIOACTIVITY AFTER INJECTION IN RATS AND MICE

The organ distribution of poly(methyl‐2‐14C‐methacrylate) nanoparticles after 0.5,1,2,6, and 24 hr and after 7 days, as well as the elimination of degradation products in urine, feces, and breath, was measured for 7 days after intravenous administration to rats. The radioactivity was determined quantitatively after preparation of the organs and qualitatively by macroautoradiography. In addition, nanoparticle distribution after intramuscular administration to mice was determined by macroautoradiography after 7, 35, and 70 days. Thirty minutes after intravenous administration, the nanoparticles were found in the lungs in high concentrations (758 μg/g fresh weight ≈ 22% of the administered dose); 60% (261 μg/g) of the dose was found in the liver. During the first 7 days, the concentration in the lungs decreased from 758 to 284 μg/g while the concentration in the liver increased from 261 to 372 μg/g (≈ 68% of the administered dose), the concentration in the spleen increased from 33 to 131 μg/g (μ 4%), and the concentration in the bones increased from 3 to 6 μg/g. In all other organs and tissues, the radioactivity decreased significantly. During the first 7 days after intravenous administration, 1% of the administered dose was eliminated in the urine, 3.5% in the feces, and 1% in the breath. After intramuscular administration, all of the 14C‐radioactivity still present in the body persisted at the injection site for 70 days. Copyright © 1979 Wiley‐Liss, Inc., A Wiley Company