Etoposide loaded PLGA and PCL nanoparticles II: biodistribution and pharmacokinetics after radiolabeling with Tc-99m.

Etoposide and nanoparticle formulations were labeled with Tc-99m and their biodistribution and pharmacokinetics were studied after intravenous administration in healthy mice and rabbits respectively. Etoposide was rapidly cleared from the body, while the disposition of nanoparticles was slower. A higher proportion of nanoparticles compared with etoposide was observed in different organs of mice. Scintigraphic images of rabbits concluded that the radioactivity shown by formulations is significantly higher after 4 and 24 h, as compared with etoposide administered in rabbits. AUC(0 - infinity), clearance and MRT are better than those obtained with etoposide administration. The overall high residence of nanoparticles, compared with etoposide, signifies the advantage of PLGA and PCL nanoparticles as drug carriers for etoposide in enhancing the bioavailability and reducing the etoposide-associated toxicity.