Abstract: The polybutylcyanoacrylate nanoparticles of ³H-labeled gentamicin were preparedin order to investigate the possi bili ty of gentamicin nanoparticles as an intracel l u lar dr ug de li ve rysystem for intracellular chemotherapy. The 3H-labeled gentamicin nanoparticles were incubated withmouse peritoneal macrophage(MPM)or rat hepatOcytes(RH)for some period,then the cells wereseparated from the nanoparticles, and finally the radiOactivity(cpm)of ³H in the cells were measuredby a liquid scintillation counter.By comparison with the solution of ³H-labeled gentamicin,a6.34times increase of cpm value in MPM after 30 min incubation , and 27. 74,9.03 and 8.36 timesincrease of MPM values in RH after 1,12, and 24 h incubation respectively l were observed bybinding gentamicin with polybutylcyanoacrylate nanoparticles,The particle size , surfactant coating,stabilizer and the gentamicin concentration were found to have some effect on the uptake ofnanoparticles by two kinds of cells.This study provided a basis for the screenning of intracellular drugdelivery system