Preparation and in vitro evaluation of B-lipiodol as a boron delivery agent for neutron capture therapy of hepatoma

Background: We prepared boron containing lipiodol (B-lipiodol), elucidated the retention of B-lipiodol in hepatoma cells and evaluated the in vitro cellular toxicity of B-lipiodol for neutron capture therapy. Materials and Methods: Human hepatoma HepG2 cells were used to examine the uptake and retention of B-lipiodol. Light microscopes were used to examine the interaction and retention of B-lipiodol globules in individual hepatoma cells. Boron and lipiodol concentrations were determined by inductively coupled plasma-atomic emission spectroscopy and neutron activation analysis, respectively. Results: The boron concentration in B-lipiodol drug could reach 2500 ppm. B-lipiodol could be stably retained in serum and culture medium. HepG2 cells appeared proficiently at internalization and persistent retention of B-lipiodol. The boron concentration reached 3.5 mu g/10(6) cells without approaching saturation at 48 h treatment. Conclusion: Hepatoma cells could actively uptake B-lipiodol and a sufficient amount of boron was retained inside the HepG2 cells which could be used for neutron capture therapy.