Gadolinium neutron-capture therapy using novel gadopentetic acid-chitosan complex nanoparticles: in vivo growth suppression of experimental melanoma solid tumor

The potential of gadolinium neutron-capture therapy (Gd-NCT) for cancer was evaluated using chitosan nanoparticles as a novel gadolinium device. The n anoparticles, incorporating 1200 mu g of natural gadolinium, were administe red intratumorally twice in mice bearing subcutaneous B16F10 melanoma. The thermal neutron irradiation was performed for the tumor site, with the flue nce of 6.32 x 10(12) neutrons/cm(2), 8 h after the second gadolinium admini stration. After the irradiation, the tumor growth in the nanoparticle-admin istered group was significantly suppressed compared to that in the gadopent etate solution-administered group, despite radioresistance of melanoma and the smaller Gd dose than that administered in past Gd-NCT trials. This stud y demonstrated the potential usefulness of Gd-NCT using gadolinium-loaded n anoparticles. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.