RESUMO
In the present study, PEG-coated pH-sensitive and PEG-folate-coated pH-sensitive liposomes containing the ¹59Gd-DTPA-BMA were prepared and radiolabeled through neutron activation technique, aiming to study the in vivo antitumoral activity and toxicity on mice bearing a previously-developed solid Ehrlich tumor. The treatment efficacy was verified through tumoral volume increase and histomorphometry studies. The toxicity of formulations was investigated through animal weight variations, as well as hematological and biochemical tests. The results showed that after 31 days of treatment, animals treated with radioactive formulations had a lower increase in tumor volume and a significantly higher percentage of necrosis compared with controls revealed by histomorphometry studies. Furthermore, mice treated with radioactive formulations exhibited lower weight gain without significant hematological or biochemical changes, except for toxicity to hepatocytes which requires more detailed studies. From the results obtained to date, we believe that the radioactive formulations can be considered potential therapeutic agents for cancer.