Study of Tissue Distribution of Potential Agents for Boron Neutron Capture Therapy Using Boron Nanoparticle Conjugates of Chlorin e<sub>6</sub> Amino Amide Derivatives
Boron neutron capture therapy using the ability of the isotope <sup>10</sup>B to capture thermal neutrons is one of the most promising tedrniques in radiation therapy. Therefore, the high accumulation and selective delivery of <sup>10</sup>B into tumor tissue are the most important requirements to achieve its efficacy. This study objective was to evaluate biodistribution of conjugates of cobalt bis-dicarbollide with chlorin e6 amino amide derivatives. Experiments were carried out on tumor-bearing Balb/c mice. Mice colon carcinoma CT-26 was used as a tumor model. Boron-containing conjugates were injected into the tail vein in a dose of 10 mg/kg. Conjugate accumulation in tumor tissue and organs was studied by laser scanning microscopy. Excitation was performed at the wavelength of 514 nm, the registered signals were in the range of 560-710 nm at intervals of 10 nm. The intensity of fluorescence signal of tissue samples was used to evaluate the amount of boron conjugate. In 3 hours after injection, a high level of fluorescence was observed in liver, spleen and lung. The contrast of muscle/tumor accumulation appears to achieve ~3. The study demonstrated the application perspectiveness of chlorin e6 boron conjugates as agents in boron neutron capture therapy.