In Vivo Application of Carboranes for Boron Neutron Capture Therapy (BNCT): Structure, Formulation and Analytical Methods for Detection

SIMPLE SUMMARY: Boron neutron capture therapy (BNCT) is an emerging anticancer treatment. The success of BNCT relies on the delivery of adequate quantities of (10)B to tumor cells. Carboranes, polyhedral clusters containing boron, carbon and hydrogen atoms, are promising candidates as boron agents in BNCT. In this review, we provide an overview and state-of-the-art description of applications of carboranes for in vivo BNCT studies. We comprehensively report: (i) the different molecules used, (ii) their formulation and administration strategies, (iii) the tumor models investigated and (iv) qualitative and quantitative methodologies for carborane detection in in vivo experiments. ABSTRACT: Carboranes have emerged as one of the most promising boron agents in boron neutron capture therapy (BNCT). In this context, in vivo studies are particularly relevant, since they provide qualitative and quantitative information about the biodistribution of these molecules, which is of the utmost importance to determine the efficacy of BNCT, defining their localization and (bio)accumulation, as well as their pharmacokinetics and pharmacodynamics. First, we gathered a detailed list of the carboranes used for in vivo studies, considering the synthesis of carborane derivatives or the use of delivery system such as liposomes, micelles and nanoparticles. Then, the formulation employed and the cancer model used in each of these studies were identified. Finally, we examined the analytical aspects concerning carborane detection, identifying the main methodologies applied in the literature for ex vivo and in vivo analysis. The present work aims to identify the current strengths and weakness of the use of carboranes in BNCT, establishing the bottlenecks and the best strategies for future applications.