In vivo insights into boron neutron capture therapy: the role of nano drug delivery systems in advancing cancer treatment

Abstract

Purpose: Boron Neutron Capture Therapy (BNCT) relies on selective accumulation of boron-10 isotopes within tumor tissue to achieve localized cell destruction. While nano-based boron delivery systems (nBDSs) show significant promise in preclinical settings, translation to clinical practice remains limited compared to conventional agents like BPA and BSH. This review critically evaluates the evolution of BNCT, focusing on biological performance and translational readiness of nBDSs. Methods: A systematic literature search was conducted across PubMed and Google Scholar covering the period 2000 to 2024. Search terms included 'BNCT,' 'nanotechnology,' 'boron delivery systems,' and 'in vivo studies.' Inclusion criteria were restricted to peer-reviewed original research articles reporting primary in vivo data on biodistribution, tumor-to-blood (T:B) ratios, and therapeutic efficacy. Review articles, conference papers, and studies lacking in vivo validation were excluded. Active and completed clinical trials were reviewed to contextualize preclinical findings against the clinical landscape. Results: Analysis of over 60 in vivo studies revealed that third-generation nBDSs, including liposomes, dendrimers, and polymeric nanoparticles, frequently outperform conventional agents in tumor selectivity and retention. Specific platforms demonstrated critical benchmarks, such as T:B ratios exceeding 20 (e.g. stimuli-responsive micelles) and complete tumor regression (e.g. albumin conjugates). Dendrimer-based systems extended mean survival time to over 59 days in glioma models. However, significant challenges persist, including high reticuloendothelial system uptake, batch-to-batch variability, and lack of Good Manufacturing Practice (GMP)-compliant scalability. No nBDS has advanced to clinical trials, highlighting a persistent translational gap. Conclusion: While nBDSs offer superior biological efficacy in preclinical models, clinical deployment is hindered by pharmaceutical and manufacturing barriers rather than biological potential. Future research must prioritize standardized in vivo protocols, hybrid carrier designs, and industrial scalability to effectively bridge the gap between experimental innovation and clinical application. Enhancing the therapeutic index through rigorous pharmacokinetic optimization is essential for development of next-generation BNCT agents.