Nano-encapsulation of Vitamin D3 Active Metabolites for Application in Chemotherapy: Formulation Study and in Vitro Evaluation

Purpose Calcitriol (1,25-dihydroxyvitamin D 3 ), the active metabolite of vitamin D 3 , is a potential anticancer agent but with high risk of hypercalcemia which limits the achievement of effective serum concentrations. Thus, calcitriol targeting delivery by nanoparticles may present a good solution. Methods Vitamin D 3 active metabolites were encapsulated into polymeric nanoparticles and different formulation parameters were tested. The growth inhibitory efficiency of these nanoparticles was carried out in vitro on human breast adenocarinoma cells (MCF-7). Results Using cholecalciferol (the inactive metabolite), different polymer and oil ratios were compared to select nanoparticles presenting high encapsulation efficiency and sustained release profile. Calcidiol/calcitriol loaded nanoparticles had good encapsulation efficiencies (around 90%) associated with sustained releases over 7 days and enhanced stability. Moreover, loaded nanoparticles showed similar growth inhibition to non-encapsulated metabolites of vitamin D 3 on day 4 and higher activities on days 7 and 10 after treatment initiation. Conclusion The nano-encapsulation of vitamin D 3 active metabolites may offer a new and potentially effective strategy for vitamin D 3 -based chemotherapy overcoming its actual limitations. The targeting delivery of vitamin D 3 metabolites should be encouraged.