³²P carriers based on hydroxyapatite-loaded iron alginate beads for nuclear medicine applications

This work is devoted to iron alginate and hydroxyapatite composites as potential ³²P carriers for nuclear medicine applications. As a result of this work beads cross-linked with trivalent iron and modified using hydroxyapatite were synthesized for the first time. The beads were characterized using optical and electron microscopy, X-ray diffraction, EDX and IR spectroscopy. A method for introducing ³²P into beads by sorption of phosphate ions from a solution was proposed. The physicochemical parameters of this process were studied using spectrophotometry and liquid scintillation counting. The incorporation of the mineral phase into iron alginate beads resulted in an enhancement of the sorption capacity towards phosphate ions from 25 to 45 mg∙g^-1. Furthermore, mineralization has been demonstrated to improve the kinetic parameters of phosphate sorption due to the additional binding sites and the isotope exchange process. Sorption values approach the maximum 1 h after the start of the experiment for the best sample. Composite beads based on iron alginate and hydroxyapatite exhibited enhanced radionuclide retention in aqueous media, saline solution, and blood serum when compared to unmodified iron alginate beads. Advancements in the retention properties of the beads post-drying were exhibited. The optimal beads, derived from iron alginate and hydroxyapatite, as obtained in acetate buffer, exhibited a 23 % release of ³²P in blood serum at 36.6 °C within a 30-day period. The results demonstrate the potential of iron alginate and hydroxyapatite composites as ³²P carriers in nuclear medicine.