title: Investigating an organ-targeting platform based on hydroxyapatite nanoparticles using a novel in situ method of radioactive ¹²⁵Iodine labeling.
abstract: In this study, we have investigated the synthesis of nanoparticles of hydroxyapatite (HAp) and hydroxyapatite coated with chitosan (HAp/Ch) and the chitosan-poly-d,l-lactide-co-glycolide polymer blend (HAp/Ch-PLGA) as an organ-targeting system. We have examined and defined the final destination, as well as the dynamics and the pathways of the synthesized particles following intravenous administration in vivo. The XRD, ZP, FT-IR and SEM analyses have confirmed that the hydroxyapatite nanoparticles with d50=72 nm are coated with polymers. Radioactive 125-Iodine ((125)I), a low energy gamma emitter, was used to develop a novel in situ method for the radiolabeling of particles and investigation of their biodistribution. (125)I-labeled particles exhibited high stability in saline and serum over the second day, which justified their use in the following in vivo studies. The biodistribution of (125)I-labeled particles after intravenous injection in rats differed significantly: HAp particles mostly targeted the liver, HAp/Ch the spleen and the liver, while HAp/Ch-PLGA targeted the lungs. Twenty-four hours post injection, HAp particles were excreted completely, while both (125)I-HAp/Ch and (125)I-HAp/Ch-PLGA were retained in the body for a prolonged period of time with more than 20% of radioactivity still found in different organs.
authors.affiliation: Centre for Fine Particles Processing and Nanotechnologies, Institute of Technical Sciences of the Serbian Academy of Science and Arts, Knez Mihailova 35/4, 11000 Belgrade, Serbia.
authors.forename: Nenad
authors.initials: N
authors.lastname: Ignjatović
authors.affiliation: Laboratory for Radioisotopes, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001 Belgrade, Serbia.
authors.forename: Sanja
authors.initials: S
authors.lastname: Vranješ Djurić
authors.affiliation: Faculty of Medicine, Department of Pharmacy, University of Niš, Bulevar dr Zorana Đinđića 81, 18000 Niš, Serbia.
authors.forename: Zarko
authors.initials: Z
authors.lastname: Mitić
authors.affiliation: Laboratory for Radioisotopes, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, 11001 Belgrade, Serbia.
authors.forename: Drina
authors.initials: D
authors.lastname: Janković
authors.affiliation: Centre for Fine Particles Processing and Nanotechnologies, Institute of Technical Sciences of the Serbian Academy of Science and Arts, Knez Mihailova 35/4, 11000 Belgrade, Serbia. Electronic address: dragan.uskokovic@itn.sanu.ac.rs.
authors.forename: Dragan
authors.initials: D
authors.lastname: Uskoković
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D017886:Durapatite; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D010316:Particle Size; D051381:Rats; D017208:Rats, Wistar; D017550:Spectroscopy, Fourier Transform Infrared; D014018:Tissue Distribution
chemical_list: D007457:Iodine Radioisotopes; D017886:Durapatite
keywords: Biodistribution; Chitosan; In situ (125)I-labeling; Nano-hydroxyapatite; Organ-targeting