Biodegradable polymers containing radioactive isotopes such as Holmium 166 (Ho) have potential applications as beta particle emitters in tumour tissues. It is also a gamma ray emitter, allowing nuclear imaging of any tissue to be acquired. It is frequently used in the form of complexes such as holmium acetylacetonate (HoAcAc), which may cause damages in tissues next to the targets cancer cells, as it is difficult to control its linkage or healthy tissues radiotherapy effects. Poly(d,l-lactic acid), PDLLA, was used to encapsulate holmium acetylacetonate (HoAcAc) using an emulsion solvent extraction/evaporation technique. Microspheres with sizes between 20-53 µm were extensively characterised. HoAcAc release from the microspheres was assessed through studies using Inductively Coupled Plasma - Optical Emission Spectroscopy, and the microspheres showed no holmium leakage after a period of 10 half-lives and following gamma irradiation. Thus, HoAcAc loaded microspheres are here presented as a potential system for brachytherapy and imaging purposes.
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http://dx.doi.org/10.1080/02652048.2018.1477843 | DOI Listing |
Phys Chem Chem Phys
July 2020
Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED Nijmegen, The Netherlands.
Microspheres containing radioactive holmium-acetylacetonate are employed in emerging radionuclide therapies for the treatment of malignancies. At the molecular level, details on the coordination geometries of the Ho complexes are however elusive. Infrared ion spectroscopy (IRIS) was used to characterize several Ho-acetylacetonate complexes derived from non-radioactive microspheres.
View Article and Find Full Text PDFMater Sci Eng C Mater Biol Appl
January 2020
Radboudumc, Department of Radiology and Nuclear Medicine, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, the Netherlands; Quirem Medical B.V, Zutphenseweg 55, 7418 AH, Deventer, the Netherlands. Electronic address:
Microspheres with high specific activities of radionuclides are very interesting for internal radiotherapy treatments. This work focuses on the formulation and characterization of inorganic microspheres with a high content of holmium and therefore a high specific radioactivity of holmium-166. Two novel formulations of inorganic microspheres were obtained by dispersing solid holmium acetylacetonate microspheres (Ho(AcAc)-ms) in NaHPO or NaOH solutions followed by 2 h incubation at room temperature.
View Article and Find Full Text PDFInt J Nanomedicine
November 2019
Instituto de Química, UNICAMP, SP, Campinas, Brazil.
Introduction: Biodegradable polymers that contain radioactive isotopes such as Holmium 166 have potential applications as beta particle emitters in tumor tissues. Also, Ho(III) is paramagnetic, which makes it suitable as a contrast agent for magnetic resonance (MR) images.
Methods: Holmium acetylacetonate (Ho(acac)) loaded poly(3-hydroxy-butyrate-co-3-hydroxy-valerate) microspheres, with 5% or 8% of 3-hydroxy-valerate (HV), were prepared by emulsification/evaporation process within 20-53 μm size.
Nucl Med Biol
April 2019
Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, the Netherlands. Electronic address:
Background: [Ho]Ho-acetylacetonate-poly(L-lactic acid) microspheres were used in radioembolization of liver malignancies by intra-arterial administration. The primary aim of this study was to assess the stability and biodistribution of these microspheres.
Materials And Methods: Peripheral blood and urine samples were obtained from two clinical studies.
Int J Pharm
September 2018
Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Radboudumc, Department of Radiology and Nuclear Medicine, Geert Grooteplein Zuid 10, 6525 GA Nijmegen, The Netherlands; Quirem Medical B.V., Zutphenseweg 55, 7418 AH Deventer, The Netherlands. Electronic address:
The aim of this study was the development of radioactive holmium phosphate microspheres (HoPO-MS) with a high holmium content and that are stable in human serum for selective internal radiation therapy (SIRT) of liver cancer. To this end, holmium acetylacetonate microspheres (HoAcAc-MS) were prepared (34.2 ± 1.
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