VITOR HUGO SOARES DE MELO
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
Artigo IPEN-doc 26487 Poly(3-hydroxi-butyrate-co-3-hydroxy-valerate) (PHB-HV) microparticles loaded with holmium acetylacetonate as potential contrast agents for magnetic resonance images2019 - AZEVEDO, MARIANGELA de B.M. de; MELO, VITOR H.S.; SOARES, CARLOS R.J.; GAMARRA, LIONEL F.; BARROS, CAIO H.N.; TASIC, LJUBICAIntroduction: 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)3) 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. Microspheres characterization was done using scanning electron microscopy, energy-dispersive X-ray, and infrared spectroscopies. The release of holmium(III) in sodium phosphate buffer (pH 7.4) was followed for 9 days with inductively coupled plasma. Finally, T2 and T2* magnetic resonance images (MRI) were acquired and compared with the MRI of the inclusion complex of holmium acetylacetonate in some β-cyclodextrins. Results: Holmium acetylacetonate loading, evaluated by thermogravimetry, was up to 20 times higher for copolymer with 5% of HV. It was shown that microspheres loaded with Ho(acac)3 exhibited an accumulation of Ho(III) on their surfaces but were stable over time, as no expressive release of holmium(III) was detected in 9-day exposition to sodium phosphate buffer. Holmium acetylacetonate in both microspheres or inclusion complexes was very efficient in obtaining T2 and T2* weighted images in magnetic resonance, thus, might be used as contrast agents. Conclusion: This is the first description of the use of inclusion complexes of holmium acetylacetonate in biodegradable polymers as contrast agents. New investigations are underway to evaluate the resistance of PHB-HV polymer microparticles to nuclear activation to assess their potential for use as radiopharmaceuticals for the treatment of liver cancer.Artigo IPEN-doc 25059 Development and characterization of polymeric microparticle of poly(D,L-lactic acid) loaded with holmium acetylacetonate2018 - AZEVEDO, MARIANGELA de B.M. de; MELO, VITOR H.S. de; SOARES, CARLOS R.J.; MIYAMOTO, DOUGLAS M.; KATAYAMA, RICARDO A.; SQUAIR, PETERSON L.; BARROS, CAIO H.N.; TASIC, LJUBICABiodegradable polymers containing radioactive isotopes such as Holmium 166 (166Ho) 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.Artigo IPEN-doc 16954 Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments2011 - MIYAMOTO, DOUGLAS M.; PIRES, GEOVANNA; LIRA, RAPHAEL A. de; MELO, VITOR H.S.; OSSO JUNIOR, JOAO A.; NASCIMENTO, NANCI; AZEVEDO, MARIANGELA de B.M. deArtigo IPEN-doc 17053 Microspheres of polyesther loaded with holmium-165: effect of gamma irradiation on the polymeric structure2011 - PIOVAN, THAIS P.G.; PIRES, GEOVANNA; LIRA, RAFAEL A. de; GERALDES, ADRIANA N.; NASCIMENTO, NANCI; MELO, VITOR H.S. de; KODAMA, YASKO; AZEVEDO, MARIANGELA de B.M. de