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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Poly(3-hydroxi-butyrate-co-3-hydroxy-valerate) (PHB-HV) microparticles loaded with holmium acetylacetonate as potential contrast agents for magnetic resonance images

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de Azevedo, Mariangela de Burgos M. [1] ; Melo, Vitor H. S. [1] ; Soares, Carlos R. J. [1] ; Gamarra, Lionel F. [2] ; Barros, Caio H. N. [3, 4] ; Tasic, Ljubica [3]
Total Authors: 6
[1] IPEN CNEN SP, Ctr Biotecnol, BR-05508000 Sao Paulo - Brazil
[2] Hosp Israelita Albert Einstein, Sao Paulo, SP - Brazil
[3] Univ Estadual Campinas, Inst Quim, Campinas, SP - Brazil
[4] Univ Coll Dublin, Sch Chem & Bioproc Engn, Dublin - Ireland
Total Affiliations: 4
Document type: Journal article
Source: INTERNATIONAL JOURNAL OF NANOMEDICINE; v. 14, p. 6869-6889, 2019.
Web of Science Citations: 0

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)(3)) loaded poly(3-hydroxy-butyrate-co-3-hydroxy-valerate) micro spheres, with 5% or 8% of 3-hydroxy-valerate (HV), were prepared by emulsification/evaporation process within 20-53 mu m 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, T-2 and T-2{*} magnetic resonance images (MRI) were acquired and compared with the MRI of the inclusion complex of holmium acetylacetonate in some beta-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 T-2 and T-2{*} 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. (AU)

FAPESP's process: 15/26058-0 - Glycoprofiling and N-glycosylation site occupancy of different human thyrotropin (hTSH) preparations of pituitary or recombinant origin
Grantee:Carlos Roberto Jorge Soares
Support type: Regular Research Grants