Silver-coated monolithic columns for separation in radiopharmaceutical applications.

In this study, we demonstrate the preparation of a macroporous monolithic column containing anchored silver nanoparticles and its use for the elimination of excess radioiodine from the radiolabeled pharmaceutical. The poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was first functionalized with cystamine and the free thiol groups liberated by reaction with borohydride. In-house-prepared silver nanoparticles were then attached by interaction with the surface thiols. The deiodization process was demonstrated with the commonly used radiopharmaceutical m-iodobenzylguanidine labeled with radionuclide iodine-125.

Quality control of iodine-131-labeled metaiodobenzylguanidine.

AIM/OBJECTIVES/BACKGROUND: Iodine-131-m-iodobenzylguanidine ([(131)I]mIBG) is used worldwide for the diagnosis and therapy of neuroendocrine tumors, particularly adrenal medullae tumors. After the synthesis and preparation of a radioiodinated MIBG drug formulation, quality control testing to determine its radiochemical purity (RCP) should be performed. European Pharmacopoeia 8.0 requires that the quality control include a test for RCP for the determination of [(131)I]mIBG. Previously reported procedures using reversed-phase conditions require long retention times. Our system enables the separation of [(131)I]mIBG within a few minutes. The aim of this work was to carry out RCP testing for [(131)I]mIBG without any type of sample pretreatment. METHODS: RCP testing for ([(131)I]mIBG has been carried out using high-performance liquid chromatography and thin-layer chromatography methods. RESULTS: A simple and rapid reversed-phase isocratic system enables the HPLC investigation of RCP testing for [(131)I]mIBG used for therapy within a few minutes. CONCLUSIONS: From the point of view of radiation protection, this method is safer, especially for therapeutic amounts of [(131)I]mIBG.

Extenso patrón hipermetabólico por activación de la grasa parda en un paciente diagnosticado de paraganglioma para-vesical secretor de catecolaminas explorado mediante 18F-FDG PET/TC / Extensive hypermetabolic pattern of brown adipose tissue activation on 18F-FDG PET/CT in a patient diagnosed of catecholamine-secreting para-vesical paraganglioma

El uso generalizado de la exploración 18F-FDG PET-TC en pacientes de cáncer ha permitido demostrar la existencia de grasa parda metabólicamente activa, también llamada tejido adiposo pardo (TAP), en sujetos humanos adultos, y conocer su distribución anatómica in vivo. Como determinantes fisiológicos de la captación de 18F-FDG por el TAP se han identificado el sexo, la edad, la temperatura y el índice de masa corporal. Hemos observado una extensa activación del TAP, incluyendo la región mesentérica, en un paciente con un paranganglioma paravesical secretor de catecolaminas. La activación extensa del TAP podría ser secundaria a la estimulación adrenérgica por un exceso de la concentración de noradrenalina circulante (AU)

The widespread use of 18F-FDG PET-CT scanning in oncological patients has allowed to demonstrate the existence of metabolically active brown fat, also called brown adipose tissue (BAT), in adult humans, and specifying its anatomical distribution in vivo. As physiological determinants to BAT 18F-FDG uptake has been identified gender, age, temperature, and body mass index. We have observed extensive activation of the BAT, including the mesenteric region, in a patient with a catecholamine-secreting para-vesical paranganglioma. The extensive BAT activation could be secondary to adrenergic stimulation due to excess of circulating norepinephrine concentration (AU)

Stabilisation of [131I]meta-iodobenzylguanidine at room temperature as organic extract in ethyl acetate/chloroform.

A method of purification of [131I]mIBG (diagnostic dose) by solvent extraction and possibility of its stabilisation by storage in ethyl acetate and chloroform at up to 40 degrees C for not less than 14 days is described. In order to further enhance the utility of this finding, the organic extract was dispensed into vials and dried. Vials containing such dried residue of [131I]mIBG stored at up to 40 degrees C was also found to be stable for at least 10 days. The final product reconstituted as aqueous solution resulted in 90% recovery with 99% radiochemical purity as assessed by previously reported methods, as well as a relatively more rapid paper chromatography method standardised by us. These interesting findings promise simpler and economic packaging besides transport of diagnostic doses of [131I]mIBG.