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Tosato M, Asti M. Lights and Shadows on the Sourcing of Silver Radioisotopes for Targeted Imaging and Therapy of Cancer: Production Routes and Separation Methods. Pharmaceuticals (Basel) 2023; 16:929. [PMID: 37513841 PMCID: PMC10383325 DOI: 10.3390/ph16070929] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
The interest in silver radioisotopes of medical appeal (silver-103, silver-104m,g and silver-111) has been recently awakened by the versatile nature of their nuclear decays, which combine emissions potentially suitable for non-invasive imaging with emissions suited for cancer treatment. However, to trigger their in vivo application, the production of silver radioisotopes in adequate amounts, and with high radionuclidic purity and molar activity, is a key prerequisite. This review examines the different production routes of silver-111, silver-103 and silver-104m,g providing a comprehensive critical overview of the separation and purification strategies developed so far. Aspects of quality (radiochemical, chemical and radionuclidic purity) are also emphasized and compared with the aim of pushing towards the future implementation of this theranostic triplet in preclinical and clinical contexts.
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Affiliation(s)
- Marianna Tosato
- Radiopharmaceutical Chemistry Section, Nuclear Medicine Unit, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy
| | - Mattia Asti
- Radiopharmaceutical Chemistry Section, Nuclear Medicine Unit, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy
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Ballan M, Vettorato E, Morselli L, Tosato M, Nardella S, Borgna F, Corradetti S, Monetti A, Lunardon M, Zenoni A, Di Marco V, Realdon N, Andrighetto A. Development of implantation substrates for the collection of radionuclides of medical interest produced via ISOL technique at INFN-LNL. Appl Radiat Isot 2021; 175:109795. [PMID: 34087532 DOI: 10.1016/j.apradiso.2021.109795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 11/19/2022]
Abstract
Accelerator-based techniques with electromagnetic mass separation are considered among the most innovative and promising strategies to produce non-conventional radionuclides for nuclear medicine. Such approach was successfully used at CERN, where the dedicated MEDICIS facility was built, and at TRIUMF, where the ISAC radioactive beam facility was used to produce unconventional α-emitters. In such framework, the Legnaro National Laboratories of the Italian Institute of Nuclear Physics (INFN-LNL) proposed the ISOLPHARM project (ISOL technique for radioPHARMaceuticals), which will exploit radionuclides producible with the SPES (Selective Production of Exotic Species) ISOL (Isotope Separation On-Line) facility to develop novel radiopharmaceuticals. The ISOL technique utilizes the irradiation with a primary beam of particles/nuclei of a production target where radionuclides are produced. A radioactive ion beam is subsequently extracted from the production target unit, and transported up to an analyzing magnet, where non-isobaric contaminants are filtered out. The so-obtained purified radioactive beam is dumped onto an implantation substrate, referred as collection target. Then, the desired nuclides can be chemically harvested from the collected isobars, and the isotopically pure atom collection can be employed to radiolabel high specific activity radiopharmaceuticals. Metallic deposition targets in the form of coated metal foils were mostly used at TRIUMF and CERN. At ISOLPHARM, a different approach is under investigation which foresees the use of soluble cold-pressed collection targets, possibly facilitating the chemical purification process of the collected radionuclides. In this study, the production and characterization of some of the ISOLPHARM collection targets is presented, in particular, soluble salts (NaCl and NaNO3) and organic materials widely used for pharmaceutical tablets production are considered. All such materials proved to be potentially suitable as collection targets, since solid samples were easily produced and resulted compatible with the vacuum conditions required for the ion implantation process. Furthermore, some of the selected substrates were used for proof-of-concept deposition tests with stable silver, to prove their suitability as ISOLPHARM deposition substrates for silver-111, a promising candidate for radiotherapy. Such tests highlighted possible scenarios useful for the development of new alternative materials, as the use of insoluble organic targets.
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Affiliation(s)
- M Ballan
- Legnaro National Laboratories, National Institute of Nuclear Physics, 35020, Legnaro, Italy.
| | - E Vettorato
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131, Padua, Italy
| | - L Morselli
- Legnaro National Laboratories, National Institute of Nuclear Physics, 35020, Legnaro, Italy; Department of Physics and Earth Science, University of Ferrara, 44122, Ferrara, Italy
| | - M Tosato
- Department of Chemical Sciences, University of Padua, 35131, Padua, Italy
| | - S Nardella
- Department of Chemical Sciences, University of Padua, 35131, Padua, Italy
| | - F Borgna
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131, Padua, Italy
| | - S Corradetti
- Legnaro National Laboratories, National Institute of Nuclear Physics, 35020, Legnaro, Italy
| | - A Monetti
- Legnaro National Laboratories, National Institute of Nuclear Physics, 35020, Legnaro, Italy
| | - M Lunardon
- Department of Physics and Astronomy, University of Padua, 35131, Padua, Italy; Padova Division, National Institute of Nuclear Physics, 35131, Padua, Italy
| | - A Zenoni
- Department of Mechanical and Industrial Engineering, University of Brescia, 25123, Brescia, Italy
| | - V Di Marco
- Department of Chemical Sciences, University of Padua, 35131, Padua, Italy
| | - N Realdon
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131, Padua, Italy
| | - A Andrighetto
- Legnaro National Laboratories, National Institute of Nuclear Physics, 35020, Legnaro, Italy
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Tosato M, Asti M, Dalla Tiezza M, Orian L, Häussinger D, Vogel R, Köster U, Jensen M, Andrighetto A, Pastore P, Marco VD. Highly Stable Silver(I) Complexes with Cyclen-Based Ligands Bearing Sulfide Arms: A Step Toward Silver-111 Labeled Radiopharmaceuticals. Inorg Chem 2020; 59:10907-10919. [PMID: 32658468 PMCID: PMC8009516 DOI: 10.1021/acs.inorgchem.0c01405] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
With a half-life of 7.45 days, silver-111 (βmax 1.04 MeV, Eγ 245.4 keV [Iγ 1.24%], Eγ 342.1 keV [Iγ 6.7%]) is a promising candidate for targeted cancer therapy with β- emitters as well as for associated SPECT imaging. For its clinical use, the development of suitable ligands that form sufficiently stable Ag+-complexes in vivo is required. In this work, the following sulfur-containing derivatives of tetraazacyclododecane (cyclen) have been considered as potential chelators for silver-111: 1,4,7,10-tetrakis(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO4S), (2S,5S,8S,11S)-2,5,8,11-tetramethyl-1,4,7,10-tetrakis(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO4S4Me), 1,4,7-tris(2-(methylsulfanyl)ethyl)-1,4,7,10-tetraazacyclododecane (DO3S), 1,4,7-tris(2-(methylsulfanyl)ethyl)-10-acetamido-1,4,7,10-tetraazacyclododecane (DO3SAm), and 1,7-bis(2-(methylsulfanyl)ethyl)-4,10,diacetic acid-1,4,7,10-tetraazacyclododecane (DO2A2S). Natural Ag+ was used in pH/Ag-potentiometric and UV-vis spectrophotometric studies to determine the metal speciation existing in aqueous NaNO3 0.15 M at 25 °C and the equilibrium constants of the complexes, whereas NMR and DFT calculations gave structural insights. Overall results indicated that sulfide pendant arms coordinate Ag+ allowing the formation of very stable complexes, both at acidic and physiological pH. Furthermore, radiolabeling, stability in saline phosphate buffer, and metal-competition experiments using the two ligands forming the strongest complexes, DO4S and DO4S4Me, were carried out with [111Ag]Ag+ and promising results were obtained.
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Affiliation(s)
- Marianna Tosato
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Mattia Asti
- Radiopharmaceutical Chemistry Section, Nuclear Medicine Unit, AUSL-IRCCS di Reggio Emilia, Viale Risorgimento 80, 42122 Reggio Emilia, Italy
| | - Marco Dalla Tiezza
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Laura Orian
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Daniel Häussinger
- Department of Chemistry, University of Basel, St. Johannsring 19, 4056, Basel, Switzerland
| | - Raphael Vogel
- Department of Chemistry, University of Basel, St. Johannsring 19, 4056, Basel, Switzerland
| | - Ulli Köster
- Institut Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - Mikael Jensen
- The Hevesy Laboratory, Department Health Technology, Technical University of Denmark (DTU), Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Alberto Andrighetto
- Italian Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell'Università 2, 35020 Legnaro (Padova), Italy
| | - Paolo Pastore
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
| | - Valerio Di Marco
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
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