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17 pages, 2332 KiB

Open AccessArticle

Automation of Copper-Mediated ¹⁸F-Fluorination of Aryl Pinacol Boronates Using 4-Dimethylaminopyridinium Triflate

by Mikhail A. Nadporojskii, Viktoriya V. Orlovskaya, Olga S. Fedorova, Dmitry S. Sysoev and Raisa N. Krasikova

Molecules 2024, 29(14), 3342; https://doi.org/10.3390/molecules29143342 - 16 Jul 2024

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Abstract

Currently, the copper-mediated radiofluorination of aryl pinacol boronates (arylBPin) using the commercially available, air-stable Cu(OTf)2Py4 catalyst is one of the most efficient synthesis approaches, greatly facilitating access to a range of radiotracers, including drug-like molecules with nonactivated aryl scaffolds. Further adjustment of this [...] Read more.

Currently, the copper-mediated radiofluorination of aryl pinacol boronates (arylBPin) using the commercially available, air-stable Cu(OTf)2Py4 catalyst is one of the most efficient synthesis approaches, greatly facilitating access to a range of radiotracers, including drug-like molecules with nonactivated aryl scaffolds. Further adjustment of this methodology, in particular, the [¹⁸F]fluoride recovery step for the routine preparation of radiotracers, has been the focus of recent research. In our recent study, an organic solution of 4-dimethylaminopyridinium trifluoromethanesulfonate (DMAPOTf) was found to be an efficient PTC for eluting radionuclides retained on the weak anion exchange cartridge, Oasis WAX 1cc, employing the inverse sorption–elution protocol. Notably, the following Cu-mediated radiofluorination of arylBPin precursors in the presence of the Cu(OTf)2(Py)4 catalyst can be performed with high efficiency in the same solvent, bypassing not only the conventional azeotropic drying procedure but any solvent replacement. In the current study, we aimed to translate this methodology, originally developed for remote-controlled operation with manual interventions, into the automated synthesis module on the TRACERlab automation platform. The adjustment of the reagent amounts and solvents allowed for high efficiency in the radiofluorination of a series of model arylBPin substrates on the TRACERlab FXFE Pro synthesis module, which was adapted for nucleophilic radiofluorinations. The practical applicability of the developed radiofluorination approach with DMAPOTf elution was demonstrated in the automated synthesis of 6-L-[¹⁸F]FDOPA. The radiotracer was obtained with an activity yield (AY; isolated, not decay-corrected) of 5.2 ± 0.5% (n = 3), with a synthesis time of ca. 70 min on the TRACERlab FX N Pro automation platform. The obtained AY was comparable with one reported by others (6 ± 1%) using the same boronate precursor, while a slightly higher AY of 6-L-[¹⁸F]FDOPA (14.5 ± 0.5%) was achieved in our previous work using commercially available Bu₄NOTf as the PTC. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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12 pages, 23396 KiB

Open AccessArticle

Tritium-Labeled Nanodiamonds as an Instrument to Analyze Bioprosthetic Valve Coatings: A Case of Using a Nanodiamond Containing Coating on a Pork Aorta

by Maria G. Chernysheva, Tianyi Shen, Gennadii A. Badun, Ivan V. Mikheev, Ivan S. Chaschin, Yuriy M. Tsygankov, Dmitrii V. Britikov, Georgii A. Hugaev and Natalia P. Bakuleva

Molecules 2024, 29(13), 3078; https://doi.org/10.3390/molecules29133078 - 28 Jun 2024

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Abstract

Coatings with xenogenic materials, made of detonation nanodiamonds, provide additional strength and increase elasticity. A functionally developed surface of nanodiamonds makes it possible to apply antibiotics. Previous experiments show the stability of such coatings; however, studies on stability in the bloodstream and calcification [...] Read more.

Coatings with xenogenic materials, made of detonation nanodiamonds, provide additional strength and increase elasticity. A functionally developed surface of nanodiamonds makes it possible to apply antibiotics. Previous experiments show the stability of such coatings; however, studies on stability in the bloodstream and calcification of the material in natural conditions have yet to be conducted. Tritium-labeled nanodiamonds (negative and positive) were obtained by the tritium activation method and used to develop coatings for a pork aorta to analyze their stability in a pig’s bloodstream using a radiotracer technique. A chitosan layer was applied from a solution of carbonic acid under high-pressure conditions to prevent calcification. The obtained materials were used to prepare a porcine conduit, which was surgically stitched inside the pig’s aorta for four months. The aorta samples, including nanodiamond-coated and control samples, were analyzed for nanodiamond content and calcium, using the radiotracer and ICP-AES methods. A histological analysis of the materials was also performed. The obtained coatings illustrate a high in vivo stability and low levels of calcification for all types of nanodiamonds. Even though we did not use additional antibiotics in this case, the development of infection was not observed for negatively charged nanodiamonds, opening up prospects for their use in developing coatings. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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15 pages, 3374 KiB

Open AccessArticle

Neurotensin (8-13) and Neuromedin N Neuropeptides Radiolabelling with Copper-64 Produced on Solid or Liquid Targets

by Diana Cocioabă, Alexandra I. Fonseca, Radu Leonte, Ivanna Hrynchak, Roxana Tudoroiu-Cornoiu, Sergio J. C. do Carmo, Bogdan Burghelea, Simona Băruță, Ana Rita Almeida, Radu Șerban, Anca Dinischiotu, Antero J. Abrunhosa and Dana Niculae

Molecules 2024, 29(6), 1390; https://doi.org/10.3390/molecules29061390 - 20 Mar 2024

Cited by 1 | Viewed by 1449

Abstract

On the verge of a theranostic approach to personalised medicine, copper-64 is one of the emerging radioisotopes in nuclear medicine due to its exploitable nuclear and biochemical characteristics. The increased demand for copper-64 for preclinical and clinical studies has prompted the development of [...] Read more.

On the verge of a theranostic approach to personalised medicine, copper-64 is one of the emerging radioisotopes in nuclear medicine due to its exploitable nuclear and biochemical characteristics. The increased demand for copper-64 for preclinical and clinical studies has prompted the development of production routes. This research aims to compare the (p,n) reaction on nickel-64 solid versus liquid targets and evaluate the effectiveness of [⁶⁴Cu]CuCl₂ solutions prepared by the two routes. As new treatments for neurotensin receptor-overexpressing tumours have developed, copper-64 was used to radiolabel Neurotensin (8-13) and Neuromedin N. High-quality [⁶⁴Cu]CuCl₂ solutions were prepared using ACSI TR-19 and IBA Cyclone Kiube cyclotrons. The radiochemical purity after post-irradiation processing reached 99% (LT) and 99.99% (ST), respectively. The irradiation of a solid target with 11.8 MeV protons and 150 μAh led to 704 ± 84 MBq/μA (17.6 ± 2.1 GBq/batch at EOB). At the end of the purification process (1 h, 90.90% activity yield), the solution for peptide radiolabelling had a radioactive concentration of 1340.4 ± 70.1 MBq/mL (n.d.c.). The irradiation of a liquid target with 16.9 MeV protons and 230 μAh resulted in 3.7 ± 0.2 GBq/batch at EOB, which corresponds to an experimental production yield of 6.89 GBq.cm3/(g.µA)_sat. Benefiting from a shorter purification process (40 min), the activity yielded 90.87%, while the radioactive concentration of the radiolabelling solution was lower (492 MBq/mL, n.d.c.). The [⁶⁴Cu]CuCl₂ solutions were successfully used for the radiolabelling of DOTA-NT(8-13) and DOTA-NN neuropeptides, resulting in a high RCP (>99%) and high molar activity (27.2 and 26.4 GBq/μmol for LT route compared to 45 and 52 GBq/μmol for ST route, respectively). The strong interaction between the [⁶⁴Cu]Cu-DOTA-NT(8-13) and the colon cancerous cell lines HT29 and HCT116 proved that the specificity for NTR had not been altered, as shown by the uptake and retention data. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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14 pages, 2957 KiB

Open AccessArticle

Synthesis and Preclinical Evaluation of Two Novel ⁶⁸Ga-Labeled Bispecific PSMA/FAP-Targeted Tracers with 2-Nal-Containing PSMA-Targeted Pharmacophore and Pyridine-Based FAP-Targeted Pharmacophore

by Arsyangela Verena, Helen Merkens, Chao-Cheng Chen, Devon E. Chapple, Lei Wang, Shreya Bendre, Antonio A. W. L. Wong, François Bénard and Kuo-Shyan Lin

Molecules 2024, 29(4), 800; https://doi.org/10.3390/molecules29040800 - 9 Feb 2024

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Abstract

Some bispecific radiotracers have been developed to overcome the limitations of monospecific tracers and improve detection sensitivity for heterogeneous tumor lesions. Here, we aim to synthesize two bispecific tracers targeting prostate-specific membrane antigen (PSMA) and fibroblast activation protein (FAP), which are key markers [...] Read more.

Some bispecific radiotracers have been developed to overcome the limitations of monospecific tracers and improve detection sensitivity for heterogeneous tumor lesions. Here, we aim to synthesize two bispecific tracers targeting prostate-specific membrane antigen (PSMA) and fibroblast activation protein (FAP), which are key markers expressed in prostate cancer. A pyridine-based FAP-targeted ligand was synthesized through multi-step organic synthesis and then connected to the 2-Nal-containing PSMA-targeted motif. The K_i(PSMA) values of Ga-complexed bispecific ligands, Ga-AV01084 and Ga-AV01088, were 11.6 ± 3.25 and 28.7 ± 6.05 nM, respectively, and the IC₅₀(FAP) values of Ga-AV01084 and Ga-AV01088 were 10.9 ± 0.67 and 16.7 ± 1.53 nM, respectively. Both [⁶⁸Ga]Ga-AV01084 and [⁶⁸Ga]Ga-AV01088 enabled the visualization of PSMA-expressing LNCaP tumor xenografts and FAP-expressing HEK293T:hFAP tumor xenografts in PET images acquired at 1 h post-injection. However, the tumor uptake values from the bispecific tracers were still lower than those obtained from the monospecific tracers, PSMA-targeted [⁶⁸Ga]Ga-PSMA-617 and FAP-targeted [⁶⁸Ga]Ga-AV02070. Further investigations are needed to optimize the selection of linkers and targeted pharmacophores to improve the tumor uptake of bispecific PSMA/FAP tracers for prostate cancer imaging. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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13 pages, 1636 KiB

Open AccessArticle

Synthesis of [¹¹C]BIIB104, an α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic-Acid-Positive Allosteric Modulator, and Evaluation of the Bio-Distribution in Non-Human Primate Brains Using Positron Emission Tomography

by Sangram Nag, Kevin Jia, Ryosuke Arakawa, Prodip Datta, Daniel Scott, Christopher Shaffer, Mohammad Mahdi Moein, Matthew Hutchison, Maciej Kaliszczak and Christer Halldin

Molecules 2024, 29(2), 427; https://doi.org/10.3390/molecules29020427 - 15 Jan 2024

Cited by 1 | Viewed by 1307

Abstract

The aim of this study was to measure the brain penetrance and kinetics of BIIB104, a first-in-class AMPA receptor potentiator developed for cognitive impairment associated with schizophrenia. It was recently halted in phase 2 clinical development, and there are a lack of tools [...] Read more.

The aim of this study was to measure the brain penetrance and kinetics of BIIB104, a first-in-class AMPA receptor potentiator developed for cognitive impairment associated with schizophrenia. It was recently halted in phase 2 clinical development, and there are a lack of tools to directly measure AMPA receptor engagement. To achieve this, the drug candidate was radiolabeled with carbon-11, and its brain penetrance and kinetics were measured in non-human primates via dynamic PET scans. Radiolabeling was achieved through a three-step nucleophilic [¹¹C]cyanation reaction in one pot, resulting in the high radioactivity and radiochemical purity (>99%) of [¹¹C]BIIB104. The study found that [¹¹C]BIIB104 entered the non-human primate brains at 4–5% ID at peak, with a homogeneous distribution. However, a mild regional heterogeneity was observed in the thalamus. The lack of conclusive evidence for a change in regional values after BIIB104 dosing suggests that any specific binding component of BIIB104 is negligible compared to the free and non-specific components in the living brain. Overall, the study demonstrated high brain uptake with minor variability in [¹¹C]BIIB104 distribution across various brain regions, its kinetics were consistent with those of passive diffusion, and the dominating components were the free concentration and non-specific binding. This information is valuable for understanding the potential effects and mechanisms of BIIB104 in the brain. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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19 pages, 5018 KiB

Open AccessArticle

Accelerator-Based Production of Scandium Radioisotopes for Applications in Prostate Cancer: Toward Building a Pipeline for Rapid Development of Novel Theranostics

by Jason P. Meier, Hannah J. Zhang, Richard Freifelder, Mohammed Bhuiyan, Phillip Selman, Megan Mendez, Pavithra H. A. Kankanamalage, Thomas Brossard, Antonino Pusateri, Hsiu-Ming Tsai, Lara Leoni, Sagada Penano, Kaustab Ghosh, Brittany A. Broder, Erica Markiewicz, Amy Renne, Walter Stadler, Ralph Weichselbaum, Jerry Nolen, Chien-Min Kao, Satish K. Chitneni, David A. Rotsch, Russell Z. Szmulewitz and Chin-Tu Chen Show full author list Hide full author list

Molecules 2023, 28(16), 6041; https://doi.org/10.3390/molecules28166041 - 13 Aug 2023

Cited by 5 | Viewed by 2379

Abstract

In the field of nuclear medicine, the β⁺ -emitting ⁴³Sc and β⁻ -emitting ⁴⁷Sc are promising candidates in cancer diagnosis and targeted radionuclide therapy (TRT) due to their favorable decay schema and shared pharmacokinetics as a true theranostic pair. [...] Read more.

In the field of nuclear medicine, the β⁺ -emitting ⁴³Sc and β⁻ -emitting ⁴⁷Sc are promising candidates in cancer diagnosis and targeted radionuclide therapy (TRT) due to their favorable decay schema and shared pharmacokinetics as a true theranostic pair. Additionally, scandium is a group-3 transition metal (like ¹⁷⁷Lu) and exhibits affinity for DOTA-based chelators, which have been studied in depth, making the barrier to implementation lower for ^43/47Sc than for other proposed true theranostics. Before ^43/47Sc can see widespread pre-clinical evaluation, however, an accessible production methodology must be established and each isotope’s radiolabeling and animal imaging capabilities studied with a widely utilized tracer. As such, a simple means of converting an 18 MeV biomedical cyclotron to support solid targets and produce ⁴³Sc via the ⁴²Ca(d,n)⁴³Sc reaction has been devised, exhibiting reasonable yields. The ^NatTi(γ,p)⁴⁷Sc reaction is also investigated along with the successful implementation of chemical separation and purification methods for ^43/47Sc. The conjugation of ^43/47Sc with PSMA-617 at specific activities of up to 8.94 MBq/nmol and the subsequent imaging of LNCaP-ENZaR tumor xenografts in mouse models with both ^43/47Sc-PSMA-617 are also presented. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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12 pages, 1808 KiB

Open AccessArticle

Characterization of a Novel M4 PAM PET Radioligand [11C]PF06885190 in Nonhuman Primates (NHP)

by Sangram Nag, Ryosuke Arakawa, Zhisheng Jia, Erik Lachapelle, Lei Zhang, Kevin Maresca, Laigao Chen, Mahabuba Jahan, Timothy Mccarthy and Christer Halldin

Molecules 2023, 28(12), 4612; https://doi.org/10.3390/molecules28124612 - 7 Jun 2023

Viewed by 2260

Abstract

Muscarinic acetylcholine receptors (mAChR), including M4, draw attention as therapeutic targets for several neurodegenerative diseases including Alzheimer’s disease (AD). PET imaging of M4 positive allosteric modulator (PAM) allows qualification of the distribution as well as the expression of this receptor under physiological conditions [...] Read more.

Muscarinic acetylcholine receptors (mAChR), including M4, draw attention as therapeutic targets for several neurodegenerative diseases including Alzheimer’s disease (AD). PET imaging of M4 positive allosteric modulator (PAM) allows qualification of the distribution as well as the expression of this receptor under physiological conditions and thereby helps to assess the receptor occupancy (RO) of a drug candidate. In this study, our aims were (a) to synthesize a novel M4 PAM PET radioligand [11C]PF06885190 (b) to evaluate the brain distribution of [¹¹C]PF06885190 in nonhuman primates (NHP) and (c) to analyze its radiometabolites in the blood plasma of NHP. Radiolabeling of [¹¹C]PF06885190 was accomplished via N-methylation of the precursor. Six PET measurements were performed using two male cynomolgus monkeys, where three PET measurements were at baseline, two after pretreatment with a selective M4 PAM compound CVL-231 and one after pretreatment with donepezil. The total volume of distribution (V_T) of [¹¹C]PF06885190 was examined using Logan graphical analysis with arterial input function. Radiometabolites were analyzed in monkey blood plasma using gradient HPLC system. Radiolabeling of [¹¹C]PF06885190 was successfully accomplished and the radioligand was found to be stable in the formulation, with radiochemical purity exceeding 99% 1 h after the end of the synthesis. [¹¹C]PF06885190 was characterized in the cynomolgus monkey brain where a moderate brain uptake was found at the baseline condition. However, it showed fast wash-out as it dropped to half of the peak at around 10 min. Change of V_T from baseline was around −10% after pretreatment with a M4 PAM, CVL-231. Radiometabolite studies showed relatively fast metabolism. Although sufficient brain uptake of [¹¹C]PF06885190 was observed, these data suggest that [¹¹C]PF06885190 might have too low specific binding in the NHP brain to be further applied in PET imaging. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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17 pages, 8524 KiB

Open AccessArticle

Removal of Cs-137 Radionuclide by Resorcinol–Formaldehyde Ion-Exchange Resins from Solutions Simulating Real Liquid Radioactive Waste

by Eduard Tokar, Mikhail Tutov, Svetlana Bratskaya and Andrei Egorin

Molecules 2022, 27(24), 8937; https://doi.org/10.3390/molecules27248937 - 15 Dec 2022

Cited by 8 | Viewed by 1780

Abstract

The efficiency of the removal of Cs-137 radionuclides with porous and non-porous resorcinol–formaldehyde resins from alkaline solutions simulating the composition of real liquid radioactive waste (LRW) streams has been evaluated. Resins were synthesized through the polycondensation of resorcinol and formaldehyde in an alkaline [...] Read more.

The efficiency of the removal of Cs-137 radionuclides with porous and non-porous resorcinol–formaldehyde resins from alkaline solutions simulating the composition of real liquid radioactive waste (LRW) streams has been evaluated. Resins were synthesized through the polycondensation of resorcinol and formaldehyde in an alkaline medium at a molar ratio of 1.8/2.2 and a temperature of 210 °C. The Cs-137 distribution coefficients on RFRs in alkaline solutions simulating LRW were above 10³ mL/g under static sorption conditions. In a model solution with pH 11, the full dynamic sorption capacity of non-porous RFR was 0.178 mmol/g. The values of the full dynamic sorption capacities of porous RFRs were 0.274 and 1.035 mmol/g for resins obtained with calcium carbonate and toluene as templates, respectively. When the sizes of RFR beads increased two-fold, the volume until 5% cesium breakthrough decreased by 20–40%. The most pronounced beneficial effect of the RFR’s porosity was observed at flow rates from 25 to 50 BV/h. It was shown that the negative effect of metal cations on Cs-137 uptake increases in the following order: Na⁺ < Mg²⁺ < Ca²⁺ < K⁺. The number of bed volumes of LRW-simulating solution decontaminated with RFRs until 5% cesium breakthrough was above 450; that is higher than the value of known commercially available analogs. The latter shows that the developed RFRs are promising for application in technological schemes of alkaline LRW processing. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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14 pages, 2974 KiB

Open AccessArticle

Production of [¹¹C]Carbon Labelled Flumazenil and L-Deprenyl Using the iMiDEV™ Automated Microfluidic Radiosynthesizer

by Hemantha Mallapura, Laurent Tanguy, Bengt Långström, Ludovic Le Meunier, Christer Halldin and Sangram Nag

Molecules 2022, 27(24), 8843; https://doi.org/10.3390/molecules27248843 - 13 Dec 2022

Cited by 8 | Viewed by 2378

Abstract

In the last decade, microfluidic techniques have been explored in radiochemistry, and some of them have been implemented in preclinical production. However, these are not suitable and reliable for preparing different types of radiotracers or dose-on-demand production. A fully automated iMiDEV™ microfluidic radiosynthesizer [...] Read more.

In the last decade, microfluidic techniques have been explored in radiochemistry, and some of them have been implemented in preclinical production. However, these are not suitable and reliable for preparing different types of radiotracers or dose-on-demand production. A fully automated iMiDEV™ microfluidic radiosynthesizer has been introduced and this study is aimed at using of the iMiDEV™ radiosynthesizer with a microfluidic cassette to produce [¹¹C]flumazenil and [¹¹C]L-deprenyl. These two are known PET radioligands for benzodiazepine receptors and monoamine oxidase-B (MAO-B), respectively. Methods were successfully developed to produce [¹¹C]flumazenil and [¹¹C]L-deprenyl using [¹¹C]methyl iodide and [¹¹C]methyl triflate, respectively. The final products 1644 ± 504 MBq (n = 7) and 533 ± 20 MBq (n = 3) of [¹¹C]flumazenil and [¹¹C]L-deprenyl were produced with radiochemical purities were over 98% and the molar activity for [¹¹C]flumazenil and [¹¹C]L-deprenyl was 1912 ± 552 GBq/µmol, and 1463 ± 439 GBq/µmol, respectively, at the end of synthesis. All the QC tests complied with the European Pharmacopeia. Different parameters, such as solvents, bases, methylating agents, precursor concentration, and different batches of cassettes, were explored to increase the radiochemical yield. Synthesis methods were developed using 3–5 times less precursor than conventional methods. The fully automated iMiDEV™ microfluidic radiosynthesizer was successfully applied to prepare [¹¹C]flumazenil and [¹¹C]L-deprenyl. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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13 pages, 1893 KiB

Open AccessArticle

Automated Optimized Synthesis of [¹⁸F]FLT Using Non-Basic Phase-Transfer Catalyst with Reduced Precursor Amount

by Olga S. Fedorova, Viktoriya V. Orlovskaya and Raisa N. Krasikova

Molecules 2022, 27(23), 8323; https://doi.org/10.3390/molecules27238323 - 29 Nov 2022

Cited by 1 | Viewed by 1833

Abstract

3′-deoxy-3′-[¹⁸F]fluorothymidine ([¹⁸F]FLT) is a positron emission tomography (PET) tracer useful for tumor proliferation assessment for a number of cancers, particularly in the cases of brain, lung, and breast tumors. At present [¹⁸F], FLT is commonly prepared by [...] Read more.

3′-deoxy-3′-[¹⁸F]fluorothymidine ([¹⁸F]FLT) is a positron emission tomography (PET) tracer useful for tumor proliferation assessment for a number of cancers, particularly in the cases of brain, lung, and breast tumors. At present [¹⁸F], FLT is commonly prepared by means of the nucleophilic radiofluorination of 3-N-Boc-5′-O-DMT-3′-O-nosyl thymidine precursor in the presence of a phase-transfer catalyst, followed by an acidic hydrolysis. To achieve high radiochemical yield, relatively large amounts of precursor (20–40 mg) are commonly used, leading to difficulties during purification steps, especially if a solid-phase extraction (SPE) approach is attempted. The present study describes an efficient method for [¹⁸F]FLT synthesis, employing tetrabutyl ammonium tosylate as a non-basic phase-transfer catalyst, with a greatly reduced amount of precursor employed. With a reduction of the precursor amount contributing to lower amounts of synthesis by-products in the reaction mixture, an SPE purification procedure using only two commercially available cartridges—OASIS HLB 6cc and Sep-Pak Alumina N Plus Light—has been developed for use on the GE TRACERlab FX N Pro synthesis module. [¹⁸F]FLT was obtained in radiochemical yield of 16 ± 2% (decay-corrected) and radiochemical purity >99% with synthesis time not exceeding 55 min. The product was formulated in 16 mL of normal saline with 5% ethanol (v/v). The amounts of chemical impurities and residual solvents were within the limits established by European Pharmacopoeia. The procedure described compares favorably with previously reported methods due to simplified automation, cheaper and more accessible consumables, and a significant reduction in the consumption of an expensive precursor. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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8 pages, 748 KiB

Open AccessArticle

Radiochemical Feasibility of Mixing of ^99mTc-MAA and ⁹⁰Y-Microspheres with Omnipaque Contrast

by Chang-Tong Yang, Pei Ing Ngam, Vanessa Jing Xin Phua, Sidney Wing Kwong Yu, Gogna Apoorva, David Chee Eng Ng and Hian Liang Huang

Molecules 2022, 27(21), 7646; https://doi.org/10.3390/molecules27217646 - 7 Nov 2022

Viewed by 2174

Abstract

Yttrium-90 (⁹⁰Y) microspheres are widely used for the treatment of liver-dominant malignant tumors. They are infused via catheter into the hepatic artery branches supplying the tumor under fluoroscopic guidance based on pre-therapy angiography and Technetium-99m macroaggregated albumin (^99mTc-MAA) planning. [...] Read more.

Yttrium-90 (⁹⁰Y) microspheres are widely used for the treatment of liver-dominant malignant tumors. They are infused via catheter into the hepatic artery branches supplying the tumor under fluoroscopic guidance based on pre-therapy angiography and Technetium-99m macroaggregated albumin (^99mTc-MAA) planning. However, at present, these microspheres are suspended in radiolucent media such as dextrose 5% (D5) solution. In order to monitor the real-time implantation of the microspheres into the tumor, the ⁹⁰Y microspheres could be suspended in omnipaque contrast for allowing visualization of the correct distribution of the microspheres into the tumor. The radiochemical purity of mixing ⁹⁰Y-microspheres in various concentrations of omnipaque was investigated. The radiochemical purity and feasibility of mixing ^99mTc-MAA with various concentrations of a standard contrast agent were also investigated. Results showed the radiochemical feasibility of mixing ⁹⁰Y-microspheres with omnipaque is radiochemically acceptable for allowing real-time visualization of radioembolization under fluoroscopy. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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Review

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13 pages, 730 KiB

Open AccessReview

Recent Advances in Preclinical Studies of the Theranostic Agent [⁶⁴Cu]CuCl₂

by Giorgia Speltri, Francesca Porto, Alessandra Boschi, Licia Uccelli and Petra Martini

Molecules 2024, 29(17), 4085; https://doi.org/10.3390/molecules29174085 - 28 Aug 2024

Cited by 1 | Viewed by 949

Abstract

⁶⁴Cu is gaining recognition not only for its diagnostic capabilities in nuclear medical imaging but also for its therapeutic and theranostic potential. The simultaneous βˉ and Auger emissions of ⁶⁴Cu can be utilized to induce a therapeutic effect on cancerous lesions. [...] Read more.

⁶⁴Cu is gaining recognition not only for its diagnostic capabilities in nuclear medical imaging but also for its therapeutic and theranostic potential. The simultaneous βˉ and Auger emissions of ⁶⁴Cu can be utilized to induce a therapeutic effect on cancerous lesions. The finding of the exceptional biodistribution characteristics of the radionuclide ⁶⁴Cu, when administered as basic copper ions, has highlighted its potential therapeutic application in cancer treatment. Preclinical and clinical research on the effectiveness of [⁶⁴Cu]CuCl₂ as a theranostic radiopharmaceutical has commenced only in the past decade. Current clinical studies are increasingly demonstrating the high specificity and uptake of [⁶⁴Cu]Cu²⁺ by malignant tissues during early cancer progression, indicating its potential for early cancer diagnosis across various organs. This short review aims to present the latest preclinical studies involving [⁶⁴Cu]CuCl₂, offering valuable insights for researchers planning new in vitro and in vivo studies to explore the theranostic potential of [⁶⁴Cu]Cu²⁺. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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23 pages, 2044 KiB

Open AccessReview

Radiolabeled Liposomes for Nuclear Imaging Probes

by Ho Ying Low, Chang-Tong Yang, Bin Xia, Tao He, Winnie Wing Chuen Lam and David Chee Eng Ng

Molecules 2023, 28(9), 3798; https://doi.org/10.3390/molecules28093798 - 28 Apr 2023

Cited by 6 | Viewed by 2354

Abstract

Quantitative nuclear imaging techniques are in high demand for various disease diagnostics and cancer theranostics. The non-invasive imaging modality requires radiotracing through the radioactive decay emission of the radionuclide. Current preclinical and clinical radiotracers, so-called nuclear imaging probes, are radioisotope-labeled small molecules. Liposomal [...] Read more.

Quantitative nuclear imaging techniques are in high demand for various disease diagnostics and cancer theranostics. The non-invasive imaging modality requires radiotracing through the radioactive decay emission of the radionuclide. Current preclinical and clinical radiotracers, so-called nuclear imaging probes, are radioisotope-labeled small molecules. Liposomal radiotracers have been rapidly developing as novel nuclear imaging probes. The physicochemical properties and structural characteristics of liposomes have been elucidated to address their long circulation and stability as radiopharmaceuticals. Various radiolabeling methods for synthesizing radionuclides onto liposomes and synthesis strategies have been summarized to render them biocompatible and enable specific targeting. Through a variety of radionuclide labeling methods, radiolabeled liposomes for use as nuclear imaging probes can be obtained for in vivo biodistribution and specific targeting studies. The advantages of radiolabeled liposomes including their use as potential clinical nuclear imaging probes have been highlighted. This review is a comprehensive overview of all recently published liposomal SPECT and PET imaging probes. Full article

(This article belongs to the Special Issue Advance in Radiochemistry)

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