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Mc Veigh M, Bellan LM. Microfluidic synthesis of radiotracers: recent developments and commercialization prospects. LAB ON A CHIP 2024; 24:1226-1243. [PMID: 38165824 DOI: 10.1039/d3lc00779k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Positron emission tomography (PET) is a powerful diagnostic tool that holds incredible potential for clinicians to track a wide variety of biological processes using specialized radiotracers. Currently, however, a single radiotracer accounts for over 95% of procedures, largely due to the cost of radiotracer synthesis. Microfluidic platforms provide a solution to this problem by enabling a dose-on-demand pipeline in which a single benchtop platform would synthesize a wide array of radiotracers. In this review, we will explore the field of microfluidic production of radiotracers from early research to current development. Furthermore, the benefits and drawbacks of different microfluidic reactor designs will be analyzed. Lastly, we will discuss the various engineering considerations that must be addressed to create a fully developed, commercially effective platform that can usher the field from research and development to commercialization.
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Affiliation(s)
- Mark Mc Veigh
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37235, USA
| | - Leon M Bellan
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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Nikiforova A, Sedov I. Molecular Design of Magnetic Resonance Imaging Agents Binding to Amyloid Deposits. Int J Mol Sci 2023; 24:11152. [PMID: 37446329 DOI: 10.3390/ijms241311152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
The ability to detect and monitor amyloid deposition in the brain using non-invasive imaging techniques provides valuable insights into the early diagnosis and progression of Alzheimer's disease and helps to evaluate the efficacy of potential treatments. Magnetic resonance imaging (MRI) is a widely available technique offering high-spatial-resolution imaging. It can be used to visualize amyloid deposits with the help of amyloid-binding diagnostic agents injected into the body. In recent years, a number of amyloid-targeted MRI probes have been developed, but none of them has entered clinical practice. We review the advances in the field and deduce the requirements for the molecular structure and properties of a diagnostic probe candidate. These requirements make up the base for the rational design of MRI-active small molecules targeting amyloid deposits. Particular attention is paid to the novel cryo-EM structures of the fibril aggregates and their complexes, with known binders offering the possibility to use computational structure-based design methods. With continued research and development, MRI probes may revolutionize the diagnosis and treatment of neurodegenerative diseases, ultimately improving the lives of millions of people worldwide.
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Affiliation(s)
- Alena Nikiforova
- Chemical Institute, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia
| | - Igor Sedov
- Chemical Institute, Kazan Federal University, Kremlevskaya 18, 420008 Kazan, Russia
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He Y, Zhu X, Wang K, Xie J, Zhu Z, Ni M, Wang S, Xie Q. Design, synthesis, and preliminary evaluation of [ 18F]-aryl flurosulfates PET radiotracers via SuFEx methods for β-amyloid plaques in Alzheimer's disease. Bioorg Med Chem 2022; 75:117087. [PMID: 36356533 DOI: 10.1016/j.bmc.2022.117087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 11/07/2022]
Abstract
[18F]BAY-94-9172, [18F]AV-45, and [18F]GE-067 were FDA approved positron emission tomography (PET) imaging radiotracer of β-amyloid plaques (Aβ) in Alzheimer's disease (AD). However, the radiochemical synthesis requires multi-step reactions and complex procedure. Recently, a protocol for radiochemical synthesis of sulfur fluoride exchange (SuFEx) using ultrafast 19F/18F isotopic exchange had been reported. We developed three pairs of novel 18F-labeled radiotracers by the "SuFEx" method for PET imaging Aβ plaques. The 18F labeling reaction can be completed quickly (30 s) at room temperature and purified using solid-phase extraction (SPE). The radiochemical purity (RCP) of the products was all greater than 95 %. In vitro fluorescent staining using Aβ-transgenesis mice section preliminary verified the affinity of tracers with Aβ. Competitive binding assay displayed high affinity of tracers for towards artificial Aβ1-42 aggregates (Ki values ranging from 3.53 ± 0.39 to 42.0 ± 4.24 nM). In vivo biodistribution and Micro-PET imaging showed that [18F]-Sulfur Fluoride β-Amyloid ([18F]SFA 1-6) could penetration the blood-brain barrier (BBB) in wild-type mice, and [18F]SFA 5-6 had a high initial brain uptake value (3.65 ± 0.9 % and 5.07 ± 0.1 % ID/g, respectively) and a fast washout (Brain uptake2 min/60 min = 4.15 and 4.61, respectively) from the brain. In vitro autoradiography demonstrated the affinity of the [18F]SFA 5-6 to Aβ plaques in AD human brain tissues. Our results suggested that [18F]SFA maybe a potential PET radiotracers for detecting Aβ in Alzheimer's disease.
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Affiliation(s)
- Yunlin He
- School of Pharmacy, Bengbu Medical College, Anhui, Bengbu 233030, China; Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Xingxing Zhu
- Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Kaixuan Wang
- School of Pharmacy, Bengbu Medical College, Anhui, Bengbu 233030, China; Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Jikui Xie
- Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Zehua Zhu
- Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Ming Ni
- Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Shicun Wang
- Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China
| | - Qiang Xie
- School of Pharmacy, Bengbu Medical College, Anhui, Bengbu 233030, China; Department of Nuclear Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, Hefei 230001, China.
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Rapid Purification and Formulation of Radiopharmaceuticals via Thin-Layer Chromatography. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238178. [PMID: 36500272 PMCID: PMC9738419 DOI: 10.3390/molecules27238178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/25/2022]
Abstract
Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g., semi-preparative radio-HPLC) to ensure adequate purity of the radiopharmaceutical. Due to the use of organic solvents during purification, additional processing is needed to reformulate the radiopharmaceutical into an injectable buffer. Recent developments in microscale radiosynthesis have made it possible to synthesize radiopharmaceuticals with vastly reduced reagent masses, minimizing impurities. This enables purification with lower-capacity methods, such as analytical HPLC, with a reduction of purification time and volume (that shortens downstream re-formulation). Still, the need for a bulky and expensive HPLC system undermines many of the advantages of microfluidics. This study demonstrates the feasibility of using radio-TLC for the purification of radiopharmaceuticals. This technique combines high-performance (high-resolution, high-speed separation) with the advantages of a compact and low-cost setup. A further advantage is that no downstream re-formulation step is needed. Production and purification of clinical scale batches of [18F]PBR-06 and [18F]Fallypride are demonstrated with high yield, purity, and specific activity. Automating this radio-TLC method could provide an attractive solution for the purification step in microscale radiochemistry systems.
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Elkawad H, Xu Y, Tian M, Jin C, Zhang H, Yu K, He Q. Recent advances in microfluidic devices for radiosynthesis of PET‐imaging probes. Chem Asian J 2022; 17:e202200579. [PMID: 35909081 DOI: 10.1002/asia.202200579] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/29/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Husamelden Elkawad
- The second affiliated hospital of Zhejiang University Nuclear Medicine and PET center CHINA
| | - Yangyang Xu
- Zhejiang University b. College of Chemical & Biological Engineering CHINA
| | - Mei Tian
- The second affiliated hospital of Zhejiang University Nuclear Medicine & PET center CHINA
| | - Chenyang Jin
- Zhejiang University b. College of Chemical & Biological Engineering CHINA
| | - Hong Zhang
- The second affiliated hospital of Zhejiang University b. College of Chemical & Biological Engineering CHINA
| | - Kaiwu Yu
- Zhejiang University b. College of Chemical & Biological Engineering CHINA
| | - Qinggang He
- Zhejiang University Chemical Engineering 38 Zheda Rd. 310027 Hangzhou CHINA
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Microliter-scale reaction arrays for economical high-throughput experimentation in radiochemistry. Sci Rep 2022; 12:10263. [PMID: 35715457 PMCID: PMC9205965 DOI: 10.1038/s41598-022-14022-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/31/2022] [Indexed: 01/14/2023] Open
Abstract
The increasing number of positron-emission tomography (PET) tracers being developed to aid drug development and create new diagnostics has led to an increased need for radiosynthesis development and optimization. Current radiosynthesis instruments are designed to produce large-scale clinical batches and are often limited to performing a single synthesis before they must be decontaminated by waiting for radionuclide decay, followed by thorough cleaning or disposal of synthesizer components. Though with some radiosynthesizers it is possible to perform a few sequential radiosyntheses in a day, none allow for parallel radiosyntheses. Throughput of one or a few experiments per day is not well suited for rapid optimization experiments. To combat these limitations, we leverage the advantages of droplet-radiochemistry to create a new platform for high-throughput experimentation in radiochemistry. This system contains an array of 4 heaters, each used to heat a set of 16 reactions on a small chip, enabling 64 parallel reactions for the rapid optimization of conditions in any stage of a multi-step radiosynthesis process. As examples, we study the syntheses of several 18F-labeled radiopharmaceuticals ([18F]Flumazenil, [18F]PBR06, [18F]Fallypride, and [18F]FEPPA), performing > 800 experiments to explore the influence of parameters including base type, base amount, precursor amount, solvent, reaction temperature, and reaction time. The experiments were carried out within only 15 experiment days, and the small volume (~ 10 μL compared to the ~ 1 mL scale of conventional instruments) consumed ~ 100 × less precursor per datapoint. This new method paves the way for more comprehensive optimization studies in radiochemistry and substantially shortening PET tracer development timelines.
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Lisova K, Wang J, Hajagos TJ, Lu Y, Hsiao A, Elizarov A, van Dam RM. Economical droplet-based microfluidic production of [ 18F]FET and [ 18F]Florbetaben suitable for human use. Sci Rep 2021; 11:20636. [PMID: 34667246 PMCID: PMC8526601 DOI: 10.1038/s41598-021-99111-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/26/2021] [Indexed: 01/22/2023] Open
Abstract
Current equipment and methods for preparation of radiopharmaceuticals for positron emission tomography (PET) are expensive and best suited for large-scale multi-doses batches. Microfluidic radiosynthesizers have been shown to provide an economic approach to synthesize these compounds in smaller quantities, but can also be scaled to clinically-relevant levels. Batch microfluidic approaches, in particular, offer significant reduction in system size and reagent consumption. Here we show a simple and rapid technique to concentrate the radioisotope, prior to synthesis in a droplet-based radiosynthesizer, enabling production of clinically-relevant batches of [18F]FET and [18F]FBB. The synthesis was carried out with an automated synthesizer platform based on a disposable Teflon-silicon surface-tension trap chip. Up to 0.1 mL (4 GBq) of radioactivity was used per synthesis by drying cyclotron-produced aqueous [18F]fluoride in small increments directly inside the reaction site. Precursor solution (10 µL) was added to the dried [18F]fluoride, the reaction chip was heated for 5 min to perform radiofluorination, and then a deprotection step was performed with addition of acid solution and heating. The product was recovered in 80 µL volume and transferred to analytical HPLC for purification. Purified product was formulated via evaporation and resuspension or a micro-SPE formulation system. Quality control testing was performed on 3 sequential batches of each tracer. The method afforded production of up to 0.8 GBq of [18F]FET and [18F]FBB. Each production was completed within an hour. All batches passed quality control testing, confirming suitability for human use. In summary, we present a simple and efficient synthesis of clinically-relevant batches of [18F]FET and [18F]FBB using a microfluidic radiosynthesizer. This work demonstrates that the droplet-based micro-radiosynthesizer has a potential for batch-on-demand synthesis of 18F-labeled radiopharmaceuticals for human use.
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Affiliation(s)
- Ksenia Lisova
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Jia Wang
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Yingqing Lu
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
| | | | | | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA.
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA.
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