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Ovdiichuk O, Lahdenpohja S, Béen Q, Tanguy L, Kuhnast B, Collet-Defossez C. [ 18F]fluoride Activation and 18F-Labelling in Hydrous Conditions-Towards a Microfluidic Synthesis of PET Radiopharmaceuticals. Molecules 2023; 29:147. [PMID: 38202730 PMCID: PMC10779751 DOI: 10.3390/molecules29010147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
18F-labelled radiopharmaceuticals are indispensable in positron emission tomography. The critical step in the preparation of 18F-labelled tracers is the anhydrous F-18 nucleophilic substitution reaction, which involves [18F]F- anions generated in aqueous media by the cyclotron. For this, azeotropic drying by distillation is widely used in standard synthesisers, but microfluidic systems are often not compatible with such a process. To avoid this step, several methods compatible with aqueous media have been developed. We summarised the existing approaches and two of them have been studied in detail. [18F]fluoride elution efficiencies have been investigated under different conditions showing high 18F-recovery. Finally, a large scope of precursors has been assessed for radiochemical conversion, and these hydrous labelling techniques have shown their potential for tracer production using a microfluidic approach, more particularly compatible with iMiDEV™ cassette volumes.
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Affiliation(s)
- Olga Ovdiichuk
- Nancyclotep, Molecular Imaging Platform, 54500 Vandoeuvre-les-Nancy, France
| | - Salla Lahdenpohja
- Université Paris Saclay, CEA Inserm, CNRS, BioMaps, 91401 Orsay, France
| | - Quentin Béen
- Nancyclotep, Molecular Imaging Platform, 54500 Vandoeuvre-les-Nancy, France
| | | | - Bertrand Kuhnast
- Université Paris Saclay, CEA Inserm, CNRS, BioMaps, 91401 Orsay, France
| | - Charlotte Collet-Defossez
- Nancyclotep, Molecular Imaging Platform, 54500 Vandoeuvre-les-Nancy, France
- Université de Lorraine, Inserm, IADI, 54000 Nancy, France
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Haveman LYF, Vugts DJ, Windhorst AD. State of the art procedures towards reactive [ 18F]fluoride in PET tracer synthesis. EJNMMI Radiopharm Chem 2023; 8:28. [PMID: 37824021 PMCID: PMC10570257 DOI: 10.1186/s41181-023-00203-5] [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: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a powerful, non-invasive preclinical and clinical nuclear imaging technique used in disease diagnosis and therapy assessment. Fluorine-18 is the predominant radionuclide used for PET tracer synthesis. An impressive variety of new 'late-stage' radiolabeling methodologies for the preparation of 18F-labeled tracers has appeared in order to improve the efficiency of the labeling reaction. MAIN BODY Despite these developments, one outstanding challenge into the early key steps of the process remains: the preparation of reactive [18F]fluoride from oxygen-18 enriched water ([18O]H2O). In the last decade, significant changes into the trapping, elution and drying stages have been introduced. This review provides an overview of the strategies and recent developments in the production of reactive [18F]fluoride and its use for radiolabeling. CONCLUSION Improved, modified or even completely new fluorine-18 work-up procedures have been developed in the last decade with widespread use in base-sensitive nucleophilic 18F-fluorination reactions. The many promising developments may lead to a few standardized drying methodologies for the routine production of a broad scale of PET tracers.
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Affiliation(s)
- Lizeth Y F Haveman
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam, The Netherlands
| | - Danielle J Vugts
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Neuroscience Amsterdam, Amsterdam, The Netherlands.
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Production of [ 11C]Carbon Labelled Flumazenil and L-Deprenyl Using the iMiDEV™ Automated Microfluidic Radiosynthesizer. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248843. [PMID: 36557975 PMCID: PMC9788284 DOI: 10.3390/molecules27248843] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
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 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.
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Wang J, van Dam RM. Economical Production of Radiopharmaceuticals for Preclinical Imaging Using Microdroplet Radiochemistry. Methods Mol Biol 2022; 2393:813-828. [PMID: 34837213 DOI: 10.1007/978-1-0716-1803-5_43] [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] [Indexed: 06/13/2023]
Abstract
The short-lived radiolabeled "tracers" needed for performing whole body imaging in animals or patients with positron-emission tomography (PET) are generally produced via automated "radiosynthesizers". Most current radiosynthesizers are designed for routine production of relatively large clinical batches and are very wasteful when only a small batch of a tracer is needed, such as is the case for preclinical in vivo PET imaging studies. To overcome the prohibitively high cost of producing small batches of PET tracers, we developed a droplet microreactor system that performs radiochemistry at the 1-10μL scale instead of the milliliter scale of conventional technologies. The overall yield for the droplet-based production of many PET tracers is comparable to conventional approaches, but 10-100× less reagents are consumed, the synthesis can be completed in much less time (<30 min), and only a small laboratory footprint and minimal radiation shielding are needed. By combining these advantages, droplet microreactors enable the economical production of small batches PET tracers on demand. Here, we describe the fabrication method of the droplet microreactor and the droplet-based synthesis of an example radiotracer ([18F]fallypride).
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Bioengineering Department, 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 & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA.
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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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Lisova K, Wang J, Chao PH, van Dam RM. A simple and efficient automated microvolume radiosynthesis of [ 18F]Florbetaben. EJNMMI Radiopharm Chem 2020; 5:30. [PMID: 33275179 PMCID: PMC7718361 DOI: 10.1186/s41181-020-00113-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Current automated radiosynthesizers are generally optimized for producing large batches of PET tracers. Preclinical imaging studies, however, often require only a small portion of a regular batch, which cannot be economically produced on a conventional synthesizer. Alternative approaches are desired to produce small to moderate batches to reduce cost and the amount of reagents and radioisotope needed to produce PET tracers with high molar activity. In this work we describe the first reported microvolume method for production of [18F]Florbetaben for use in imaging of Alzheimer's disease. PROCEDURES The microscale synthesis of [18F]Florbetaben was adapted from conventional-scale synthesis methods. Aqueous [18F]fluoride was azeotropically dried with K2CO3/K222 (275/383 nmol) complex prior to radiofluorination of the Boc-protected precursor (80 nmol) in 10 μL DMSO at 130 °C for 5 min. The resulting intermediate was deprotected with HCl at 90 °C for 3 min and recovered from the chip in aqueous acetonitrile solution. The crude product was purified via analytical scale HPLC and the collected fraction reformulated via solid-phase extraction using a miniature C18 cartridge. RESULTS Starting with 270 ± 100 MBq (n = 3) of [18F]Fluoride, the method affords formulated product with 49 ± 3% (decay-corrected) yield,> 98% radiochemical purity and a molar activity of 338 ± 55 GBq/μmol. The miniature C18 cartridge enables efficient elution with only 150 μL of ethanol which is diluted to a final volume of 1.0 mL, thus providing a sufficient concentration for in vivo imaging. The whole procedure can be completed in 55 min. CONCLUSIONS This work describes an efficient and reliable procedure to produce [18F]Florbetaben in quantities sufficient for large-scale preclinical applications. This method provides very high yields and molar activities compared to reported literature methods. This method can be applied to higher starting activities with special consideration given to automation and radiolysis prevention.
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Affiliation(s)
- Ksenia Lisova
- Physics & Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, 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 & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Philip H Chao
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - R Michael van Dam
- Physics & Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA.
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA.
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Wang J, Holloway T, Lisova K, van Dam RM. Green and efficient synthesis of the radiopharmaceutical [ 18F]FDOPA using a microdroplet reactor. REACT CHEM ENG 2020; 5:320-329. [PMID: 34164154 PMCID: PMC8218909 DOI: 10.1039/c9re00354a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From an efficiency standpoint, microdroplet reactors enable significant improvements in the preparation of radiopharmaceuticals due to the vastly reduced reaction volume. To demonstrate these advantages, we adapt the conventional (macroscale) synthesis of the clinically-important positron-emission tomography tracer [18F]FDOPA, following the nucleophilic diaryliodonium salt approach, to a newly-developed ultra-compact microdroplet reaction platform. In this first microfluidic implementation of [18F]FDOPA synthesis, optimized via a high-throughput multi-reaction platform, the radiochemical yield (non-decay-corrected) was found to be comparable to macroscale reports, but the synthesis consumed significantly less precursor and organic solvents, and the synthesis process was much faster. In this initial report, we demonstrate the production of [18F]FDOPA in 15 MBq [400 μCi] amounts, sufficient for imaging of multiple mice, at high molar activity.
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Affiliation(s)
- Jia Wang
- Department of Bioengineering, Henry Samueli School of Engineering
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Travis Holloway
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Ksenia Lisova
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Physics in Biology and Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Department of Bioengineering, Henry Samueli School of Engineering
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Physics in Biology and Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
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Wang J, van Dam RM. High-Efficiency Production of Radiopharmaceuticals via Droplet Radiochemistry: A Review of Recent Progress. Mol Imaging 2020; 19:1536012120973099. [PMID: 33296272 PMCID: PMC7731702 DOI: 10.1177/1536012120973099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/02/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
New platforms are enabling radiochemistry to be carried out in tiny, microliter-scale volumes, and this capability has enormous benefits for the production of radiopharmaceuticals. These droplet-based technologies can achieve comparable or better yields compared to conventional methods, but with vastly reduced reagent consumption, shorter synthesis time, higher molar activity (even for low activity batches), faster purification, and ultra-compact system size. We review here the state of the art of this emerging direction, summarize the radiotracers and prosthetic groups that have been synthesized in droplet format, describe recent achievements in scaling up activity levels, and discuss advantages and limitations and the future outlook of these innovative devices.
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
| | - R. Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
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Wang J, Chao PH, Slavik R, van Dam RM. Multi-GBq production of the radiotracer [18F]fallypride in a droplet microreactor. RSC Adv 2020; 10:7828-7838. [PMID: 35492189 PMCID: PMC9049805 DOI: 10.1039/d0ra01212b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 02/11/2020] [Indexed: 12/17/2022] Open
Abstract
Microfluidics offers numerous advantages for the synthesis of short-lived radiolabeled imaging tracers: performing 18F-radiosyntheses in microliter-scale droplets has exhibited high efficiency, speed, and molar activity as well as low reagent consumption. However, most reports have been at the preclinical scale. In this study we integrate a [18F]fluoride concentrator and a microdroplet synthesizer to explore the possibility of synthesizing patient doses and multi-patient batches of clinically-acceptable tracers. In the integrated system, [18F]fluoride (up to 41 GBq [1.1 Ci]) in [18O]H2O (1 mL) was first concentrated ∼80-fold and then efficiently transferred to the 8 μL reaction chip as a series of small (∼0.5 μL) droplets. Each droplet rapidly dried at the reaction site of the pre-heated chip, resulting in localized accumulation of large amounts of radioactivity in the form of dried [18F]TBAF complex. The PET tracer [18F]fallypride was synthesized from this concentrated activity in an overall synthesis time of ∼50 min (including radioisotope concentration and transfer, droplet radiosynthesis, purification, and formulation), in amounts up to 7.2 GBq [0.19 Ci], sufficient for multiple clinical PET scans. The resulting batches of [18F]fallypride passed all QC tests needed to ensure safety for clinical injection. This integrated technology enabled for the first time the impact of a wide range of activity levels on droplet radiosynthesis to be studied. Furthermore, this substantial increase in scale expands the applications of droplet radiosynthesis to the production of clinically-relevant amounts of radiopharmaceuticals, and potentially even centralized production of clinical tracers in radiopharmacies. The overall system could be applied to fundamental studies of droplet-based radiochemical reactions, or to the production of radiopharmaceuticals labeled with a variety of isotopes used for imaging and/or targeted radiotherapeutics. Using a micro-cartridge based radionuclide concentrator enables the production of multiple (10 s) of clinical doses of the PET tracer [18F]fallypride with a droplet micro-reactor platform (8 μL).![]()
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Affiliation(s)
- Jia Wang
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
| | - Philip H. Chao
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
| | - Roger Slavik
- Ahmanson Translational Imaging Division
- David Geffen School of Medicine
- University of California
- Los Angeles
- USA
| | - R. Michael van Dam
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
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Liu Z, Yu L, Cheng K, Feng Y, Qiu P, Gai Y, Zhou M. Optimization, automation and validation of the large-scale radiosynthesis of Al 18F tracers in a custom-made automatic platform for high yield. REACT CHEM ENG 2020. [DOI: 10.1039/d0re00144a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A custom-made automatic platform was designed and developed for large scale Al18F tracer synthesis with high yield.
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Affiliation(s)
- Zhiguo Liu
- Department of PET/CT Center
- Shandong Cancer Hospital and Institute
- Shandong First Medical University and Shandong Academy of Medical Sciences
- Jinan
- China
| | - Lun Yu
- Department of PET-CT Center
- Chenzhou No. 1 People's Hospital
- Chenzhou 423000
- China
| | - Kai Cheng
- Department of PET/CT Center
- Shandong Cancer Hospital and Institute
- Shandong First Medical University and Shandong Academy of Medical Sciences
- Jinan
- China
| | - Yabo Feng
- Department of PET-CT Center
- Chenzhou No. 1 People's Hospital
- Chenzhou 423000
- China
| | - Pengfei Qiu
- Breast Cancer Center
- Shandong Cancer Hospital and Institute
- Shandong First Medical University and Shandong Academy of Medical Sciences
- Jinan 250117
- China
| | - Yongkang Gai
- Department of Nuclear Medicine
- Union Hospital
- Tongji Medical College
- Huazhong University of Science and Technology
- Hubei Province Key Laboratory of Molecular Imaging
| | - Ming Zhou
- Department of Nuclear Medicine
- Xiangya Hospital
- Central South University
- Changsha 410008
- China
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Lisova K, Chen BY, Wang J, Fong KMM, Clark PM, van Dam RM. Rapid, efficient, and economical synthesis of PET tracers in a droplet microreactor: application to O-(2-[ 18F]fluoroethyl)-L-tyrosine ([ 18F]FET). EJNMMI Radiopharm Chem 2019; 5:1. [PMID: 31893318 PMCID: PMC6938530 DOI: 10.1186/s41181-019-0082-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Conventional scale production of small batches of PET tracers (e.g. for preclinical imaging) is an inefficient use of resources. Using O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET), we demonstrate that simple microvolume radiosynthesis techniques can improve the efficiency of production by consuming tiny amounts of precursor, and maintaining high molar activity of the tracers even with low starting activity. PROCEDURES The synthesis was carried out in microvolume droplets manipulated on a disposable patterned silicon "chip" affixed to a heater. A droplet of [18F]fluoride containing TBAHCO3 was first deposited onto a chip and dried at 100 °C. Subsequently, a droplet containing 60 nmol of precursor was added to the chip and the fluorination reaction was performed at 90 °C for 5 min. Removal of protecting groups was accomplished with a droplet of HCl heated at 90 °C for 3 min. Finally, the crude product was collected in a methanol-water mixture, purified via analytical-scale radio-HPLC and formulated in saline. As a demonstration, using [18F]FET produced on the chip, we prepared aliquots with different molar activities to explore the impact on preclinical PET imaging of tumor-bearing mice. RESULTS The microdroplet synthesis exhibited an overall decay-corrected radiochemical yield of 55 ± 7% (n = 4) after purification and formulation. When automated, the synthesis could be completed in 35 min. Starting with < 370 MBq of activity, ~ 150 MBq of [18F]FET could be produced, sufficient for multiple in vivo experiments, with high molar activities (48-119 GBq/μmol). The demonstration imaging study revealed the uptake of [18F]FET in subcutaneous tumors, but no significant differences in tumor uptake as a result of molar activity differences (ranging 0.37-48 GBq/μmol) were observed. CONCLUSIONS A microdroplet synthesis of [18F]FET was developed demonstrating low reagent consumption, high yield, and high molar activity. The approach can be expanded to tracers other than [18F]FET, and adapted to produce higher quantities of the tracer sufficient for clinical PET imaging.
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Affiliation(s)
- Ksenia Lisova
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Bao Ying Chen
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, 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 & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Kelly Mun-Ming Fong
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Peter M Clark
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - R Michael van Dam
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA.
- Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, USA.
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Wang J, Chao PH, van Dam RM. Ultra-compact, automated microdroplet radiosynthesizer. LAB ON A CHIP 2019; 19:2415-2424. [PMID: 31187109 PMCID: PMC7416997 DOI: 10.1039/c9lc00438f] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Application of microfluidics offers numerous advantages in the field of radiochemistry and could enable dramatic reductions in the cost of producing radiotracers for positron emission tomography (PET). Droplet-based microfluidics, in particular, requires only microgram quantities of expensive precursors and reagents (compared to milligram used in conventional radiochemistry systems), and occupies a more compact footprint (potentially eliminating the need for specialized shielding facilities, i.e. hot cells). However, the reported platforms for droplet radiosynthesis have several drawbacks, including high cost/complexity of microfluidic reactors, requirement for manual intervention (e.g. for adding reagents), or difficulty in precise control of droplet processes. We describe here a platform based on a particularly simple chip, where reactions take place atop a hydrophobic substrate patterned with a circular hydrophilic liquid trap. The overall supporting hardware (heater, rotating carousel of reagent dispensers, etc.) is very simple and the whole system could be packaged into a very compact format (about the size of a coffee cup). We demonstrate the consistent synthesis of [18F]fallypride with high yield, and show that protocols optimized using a high-throughput optimization platform we have developed can be readily translated to this device with no changes or re-optimization. We are currently exploring the use of this platform for routine production of a variety of 18F-labeled tracers for preclinical imaging and for production of tracers in clinically-relevant amounts by integrating the system with an upstream radionuclide concentrator.
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
| | - Philip H Chao
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA. and Department of Bioengineering, UCLA, Los Angeles, CA, USA
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Rios A, Wang J, Chao PH, van Dam RM. A novel multi-reaction microdroplet platform for rapid radiochemistry optimization. RSC Adv 2019; 9:20370-20374. [PMID: 35514735 PMCID: PMC9065505 DOI: 10.1039/c9ra03639c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2019] [Indexed: 12/20/2022] Open
Abstract
During the development of novel tracers for positron emission tomography (PET), the optimization of the synthesis is hindered by practical limitations on the number of experiments that can be performed per day. Here we present a microliter droplet chip that contains multiple sites (4 or 16) to perform reactions simultaneously under the same or different conditions to accelerate radiosynthesis optimization. Multi-reaction microdroplet chip enables rapid radiotracer optimization for positron emission tomography.![]()
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Affiliation(s)
- Alejandra Rios
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA
| | - Jia Wang
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - Philip H Chao
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - R Michael van Dam
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA.,Department of Bioengineering, UCLA USA.,Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA USA
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Abstract
The emerging technology of digital microfluidics is opening up the possibility of performing radiochemistry at the microliter scale to produce tracers for positron emission tomography (PET) labeled with fluorine-18 or other isotopes. Working at this volume scale not only reduces reagent costs but also improves specific activity (SA) by reducing contamination by the stable isotope. This technology could provide a practical means to routinely prepare high-SA tracers for applications such as neuroimaging and could make it possible to routinely achieve high SA using synthesis strategies such as isotopic exchange. Reagent droplets are controlled electronically, providing high reliability, a compact control system, and flexibility for diverse syntheses with a single-chip design. The compact size may enable the development of a self-shielded synthesizer that does not require a hot cell. This article reviews the progress of this technology and its application to the synthesis of PET tracers.
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Affiliation(s)
- Pei Yuin Keng
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology University of California, Los Angeles
| | - R. Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology University of California, Los Angeles
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