Advances in the automated synthesis of 6-[18F]Fluoro-L-DOPA

AbstractThe neurotracer 6-[18F] FDOPA has been, for many years, a powerful tool in PET imaging of neuropsychiatric diseases, movement disorders and brain malignancies. More recently, it also demonstrated good results in the diagnosis of other malignancies such as neuroendocrine tumours, pheochromocytoma or pancreatic adenocarcinoma.The multiple clinical applications of this tracer fostered a very strong interest in the development of new and improved methods for its radiosynthesis. The no-carrier-added nucleophilic 18F-fluorination process has gained increasing attention, in recent years, due to the high molar activities obtained, when compared with the other methods although the radiochemical yield remains low (17–30%). This led to the development of several nucleophilic synthetic processes in order to obtain the product with molar activity, radiochemical yield and enantiomeric purity suitable for human PET studies.Automation of the synthetic processes is crucial for routine clinical use and compliance with GMP requirements. Nevertheless, the complexity of the synthesis makes the production challenging, increasing the chance of failure in routine production. Thus, for large-scale clinical application and wider use of this radiopharmaceutical, progress in the automation of this complex radiosynthesis is of critical importance.This review summarizes the most recent developments of 6-[18F]FDOPA radiosynthesis and discusses the key issues regarding its automation for routine clinical use.

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Robust and Facile Automated Radiosynthesis of [18F]FSPG on the GE FASTlab

Molecular Imaging and Biology ◽

10.1007/s11307-021-01609-w ◽

2021 ◽

Author(s):

Richard Edwards ◽

Hannah E. Greenwood ◽

Graeme McRobbie ◽

Imtiaz Khan ◽

Timothy H. Witney

Keyword(s):

Large Scale ◽

Radiochemical Purity ◽

Radiochemical Yield ◽

Automated Synthesis ◽

Molar Activity ◽

Positron Emission ◽

Optimized Protocol ◽

Cancer Types ◽

Automated Procedures ◽

Phosphate Buffered Saline

Abstract Purpose (S)-4-(3-18F-Fluoropropyl)-ʟ-Glutamic Acid ([18F]FSPG) is a radiolabeled non-natural amino acid that is used for positron emission tomography (PET) imaging of the glutamate/cystine antiporter, system xC-, whose expression is upregulated in many cancer types. To increase the clinical adoption of this radiotracer, reliable and facile automated procedures for [18F]FSPG production are required. Here, we report a cassette-based method to produce [18F]FSPG at high radioactivity concentrations from low amounts of starting activity. Procedures An automated synthesis and purification of [18F]FSPG was developed using the GE FASTlab. Optimization of the reaction conditions and automated manipulations were performed by measuring the isolated radiochemical yield of [18F]FSPG and by assessing radiochemical purity using radio-HPLC. Purification of [18F]FSPG was conducted by trapping and washing of the radiotracer on Oasis MCX SPE cartridges, followed by a reverse elution of [18F]FSPG in phosphate-buffered saline. Subsequently, the [18F]FSPG obtained from the optimized process was used to image an animal model of non-small cell lung cancer. Results The optimized protocol produced [18F]FSPG in 38.4 ± 2.6 % radiochemical yield and >96 % radiochemical purity with a molar activity of 11.1 ± 7.7 GBq/μmol. Small alterations, including the implementation of a reverse elution and an altered Hypercarb cartridge, led to significant improvements in radiotracer concentration from <10 MBq/ml to >100 MBq/ml. The improved radiotracer concentration allowed for the imaging of up to 20 mice, starting with just 1.5 GBq of [18F]Fluoride. Conclusions We have developed a robust and facile method for [18F]FSPG radiosynthesis in high radiotracer concentration, radiochemical yield, and radiochemical purity. This cassette-based method enabled the production of [18F]FSPG at radioactive concentrations sufficient to facilitate large-scale preclinical experiments with a single prep of starting activity. The use of a cassette-based radiosynthesis on an automated synthesis module routinely used for clinical production makes the method amenable to rapid and widespread clinical translation.

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Click Chemistry Expedited Radiosynthesis: Sulfur [18F]fluoride Exchange of Aryl Fluorosulfates

10.26434/chemrxiv.10314647.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Qinheng Zheng ◽

Hongtao Xu ◽

Hua Wang ◽

Wen-Ge Han Du ◽

Nan Wang ◽

...

Keyword(s):

Click Chemistry ◽

High Performance ◽

Isotopic Exchange ◽

Tumor Imaging ◽

Radiochemical Yield ◽

Exchange Method ◽

Molar Activity ◽

Positron Emission ◽

Sulfur Fluoride

The lack of simple, efficient [18F]fluorination processes and new target-specific organofluorine probes remains the major challenge of fluorine-18-based positron emission tomography (PET). We report here a fast isotopic exchange method for the radiosynthesis of aryl [18F]fluorosulfate based PET agents enabled by the emerging sulfur fluoride exchange (SuFEx) click chemistry. The method has been applied to the fully-automated 18F-radiolabeling of twenty-five structurally diverse aryl fluorosulfates with excellent radiochemical yield (83–100%) and high molar activity (up to 281 GBq µmol–1) at room temperature in 30 seconds. The purification of radiotracers requires no time-consuming high-performance liquid chromatography (HPLC), but rather a simple cartridge filtration. The utility of aryl [18F]fluorosulfate is demonstrated by the in vivo tumor imaging by targeting poly(ADP-ribose) polymerase 1 (PARP1).

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Recent Developments in the Downstream Processing of Phycobiliproteins from Algae: A Review

Current Biochemical Engineering ◽

10.2174/2212711906999210101230613 ◽

2021 ◽

Vol 06 ◽

Author(s):

Ayekpam Chandralekha Devi ◽

G. K. Hamsavi ◽

Simran Sahota ◽

Rochak Mittal ◽

Hrishikesh A. Tavanandi ◽

...

Keyword(s):

Cell Wall ◽

Large Scale ◽

Downstream Processing ◽

Review Article ◽

Current Status ◽

Wall Structure ◽

Scale Production ◽

Cell Wall Disruption ◽

Recent Developments ◽

Macro Algae

Abstract: Algae (both micro and macro) have gained huge attention in the recent past for their high commercial value products. They are the source of various biomolecules of commercial applications ranging from nutraceuticals to fuels. Phycobiliproteins are one such high value low volume compounds which are mainly obtained from micro and macro algae. In order to tap the bioresource, a significant amount of work has been carried out for large scale production of algal biomass. However, work on downstream processing aspects of phycobiliproteins (PBPs) from algae is scarce, especially in case of macroalgae. There are several difficulties in cell wall disruption of both micro and macro algae because of their cell wall structure and compositions. At the same time, there are several challenges in the purification of phycobiliproteins. The current review article focuses on the recent developments in downstream processing of phycobiliproteins (mainly phycocyanins and phycoerythrins) from micro and macroalgae. The current status, the recent advancements and potential technologies (that are under development) are summarised in this review article besides providing future directions for the present research area.

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Lentiviral Vectors for Delivery of Gene-Editing Systems Based on CRISPR/Cas: Current State and Perspectives

Viruses ◽

10.3390/v13071288 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1288

Author(s):

Wendy Dong ◽

Boris Kantor

Keyword(s):

Large Scale ◽

Lentiviral Vector ◽

Clinical Applications ◽

Scale Production ◽

Base Editing ◽

Epigenome Editing ◽

Vector Systems ◽

Dividing Cells

CRISPR/Cas technology has revolutionized the fields of the genome- and epigenome-editing by supplying unparalleled control over genomic sequences and expression. Lentiviral vector (LV) systems are one of the main delivery vehicles for the CRISPR/Cas systems due to (i) its ability to carry bulky and complex transgenes and (ii) sustain robust and long-term expression in a broad range of dividing and non-dividing cells in vitro and in vivo. It is thus reasonable that substantial effort has been allocated towards the development of the improved and optimized LV systems for effective and accurate gene-to-cell transfer of CRISPR/Cas tools. The main effort on that end has been put towards the improvement and optimization of the vector’s expression, development of integrase-deficient lentiviral vector (IDLV), aiming to minimize the risk of oncogenicity, toxicity, and pathogenicity, and enhancing manufacturing protocols for clinical applications required large-scale production. In this review, we will devote attention to (i) the basic biology of lentiviruses, and (ii) recent advances in the development of safer and more efficient CRISPR/Cas vector systems towards their use in preclinical and clinical applications. In addition, we will discuss in detail the recent progress in the repurposing of CRISPR/Cas systems related to base-editing and prime-editing applications.

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Novel late-stage radiosynthesis of 5-[18F]-trifluoromethyl-1,2,4-oxadiazole (TFMO) containing molecules for PET imaging

Scientific Reports ◽

10.1038/s41598-021-90069-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nashaat Turkman ◽

Daxing Liu ◽

Isabella Pirola

Keyword(s):

Late Stage ◽

Histone Deacetylases ◽

Radiochemical Purity ◽

Radiochemical Yield ◽

Single Step ◽

The Novel ◽

Molar Activity ◽

The Central Nervous System ◽

Class Iia Hdacs ◽

18F Fluoride

AbstractSmall molecules that contain the (TFMO) moiety were reported to specifically inhibit the class-IIa histone deacetylases (HDACs), an important target in cancer and the disorders of the central nervous system (CNS). However, radiolabeling methods to incorporate the [18F]fluoride into the TFMO moiety are lacking. Herein, we report a novel late-stage incorporation of [18F]fluoride into the TFMO moiety in a single radiochemical step. In this approach the bromodifluoromethyl-1,2,4-oxadiazole was converted into [18F]TFMO via no-carrier-added bromine-[18F]fluoride exchange in a single step, thus producing the PET tracers with acceptable radiochemical yield (3–5%), high radiochemical purity (> 98%) and moderate molar activity of 0.33–0.49 GBq/umol (8.9–13.4 mCi/umol). We validated the utility of the novel radiochemical design by the radiosynthesis of [18F]TMP195, which is a known TFMO containing potent inhibitor of class-IIa HDACs.

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On the geophysical processes impacting palaeo-sea-level observations

Geoscience Letters ◽

10.1186/s40562-021-00184-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Yusuke Yokoyama ◽

Anthony Purcell

Keyword(s):

Sea Level ◽

Large Scale ◽

Global Climate ◽

Sea Level Change ◽

Sea Level Changes ◽

Factors Affecting ◽

Ice Volume ◽

Level Change ◽

Recent Developments ◽

Geophysical Processes

AbstractPast sea-level change represents the large-scale state of global climate, reflecting the waxing and waning of global ice sheets and the corresponding effect on ocean volume. Recent developments in sampling and analytical methods enable us to more precisely reconstruct past sea-level changes using geological indicators dated by radiometric methods. However, ice-volume changes alone cannot wholly account for these observations of local, relative sea-level change because of various geophysical factors including glacio-hydro-isostatic adjustments (GIA). The mechanisms behind GIA cannot be ignored when reconstructing global ice volume, yet they remain poorly understood within the general sea-level community. In this paper, various geophysical factors affecting sea-level observations are discussed and the details and impacts of these processes on estimates of past ice volumes are introduced.

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Electrochemical Biosensors in Food Safety: Challenges and Perspectives

Molecules ◽

10.3390/molecules26102940 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2940

Author(s):

Antonella Curulli

Keyword(s):

Food Industry ◽

Electrochemical Sensors ◽

Cost Effective ◽

Electrochemical Biosensors ◽

Food Chains ◽

Sensing Systems ◽

Highly Sensitive ◽

Skilled Personnel ◽

Recent Developments ◽

Key Issues

Safety and quality are key issues for the food industry. Consequently, there is growing demand to preserve the food chain and products against substances toxic, harmful to human health, such as contaminants, allergens, toxins, or pathogens. For this reason, it is mandatory to develop highly sensitive, reliable, rapid, and cost-effective sensing systems/devices, such as electrochemical sensors/biosensors. Generally, conventional techniques are limited by long analyses, expensive and complex procedures, and skilled personnel. Therefore, developing performant electrochemical biosensors can significantly support the screening of food chains and products. Here, we report some of the recent developments in this area and analyze the contributions produced by electrochemical biosensors in food screening and their challenges.

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Clinician checklist for assessing suitability of machine learning applications in healthcare

BMJ Health & Care Informatics ◽

10.1136/bmjhci-2020-100251 ◽

2021 ◽

Vol 28 (1) ◽

pp. e100251

Author(s):

Ian Scott ◽

Stacey Carter ◽

Enrico Coiera

Keyword(s):

Machine Learning ◽

Large Scale ◽

Clinical Decision Making ◽

Improve Patient Care ◽

Clinical Decision ◽

Routine Care ◽

Machine Learning Algorithms ◽

Clinical Settings ◽

Machine Learning Applications ◽

Key Issues

Machine learning algorithms are being used to screen and diagnose disease, prognosticate and predict therapeutic responses. Hundreds of new algorithms are being developed, but whether they improve clinical decision making and patient outcomes remains uncertain. If clinicians are to use algorithms, they need to be reassured that key issues relating to their validity, utility, feasibility, safety and ethical use have been addressed. We propose a checklist of 10 questions that clinicians can ask of those advocating for the use of a particular algorithm, but which do not expect clinicians, as non-experts, to demonstrate mastery over what can be highly complex statistical and computational concepts. The questions are: (1) What is the purpose and context of the algorithm? (2) How good were the data used to train the algorithm? (3) Were there sufficient data to train the algorithm? (4) How well does the algorithm perform? (5) Is the algorithm transferable to new clinical settings? (6) Are the outputs of the algorithm clinically intelligible? (7) How will this algorithm fit into and complement current workflows? (8) Has use of the algorithm been shown to improve patient care and outcomes? (9) Could the algorithm cause patient harm? and (10) Does use of the algorithm raise ethical, legal or social concerns? We provide examples where an algorithm may raise concerns and apply the checklist to a recent review of diagnostic imaging applications. This checklist aims to assist clinicians in assessing algorithm readiness for routine care and identify situations where further refinement and evaluation is required prior to large-scale use.

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mRNA-Based Vaccines

Vaccines ◽

10.3390/vaccines9040390 ◽

2021 ◽

Vol 9 (4) ◽

pp. 390

Author(s):

Frank Kowalzik ◽

Daniel Schreiner ◽

Christian Jensen ◽

Daniel Teschner ◽

Stephan Gehring ◽

...

Keyword(s):

Large Scale ◽

New Technologies ◽

Vaccine Development ◽

Effective Means ◽

Cost Effective ◽

Clinical Applications ◽

Cell Mediated Immunity ◽

Healthy Individuals ◽

Emerging Pathogens ◽

Cell Genome

Increases in the world’s population and population density promote the spread of emerging pathogens. Vaccines are the most cost-effective means of preventing this spread. Traditional methods used to identify and produce new vaccines are not adequate, in most instances, to ensure global protection. New technologies are urgently needed to expedite large scale vaccine development. mRNA-based vaccines promise to meet this need. mRNA-based vaccines exhibit a number of potential advantages relative to conventional vaccines, namely they (1) involve neither infectious elements nor a risk of stable integration into the host cell genome; (2) generate humoral and cell-mediated immunity; (3) are well-tolerated by healthy individuals; and (4) are less expensive and produced more rapidly by processes that are readily standardized and scaled-up, improving responsiveness to large emerging outbreaks. Multiple mRNA vaccine platforms have demonstrated efficacy in preventing infectious diseases and treating several types of cancers in humans as well as animal models. This review describes the factors that contribute to maximizing the production of effective mRNA vaccine transcripts and delivery systems, and the clinical applications are discussed in detail.

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Clinically Applicable Cyclotron-Produced Gallium-68 Gives High-Yield Radiolabeling of DOTA-Based Tracers

Biomolecules ◽

10.3390/biom11081118 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1118

Author(s):

Emma Jussing ◽

Stefan Milton ◽

Erik Samén ◽

Mohammad Mahdi Moein ◽

Lovisa Bylund ◽

...

Keyword(s):

Metal Ion ◽

Metal Content ◽

Gamma Spectroscopy ◽

Radiochemical Yield ◽

High Yield ◽

Automated Synthesis ◽

Molar Activity ◽

Icp Ms ◽

Gallium 68 ◽

Fe Impurities

By using solid targets in medical cyclotrons, it is possible to produce large amounts of 68GaCl3. Purification of Ga3+ from metal ion impurities is a critical step, as these metals compete with Ga3+ in the complexation with different chelators, which negatively affects the radiolabeling yields. In this work, we significantly lowered the level of iron (Fe) impurities by adding ascorbate in the purification, and the resulting 68GaCl3could be utilized for high-yield radiolabeling of clinically relevant DOTA-based tracers. 68GaCl3 was cyclotron-produced and purified with ascorbate added in the wash solutions through the UTEVA resins. The 68Ga eluate was analyzed for radionuclidic purity (RNP) by gamma spectroscopy, metal content by ICP-MS, and by titrations with the chelators DOTA, NOTA, and HBED. The 68GaCl3eluate was utilized for GMP-radiolabeling of the DOTA-based tracers DOTATOC and FAPI-46 using an automated synthesis module. DOTA chelator titrations gave an apparent molar activity (AMA) of 491 ± 204 GBq/µmol. GMP-compliant syntheses yielded up to 7 GBq/batch [68Ga]Ga-DOTATOC and [68Ga]Ga-FAPI-46 (radiochemical yield, RCY ~ 60%, corresponding to ten times higher compared to generator-based productions). Full quality control (QC) of 68Ga-labelled tracers showed radiochemically pure and stable products at least four hours from end-of-synthesis.

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