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Journal of Labelled Compounds & Radiopharmaceuticals

Crist N Filer
This review discusses the synthetic methods used to tritiate nonmorphinan alkaloids as well as their applications.
January 10, 2017: Journal of Labelled Compounds & Radiopharmaceuticals
Naiara Vazquez, Stephan Missault, Christel Vangestel, Steven Deleye, David Thomae, Pieter Van der Veken, Koen Augustyns, Steven Staelens, Stefanie Dedeurwaerdere, Leonie Wyffels
MMP-9 is a zinc-dependent endopeptidase that is involved in the proteolytic degradation of the extracellular matrix and plays an important role in cancer migration, invasion, and metastasis. The aim of this study was to evaluate the potential of MMP-tracers [(18) F]BR420 and [(18) F]BR351 for MMP-9 imaging in a colorectal cancer xenograft model. [(18) F]BR420 and [(18) F]BR351 were synthesized using an automated synthesis module. For [(18) F]BR420, a novel and improved radiosynthesis was developed. Plasma stability and MMP-9-targeting capacity of both radiotracers was compared in the Colo205 colorectal cancer model...
December 21, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Lynda J Brown, Giuseppe Pileio, Malcolm H Levitt, Richard C D Brown
Unsymmetrical perdeuterated doubly (13) C labelled oxalates exhibit extended lifetimes in the nuclear singlet state. Synthesis of 1,2 (13) C2 oxalates from commercially available precursors is described, facilitating preparation of unsymmetrical oxalates in a controlled manner.
December 19, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Falguni Basuli, Xiang Zhang, Carolyn Woodroofe, Elaine M Jagoda, Peter L Choyke, Rolf E Swenson
Fluorine-18 labeling of biomolecules are mostly performed by an indirect labeling method using a prosthetic group. Fluorine-18 labeled 6-fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester is a useful prosthetic group to radiolabel a protein. Recently we reported an improved preparation of this prosthetic group. To test the conjugation efficiency of the labeled ester prepared by this method we have performed conjugation reactions with two different peptides and a protein. Prostate-specific membrane antigen (PSMA) targeting peptide [(18) F]DCFPyL, αvβ3 integrin receptors targeting peptide [(18) F]c(RGDfK) and [(18) F]albumin were prepared in good radiochemical yields...
December 18, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Tomáš Elbert, Mahadeo R Patil, Aleš Marek
No abstract text is available yet for this article.
December 15, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Pavel Barta, Jiri Janousek, Katerina Zilkova, Frantisek Trejtnar
Radioimmunoassay belongs to the analytical method enabling highly specific and sensitive quantification of molecules. The verification of the real-time radioimmunoassay technology usefulness for ligand-quality characteristics evaluation such as concentration, influence of radiolabeling on binding affinity and stability was estimated. The anti-epidermal growth factor receptor antibody (131) I-cetuximab was employed as the ligand antibody. The concentration of (131) I-cetuximab was derived from the shape of binding curves coming from the ligand-receptor interaction...
December 13, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Brad D Maxwell, Scott B Tran
Tetrazoles are a common heterocyclic functionality in many biologically active molecules. [1-(14) C]2-(1H-Tetrazol-5-yl)acetic acid was required as an intermediate in the synthesis of a development candidate as part of a discovery phase program to complete metabolic profiling studies. [1-(14) C]2-(1H-Tetrazol-5-yl)acetic acid was prepared in 4 steps overall and in 3 radiochemical steps from K(14) CN in an overall 32% radiochemical yield.
December 13, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Gholamhossein Shirvani, Abbas Shockravi, Mohsen Amini, Nader Saemian
Metallo-beta-lactamase enzymes make bacteria resistant to a broad range of commonly used beta-lactam antibiotics. Several thiol derivatives of L-amino acids have been shown their inhibitory effects against the metallo-β-lactamase IMP-1. In this study, (2-mercaptoacetyl)-L-tryptophan as a new inhibitor of MBLs labeled with carbon-14 in the 2-position of the indole ring was prepared from [2-(14) C]indole as a key synthetic intermediate based on chiral pool strategy. The overall synthesis was carried out in ten-step with the overall radiochemical yield 3...
December 12, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Philipp Amsler, Wolf Thierry, Lanshoeft Christian, Bettighofer Anja, Eisfeld Jochen, Moenius Thomas, Probst Claudia, Etter Coralie, Olivier Heudi
Here we describe the production of stable isotope labeled human immunoglobulin G1 ([(13) C]-hIgG1) using [(13) C]-L-lysine/arginine labeled-hIgG1. The fermentation process was run in shake flasks containing labeled arginine (Arg) and lysine (Lys) which were incorporated into the produced recombinant hIgG1. The [(13) C]-hIgG1 was purified and label incorporation was determined to be >99% at all Lys and Arg moieties. Sequence coverage was confirmed by peptide mapping. [(13) C]-hIgG1 was then used as an IS for the development of a LC-MS/MS method applicable to the quantitative analysis of human all types of hIgG1 in rat serum...
December 12, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Koki Hasegawa, Emi Kawachi, Yoshinari Uehara, Tsuyoshi Yoshida, Satoshi Imaizumi, Masahiro Ogawa, Shin-Ichiro Miura, Keijiro Saku
We examined the (68) Ga labeling of the α-helical peptide, DOTA-FAMP, and evaluated conformational changes during radiolabeling. (68) Ga-DOTA-FAMP is a positron emission tomography probe candidate for atherosclerotic plaques. The labeling yield achieved by Zhernosekov's method (using acetone for (68) Ga purification) was compared with that achieved by the original and 2 modified Mueller's methods (using NaCl solution). Modified method I involves desalting the (68) Ga prior to labeling, and modified method II involves the inclusion of ethanol in the labeling solution...
December 7, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Sankha Chattopadhyay, Md Neyar Alam, Madhu Smita, Umesh Kumar, Sujata Saha Das, Luna Barua
Gallium-68 radioisotope is an excellent source in clinical positron emission tomography application due to its ease of availability from germanium-68 ((68) Ge)/gallium-68 ((68) Ga) generator having a shelf life of 1 year. In this paper, a modified method for purification of the primary eluate of (68) Ge-(68) Ga generator by using a small cation exchange resin (Dowex-50) column has been described. The breakthrough of (68) Ge before and after purification of (68) Ga eluate was 0.014% and 0.00027%, respectively...
December 1, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Boris A Czeskis, Darlene K Satonin
The synthesis of the radiolabeled glucagon receptor antagonist 1-[(14) C] was accomplished based on decarboxylative iodination of acid 2 followed by "reattachment" of (14) C carboxylic function. The method allowed a significant reduction in the number of steps in preparation of the radiolabeled compound. Iodide 4, obtained by the halodecarboxylation, was converted to cyanide 5-[(14) C], which was hydrolyzed to provide the radiolabeled acid 2-[(14) C]. Coupling with β-alanine fragment and hydrolysis of ester 6-[(14) C] completed the synthesis of the target molecule 1-[(14) C]...
December 1, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Sally Wagner, Rodrigo Teodoro, Winnie Deuther-Conrad, Mathias Kranz, Matthias Scheunemann, Steffen Fischer, Barbara Wenzel, Ute Egerland, Norbert Hoefgen, Jörg Steinbach, Peter Brust
Cyclic nucleotide phosphodiesterase 10A (PDE10A) regulates the level of the second messengers cAMP and cGMP in particular in brain regions assumed to be associated with neurodegenerative and psychiatric diseases. A better understanding of the pathophysiological role of the expression of PDE10A could be obtained by quantitative imaging of the enzyme by positron emission tomography (PET). Thus, in this study we developed, radiolabeled, and evaluated a new PDE10A radioligand, 8-bromo-1-(6-[(18) F]fluoropyridin-3-yl)-3,4-dimethylimidazo[1,5-a]quinoxaline ([(18) F]AQ28A)...
November 29, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Paul Allen, Ryan A Bragg, Moya Caffrey, Cecilia Ericsson, Michael J Hickey, Lee P Kingston, Charles S Elmore
As part of a medicinal chemistry program aimed at developing a highly potent and selective cathepsin C inhibitor, tritium, carbon-14, and stable isotope-labeled materials were required. The synthesis of tritium-labeled methanesulfonate 5 was achieved via catalytic tritiolysis of a chloro precursor, albeit at a low radiochemical purity of 67%. Tritium-labeled AZD5248 was prepared via a 3-stage synthesis, utilizing amide-directed hydrogen isotope exchange. Carbon-14 and stable isotope-labeled AZD5248 were successfully prepared through modifications of the medicinal chemistry synthetic route, enabling the use of available labeled intermediates...
November 21, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Kai Cao, John A Brailsford, Ming Yao, Janet Caceres-Cortes, Robert Espina, Samuel J Bonacorsi
Two regioisomeric glucuronide metabolites of dapagliflozin (BMS-512148) were synthesized and used to elucidate the structures of dapagliflozin metabolites observed in human urine samples. The structures of the synthetic metabolites were assigned by HMBC, ROESY, and TOCSY experiments. Analogues of these metabolites containing carbon-13 as a stable-label were also prepared for use as internal standards for the analysis of urine samples obtained from patients participating in clinical studies. This article is protected by copyright...
November 21, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Ramesh Neelamegam, Daniel L Yokell, Peter A Rice, Shozo Furumoto, Yukitsuka Kudo, Nobuyuki Okamura, Georges El Fakhri
The radiotracer, [(18) F]-THK-5351 is a highly selective and high binding affinity PET imaging agent for aggregates of hyper-phosphorylated tau protein. Our report is a simplified one-pot, two-step radiosynthesis of [(18) F]-THK-5351. This report is broadly applicable for routine clinical production and multi-center trials on account of favorable half-life of flourine-18 and the use of a commercially available radiosynthesis module, the GE TRACERlab™ FXFN . First, the O-THP protected tosyl precursor underwent nucleophilic fluorinating reaction with potassium cryptand fluoride ([(18) F] fluoride (K[(18) F]/K222 )) in DMSO at 110 °C for 10 min followed by O-THP removal by using diluted hydrochloric acid (HCl) at same temperature...
November 17, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Jianguo Lin, Ling Qiu, Gaochao Lv, Ke Li, Wei Wang, Guiqing Liu, Xueyu Zhao, Shanshan Wang
Technetium-99m-based radiopharmaceuticals have been used widely as diagnostic agents in the nuclear medicine. Chlorambucil (CLB) as one typical alkylating drug exhibits excellent inhibition effects against many human malignancies. To develop and explore a novel potential imaging agent for early diagnosis of tumors, tricarbonyl technetium-99m and rhenium complexes on the basis of the tridentate ligand dipicolylamine (DPA) bound to the chlorambucil pharmacophore were designed and synthesized: (99m) Tc-DPA-CLB (3) and Re-DPA-CLB (4)...
November 16, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Nafise Salek, Mohsen Mehrabi, Simindokht Shirvani Arani, Ali Bahrami Samani, Mostafa Erfani, Sara Vosoghi, Mohammad Ghannadi Maragheh, Mojtaba Shamsaei
In this study, the radiocomplexation of risedronic acid, a potent bisphosphonate with a no carrier added (NCA) (177) Lu, was investigated and followed by quality control studies, biodistribution evaluation, and dosimetry study for human based on biodistribution data in Wistar rats. The moderate energy β(-) emitter, (177) Lu (T½  = 6.7 days, Eβmax  = 497 keV), has been considered as a potential agent for development of bone-seeking radiopharmaceuticals. Because the specific activity of the radiolabeled carrier molecules should be high, the NCA radionuclides have an effective role in nuclear medicine...
November 15, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Melanie Cavani, Dirk Bier, Marcus Holschbach, Heinz H Coenen
An improved high yielding radiosynthesis of the known thiol-reactive maleimide-containing prosthetic group1-[3-(2-[(18) F]fluoropyridine-3-yloxy)propyl]pyrrole-2,5-dione ([(18) F]FPyME) is described. The target compound was obtained by a two-step one-pot procedure starting from a maleimide-containing nitro-precursor that was protected as a Diels-Alder adduct with 2,5-dimethylfurane. Nucleophilic radiofluorination followed by heat induced deprotection through a Retro Diels Alder reaction yielded, after chromatographic isolation, [(18) F]FPyME with a radiochemical yield of 20% in about 60 min overall synthesis time...
November 13, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
Karoline T Neumann, Anders T Lindhardt, Benny Bang-Andersen, Troels Skrydstrup
A new synthetic route to the Tau binder, THK-523, is disclosed herein, which can easily be adapted to (13) C- and D-isotope labeling. The synthesis proceeds via two key reactions, namely, a Pd-catalyzed carbonylative Sonogashira coupling and a reductive ring-closing step with hydrogen or deuterium gas. By carrying out these reactions in a 2-chamber reactor we reported previously, ex situ-generated carbon monoxide and hydrogen/deuterium can be applied in stoichiometric quantities, thereby facilitating isotope labeling of this Tau-binding compound...
November 13, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
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