Objective: To investigate the preparation and the encapsulation efficiency of 125I-oligonucleotide(ON)-long-circulation liposomes (LCL).
Methods: (1) Oligonucleotide was labeled with 125I using thallium chloride tetrahydrate (TICl3) as an oxidizing agent. 125I-oligonucleotide was separated from free 125I by Sephadex G25 column chromatography. The following radiolabeling efficiency, radiochemistry purity and specific radioactivity were obtained respectively. Subsequently, the stability of 125I-ON was observed. (2) 125I-ON-LCL were prepared by means of reverse-phase evaporation. The quality of 125I-ON-LCL was evaluated after the crude LCL were repeatedly extruded through 400 nm, 200 nm, 100 nm polycarbonate membranes consecutively. Results (1) The radiolabeling efficiency, radiochemistry purity and specific radioactivity of 125I-antisense oigonucleotide (ASON) were (72.80 +/- 0.68)%, (98. 33 +/- 0.39)% and (0.63 +/- 0.11) MBq/microg; of 125I-sense oigonucleotide (SON) were (72.21 +/- 0.60)%, (98.28 +/- 0.36)%, (0.63 +/- 0.14) MBq/microg; and of 125I-nonsense oligonucleotide (NON) were (72.77 +/- 0.81)%, (98.42 +/- 0.40)%, (0.62 +/- 0.11) MBq/microg, respectively. (2) The radiochemistry purity of 125I-ON, in 0.01 mol/L HEPES buffer and human serum at 1 h, 2 h and 4 h were all above 93%, 80%, respectively. (3) LCL formulations were 115 nm in mean diameter with a PDI (polydispersibility index) of 0.103 and Zeta potential of -29.23. The encapsulation efficiencies of 125I-ASON, 125I-SON and 125I-NON were (66.21 +/- 0.21)%, (70.93 +/- 0.03)% and (67.67 +/- 0.10)% respectively.
Conclusion: LCL were prepared in high loading efficiency for 125I-ON with small particle sizes and symmetric distributions.
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Pharmaceuticals (Basel)
January 2025
Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany.
The radiotracer [F]JK-PSMA-7, a prostate cancer imaging agent for positron emission tomography (PET), was previously synthesized by indirect radiofluorination using an F-labeled active ester as a prosthetic group, which had to be isolated and purified before it could be linked to the pharmacologically active Lys-urea-Glu motif. Although this procedure could be automated on two-reactor modules like the GE TRACERLab FX2N (FXN) to afford the tracer in modest radiochemical yields (RCY) of 18-25%, it is unsuitable for cassette-based systems with a single reactor. To simplify implementation on an automated synthesis module, the radiosynthesis of [F]JK-PSMA-7 was devised as a one-pot, two-step reaction.
View Article and Find Full Text PDFAm J Nucl Med Mol Imaging
December 2024
Cyclotron and Radiochemistry Core, Karmanos Cancer Institute Detroit, MI, USA.
Colony-stimulating factor 1 receptor (CSF1R) is almost exclusively expressed on microglia in the human brain and thus, has promise as a biomarker for imaging microglia density as a proxy for neuroinflammation. [C]CPPC is a radiotracer with selective affinity to CSF1R, and has been evaluated for in-human microglia PET imaging. The flourine-18 labeled CPPC derivative, 5-cyano-N-(4-(4-(2-[F]fluoroethyl)piperazin-1-yl)-2-(piperidin-1-yl)phenyl)furan-2-carboxamide ([F]FCPPC), was previously synthesized, however, with a low radiochemical yield using manual radiosynthesis.
View Article and Find Full Text PDFEJNMMI Radiopharm Chem
January 2025
Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
Background: Poly (ADP-ribose) polymerase (PARP) enzymes are crucial for the repair of DNA single-strand breaks and have become key therapeutic targets in homologous recombination-deficient cancers, including prostate cancer. To enable non-invasive monitoring of PARP-1 expression, several PARP-1-targeting positron emission tomography (PET) tracers have been developed. Here, we aimed to preclinically investigate [carbonyl-C]DPQ as an alternative PARP-1 PET tracer as it features a strongly distinct chemotype compared to the frontrunners [F]FluorThanatrace and [F]PARPi.
View Article and Find Full Text PDFA successful positron emission tomography imaging program involving carbon-11 radiotracers demands fast, efficient, and reliable synthesis methods, requiring an on-site cyclotron and radiochemistry group, as well as clinical staff trained to operate under the unique constraints of the carbon-11 radionuclide. This study examines the merits and advantages of a captive solvent 'loop method' of radiolabeling four tracers with the carbon-11 radionuclide, producing the radioligands [C]ER-176, [C]MRB, [C]mHED, and [C]PiB. The 'loop method' is compared against the traditional reactor-based method of carbon-11 methylation in the course of synthesizing the same radiotracers on the identical automated platform.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
January 2025
Center for Radiopharmaceutical Sciences, PSI Center for Life Sciences, Villigen-PSI, 5232, Switzerland.
Purpose: Terbium-149 is a short-lived α-particle emitter, potentially useful for tumor-targeted therapy. The aim of this study was to investigate terbium-149 in combination with the somatostatin receptor (SSTR) agonist DOTATATE and the SSTR antagonist DOTA-LM3. The radiopeptides were evaluated to compare their therapeutic efficacy in vitro and in vivo.
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