In the interest of developing in vivo positron emission tomography (PET) probes for neuroimaging of calcium channels, we have prepared a carbon-11 isotopologue of a dihydropyridine Ca2+-channel antagonist, isradipine. Desmethyl isradipine (4-(benzo[c][1,2,5]oxadiazol-4-yl)-5-(isopropoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine -3-carboxylic acid) was reacted with [11C]CH3I in the presence of tetrabutylammonium hydroxide in DMF in an HPLC injector loop to produce the radiotracer in a good yield (6 ± 3% uncorrected radiochemical yield) and high specific activity (143 ± 90 GBq·µmol-1 at end-of-synthesis). PET imaging of normal rats revealed rapid brain uptake at baseline (0.37 ± 0.08% ID/cc (percent of injected dose per cubic centimeter) at peak, 15-60 s), which was followed by fast washout. After pretreatment with isradipine (2 mg·kg-1, i.p.), whole brain radioactivity uptake was diminished by 25%-40%. This preliminary study confirms that [11C]isradipine can be synthesized routinely for research studies and is brain penetrating. Further work on Ca2+-channel radiotracer development is planned.
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http://dx.doi.org/10.3390/molecules20069550 | DOI Listing |
EJNMMI Radiopharm Chem
September 2024
Department of Medical Imaging, Henan Provincial People's Hospital & the People's Hospital of Zhengzhou University, Zhengzhou, 450003, China.
Background: A novel positron emission tomography (PET) imaging tracer, [F] SynVesT-1, targeting synaptic vesicle glycoprotein 2 (SV2A), has been developed to meet clinical demand. Utilizing the Trasis AllinOne-36 (AIO) module, we've automated synthesis to Good Manufacturing Practice (GMP) standards, ensuring sterile, pyrogen-free production. The fully GMP-compliant robust synthesis of [F] SynVesT-1 boosting reliability and introducing a significant degree of simplicity and its comprehensive validation for routine human use.
View Article and Find Full Text PDFJ Vis Exp
May 2024
Radiopharmaceutical Production and Development Centre (RAPID), Medical Technology and Physics Department, Sir Charles Gairdner Hospital.
[Ga]Ga-FAPI-46 is a promising new tracer for the imaging of fibroblast activation protein (FAP) by positron emission tomography (PET). Labeled FAP inhibitors (FAPIs) have demonstrated uptake in various types of cancers, including breast, lung, prostate, pancreatic and colorectal cancer. FAPI-PET also possesses a practical advantage over FDG-PET as fasting and resting are not required.
View Article and Find Full Text PDFJ Labelled Comp Radiopharm
July 2024
Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
A new automated radiosynthesis of [C]2-(2,6-difluoro-4-((2-(N-methylphenylsulfonamido)ethyl)thio)phenoxy)acetamide ([C]K2), a radiopharmaceutical for the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor, is reported. Although manual syntheses have been described, these are unsuitable for routine production of larger batches of [C]K2 for (pre)clinical PET imaging applications. To meet demands for the imaging agent from our functional neuroimaging collaborators, herein, we report a current good manufacturing practice (cGMP)-compliant synthesis of [C]K2 using a commercial synthesis module.
View Article and Find Full Text PDFEJNMMI Radiopharm Chem
April 2024
Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.
Background: 6-Bromo-7-[C]methylpurine ([C]BMP) is a radiotracer for positron emission tomography (PET) to measure multidrug resistance-associated protein 1 (MRP1) transport activity in different tissues. Previously reported radiosyntheses of [C]BMP afforded a mixture of 7- and 9-[C]methyl regioisomers. To prepare for clinical use, we here report an improved regioselective radiosynthesis of [C]BMP, the results of a non-clinical toxicity study as well as human dosimetry estimates based on mouse PET data.
View Article and Find Full Text PDFJACS Au
March 2024
Department of Radiology, Biomedical Imaging University of California, San Francisco, San Francisco, California 94158, United States.
Imaging is increasingly used to detect and monitor bacterial infection. Both anatomic (X-rays, computed tomography, ultrasound, and MRI) and nuclear medicine ([In]-WBC SPECT, [F]FDG PET) techniques are used in clinical practice but lack specificity for the causative microorganisms themselves. To meet this challenge, many groups have developed imaging methods that target pathogen-specific metabolism, including PET tracers integrated into the bacterial cell wall.
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