[13N]Ammonia is one of the most commonly used Positron Emission Tomography (PET) radiotracers in humans to assess myocardial perfusion and measure myocardial blood flow. Here, we report a reliable semi-automated process to manufacture large quantities of [13N]ammonia in high purity by proton-irradiation of a 10 mM aqueous ethanol solution using an in-target process under aseptic conditions. Our simplified production system is based on two syringe driver units and an in-line anion-exchange purification for up to three consecutive productions of ~30 GBq (~800 mCi) (radiochemical yield = 69 ± 3% n.d.c) per day. The total manufacturing time, including purification, sterile filtration, reformulation, and quality control (QC) analyses performed before batch release, is approximately 11 min from the End of Bombardment (EOB). The drug product complies with FDA/USP specifications and is supplied in a multidose vial allowing for two doses per patient, two patients per batch (4 doses/batch) on two separate PET scanners simultaneously. After four years of use, this production system has proved to be easy to operate and maintain at low costs. Over the last four years, more than 1000 patients have been imaged using this simplified procedure, demonstrating its reliability for the routine production of large quantities of current Good Manufacturing Practices (cGMP)-compliant [13N]ammonia for human use.

blocker losartan is used in patients with renal and cardiovascular diseases. [ 18 F]fluoropyridine-losartan has shown favorable binding profile for quantitative renal PET imaging of AT 1 R with selective binding in rats and pigs, low interference of radiometabolites and appropriate dosimetry for clinical translation. A new approach was developed to produce [ 18 F]fluoropyridine-losartan in very high molar activity. Automated radiosynthesis was performed in a three-step, two-pot, and two-HPLCpurification procedure within 2 h. Pure [ 18 F]FPyKYNE was obtained by radiofluorination of NO 2 PyKYNE and silica-gel-HPLC purification (40 ± 9%), preventing the formation of nitropyridine-losartan in the second step. Conjugation with trityl-losartan azide via click chemistry, followed by acid hydrolysis, C18-HPLC purification and reformulation provided [ 18 F]fluoropyridine-losartan in 11 ± 2% (decay-corrected from [ 18 F]fluoride, EOB). Using tris [(1-(3-hydroxypropyl)-1H-1,2,3-triazol-4-yl)methyl]-amine (THPTA) as a Cu(I)stabilizing agent for coupling [ 18 F]FPyKYNE to the unprotected losartan azide afforded [ 18 F]fluoropyridine-losartan in similar yields (11 ± 3%, decaycorrected from [ 18 F]fluoride, EOB). Reverse-phase HPLC was optimized by reducing the pH of the mobile phase to achieve complete purification and high