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The strange case of the [13N]NH3

2015; Lippincott Williams & Wilkins; Volume: 37; Issue: 4 Linguagem: Inglês

10.1097/mnm.0000000000000453

1473-5628

Massimo Statuto, Elisa Galli, Francesco Bertagna, Elena Migliorati, Isabella Zanella, Diego Di Lorenzo, Antonio De Agostini, Carlo Rodella, Pietro Apostoli, Luigi Caimi, Raffaele Giubbini, Giorgio Biasiotto,

Medical Imaging and Pathology Studies

Objective PET radiopharmaceuticals are often injected in patients before all quality controls are performed and before sterility results are available. We propose a process validation to produce very safe and pure [13N]NH3 for human use. Methods [13N]NH3 was produced in the cyclotron target. Online purification was performed by anionic exchange resin. All the production steps were subjected to a sterility test. Some additional controls were added to those required by the monograph. Results The radiochemical yield of the syntheses was 26.3 and 61.5% corrected for decay, with a radiochemical purity of 100%. In addition to quality controls requested by the European Pharmacopeia monograph, we carefully analyzed the product for the presence of possible contaminants. Some elements, mainly metals, were found in very low amounts at concentrations in the range of ppb. The radionuclidic purity was verified. The achievement of the parameters of osmolality, by addition of saline solution to the preparation, made the analysis of chemical purity difficult and worsened the measurement of radiochemical purity by high performance liquid chromatography. Only pH control is necessary before administration to patients and therefore a safe production process was set up to prevent microbiological contamination. All phases were carefully standardized, starting from in-target production of [13N]NH3, to final splitting in the syringes. Sterility tests showed no bacterial growth, indicating the safety of the production process. Conclusion All our syntheses followed the monograph indications and were optimal to obtain PET imaging of a patient's myocardium.