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Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941
Published on: April 28, 2019
The strange case of the [13N]NH3: validation of the production process for human use
Massimo Statuto1, Elisa Galli, Francesco Bertagna
1aDepartment of Nuclear Medicine bBiotechnology Laboratory cMedical Physics Department dUnit of Occupational Health and Industrial Hygiene, Civic Hospital of Brescia eDepartment of Medical and Surgical Specialties, Radiological Sciences and Public Health, Section of Nuclear Medicine fDepartment of Molecular and Translational Medicine gUnit of Occupational Health and Industrial Hygiene, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy.
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 [N]NH3 for human use.
Methods:
[N]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 [N]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.
