Improved GMP-compliant multi-dose production and quality control of 6-[18F]fluoro-L-DOPA

Background: 6-[18F]Fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) is a frequently used radiopharmaceutical for detecting neuroendocrine and brain tumors and for the differential diagnosis of Parkinson’s disease. To meet the demand for FDOPA, a high-yield GMP-compliant production method is required. Therefore, this study aimed to improve the FDOPA production and quality control procedures to enable distribution of the radiopharmaceutical over distances. FDOPA was prepared by electrophilic fluorination of the trimethylstannyl precursor with [18F]F2, produced from [18O]2 via the double-shoot approach, leading to FDOPA with higher specific activity as compared to FDOPA which was synthesized, using [18F]F2 produced from 20Ne, leading to FDOPA with a lower specific activity. The quality control of the product was performed using a validated UPLC system and compared with quality control with a conventional HPLC system. Impurities were identified using UPLC-MS. Results: The [18O]2 double-shoot radionuclide production method yielded significantly more [18F]F2 with less carrier F2 than the conventional method starting from 20Ne. After adjustment of radiolabeling parameters substantially higher amounts of FDOPA with higher specific activity could be obtained. Quality control by UPLC was much faster and detected more side-products than HPLC. UPLC-MS showed that the most important side-product was FDOPA-quinone, rather than 6-hydroxydopa as suggested by the European Pharmacopoeia. Conclusion: The production and quality control of FDOPA were significantly improved by introducing the [18O]2 double-shoot radionuclide production method, and product analysis by UPLC, respectively. As a result, FDOPA is now routinely available for clinical practice and for distribution over distances

Improving metabolic stability of fluorine-18 labeled verapamil analogs

INTRODUCTION: Fluorine-18 labeled positron emission tomography (PET) tracers were developed to obtain more insight into the function of P-glycoprotein (P-gp) in relation to various conditions. They allow research in facilities without a cyclotron as they can be transported with a half-life of 110 min. As the metabolic stability of previously reported tracers [18F]1 and [18F]2 was poor, the purpose of this study was to improve this stability using deuterium substitution, creating verapamil analogs [18F]1-d4, [18F]2-d4, [18F]3-d3 and [18F]3-d7. METHODS: The following deuterium containing tracers were synthesized and evaluated in mice and rats: [18F]1-d4, [18F]2-d4, [18F]3-d3 and [18F]3-d7. RESULTS: The deuterated analogs [18F]2-d4, [18F]3-d3 and [18F]3-d7 showed increased metabolic stability compared with their non-deuterated counterparts. The increased metabolic stability of the methyl containing analogs [18F]3-d3 and [18F]3-d7 might be caused by steric hindrance for enzymes. CONCLUSION: The striking similar in vivo behavior of [18F]3-d7 to that of (R)-[11C]verapamil, and its improved metabolic stability compared with the other fluorine-18 labeled tracers synthesized, supports the potential clinical translation of [18F]3-d7 as a PET radiopharmaceutical for P-gp evaluation

The added value of Good Manufacturing Practices (GMP) in the production of radiopharmaceuticals

Manufacturers of medicinal products including radiopharmaceuticals have to follow regulations from their governmental organizations as well as professional societies to ensure built-in quality combined with patient safety issues. This chapter is a concise review of Good Manufacturing Practices (GMP) with a special focus on the production of radiopharmaceuticals. Furthermore, attention is given to the added value of GMP as a tool for providing more insights and awareness. Working under GMP conditions leads to potentially faster problem solving in daily practice, as compared to the “skills-only”-based approach. The latter had been a mainstay for a long time but is being more and more replaced by a “skills-based and oversight approach” nowadays