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Objectives: In the context of a supply disruption of mebrofenin (Cholediam)-based kits for radiolabelling with technetium-99m [ 99m Tc], the medicine agencies allowed the importation of a back-up radiopharmaceutical diagnostic agent, etifenin (Techida), to ensure continuous management of patients with hepatobiliary disorders in nuclear medicine departments. There are still issues regarding the measurement of radiochemical purity (RCP) with these kits based on the European Pharmacopoeia and the Summary of Product Characteristics (SPC). This study aims to identify and to optimise, in a clinical context, the most suitable thin layer chromatography (TLC) method for the determination of the RCP in terms of speed of response and reliability for [ 99m Tc]Tc-mebrofenin and [ 99m Tc]Tc-etifenin., Methods: [ 99m Tc]Tc-etifenin (n=4) and [ 99m Tc]Tc-mebrofenin (n=5) were individually controlled using six different TLC methods and one high-performance liquid chromatography (HPLC) method for impurity identification ([ 99m Tc](TcO 2 ) n and Na[ 99m Tc]TcO 4 ), RCP (%) and duration of analysis (min). Two TLC methods were selected according to the recommendations of the Pharmacopoeia and SPC, two others were exactly the same but with a heating step, and the other two corresponded to a mix between the methods of the SPC and the Pharmacopoeia that were chosen to optimise RCP determination parameters., Results: Radio-HPLC analysis allowed effective separation of [ 99m Tc]Tc-etifenin and [ 99m Tc]Tc-mebrofenin with a retention time of 8.05±0.02 min and 8.94±0.07 min, respectively, from Na[ 99m Tc]TcO 4 (retention time 2.76±0.03 min). HPLC showed an absence of Na[ 99m Tc]TcO 4 for [ 99m Tc]Tc-mebrofenin and 0.2% for [ 99m Tc]Tc-etifenin. Among the TLC methods, we identified the most suitable method which ensures the most compliant RCP (98.3±0.9%) in a time of 31.5±1.1 min. Also, it allowed a time saving of 15 min compared with the methods proposed by the Pharmacopoeia and the SPCs., Conclusion: We propose a TLC method that accelerates quality control by an average of 15 min while guaranteeing a reliable RCP., Competing Interests: Competing interests: None declared., (© European Association of Hospital Pharmacists 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Technetium-99m mercapto-acetyl-triglycine ([ 99m Tc]Tc-MAG3) is a radiopharmaceutical diagnostic agent used in nuclear medicine intended for the exploration of nephrological and urological disorders. Patient safety and reliability of this imaging procedure especially depend on the radiochemical purity (RCP) of the [ 99m Tc]Tc-MAG3 preparation. Recently, the Summary of Product Characteristics (SPC) of NephroMAG, a kit dedicated to [ 99m Tc]Tc-MAG3 preparation, proposed a two-strip thin layer chromatography (TLC) based quality control (QC) method. Also, Straub et al recently proposed another TLC based QC method. We sought to evaluate the transferability of these QC methods in our hospital radiopharmacy and compared them to our currently employed TLC method and radio-HPLC (high-pressure liquid chromatography) to select the most appropriate in the context of hospital radiopharmacy., Methods: Ten consecutive [ 99m Tc]Tc-MAG3 preparations were controlled using: HPLC combined with a radiodetector (radio-HPLC), a single strip TLC method (method 1) in current use in our centre, a two-strip TLC method described in the SPC (method SPC) and a two-strip TLC method (method 2) described by Straub et al . Quantitative results for the four tested QC methods were measured and compared in terms of RCP (%), sodium pertechnetate ([ 99m Tc]TcO 4 - ) (%) and duration of analysis (min)., Results: RCP was significantly different between method SPC and radio-HPLC (p<0.001) and method 2 (p<0.001). Also, the percentage of [ 99m Tc]TcO 4 - was statistically different between the radio-HPLC and the method SPC (p<0.001), but not with the method 1 and method 2 group (p>0.05). The duration of analysis (min) was significantly different between the four QC procedures (p<0.001) with method 2 and method SPC being the quickest., Conclusions: Our study showed it is possible to transfer and select a quick and reliable QC method for the preparation of NephroMAG kits in our centre. We therefore advise the widespread use of the method from Straub et al in hospital radiopharmacies., Competing Interests: Competing interests: None declared., (© European Association of Hospital Pharmacists 2023. No commercial re-use. See rights and permissions. Published by BMJ.)