Possible Impurities in Radiopharmaceuticals and Corresponding Test Methods

The main quality attributes of radiopharmaceuticals that ensure their effectiveness and safety and are unique to their specifications are activity, radionuclide identity, radionuclide purity, and radiochemical purity. The aim of this study was to analyse the possibility of formation and methods for determination of various impurities in radiopharmaceuticals based on radionuclides of several groups: technetium-99m and rhenium-188; iodine and fluorine-18 isotopes; and gallium-68 and some other metallic radionuclides used in theranostic schemes combining radionuclide diagnostics and radionuclide therapy. The article analyses the sources for the formation of radionuclide, radiochemical, and chemical impurities; the influence of these impurities on visualisation quality and dosimetric characteristics of radiopharmaceuticals; various approaches to the methods of impurity detection and quantification; compendial requirements to the quality of radiopharmaceuticals; and research results reported in publications. The article demonstrates the need for the development and certification of Russian reference standards for testing quality attributes of radiopharmaceuticals as part of harmonisation of the State Pharmacopoeia of the Russian Federation with the Pharmacopoeia of the Eurasian Economic Union and the European Pharmacopoeia.

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