Pharmacopeial parametric release strategy in microbiological quality control of radiopharmaceuticals

Abstract

Nuclear medicine is used to assess body functionality at various levels of biological organization and is increasingly employed for both diagnostic and therapeutic purposes. Nearly 5% of radiopharmaceuticals are used therapeutically, whereas approximately 95% are used for diagnosis. Diagnostic radiopharmaceuticals are generally considered safe because they are administered in subpharmacological doses, and the radiotracer components are employed in minimal doses. Consequently, the radiation exposure to the body during nuclear medicine investigations is typically low. However, when radiopharmaceuticals are used for therapeutic applications such as tumor ablation and bone pain palliation, the emitted radiation is highly localized and potent. Radiotracers and radiation doses are more carefully selected for young patients, as the radiation-induced risk of adverse health effects is greater in children than in adults. Radiopharmaceutical preparations should adhere to the established standards of pharmacopoeia worldwide to ensure safety and efficacy. Adherence to current good manufacturing practices, sterility, and good radiation practices are prerequisites for ensuring effective quality assurance and quality control systems during radiopharmaceutical preparation. The quality control test parameter for radiopharmaceuticals primarily involves physicochemical and biological tests. However, significant concerns exist regarding the biological testing of radiopharmaceuticals, necessitating their parametric release. The time-intensive traditional sterility test, bacterial endotoxin test, and rabbit pyrogen tests have been critical quality control issues due to the short half-lives of most radiopharmaceuticals, as they should be dispensed at the earliest to ensure optimal diagnostic/therapeutic benefit. Therefore, manufacturers of radiopharmaceuticals, dispensers, and nuclear medicine specialists should be cognizant of the issues posed by biological quality control as a primary obstacle to ensuring consistent quality through parametric release from a compendial test method standpoint.