THE STUDY OF THE ANTIMICROBIAL PROPERTIES OF THE RADIOPHARMACEUTICAL ¹⁸F-FDG

Ensuring sterility is a prerequisite for the clinical use of radiopharmaceuticals (RPs), as any breach is associated with risks to patient health. This requirement is particularly important for intravenously administered drugs, such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG), which is widely used in clinical practice for positron emission tomography (PET). The uniqueness of ¹⁸F-fluorodeoxyglucose lies not only in its diagnostic value but also in the specific requirements for its production and quality control, due to the short half-life of the radionuclide ¹⁸F. In this regard, the question arises as to whether the intrinsic ionizing radiation of the drug may possess antimicrobial potential and contribute to ensuring its microbiological safety. Assessment of the drug’s ability to suppress the viability of microorganisms that may potentially overcome standard aseptic manufacturing conditions and sterilization is aimed at reducing the risks of microbial contamination and increasing patient safety, which is particularly important for immunocompromised patients.

The present study is aimed at the experimental investigation of the hypothesis to determine whether the drug has, and to what extent, the ability to exert antimicrobial action by virtue of its own ionizing radiation. To carry out an experimental assessment of the ability of the radiopharmaceutical ¹⁸F-fluorodeoxyglucose to suppress the viability of microorganisms, depending on the activity of the ¹⁸F radionuclide.

An experimental study was performed to evaluate the inhibitory activity of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) against the sanitary-indicative microorganism Bacillus subtilis (ATCC: 6633).

Antimicrobial action was assessed by the direct inoculation method into fluid thioglycollate medium. 1 mL of the radiopharmaceutical with varying activity levels (200–1400 MBq) was added to test tubes. Control samples included: sterile medium, physiological solution, and “cold” fluorodeoxyglucose (F-FDG) with a stable fluorine isotope.

The intensive growth of culture was observed in the control: medium. In an experiment with ¹⁸F-fluorodeoxyglucose, there was a growth ‘gradient’ of the culture, depending on the levels of radionuclide activity.

Based on the obtained data, the ¹⁸F-labeled radiopharmaceutical, in the activity range of 200-1400 MBq, does not have significant antimicrobial activity against Bacillus subtilis.

The obtained results showed that the investigated range of activities (200-1400 MBq) does not ensure complete suppression of culture growth. Thus, in manufacturing, aseptic synthesis must be strictly observed in addition to the final sterilization of radiopharmaceuticals. Further investigation is ongoing.

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