AXUMIN Solution for injection Ref.[10080] Active ingredients: Fluciclovine ¹⁸F

11.1 Chemical Characteristics

Axumin contains the fluorine 18 (F 18) labeled synthetic amino acid analog fluciclovine. Fluciclovine F 18 is a radioactive diagnostic agent used with PET imaging. Chemically, fluciclovine F 18 is (1r, 3r)-1-amino-3[¹⁸F]fluorocyclobutane-1-carboxylic acid. The molecular weight is 132.1 and the structural formula is:

Axumin is a sterile, non-pyrogenic, clear, colorless, hyperosmolal (approximately 500-540 mOsm/kg) injection for intravenous use. Each milliliter contains up to 2 micrograms of fluciclovine, 335 to 8200 MBq (9 to 221 mCi) fluciclovine F 18 at calibration time and date, and 20 mg trisodium citrate in water for injection. The solution also contains hydrochloric acid, sodium hydroxide and has a pH between 4 and 6.

11.2 Physical Characteristics

Fluorine 18 (F 18) is a cyclotron produced radionuclide that decays by positron emission (ß+ decay, 96.7%) and orbital electron capture (3.3%) to stable oxygen 18 with a physical half-life of 109.7 minutes. The positron can undergo annihilation with an electron to produce two gamma rays; the energy of each gamma ray is 511 keV (Table 2).

Table 2. Principal Radiation Produced from Decay of Fluorine 18 Radiation:

11.3 External Radiation

The point source air-kerma coefficient for F 18 is 3.75 × 10 ^-17 Gy m²/(Bq s). The first half-value thickness of lead (Pb) for F 18 gamma rays is approximately 6 mm. The relative reduction of radiation emitted by F 18 that results from various thicknesses of lead shielding is shown in Table 3. The use of 8 cm of Pb will decrease the radiation transmission (i.e., exposure) by a factor of about 10,000.

Table 3. Radiation Attenuation of 511 keV Gamma Rays by Lead Shielding: