POSLUMA

11 DESCRIPTION 11.1 Chemical Characteristics POSLUMA (flotufolastat F 18) injection is a radioactive diagnostic agent for intravenous use.​​​‍​​‍​​​​‍​​‍‍ The active ingredient of POSLUMA is flotufolastat F 18 gallium, of which the molecular structure includes a DOTAGA complex with nonradioactive gallium. Radioactive fluorine-18 is covalently bound to silicon. Chemically, flotufolastat F 18 gallium is gallate(6-), [(4 S ,8 S ,13 R ,27 R ,30 R ,35 S )-35-[4,10-bis[(carboxy-k O )methyl]-7-(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl-k N 1 ,k N 4 ,k N 7 ,k N 10 ]-30-[[[4-[bis(1,1-dimethylethyl)fluoro- 18 F -silyl]benzoyl]amino]methyl]-1,36-dihydroxy-1,6,11,18,21,29,32,36-octaoxo-5,7,12,17,22,28,31-heptaazahexatriacontane-4,8,13,27-tetracarboxylato(9-)]-, hydrogen (1:6). The molecular weight is 1537.3 g/mol and the structural formula is: POSLUMA is a sterile, non-pyrogenic, clear, colorless, and isotonic solution. Each mL contains up to 20 mcg of flotufolastat gallium, up to 5,846 MBq (158 mCi) as flotufolastat F 18 gallium at end of synthesis, and the following inactive ingredients: 6.3% (v/v) alcohol, 1.9 mg anhydrous citric acid, 7.2 mg sodium chloride, and 0.75 mg sodium hydroxide to adjust pH between 4 and 6. POSLUMA contains no preservative. Structural Formula 11.2 Physical Characteristics POSLUMA contains fluorine-18 (F 18) which is a cyclotron produced radionuclide that decays by positron emission (β+ decay, 96.7%) and orbital electron capture (3.3%) to stable oxygen-18 with a physical half-life of 109.8 minutes ( Table 3 ). The principal photons useful for diagnostic imaging are the coincident pair of 511 keV gamma photons, resulting from the interaction of the emitted positron with an electron ( Table 4 ). Table 3: Physical Decay Chart for Fluorine-18 Minutes Fraction Remaining 0 1 15 0.909 30 0.826 60 0.683 110 0.5 220 0.25 Table 4: Principal Radiation Produced from Decay of Fluorine-18 Energy (keV) Abundance (%) Positron 249.8 96.7 Gamma 511 193.5 11.3 External Radiation The point source air-kerma coefficient for F 18 is 3.75 × 10 -17 Gy m 2 /(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 5 . The use of 8 cm of Pb will decrease the radiation transmission (i.e., exposure) by a factor of about 10,000. Table 5: Radiation Attenuation of 511 keV Gamma Rays by Lead Shielding Shield Thickness cm of Lead (Pb) Coefficient of Attenuation 0.6 0.5 2 0.1 4 0.01 6 0.001 8 0.0001