POSLUMA Solution for injection Ref.[109999] Active ingredients: Flotufolastat ¹⁸F

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- ¹⁸F-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: not more than 10% (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.

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:

Table 4. Principal Radiation Produced from Decay of Fluorine-18:

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 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: