florbetapir f 18 - Generic Medications

11.1 Drug Characteristics AMYVID (florbetapir F 18 injection) is a radioactive diagnostic drug for intravenous use. Chemically, florbetapir F 18 is (E)-4-(2-(6-(2-(2-(2[ 18 F] fluoroethoxy)ethoxy)ethoxy)pyridine-3-yl)vinyl)-N-methylbenzamine. The molecular weight is 359 and the structural formula is: AMYVID is a sterile, non-pyrogenic clear, colorless solution. Each mL contains 0.1 mcg to 19 mcg of florbetapir and 500 MBq to 1,900 MBq (13.5 mCi to 51 mCi) of florbetapir F 18 at EOS and the following inactive ingredients: 4.5 mg sodium ascorbate and 0.1 mL dehydrated alcohol in 0.9% sodium chloride injection. The pH of the solution is between 5.5 and 8.0. Structural Formula 11.2 Nuclear Physical Characteristics Fluorine-18 (F 18) decays by positron (β + ) emission to oxygen-18 and has a physical half-life of 109.8 minutes. 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 3 ). Table 3: Principal Radiation Produced from Decay of Fluorine-18 Radiation Energy Level (keV) Abundance (%) Positron 249.8 96.9 Gamma 511 193.5 The point source air-kerma coefficient for F 18 is 3.74E -17 Gy m 2 /(Bq s); this coefficient was formerly defined as the specific gamma-ray constant of 5.7 R/hr/mCi at 1 cm. 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 4 . The use of ~8 cm of Pb will decrease the radiation transmission (i.e., exposure) by a factor of about 10,000. Table 4: 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 For use in correcting for physical decay of this radionuclide, the fractions remaining at selected intervals after calibration are shown in Table 5 . Table 5: Physical Decay Chart for Fluorine-18 Minutes Fraction Remaining 0 1.00 15 0.909 30 0.826 60 0.683 110 0.500 220 0.250 440 0.060