tauvid - Medication Listings

11.1 Chemical Characteristics TAUVID contains flortaucipir fluorine 18 (F 18). Chemically, flortaucipir F 18 is 7-(6-[F-18]fluoropyridin-3-yl)-5H-pyrido[4,3-b]indole. The molecular weight is 262.27, the molecular formula is C 16 H 10 [ 18 F]N 3, and the structural formula is: TAUVID is a sterile, non-pyrogenic solution for intravenous injection. The clear, colorless solution free of visible particulate matter is supplied ready to use, and each milliliter contains up to 2 micrograms of flortaucipir and 300 to 3,700 MBq (8.1 to 100 mCi) flortaucipir F 18 at end of synthesis, 1.5 mg of L-cysteine hydrochloride monohydrate USP, 2.1 mg of dibasic sodium phosphate anhydrous USP, up to 55 of micrograms hydrogen chloride and 0.1 mL dehydrated alcohol in 0.9% sodium chloride injection USP. The pH of the solution is between 5.5 and 7.5. Structural Formula 11.2 Physical Characteristics TAUVID is radiolabeled with fluorine 18 (F 18), a cyclotron produced radionuclide that decays by positron emission to stable oxygen 18 with a 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 11.3 External Radiation The point source air-kerma coefficient for F18 is 3.74E -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 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