flurpiridaz f 18 - Generic Medications

11.1 Chemical Characteristics FLYRCADO (flurpiridaz F 18) injection is a radioactive diagnostic drug for intravenous use. The molecular formula of flurpiridaz F 18 is C 18 H 22 Cl 18 FN 2 O 3 , the molecular mass is 367.8, and the structural formula is: Chemically, flurpiridaz F 18 is 2- tert -butyl-4-chloro-5-[[4-(2-( 18 F)fluoranylethoxymethyl)phenyl]methoxy]pyridazin-3-one. FLYRCADO is a sterile, preservative-free, non-pyrogenic, clear, colorless to yellow radioactive solution. Each mL contains 190 MBq to 2,050 MBq (5 mCi to 55 mCi) of flurpiridaz F 18 at end of synthesis, up to 2.3 mcg flurpiridaz, and the following inactive ingredients: 45 mg hydroxypropyl-β-cyclodextrin (as a solubilizer and co-radiostabilizer), 35 mg L-(+)-ascorbic acid (as a radiostabilizer), 8.2 mg sodium hydroxide, and 55.2 mg anhydrous ethanol, in water for injection. The pH of the solution is between 5.5 and 8. Chemical Structure 11.2 Physical Characteristics Fluorine-18 decays by positron (β+) emission and has a half-life of 109.8 minutes. The principal photons useful for diagnostic imaging are the 511 keV gamma photons, resulting from the interaction of the emitted positron with an electron. Principal emission data for fluorine-18 are shown in Table 4. Table 4 – Principal Radiation Emission Data for Fluorine-18 Radiation/Emission % per Disintegration Mean Energy (keV) Positron 96.7 249.8 Gamma 193.5 511 11.3 External Radiation The point source air-kerma rate constant for fluorine-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 fluorine-18 gamma rays is approximately 6 mm. The relative reduction of radiation emitted by fluorine-18 that results from various thicknesses of lead shielding is shown in Table 5. The use of about 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 Shielding Thickness cm of Lead (Pb) Coefficient of Attenuation 0.6 0.5 2 0.1 4 0.01 6 0.001 8 0.0001