tetrofosmin - Medications

11.1 Chemical Characteristics MYOVIEW is a kit for the preparation of technetium Tc99m tetrofosmin injection for intravenous use. Technetium Tc99m tetrofosmin is a radioactive diagnostic agent. Each multiple-dose 10 mL glass vial contains a sterile, non-pyrogenic, lyophilized powder of 0.23 mg tetrofosmin [6,9-bis(2-ethoxyethyl)-3,12-dioxa-6,9-diphosphatetradecane], 0.03 mg stannous chloride dihydrate, (minimum stannous tin 0.015 mg; total stannous and stannic tin 0.0522 mg) 0.32 mg disodium sulphosalicylate, 1 mg sodium D-gluconate, and 1.8 mg sodium hydrogen carbonate. The lyophilized powder is sealed under a nitrogen atmosphere with a rubber closure. The product contains no antimicrobial preservative. The chemical formula of tetrofosmin is C 18 H 40 O 4 P 2 with the following structural formula: C 18 H 40 O 4 P 2 When sterile, pyrogen-free sodium pertechnetate Tc99m in isotonic saline is added to the vial, a Tc99m complex of tetrofosmin is formed. The radiolabeled product is a clear solution and the pH is in the range of 7.5 to 9.0. Chemical Structure 11.2 Physical Characteristics Technetium Tc99m decays by isomeric transition with a physical half-life of 6 hours. Photons that are useful for imaging studies are listed in Table 2. Table 2 Principal radiation emission data - technetium Tc99m Radiation Mean % disintegration Mean energy (keV) Gamma 2 88.5 140.5 11.3 External Radiation The air-kerma-rate (exposure-rate) constant for technetium Tc99m is 5.23 m 2 ∙pGy∙(MBq) −1 ∙s −1 [0.795 cm 2 ∙R∙(mCi) −1 ∙h −1 ]. A range of values for the relative radiation attenuation by various thicknesses of Pb shielding is shown in Table 3. For example, the use of 3 mm thick Pb will decrease the external radiation exposure by a factor of approximately 1,000. Table 3 Radiation attenuation by lead shielding Shield thickness (Pb) mm Factor of attenuation 0.25 0.5 1 10 -1 2 10 -2 3 10 -3 4 10 -4 5 10 -5 To correct for physical decay of this radionuclide, the fractions that remain at selected intervals relative to the time of calibration are shown in Table 4. Table 4 Physical decay chart - Tc99m half-life 6 hours Hours Fraction Remaining Hours Fraction Remaining 0 Calibration time (time of preparation) 1.000 7 0.446 1 0.891 8 0.397 2 0.794 9 0.354 3 0.707 10 0.315 4 0.630 11 0.281 5 0.562 12 0.250 6 0.500 24 0.063

11.1 Chemical Characteristics MYOVIEW 30 mL is a kit for the preparation of technetium Tc99m tetrofosmin injection for intravenous use. Technetium Tc99m tetrofosmin is a radioactive diagnostic agent. Each multiple-dose 30 mL glass vial contains a sterile, non-pyrogenic, lyophilized powder of 1.38 mg tetrofosmin [6,9-bis(2-ethoxyethyl)-3,12-dioxa-6,9-diphosphatetradecane], 0.09 mg stannous chloride dihydrate, (minimum stannous tin 0.015 mg; total stannous and stannic tin 0.0522 mg) 1.92 mg disodium sulphosalicylate, 3 mg sodium D-gluconate, and 11 mg sodium hydrogen carbonate, and 3 mg ascorbic acid. The lyophilized powder is sealed under a nitrogen atmosphere with a rubber closure. The product contains no antimicrobial preservative. The chemical formula of tetrofosmin is C 18 H 40 O 4 P 2 with the following structural formula: When sterile, pyrogen-free sodium pertechnetate Tc99m in isotonic saline is added to the vial, a Tc99m complex of tetrofosmin is formed. The radiolabeled product is a clear solution and the pH is in the range of 7.5 to 9.0. Chemical Structure 11.2 Physical Characteristics Technetium Tc99m decays by isomeric transition with a physical half-life of 6 hours. Photons that are useful for imaging studies are listed in Table 2. Table 2 Principal radiation emission data - technetium Tc99m Radiation Mean % disintegration Mean energy (keV) Gamma 2 88.5 140.5 11.3 External Radiation The air-kerma-rate (exposure-rate) constant for technetium Tc99m is 5.23 m 2 ∙pGy∙(MBq) –1 ∙s –1 [0.795 cm 2 ∙R∙(mCi) –1 ∙h –1 ]. A range of values for the relative radiation attenuation by various thicknesses of Pb shielding is shown in Table 3. For example, the use of 3 mm thick Pb will decrease the external radiation exposure by a factor of approximately 1,000. Table 3 Radiation attenuation by lead shielding Shield thickness (Pb) mm Factor of attenuation 0.25 0.5 1 10 -1 2 10 -2 3 10 -3 4 10 -4 5 10 -5 To correct for physical decay of this radionuclide, the fractions that remain at selected intervals relative to the time of calibration are shown in Table 4. Table 4 Physical decay chart - Tc99m half-life 6 hours Hours Fraction Remaining Hours Fraction Remaining 0 Calibration time (time of preparation) 1.000 7 0.446 1 0.891 8 0.397 2 0.794 9 0.354 3 0.707 10 0.315 4 0.630 11 0.281 5 0.562 12 0.250 6 0.500 24 0.063