technetium tc 99m medronate - Generic Medications

Each reaction vial contains a sterile, nonpyrogenic, nonradioactive lyophilized mixture of 20 mg medronic acid, 1 mg ascorbic acid, 0.13 mg (minimum) stannous fluoride, SnF 2 and 0.38 mg total tin, maximum (as stannous fluoride, SnF 2 ). The pH is adjusted with sodium hydroxide or hydrochloric acid to 6.5 (6.3 to 6.7) prior to lyophilization. The vial does not contain a preservative. The contents of the vial are lyophilized and sealed under nitrogen at the time of manufacture. The pH of the reconstituted product is 5.4 to 6.8. The structure of medronic acid is given below: The precise structure of technetium Tc 99m medronate is unknown at this time. When sterile, pyrogen-free sodium pertechnetate Tc 99m injection is added to the vial, the diagnostic agent technetium Tc 99m medronate is formed for administration by intravenous injection. Structure of Medronic Acid

DRAXIMAGE® MDP-25 Kit for the Preparation of Technetium Tc 99m Medronate Injection For Intravenous Use DIAGNOSTIC – FOR SKELETAL IMAGING DESCRIPTION The kit consists of reaction vials which contain the sterile, non-pyrogenic,non-radioactive ingredients necessary to produce Technetium Tc 99m Medronate Injection for diagnostic use by intravenous injection. MDP-25 reaction vials are intended to be used as multidose vials. Each 10 mL MDP-25 reaction vial contains 25.0 mg medronic acid and not less than 2.0 mg of stannous chloride dihydrate (maximum total tin expressed as stannous chloride dihydrate 3.0 mg) and 5.0 mg of p-aminobenzoic acid in lyophilized form under an atmosphere of nitrogen. The pH is adjusted to 6.8 to 6.9 with HCI or NaOH prior to lyophilization. The addition of sterile, non-pyrogenic, and oxidant-free sodium pertechnetate Tc-99m sterile solution produces a rapid labeling which is essentially quantitative and which remains stable in vitro throughout the 12-hours life of the preparation. No bacteriostatic preservative is present. The structural formula of medronic acid is: PHYSICAL CHARACTERISTICS Technetium Tc-99m decays by isomeric transition with a physical half-life of 6.02 hours. 1 The principal photon that is useful for detection and imaging studies is listed in Table 1. Table 1 Principal Radiation Emission Data Radiation Mean % / Disintegration Energy (keV) Gamma-2 89.07 140.5 EXTERNAL RADIATION The specific gamma ray constant for Tc-99m is 0.78 R/mCi-hr at 1 cm. The first half value layer is 0.017 cm of lead. To facilitate control of the radiation exposure from millicurie amounts of this radionuclide, the use of a 0.25 cm thickness of lead will attenuate the radiation emitted by a factor of about 1000. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from interposition of various thicknesses of lead is shown in Table 2. Table 2 Radiation Attenuation by Lead Shielding Shield Thickness (Pb) cm Coefficient of Attenuation 0.017 0.08 0.16 0.25 0.33 0.5 10 -1 10 -2 10 -3 10 -4 To correct for physical decay of this radionuclide, the fractions that remain at selected intervals after the time of calibration are shown in Table 3. 1 Kocher, David C.: “Radioactive Decay Data Tables”, DOE/TIC-11026, 108 (1981) Table 3 Physical Decay Chart: Tc-99m, half-life 6.02 hours Hours Fraction Remaining Hours Fraction Remaining 0* 1 2 3 4 5 6 1.000 0.891 0.794 0.708 0.631 0.562 0.501 7 8 9 10 11 12 0.447 0.398 0.355 0.316 0.282 0.251 *Calibration time Structure