MDP Multidose Kit

DRUG DESCRIPTION

Each kit contains 10 multidose reaction vials, each containing 10 mg of medronic acid, 0.17 mg (minimum) stannous chloride (maximum stannous and stannic chloride 0.29 mg), and 2 mg ascorbic acid. The contents of the vial are sterile, pyrogen-free, lyophilized and sealed under nitrogen. The pH has been adjusted to 4.0-7.8 with hydrochloric acid and sodium hydroxide.

Administration is by intravenous injection for diagnostic use, after reconstitution with oxidant-free sodium pertechnetate Tc99m injection. The product as supplied is sterile and pyrogen-free.

The precise structure of stannous technetium Tc99m medronate complex is unknown at this time.

Physical Characteristics

Technetium Tc99m 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 Data¹

Radiation	Mean %/Disintegration	Mean Energy (keV)
Gamma-2	89.07	140.5
1Kocher, David C, “Radioactive Decay Data Tables,” DOE/TIC-11026, 108 (1981).

External Radiation

The specific gamma ray constant for Tc99m is 0.78 R/hr-mCi at 1 cm. The first half-value layer is 0.017 cm of Pb. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from interposition of various thicknesses of Pb is shown in Table 2. For example, the use of a 0.25 cm thickness of Pb will attenuate the radiation emitted by a factor of 1,000.

Table 2. Radiation Attenuation of Lead (Pb) Shielding

Shield Thickness (Pb) cm	Coefficient of Attenuation
0.017	0.5
0.08	10-1
0.16	10-2
0.25	10-3
0.33	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.

Table 3. Physical Decay Chart: Tc99m, half-life 6.02 hours

Hours	Fraction Remaining	Hours	Fraction Remaining
0*	1.000	5	0.562
1	0.891	6	0.501
2	0.794	8	0.398
3	0.708	10	0.316
4	0.631	12	0.251
*Calibration Time