Source: FDA, National Drug Code (US) Revision Year: 2020
Drax Exametazime (kit for the preparation of technetium Tc 99m exametazime for leukocyte labeling) prepares a radioactive diagnostic agent. Each single-dose vial contains a sterile, non-pyrogenic, lyophilized mixture of 0.5 mg exametazime, 7.6 mcg stannous chloride dihydrate (minimum stannous tin 0.6 mcg; maximum total stannous and stannic tin 4 mcg per vial) and 4.5 mg sodium chloride, sealed under nitrogen atmosphere with a rubber closure. The product contains no antimicrobial preservative.
The chemical formula of exametazime is C13H28N4O2, with the following structural formula:
Prior to publication of the USAN, exametazime [also known as (RR,SS)-4.8-diaza-3,6,6,9-tetramethylundecane-2, 10-dione bisoxime] was known as hexamethylpropylene amine oxime (HM-PAO). The name HM-PAO appears in many publications.
When Tc 99m pertechnetate in Sodium Chloride Injection, USP (0.9%) is added to Drax Exametazime vial, a Tc 99m complex of exametazime is formed.
Tc 99m 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 – Tc 99m:
| Radiation | Mean %/Disintegration | Mean Energy (keV) |
|---|---|---|
| Gamma 2 | 88.5 | 140.5 |
The air-kerma-rate (exposure-rate) constant for technetium Tc 99m is 5.23 m²·pGy·(MBq)-1·s-1 [0.795 cm²·R·(mCi)-1·h-1]. The first half-value thickness of lead (Pb) for Tc 99m is 0.25 mm. 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 3. For example, the use of a 3 mm thickness of 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 | Coefficient 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 – Tc 99m half-life 6 hours:
| Hours | Fraction Remaining | Hours | Fraction Remaining |
|---|---|---|---|
| 0* | 1.00 | 7 | 0.45 |
| 1 | 0.89 | 8 | 0.4 |
| 2 | 0.79 | 9 | 0.35 |
| 3 | 0.71 | 10 | 0.32 |
| 4 | 0.63 | 11 | 0.28 |
| 5 | 0.56 | 12 | 0.25 |
| 6 | 0.50 | 24 | 0.063 |
* Calibration time (time of preparation)
| Dosage Forms and Strengths |
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Drax Exametazime is a kit containing five (5) single-dose vials. Each 10 mL, clear glass vial contains a non-radioactive lyophilized mixture of: 0.5 mg exametazime, 7.6 mcg stannous chloride dihydrate (minimum stannous tin 0.6 mcg; maximum total stannous and stannic tin 4 mcg per vial) and 4.5 mg sodium chloride, sealed under nitrogen atmosphere with a rubber closure. When reconstituted with the technetium Tc 99m eluate, each vial will contain a clear, colorless, and foreign particles-free solution of 370 MBq up to 2000 MBq (10 mCi up to 54 mCi) [74-370 MBq/mL (2-10 mCi/mL)]. The radioactive solution produced will be used for leukocyte labeling before intravenous administration to the patient. |
| How Supplied |
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Drax Exametazime kit (NDC 65174-200-05) comprises:
Sodium Pertechnetate Tc 99m is not part of Drax Exametazime kit. Before reconstitution and radiolabeling with Tc 99m, the contents of the kit are not radioactive. |
| Drug | Countries | |
|---|---|---|
| DRAX EXAMETAZIME | United States |
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