METHOD OF USING AN ALUMINA IN A MOLYBDENUM/TECHNETIUM-99m GENERATOR

Abstract

A Molybdenum/Technetium 99-m generator containing a metal-molybdate containing powder and an alumina sorbent. A preferred alumina sorbent is a gamma-phase alumina (γ-Al.sub.2O.sub.3), a chi-phase alumina (χ-Al.sub.2O.sub.3), or a combination thereof.

Claims

1. A Molybdenum/Technetium 99-m generator comprising: a metal-molybdate (Mo) containing powder; and a guard filter comprising an alumina.

2. The Molybdenum/Technetium 99-m generator according to claim 1, wherein the alumina is selected from the group consisting of a gamma-phase aluminum oxide (γ-Al.sub.2O.sub.3), a chi-phase aluminum oxide (χ-Al.sub.2O.sub.3), and a combination thereof.

3. The Molybdenum/Technetium 99-m generator according to claim 1, wherein the guard filter further comprises a material selected from the group consisting of MSU-X mesoporous alumina, Polymeric Titania Compound (PTC), Polymer Embedded Nanocrystalline Titania, Polymeric Zirconia Compound (PZC), Tetragonal Nano Zirconia, chitosan-based products, iron, activated carbon, and a combination thereof.

4. A Molybdenum/Technetium 99-m generator comprising: a metal-molybdate containing powder; and a gamma-phase aluminum oxide (γ-Al.sub.2O.sub.3).

5. The Molybdenum/Technetium 99-m generator according to claim 4, wherein the Molybdenum/Technetium 99-m generator comprises a column.

6. The Molybdenum/Technetium 99-m generator according to claim 5, wherein the column comprises a Mo powder bed containing the metal-molybdate containing powder.

7. The Molybdenum/Technetium 99-m generator according to claim 5, wherein the column comprises a guard filter bed containing the gamma-phase aluminum oxide (γ-Al.sub.2O.sub.3).

8. The Molybdenum/Technetium 99-m generator according to claim 7, wherein the guard filter bed further comprises a material selected from the group consisting of MSU-X mesoporous alumina, Polymeric Titania Compound (PTC), Polymer Embedded Nanocrystalline Titania, Polymeric Zirconia Compound (PZC), Tetragonal Nano Zirconia, chitosan-based products, iron, activated carbon, and a combination thereof.

9. The Molybdenum/Technetium 99-m generator according to claim 7, wherein the guard filter bed has a bed height (Length) and a column inner diameter (D) in a ratio of L/D in a range of 0.25 to 10.

10. The Molybdenum/Technetium 99-m generator according to claim 4, wherein a mass ratio of the gamma-phase aluminum oxide to the metal-molybdate powder (Al:P) is in a range of 0.025:1 to 5:1.

11. A Molybdenum/Technetium 99-m generator comprising: a metal-molybdate containing powder; and a chi-phase aluminum oxide (χ-Al.sub.2O.sub.3).

12. The Molybdenum/Technetium 99-m generator according to claim 11, wherein the Molybdenum/Technetium 99-m generator comprises a column.

13. The Molybdenum/Technetium 99-m generator according to claim 12, wherein the column comprises a Mo powder bed containing the metal-molybdate containing powder.

14. The Molybdenum/Technetium 99-m generator according to claim 12, wherein the column comprises a guard filter bed containing the chi-phase aluminum oxide (χ-Al.sub.2O.sub.3).

15. The Molybdenum/Technetium 99-m generator according to claim 14, wherein the guard filter bed further comprises a material selected from the group consisting of MSU-X mesoporous alumina, Polymeric Titania Compound (PTC), Polymer Embedded Nanocrystalline Titania, Polymeric Zirconia Compound (PZC), Tetragonal Nano Zirconia, chitosan-based products, iron, activated carbon, and a combination thereof.

16. The Molybdenum/Technetium 99-m generator according to claim 14, wherein the guard filter bed has a bed height (Length) and a column inner diameter (D) in a ratio of L/D in a range of 0.25 to 10.

17. The Molybdenum/Technetium 99-m generator according to claim 11, wherein a mass ratio of the chi-phase aluminum oxide to the metal-molybdate powder (Al:P) is in a range of 0.025:1 to 5:1.

18. A method of using, the method comprising: introducing a guard filter comprising an alumina selected from the group consisting of γ-Al.sub.2O.sub.3, χ-Al.sub.2O.sub.3, and a combination thereof into a Molybdenum/Technetium 99-m generator, the Molybdenum/Technetium 99-m generator comprising a metal-molybdate (Mo) containing powder.

19. The method of using according to claim 18, wherein the guard filter further comprises a material selected from the group consisting of MSU-X mesoporous alumina, Polymeric Titania Compound (PTC), Polymer Embedded Nanocrystalline Titania, Polymeric Zirconia Compound (PZC), Tetragonal Nano Zirconia, chitosan-based products, iron, activated carbon, and a combination thereof.

20. The method of using according to claim 18, wherein the guard filter has a pH in a range of 3.5 to 7.5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will become more fully understood from the detailed description and the accompanying drawings, which are not necessarily to scale, wherein:

[0020] FIG. 1 illustrates a prior art conventional Mo/Tc-99m generator.

[0021] FIG. 2 illustrates the morphology of Brockmann I alumina (α-Al.sub.2O.sub.3).

[0022] FIG. 3 illustrates a Mo/Tc-99m generator in accordance with an aspect of the present invention.

[0023] FIG. 4 illustrates the morphology of a gamma alumina (γ-Al.sub.2O.sub.3) that may be used in accordance with the present invention.

[0024] FIG. 5 illustrates the morphology of a chi-phase aluminum oxide (χ-Al.sub.2O.sub.3) that may be used in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. As used in the specification, and in the appended claims, the singular forms “a”, “an”, “the”, include plural referents unless the context clearly dictates otherwise.

[0026] The term “metal-molybdate” (also referred to herein as metal-Mo), as used herein, generally refers to either a metal-molybdate, metal-molybdenum, molybdenum-metalate, or any form of Mo-metal or metal-Mo species.

[0027] FIG. 3 illustrates a Mo/Tc-99m generator 100 in accordance with an embodiment of the present invention. As shown in FIG. 3, Mo/Tc-99m generator 100 has one or more columns 110, the one or more columns 110 having a Mo powder-containing bed 120 having a length-to-diameter (L.sub.Mo/D.sub.Mo) ratio, an optional boundary layer 130 to prevent particle migration, and a guard filter material-containing bed (γ-Al.sub.2O.sub.3 or χ-Al.sub.2O.sub.3 shown) 140 having a length-to-diameter (L/D) ratio. Using Mo/Tc-99m generator 100, TcO.sub.4− is eluted using 0.9% NaCl saline, for example. Boundary layer 130 is a separator used to control fine powder from migrating from one layer to the next. Boundary layer 130 may comprise alumina oxide, PVDF (polyvinylidene difluoride), PES (polyethersulfone), MCE (mixed cellulose ester), or glass microfibers.

[0028] In an embodiment of the present invention, a Mo/Tc-99m generator has a column with a guard filter material-containing bed height (Length) and a column inner diameter (D). Preferably, the length-to-diameter (LID) ratio is in a range of 0.25 to 10 to exhibit a desirable filtering performance in terms of molybdenum (Mo) breakthrough. Filtering is important because it blocks the draw of Mo into solution that is tagged to a pharmaceutical drug injected into the human body. If unmitigated, Mo could expose patients to potentially high and unnecessary doses of radiation.

[0029] In an embodiment of the present invention, a Mo/Tc-99m generator comprises a metal-molybdate powder and an alumina as a guard filter. Elutions pass through a bed of the metal-molybdate powder and elute both Mo and Tc. The Mo is selectively purified using the alumina as the guard or prevention filter to reduce Mo breakthrough.

[0030] The guard filter is an alumina, preferably, gamma-phase alumina (γ-Al.sub.2O.sub.3), chi-phase alumina (χ-Al.sub.2O.sub.3), or a combination thereof. Alpha-phase alumina (α-Al.sub.2O.sub.3) can be used in combination with γ-Al.sub.2O.sub.3 and/or χ-Al.sub.2O.sub.3. Alternatively, other guard filter materials that do not appreciably sorb the desired TcO.sub.4− but sorb the unwanted Mo species and other undesired impurities may be used in combination with γ-Al.sub.2O.sub.3 and/or χ-Al.sub.2O.sub.3 and are selected from the group consisting of, MSU-X mesoporous alumina, Polymeric Titania Compound (PTC), Polymer Embedded Nanocrystalline Titania, Polymeric Zirconia Compound (PZC), Tetragonal Nano Zirconia, chitosan-based products, iron, and activated carbon.

[0031] An advantage of using γ-Al.sub.2O.sub.3 or χ-Al.sub.2O.sub.3 is the reduction in major impurities. Although elution time with γ-Al.sub.2O.sub.3 or χ-Al.sub.2O.sub.3 may vary, elution time should be as low as reasonably achievable. Elution time is expected to be less than 10 minutes, preferably less than 5 minutes. FIG. 4 illustrates the morphology of a gamma-phase alumina (γ-Al.sub.2O.sub.3) that may be used in accordance with the present invention. FIG. 5 illustrates the morphology of a chi-phase aluminum oxide (χ-Al.sub.2O.sub.3) that may be used in accordance with the present invention.

[0032] In an embodiment of the invention, a mass ratio of gamma-phase alumina to metal-molybdate powder (Al:P) in a range of 0.025:1 (Al:P) to 5:1 (Al:P) may be used to efficiently filter Mo from the metal-molybdate containing powder in a generator.

[0033] In an embodiment of the invention, a mass ratio of chi-phase alumina to metal-molybdate powder (Al:P) in a range of 0.025:1 (Al:P) to 5:1 (Al:P) may be used to filter Mo from the metal-molybdate containing powder in a generator.

[0034] In an embodiment of the present invention, the release of Tc-99m meets the United States Pharmacopeia (USP) monograph standards for “Sodium Pertechnetate Tc-99m Injection.” In an embodiment of the present invention, there is an efficient release of Tc-99m and thereby meeting the USP specification for radiopurity in which the ratio of Mo to Tc-99m must be less than (<) 0.15 μCi/mCi.

Comparative Example

[0035]

TABLE-US-00001 TABLE 1 Alumina Al:P Ratio Tc-99m Yield (%) Brockmann I series, acid 1A1:1P 16 activated α-Al.sub.2O.sub.3 Brockmann I series, acid 0.5Al:1P Ratio 35 activated α-Al.sub.2O.sub.3 γ-Al.sub.2O.sub.3 0.1Al:1P Ratio 89 χ-Al.sub.2O.sub.3 0.1Al:1P Ratio 89

[0036] The data in Table 1 suggested that the Brockmann I sorbent is too inefficient with the highest Tc-99m yield at only 35%. The γ-Al.sub.2O.sub.3 and the χ-Al.sub.2O.sub.3, however, yielded 89% Tc-99m. Moreover, the γ-Al.sub.2O.sub.3 and the χ-Al.sub.2O.sub.3 achieved the highest yield with a ratio of Al.sub.2O.sub.3 to Powder of 0.1:1. The γ-Al.sub.2O.sub.3 and the χ-Al.sub.2O.sub.3 performed better using far less material than the Brockmann I sorbent. Thus, it was concluded that traditional alumina will have poor elution efficiency when using the powder bed.

Example

[0037] The following test was conducted. Chromatography columns having the guard filters listed in Table 2 were eluted, and a L/D of each guard filter was measured. Measurements are shown in Table 2.

TABLE-US-00002 TABLE 2 Bed Height Inner Diameter Column (mm) (mm) L/D γ-Al.sub.2O.sub.3 53.36 19.9 2.68 (literature) γ-Al.sub.2O.sub.3 45.28 19.9 2.27 χ-Al.sub.2O.sub.3 36.07 19.9 1.81

[0038] It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements.