Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
  • G21G1/00—Arrangements for converting chemical elements by electromagnetic radiation, corpuscular radiation or particle bombardment, e.g. producing radioactive isotopes
  • G21G1/0005—Isotope delivery systems
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
  • G21G4/00—Radioactive sources
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
  • G21G4/00—Radioactive sources
  • G21G4/04—Radioactive sources other than neutron sources
  • G21G4/06—Radioactive sources other than neutron sources characterised by constructional features
  • G21G4/08—Radioactive sources other than neutron sources characterised by constructional features specially adapted for medical application

Definitions

• the invention relates to a method and apparatus for isolating a 68 Ga radionuclide from a 68 Ge / Ga generator eluate and for labeling a label precursor with the ⁇ 8 Ga radionuclide to form a radiopharmaceutical.
• PET positron emission tomography
• known radionuclide generators are used, the daughter radionuclides obtained generally having short half-lives Ty 2 in comparison with their parent radionuclides.
• Such radionuclide generators are based on a concept of effective radiochemical separation of decaying parent and daughter radionuclides in such a way that the daughter nuclide is to be obtained in radionuclide and radiochemically as pure form as possible.
• radionuclide generators Compared to in-house radionuclide production facilities such as accelerators or nuclear reactors, the availability of short-lived radionuclides from radionuclide generators offers a cheap and easy alternative.
• radionuclide generators over the last three decades has always been shaped by the growing spectrum of applications of radionuclides and labeled agents in medicine, particularly for nuclear medicine diagnostics and therapy.
• promising applications of generator-based therapeutic radionuclides in nuclear medicine, oncology and cardiology have been developed in recent years. This growing importance of radionuclide generators has stimulated a broad development of radionuclide production for radionuclide generators, for adequate radiochemical separations as well as for reliable engineering design of radionuclide generator systems.
• the potential of the daughter's technetium for medical uses soon became apparent, and indeed the first clinical applications were described in 1961, which have since revolutionized radiopharmaceutical chemistry and nuclear medicine.
• Radionuclide generator developments have often been systematized. Detailed reports have covered several aspects: parent-daughter half-lives, reactor-produced nuclides, accelerator-produced nuclides, cyclotron production of generator mother nuclides, ultra-short-lived generator-produced radionuclides, generator-based positron-emitting radionuclides, clinical applications.
• the initial generator systems separated 68 Ga as an EDTA complex of 68 Ge adsorbed on alummia or zirconia, with the resultant neutral [ 68 Ga] EDT A solution serving as a Tissue tumor.
• 68 Ge was retained on antimony oxide Sb 2 O 5 and 68 Ga was determined with oxalate solutions.
• Anion exchange resins and dilute HF solutions as eluent allowed highly effective separations due to the significant edges differences in the distribution coefficients of the elements.
• the breakthrough at 68 Ge was less than 10 "4 percent up to 600 elutions, the 68 Ga yield was greater than 90%.
• 68 Ge / 68 Ga generators were developed leading to ionic 68 Ga 3+ eluates.
• 68 Ge was fixed on inorganic matrices such as alumina Al (OH) 3 and Fe (OH) 3 , on SnO 2 , ZrO 2 , TiO 2 or CeO 2 .
• Ziim (IV) oxide SnO 2 showed the best parameters for 68 Ge breakthrough (10 "6 -10 " 5 % by bolus) and 68 Ga 3+ elution yield (70-80%) in 1 M HCl.
• the 68 Ge content defines the radiochemical purity of the separated 68 Ga fraction. Even an initial contamination of about 10 "2 %, corresponding to, for example, 1 ⁇ Ci 68 Ge in a 68 Ga fraction of a 10 mCi 68 Ge / Ga generator system, already appears marginal with regard to a subsequent medical application.
• 68 Ga eluate volume and chemical purity are further important data for the use of 68 Ga for the synthesis of radiopharmaceuticals.
• the generator eluate may contain chemical and radiochemical contaminants that prevent efficient high yielding radiochemical labeling yields.
• chemical contaminants can be from: the generator column material (eg, TiO 2 ); trivalent Fe, which is ubiquitous in trace amounts and can be introduced in particular with various electrolytes during generator production or use;
• 68 Zn as a stable metallic contaminant that is systemically inherently generated as a decay product of 8 Ga on the generator column; 68 Ge as a mother-Radionuldid, even small contaminations of less than 0.01% of the 68 Ge in the eluate represent a similar number of atoms as the 68 Ga itself, - and which can be radiotoxic and chemically toxic.
• this contamination is also radiochemically relevant, in particular with regard to potential medical applications.
• the post-elution procedure should therefore explicitly include a chemical strategy for further separation of the 68 Ge.
• the 68 Ga-labeling of potential radiopharmaceuticals plays a central role, for which the corresponding chemical reaction parameters must be optimized.
• the trivalent gallium already hydrolyzes above pH> 2 and has a pronounced tendency to adsorb on surfaces of glass and polymers at pH> 3, in particular in the state of low 68 Ga concentrations (no-carrier-added), as they result from the generator system results.
• special reaction conditions have to be chosen because of the complexing kinetics as well as because of the aqua-chemistry of the Ga (III) cation.
• the object of the invention is to provide a method and a Vorrichtimg to provide the high purity 68 Ga eluate, which is largely free of chemical and radiochemical impurities, with high yield and very low Eluatvolumen available.
• Marking of marker precursors can be optimized. Furthermore, a method for
• This object is achieved according to the invention by a process in which initial ⁇ 8 Ge / Ga generator eluate is fed directly to a cation exchanger and 68 Ga is quantitatively adsorbed on the cation exchanger, simultaneously chemically and radiochemically purified and the 68 Ga radionuclide with a Marl ⁇ réellesvoiiäufer from a ligand or a peptide or protein covalently liganded with a ligand is combined to form a radiopharmaceutical.
• the cation exchanger from the group of strongly acidic cation exchanger polystyrene / divinylbenzene (DVB) resins is selected with a DVB content of 2 to 20%, based on the crosslinked polymers of the resins, and becomes the matrix of the cation exchanger with 68 Ga loaded.
• the sulfonated polystyrene / divinylbenzene (DVB) resins have a gel-like structure and permanently have negatively charged sulfonic acid groups. Each of these active groups has a fixed electrical charge and is in equilibrium with a number of equivalent oppositely charged ions which are free to exchange with other ions of the same charge.
• the 68 Ga fraction adsorbed on the cation exchanger is further purified with acid solutions of the HCl / acetone or HCl / ethanol type or analogous systems in such a way that chemical impurities such as Fe (III) and Zn (II) are eluted from the cation exchanger become.
• chemical impurities such as Fe (III) and Zn (II) are eluted from the cation exchanger become.
• the chemically and radiochemically pure 68 Ga radionuclide obtained by the elution can be used directly for the synthesis of radiopharmaceuticals.
• the device for isolating a chemically and radiochemically purified 68 Ga radionuclide from a 68 Ge / Ga generator eluate and for marking a marking precursor with the 68 Ga radionuclide comprises in an embodiment of the invention one via a line with a 68 Ge / Ga generator connected conveyor, a number of feeders for purifying the 68 Ga fraction adsorbed on a cation exchanger, a synthesis Device in which a line leads from the exit of the cation exchanger, and in which the 68 Ga radionuclide and the labeling precursor are converted into a radiopharmaceutical, and for cleaning the radiopharmaceutical a cartridge to the input conveyors are connected via lines and their output via a 3-way valve is connected to a line leading out of the synthesis device, a storage vessel and a product vessel for receiving the radiopharmaceutical.
• the apparatus and its operation is to isolate a Ga fraction from a Ge / Ga generator, purify and reduce volume to obtain the 68 Ga radionuclide, and label precursors with the purified 6S Ga radionuclide described. Show it:
• Fig. 1 shows schematically the device according to the invention
• Fig. 2 shows the flow chart of the operation of the device.
• the device according to FIG. 1 comprises a Ge / Ga generator 1 to which a delivery device 2, for example in the form of a piston, a syringe or a peristaltic pump (peristaltic pump), is connected upstream via a line.
• a delivery device 2 for example in the form of a piston, a syringe or a peristaltic pump (peristaltic pump)
• the baineinrichtimg 2 is connected in a manner not shown with a liquid-filled storage or reservoir, if it is a Schlauchradpumpe. In the case of a piston or a syringe these are filled directly with a liquid.
• the output of the generator 1 is connected via a first 3-way valve 12 with the cation exchanger 14 on the input side.
• conveyors 3, 4, 5, 6, 7 are connected via lines to the 3-way valve 12.
• the zra conveyor 2 made statements also apply.
• a returnable valve can also be used. It is also possible to install in the individual lines control valves, open-close valves or taps that open the single line differently wide if necessary or fully open or completely shut off.
• 68 Ge / Ga radionuclide generators it is preferred, in a manner not shown, several 68 Ge / Ga radionuclide generators simultaneously or sequentially eluted and the common initial eluates transferred to the cation exchanger 14.
• the 68 Ge / Ga generators can still be operated or used even if their initial Ga eluate already contains an unduly high amount of 68 Ge. This significantly extends the useful life of a 68 Ge / Ga generator, especially for generators with 50 or more mCi 68 Ge.
• the cation exchanger 14 is connected on the output side to a second 3-way valve 15.
• a line 25 leads from the 3-way valve 15 to a waste container 19, a further line 23 leads from the 3-way valve 15 into a marking vessel 21, which is arranged in a synthesis device 20 of the device.
• the heatable synthesis device 20 is equipped with a heater 22 and is seated on a vertically movable table 27. By lowering the table 27 access to the marking vessel 21 is facilitated.
• the components of the device described so far are used to isolate the 68 Ga eluate, its volume reduction and purification.
• a stable plate can accommodate the synthesis device 20, as well as a laterally movable on rails or rollers slide.
• a line 24 leads from the marking vessel 21 to a third 3-way valve 13.
• Directional valve 13 is connected on the input side to a cartridge 11. From the 3-way valve 13 further leads a line 25 to a storage vessel 18 for the cleaned marking agent. Another line 26 connects the storage vessel 18 with the product vessel 17. In this line 26, a filter 16 is arranged before entering the product vessel 17. In the product vessel 17, the radiopharmaceutical is provided for administration and may be withdrawn therefrom at any time.
• the unit of filter 16, product vessel 17, line 26 is used for sterile filtration, which is an independent process step that can be carried out in isolation. If necessary, therefore, the unit 16, 17 decoupled from the overall device and operated independently.
• the cation exchanger is a strongly acidic cation exchanger from the group polystyrene / divinylbenzene (DVB) resins with a DVB content of 2 to 20%, based on the crosslinked polymers of the resins.
• the sulfonated polystyrene / divinylbenzene (DVB) resins have a gel-like structure and permanently have negatively charged sulfonic acid groups. Each of these active groups has a fixed electrical charge and is in equilibrium with a number of equivalent oppositely charged ions which are free to exchange with other ions of the same charge.
• an acidic solution of HCl / acetone or HCl / ethanol or analogous systems is pressed into the cation exchanger 14 via the first 3-way valve 12 by the delivery devices 3, and Fe (III) and Zn (II) are flushed out and flushed via the open Nete second 3-way valve 15 passed into the waste container 19.
• the conveyor 4 is forced air through the lines to rinse them and remove any residues of Fe (III) and Zn (II).
• the solution 5 which is filled with a second acidic solution of HCl / acetone or HCl / ethanol or analogous systems, this solution is supplied through the 3-way valve 12 to the cation exchanger 14 and by this acidic solution 68 Ga eluted from the cation exchanger and introduced via the 3-way valve 15 and line 23 into the marking vessel 21.
• the remaining residues of Ti (IV) on the cation exchanger 14 are at first rinsed with HCl from the conveyors 6 at the appropriate time and discharged into the waste container 19; Subsequently, the cation exchanger is washed analogously with water from the conveying devices 7, whereby the cation exchanger is finally ready for a new procedure.
• the labeling vessel can either be empty and then used to fill balloons with the now minimized 68 Ga volume or for the synthesis of radiopharmaceuticals.
• the last case is described below:
• the marking precursor with the purified 68 Ga Radion ⁇ did to the radiopharmaceutical is marked.
• This precursor orders from a ligand or peptide or protein covalently linked to a ligand, or another component wherein the Ga radionuclide is chemically bound by the ligand.
• the ligand is selected, inter alia, from the group of linear or cyclic Plyaminopolycarboiiklaren (DTP A, EDTA or DOTA, etc.) or other, also phosphorus and sulfur donor atoms containing Ligandstrulcturen, the peptide from the group octreotide, bombesin, gastrin and vam, wherein the respectively selected Peptide have a high affinity to tumor cells or Tiunorzellmembran-receptive receptors as well as to receptors on other organs.
• modified proteins in the form of antibodies can be used for binding to tumor antigens.
• the optimum temperature is equal / higher than 95 ° C.
• the pH of the labeling precursor in the labeling vessel 21 is in the range 2 to 5 Flu "the radiopharmaceutical 68 Ga-DOTATOC, a preferred pH value, for example 2.3.
• the pH is, by the volume of water and labeling precursor It is also possible to adjust the pH with the aid of a buffer solution or, for example, HEPES, which results in a modified optimum pH value can result.
• the amount of the label precursor of a ligand or ligand covalently linked to a peptide or protein, such as DOTATOC, in the labeling vessel 21 is about 1 to 100 nmol, preferably 7 to 14 nmol, plus an appropriate volume of water or buffer or HEPES or analogous systems to adjust the pH.
• the liquid containing beneficiatiu ⁇ g 8 is operated with open 3-way valve 13 so that via line 24 from the marker vessel 21, the radiopharmaceutical applied to the cartridge 11 and is fixed. Thereafter, the 3-way valve 13 closes the line 24 and opens the line 25, which leads into the storage vessel 18 - or optionally in another, not shown storage vessel.
• the cartridge 11 is washed with pure water or analogous solvents which elute free 68 Ga or other non-labeled 68 Ga species, and removed in a manner not shown, for example, back into the now no longer required marking vessel 21.
• the conveyor 10 which contains less than 0.5 ml of ethanol or analogous solvents, the elution of the radiopharmaceutical, for example, 68 Ga-DOTATOC from the cartridge 11 and its introduction into the storage vessel 18, which contains an isotonic saline solution ,
• the specified fraction can also be determined in an empty storage vessel 18, which in principle allows the removal of the ethanol or analogous solvent.
• the 3-way valve 13 closes the line 25 and by means of a device, not shown, the radiopharmaceutical is drawn through the conduit 26 from the storage vessel 18 and introduced via a filter 16 into the product vessel 17.
• a filter 16 is a sterile filtering, so that thereafter the radiopharmaceutical is ready for use.
• the binding of the 68 Ga to the labeling precursor is more than 75%, based on the decay-corrected activity of the initial 68 Ge / Ga generator eluate.
• the reactivity of the label precursor at 10 mCi of the 68 Ge / Ga generator eluate is up to 80%, 90%, and my- as 95% after one, five, and ten minutes.
• the duration of the procedure from application of the initial generator eluate to the provision of the radiopharmaceutical is about 20 minutes.
• the conveyors 2 to 10 and the lines connected to them can be subjected to negative pressure in order to transport the solutions through the lines.
• the octapeptide octreotide has a high affinity for the sstr2 subtype of human somatostatin receptor-expressing tumors, and the conjugated macrocyclic bifunctional chelator DOTA coordinately binds the trivalent 68 Ga 3+ with high thermodynamic and kinetic stability also in vivo.
• this type of 68 Ga-labeled compounds allows excellent visualization of tumors and small metastases.
• This 68 Ga tumor targeting approach may potentially be extended to a variety of other tumors, using other peptides.
• 68 Ga also finds applications in myocardial perfusion diagnostics in the form of the [ 68 Ga] BAT-TECH complex as a perfusion tracer. This shows that, in principle, any type of 68 Ga labeling via ligand structures can be used for nuclear medical diagnostics altogether or will be in the future.
• the "kit” -like synthesis also offers a further advantage as the Nutzimg of PET depending on an in-house direct production of established positron emitters such as' 8 F.
• the device is also suitable for concentrating and purifying radiogallium solutions. It is also suitable for purifying, reducing the volume of gallium radioisotopes and marking mark precursors with the 66 Ga or 67 Ga radioisotope.
• the device is equally well suited for labeling ligands or ligand-covalently linked peptide or protein with radionuclides other than 68 Ga.
• radionuclides other than 68 Ga.
• An example of this is 90 Y, where the eluate has to be purified from other metals.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
• Peptides Or Proteins (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Cephalosporin Compounds (AREA)

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