Organic compounds -- part of the class 532-570 series – Organic compounds – Radioactive metal containing
Patent
1990-09-07
1994-04-05
Stoll, Robert L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Radioactive metal containing
534 10, A61K 4902, A61K 4300
Patent
active
053002784
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The present invention relates to a process for the preparation of complexes of a transition metal chosen from among .sup.99m Tc, .sup.186 Re and .sup.188 Re usable as radiopharmaceutical products or for the synthesis of novel radiopharmaceutical products.
More specifically, it relates to the preparation of nitride complexes of a transition metal M chosen from among 99mTc, .sup.186 Re and .sup.188 Re having a portion M.tbd.N in which M represents 99mTc, .sup.186 Re or .sup.188 Re.
These radioactive transition metal complexes are usable as radiopharmaceutical products in diagnosis or therapy.
Technetium 99-m complexes are more particularly used for diagnosis, whereas rhenium 186 or 188 complexes are preferably used in therapy.
The radiopharmaceutical products using the radionuclide .sup.99m TC are compounds which are frequently used in nuclear medicine for diagnosis purposes due to the physical and chemical characteristics of said radionuclide.
Thus, the latter only gives a gamma emission, has an optimum gamma energy for the external detection (140 Kev) and has a short physical half-life (6.02 h), which only gives a low irradiation dose to the patient. In addition, the radionuclide is not expensive and is commercially available. Finally, the richness of the chemistry of technetium makes it possible to obtain a large variety of radiopharmaceutical products.
Thus, as indicated by E. DEUTSCH et al in Progr. Inorg. Chem. (Australia), vol. 30, pp. 76-106, 1983, technetium can form very varied complexes with numerous ligands in oxidation states ranging from VII to -I and coordination numbers from 4 to 9.
Among the numerous complexes of table I of pp. 79-83 of said document, are complexes of 99-Tc in oxidation state V in accordance with the formulas:
These complexes were prepared by Kaden et al according to the process described in Isotopenpraxis, 1981, 17(4), pp. 174/5, with a view to use as a catalyst in the complex reduction reaction of elementary nitrogen into ammonia discovered by Volpin and Shur. This process consists of reacting .sup.99 Tc pertechnetate with hydrazine hydrochloride and triphenyl phosphine.
For this preparation, use is made of 800 mg of NH.sub.4.sup.9 TcO.sub.4 -and a molar ratio of TcO.sub.4 --/NH.sub.2 NH.sub.2, 2HCl of 0.46, i.e. a Tc quantity well above that which can be used for the preparation of radiopharmaceutical products or where the quantities involved represent approximately 10 mCi of .sup.99m Tc, i.e. 8.10.sup.-6 mg of 99mTc.
Thus, the source of .sup.99m Tc is the .sup.99 Mo-.sup.99m Tc generator, which generally supplies an aqueous 0.154M NaCl solution either in the pure state or containing stabilizing agents, in which the pertechnetate ion (.sup.99m TcO.sub.4.sup.- +.sup.99m TcO.sub.4.sup.-) is present in total concentrations between 10.sup.-7 and 10.sup.-9 mole/l.
In addition, the preparation process described by Kaden et al, which corresponds to a macroscopic synthesis, cannot be extrapolated to the synthesis of nitride complexes of .sup.99m Tc on a microscopic scale, where the molar ratios between .sup.99m Tc and the reagents are necessarily very low. Moreover, the operating procedure described by Kaden et al, which requires a separation by distillation, is not suitable for the preparation of radiopharmaceutical products and is not practical in a hospital environment, i.e. where the radiopharmaceutical products have to be prepared at the time of their use.
In addition, a process for the preparation of radiopharmaceutical products based on technetium 99m complexes and having a portion (Tc.tbd.N).sup.2+ is known, which uses a completely different procedure. Thus, according to this process, which is described by J. Baldas et al in J. Chem. Soc. Dalton Trans. 1981, pp. 1798-1801, Int. J. Appl. Radiat. Ost. 36 1985, pp. 133-139 and in International Patent Application W085/03063, preparation firstly takes place of a compound of formula R.sup.+ [.sup.99m Tc.tbd.NX.sub.4 ], in which R.sup.+ is a cation such as sodium or ammonium and X represents a halogen atom such as C
REFERENCES:
patent: 4374821 (1983-02-01), Glavan et al.
patent: 4419339 (1983-12-01), Neirinckx
patent: 4897255 (1990-01-01), Fritzberg et al.
patent: 4917879 (1990-04-01), Deutsch et al.
patent: 5002754 (1991-03-01), Deutsch
Chemical Abstracts, vol. 95, No. 2, Jul. 13, 1981, (Columbus, Ohio, US), L. Kaden, et al.: "Nitrido complexes of technetium(V)", p. 716.
Chemical Abstracts, vol. 102, No. 24, Jun. 17, 1985 (Columbus, Ohio, US), U. Abram et al.: "Lipophilic technetium complexes. III. Chelate complexes of technetium-nitrido core", p. 694.
"Lipophilic Technetium Complexes", Abram et al., Inorganica Chimica Acta, 109 (1985) L9-L11.
"Lipophilic Technetiun Complexes", Abram et al., Journal of Radioanalytical & Nucl. Chem., Articles, vol. 102, No. 2, (1986), 309-320.
L. Kaden et al. "Nitrido Complexes of Technitium(V), Isotopenpraxis", 1981, 17(4), 174-5, CA: 95:17322r.
Bardy Andre
Duatti Adriano
Magon Luciano
Marchi Andrea
Pasqualini Roberto
Cis Bio International
Covert John M.
Stoll Robert L.
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