RU2602502C2 - Method of producing radiopharmaceuticals of poly-n-vinylamides class with metals of manganese group - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing radiopharmaceuticals class poly-N-vinylamides with metals of manganese subgroup. Method involves synthesis of a radioisotopes-carrier polymer containing amino groups and performing radio-labelling. Polymer-carrier used is a water-soluble copolymer of N-vinylpyrrolidone with vinyl/allylamine with the molecular weight of 3,000-60,000 Da, the content of N-vinylpyrrolidone of m=20-70 mol% and vinyl/allylamine of n=80-30 mol%, the content of primary amino groups of 5-25 mol%. Radioisotope used are compounds of transition metals in the form of permetallates (MO₄ ^-): ^99mTcO₄ ^- or ^{186, 188}ReO₄ ^-. Herewith the reaction of the copolymer-carrier with the radioisotope is performed by direct incorporation in water or an aqueous-alcoholic solution in an inert gas atmosphere at the temperature of 30-97 °C, pH 1÷5.5 and the concentration of the copolymer-carrier in the solution of 5-20 wt% for 0.1-1.0 hours to produce a metal-polymer conjugate of the following general formula:

, where m, n are the numbers of repeating links of N-vinylpyrrolidone and vinyl/allylamine respectively x=0, 1, M=^99mTc, ^{186, 188}Re.

EFFECT: invention enables to obtain hybrid water-soluble macromolecular carriers of radioisotopes used for organism neoplasm diagnostics by single-photon emission tomography methods.

1 cl, 5 ex

Description

The proposal relates to the field of chemistry of macromolecular compounds and nuclear medicine and relates to the field of the creation of carrier polymers for the targeted transport of radioactive isotopes (radiotracers, radiopharmaceuticals (RFP)) with the aim of diagnosing neoplasms of the body using single photon emission tomography (SPECT) with registration of single photon beta radiation from Τ _1/2 = 60 min and an energy of Εγ 142.7 kVE (radionuclide technetium-99m) and therapy of neoplasms of the body (radionuclide rhenium-188, T _1/2 = 17.00 h, E _β = 1965.4 kVE).

The radioactive isotopes of technetium-99m and rhenium-188 are currently widely accepted in clinical practice for the diagnosis and treatment of skeletal neoplasms, tumor development mechanisms of various etymologies, as well as inflammatory diseases. Currently known methods of introducing isotopes of these metals in the composition of low molecular weight carriers of radioactive isotopes of metals [US 20050169838, 2005; US 5102990, 1992]. As carriers for radioactive metal isotopes, peptides, steroids, receptor ligands, fatty acids, antibodies, etc. are used [US 7179444 B2, 2009; EP 1,797,904 B1, 2010; EP 1051980 A2, 1999].

Currently, in medical practice, more than 80% of studies performed by the SPECT method account for technetium-99m radionuclide ( ^99m Tc) due to its availability (commercial generators), optimal emissive characteristics and a sufficiently long half-life (T _1/2 6 h ., Εγ 142.7 kev) [M. Welch, M. Redwanly Handbook of Radiopharmaceuticals, 2003].

A significant drawback of introducing heavy metals into the composition of small molecules (for example, short peptides) is the inevitable violation of the natural transport properties of small molecules. Successful, but irregular examples are accepted in the global clinical practice radiopharmaceuticals, such as, for example, In-111 Octreoscan [US 5753627 and 5776894, 1998] and Ga-68 DOTATOC [EP 2663571 A1, 2013].

A reasonable alternative to short peptides are macromolecules with a high molecular weight (proteins, antibodies), since the introduction of a heavy metal does not significantly affect the properties of the resulting conjugate, for example Y-90 (In-111) Zevalin® (ibritumomab tiuxetan) [US 5736137, 1998; US 5776456, 1998; US 5843439, 1998; US 6207858, 1999; US 6399061, 2002; US 6682734, 2004; US 6994840, 2006; US 7229620, 2007; US 7381560, 2008; US 7422739, 2008].

One of the significant drawbacks of the given analogues is the introduction of a bulky multidentate bifunctional chelate unit for binding a radioactive metal, which can also lead to a violation of the native properties of a biologically active radioactive metal transporter molecule.

Unmodified polymer structures such as cyclopeptides [US 7666392, 2010], macrocyclic conjugates [US 20110293517, 2009], linear polyethylene oxides [US 5583206, 1996], grafted dextrans [Mol. Pharmaceutics, 2011, 8 (2), pp 609-620], synthetic biologically active polymers [US 6352682, 2002; US20080064841, 2007; US 7951846, 2011], of which the closest is the method of US 7951846.

Significant disadvantages of the prototype are: a complex procedure for the isolation, purification and identification of biologically active carrier molecules of a radioactive isotope; uncontrolled administration of chelating sites for metal binding due to the presence of a large number of free active functional amino and carboxyl groups; extremely high cost of end radiopharmaceuticals.

, $${}^{\text{188}}{\text{ReO}}_{\text{4}}^{\text{-}}$$

).The technical task and the positive result of the proposed method is to obtain water-soluble polymer complexes labeled with radioactive isotopes of technetium-99m and rhenium-188, for the treatment and diagnosis of neoplasms of the body using synthetic water-soluble polycations - copolymers of N-vinylamides (N-vinylpyrrolidone ( VP)) and N-vinylamine (VA), N-allylamine (AA) containing free protonated amino groups capable of forming stable van der Waals bonds with perme late ions ( $${}^{\text{99m}}{\text{Tco}}_{\text{four}}^{\text{-}}$$

, $${}^{\text{188}}{\text{Reo}}_{\text{four}}^{\text{-}}$$

)

Similar metal-polymer complexes with chitosans are known that are stable in a wide pH range, as well as in the presence of various competitive complexing agents [Stumm W, Morgan JJ., Aquatic chemistry. New York: Wiley; 1996. p. 516, Park JW, Park MO, Park KK ,. Bull Korean Chem Soc 1984; Vol. 5, No 3, p. 108-112].

Carrier copolymers are characterized in that they use complex copolymers based on the class of N-vinylamides containing protonated amino groups (1-20 mol.%) With a molecular weight (5-100 kDa).

The obtained polymer metal complexes are also distinguished by the fact that, unlike most radiopharmaceuticals based on the technetium-99m rhenium-188 radionuclides, they do not require restoration of the initial permetallates to a low-valence state (+ 5- + 1).

The method is characterized in that the interaction of the carrier polymer with a radioactive component with a polymer concentration of 1-20% of the mass. carried out in an aqueous solution of a carrier polymer with a low pH value (1-2) with a specific activity of permetallate ion of 1-4 GBq / ml of generator eluate.

As a result of radiochemical synthesis, biologically active copolymer structures are produced, labeled with radioactive isotopes of metals, with various hydrodynamic characteristics, depending on the number of active amino groups and the molecular weight of the copolymer.

или $${}^{188}\mathrm{Re}{O}_4^{-}{/}^{186}\mathrm{Re}{O}_4^{-}$$

, при этом взаимодействие сополимера-носителя с радиоизотопом проводят прямой инкорпорацией в воде иди водно-спиртовом растворе в атмосфере инертного газа при температуре 30-97°C, pH 1÷5.5 и концентрации сополимера-носителя в растворе 5-20 масс. % в течение 0,1-1,0 часа с получением металл-полимерного конъюгата следующей общей формулы:The stated technical problem is solved by the described method for producing radiopharmaceuticals of the class poly-N-vinylamides with metals of the manganese group, including the synthesis of a polymer carrier of radioisotopes containing amino groups and the performance of the radiolabeling process, while a water-soluble copolymer of N-vinylpyrrolidone with allylamine with molecular is used as a carrier polymer weighing 3000-60000 Yes, the content of N-vinylpyrrolidone m = 20-70 mol. % and allylamine n = 80-30 mol. %, the content of primary amino groups of 5-25 mol. %, and as a radioisotope using compounds of transition metals in the form of permetallates: $${}^{\text{99m}}{\text{Tco}}_{\text{four}}^{\text{-}}$$

or $${}^{188}\mathrm{Re}{O}_{\mathrm{four}}^{-}{/}^{186}\mathrm{Re}{O}_{\mathrm{four}}^{-}$$

wherein the interaction of the carrier copolymer with the radioisotope is carried out by direct incorporation in water of an aqueous-alcoholic solution in an inert gas atmosphere at a temperature of 30-97 ° C, pH 1 ÷ 5.5 and the concentration of the carrier copolymer in the solution of 5-20 mass. % for 0.1-1.0 hours to obtain a metal-polymer conjugate of the following general formula:

,

,

where m, n is the number of repeating units of N-vinylpyrroldone and allylamine, respectively

In the proposed method, a carrier copolymer is obtained, which includes, at the first stage, the copolymerization of VP and VFA / AA, and at the second stage, the binding of free amino groups of the flexible chain random copolymer with the generation of technetium-99m and rhenium-188 radionuclides in acidic media with the subsequent neutralization of the target drug to pH values close to physiological (pH 6.0-7.5), stable for 24 hours, at least.

, в зависимости от pH, концентрации полимера и времени реакции, и не требует дополнительной очистки конечного продукта, что является существенным преимуществом по отношению к существующим аналогам.It should be noted that, in contrast to the above analogues, the radiochemical synthesis of the target polymer preparation by the proposed method allows to achieve 90-95% of the yield of radiochemical synthesis by $${}^{\text{99m}}{\text{Tco}}_{\text{four}}^{\text{-}}{/}^{188}\mathrm{Re}{O}_{\mathrm{four}}^{-}$$

, depending on pH, polymer concentration and reaction time, and does not require additional purification of the final product, which is a significant advantage over existing analogues.

The essence of this method is disclosed below by examples of its experimental implementation.

Example 1. The synthesis of the polymer carrier (precursor) VP-VA.

The copolymerization was carried out in an argon atmosphere at 60 ° C in ethanol for 48 hours. The mass concentration of monomers was 50 mass. %, the concentration of the initiator AIBN (2, 2 - dinitrile azoisobutyric acid) - 1 mass. % of monomer content. The polymers were isolated by precipitation into diethyl ether and purified by dialysis on a membrane with an exclusion limit of 1000 Da (Spectra / Por 7, USA) with an aqueous 2% NaCl solution for 24 hours and water for 24 hours as well. Then, the copolymers were freeze-dried.

Example 2. Radiolabeling of the polymer carrier with radionuclides technetium-99m and rhenium-188 was carried out according to the optimized protocol.

Technetium-99m / rhenium-188 generator eluate (manufactured by ZAO Cyclotron, Obninsk, or FSUE NPO VG Khlopin Radium Institute) with a specific activity of 1-4 GBq / ml (0.3 ml) with a pH of 7.0 was added to an aqueous VP-AA solution (13 kDa) (C = 10 ^-2 M, 0.3 ml). The reaction mixture was heated for 30 min at 80 ° C. It was shown that the initial permetallate binds completely with the copolymer substrate. Rf of the metal-polymer complex is ≈0.6 with respect to permetallate (Rf≈1) in the eluting system of acetonitrile-0.1 M HCl (90:10). The yield of the radiochemical reaction was 90%.

Example 3. Generator eluate of technetium-99m / rhenium-188 (manufactured by ZAO Cyclotron, Obninsk, or FSUE NPO Radium Institute named after VG Khlopin) with a specific activity of 1-4 GBq / ml (0.3 ml) with pH 7.0 was poured into an aqueous solution of VP-VA (40 kDa) (C = 10 ^-2 M, 0.3 ml). The reaction mixture was heated for 50 min at 90 ° C. The reaction progress was monitored by TLC on Kieselgel 60 plates (Merck, Germany). It was shown that the initial permetallate binds completely with the copolymer substrate. The Rf of the metal-polymer complex was ≈0.6 with respect to permetallate (Rf≈1) in the eluting system of acetonitrile-0.1 M HCl (90:10). The yield of the radiochemical reaction was 95%.

Example 4. Generator eluate of technetium-99m / rhenium-188 (manufactured by ZAO Cyclotron, Obninsk or FSUE NPO Radium Institute named after VG Khlopin) with a specific activity of 1-4 GBq / ml (0.3 ml) with pH 7.0 was poured into an aqueous solution of VP-AA (40 kDa) (C = 10 ^-1 M, 0.3 ml). The reaction mixture was heated for 20 min at 70 ° C. The reaction progress was monitored by TLC on Kieselgel 60 plates (Merck, Germany). It was shown that the initial permetallate binds completely with the copolymer substrate. The Rf of the metal-polymer complex was ≈0.6 with respect to permetallate (Rf≈1) in the elution system acetonitrile-0.1 M HCl (80:20). The yield of the radiochemical reaction was 60%.

Example 5. Generator eluate of technetium-99m / rhenium-188 (manufactured by ZAO Cyclotron, Obninsk or FSUE NPO Radium Institute named after VG Khlopin) with a specific activity of 1-4 GBq / ml (0.3 ml) with pH 7.0 was poured into an aqueous solution of VP-VA (100 kDa) (C = 10 ^-1 M, 0.3 ml). The reaction mixture was heated for 20 min at 70 ° C. The reaction progress was monitored by TLC on Kieselgel 60 plates (Merck, Germany). It was shown that the initial permetallate binds completely with the copolymer substrate. The Rf of the metal – polymer complex was ≈0.6 with respect to permetallate (Rf≈1) in the elution system acetonitrile-0.1 M HCl (80:10). The yield of the radiochemical reaction was 85%.

Thus, the developed water-soluble polymer complexes of radioisotopes based on copolymers of N-vinylamides (N-vinylpyrrolidone (VP)), N-vinylamine (VA) and N-allylamine (AA) containing protonated amino groups, and the method for their preparation allows the creation of new macromolecular radio tracers that do not require the reduction of permetallates of the manganese subgroup to low-valence states. This indicates the compliance of this technical solution with all the required criteria of the invention protected by a patent.

Claims (1)

A method of producing radiopharmaceuticals of the class of poly-N-vinylamides with metals of a subgroup of manganese, comprising synthesizing a polymer carrier of radioisotopes containing amino groups and performing a radiolabeling process, characterized in that a water-soluble copolymer of N-vinylpyrrolidone with vinyl / allylamine with molecular is used as a carrier polymer weight of 3000-60000 Yes, the content of N-vinylpyrrolidone m = 20-70 mol.% and vinyl / allylamine n = 80-30 mol.%, the content of primary amino groups 5-25 mol.%, and transition compounds are used as a radioisotope Ferrous materials permetallatov form (MO ₄ ^{-): 99m} TcO ₄ ^- or ^{186, 188} ReO ₄ ^-, wherein the interaction of the carrier copolymer with direct incorporation of radioisotope is carried into the water go hydroalcoholic solution in an inert gas atmosphere at a temperature of 30-97 ° C, pH 1 ÷ 5.5 and the concentration of the copolymer carrier in a solution of 5-20 wt.% For 0.1-1.0 hours to obtain a metal-polymer conjugate of the following general formula:

, where m, n is the number of repeating units of N-vinylpyrrolidone and vinyl / allylamine, respectively, x = 0, 1, M = ^99m Tc, ^{186, 188} Re.