Nanostructures and their uses

Abstract

The present disclosure relates to a plurality of spherical nanostructures having a dispersity of 1 to 1.8 and a volume average hydrodynamic diameter of 13 nm to 90 nm, each nanostructure comprising a polymer backbone of monomeric residues, wherein the average number of bonds from each monomeric residue is within the range of 3.0 to less than 6.0, and at least 90% of the monomeric residues comprise two geminal chelating groups, each chelating group being independently selected from the group consisting of -PO(OR 1 )(OR 2 ) and R 1 and R 2 are independently selected from the group consisting of a negative charge and H, and "-" indicates an internal bond of a monomer residue. The present disclosure also relates to methods for making such nanostructures, uses of such nanostructures, as well as pharmaceutical compositions comprising such nanostructures.

Description

[Technical field]

[0001] The present disclosure relates to chelating polymer nanostructures that have use as intermediates in the manufacture of nanostructures that have use in total body radiation therapy and cancer imaging. [Background technology]

[0002] The gold standard of cancer treatment is surgery. When surgery alone is not curative, multimodality treatment plans including chemotherapy and radiation therapy are used. Currently, approximately half of all cancer patients are treated with radiation therapy, either alone or in combination with other treatments. Radiation delivered as an external beam offers a relatively simple and practical approach to cause radiation damage to tumors. Although the intensity, location, and timing of external radiation can be well controlled and adjusted, drawbacks associated with this technique include destruction of normal tissue in the path of the beam, as well as damage to tissue surrounding the tumor. The risk of damaging surrounding healthy tissues makes external radiation therapy inconvenient for tumors located deep within and adjacent to vital organs. Furthermore, high radiation doses are often required to penetrate the tissue. Moreover, external radiation therapy often requires patients to make daily visits to the hospital for extended periods of time to be effective.

[0003] Total body radiation therapy, in which radioactive material is delivered internally to the tumor, offers a solution to many of the above-mentioned disadvantages associated with external radiation therapy.

[0004] Currently, the radionuclides most commonly used for total body radiation therapy in the clinic are beta emitters. Beta particles with energies between 0.1 and 2.2 MeV can target tumor cells in close proximity to neovasculature due to their maximal tissue penetration range (1-10 mm) and their ability to indirectly kill cells along longer path lengths due to the cross-fire effect. 131Radionuclides such as I are used alone or conjugated to monoclonal antibodies or peptides to allow tumor-targeted radioimmunotherapy. The clinical use of alpha emitters is less common, but 223 Some, such as Ra, show clinical potential.

[0005] Recent advances in nanotechnology have led to the development of novel nanocarriers designed for cancer detection and screening, in vivo molecular and cellular imaging, and therapeutic drug delivery. However, despite the large number of publications on nanosized carriers for cancer therapeutics, relatively few have made it into clinical trials and only a handful have been approved by the FDA.

[0006] The rationale for the suitability of nanosized materials as tumor-targeting radiation carriers is related to the enhanced vascular permeability and retention (EPR) effect. The EPR effect is based on the fact that capillaries in healthy tissues are practically impermeable to molecules larger than 3-4 nm, while capillaries in rapidly growing tumor tissues are much leakier. In addition, solid tumors tend to lack functional lymphatic vessels. These features combine to limit the removal of extravasated nanomaterials from most solid tumors and lead to the accumulation of nanosized materials within the tumor. EPR-mediated drug targeting is commonly referred to as passive tumor targeting, since it relies exclusively on the pathological properties of the target tissue, i.e., increased leakiness and poor lymphatic drainage.

[0007] EP 2923712 A1 discloses nanostructures with a hydrodynamic diameter of 8-100 nm, which can be used for imaging and / or radiotherapy.

[0008] US Patent Application Publication No. 20140004048 describes nanoparticles that have been dendrimerized to enhance the solubility of the nanoparticles.

[0009] Many approaches to radioisotope therapy that involve purported nanocarriers suffer from the drawback that they are not actually nanocarriers because they are larger than 100 nm, and also suffer from the drawback that they do not effectively deliver the radioisotope to tumor tissue due to their large size. WO 2004 / 040972 is an example of a carrier that is larger than 100 nm. Summary of the Invention

[0010] According to a first aspect, the above and other objects are achieved in whole or at least in part by a composition as defined in claim 1. According to this claim, the above objects are achieved by a plurality of spherical nanostructures, the plurality of spherical nanostructures having a dispersity of 1 to 1.8, the nanostructures having a volume average hydrodynamic diameter of 13 nm to 90 nm, each nanostructure comprising a polymeric backbone of monomeric residues, the average number of bonds from each monomeric residue being in the range of 3.0 to less than 6.0, the linkages between the monomeric residues being Si-O-Si, each nanostructure comprising 10% to 25% silicon by weight, at least 90% of the monomeric residues having 5 to 11 carbon atoms, at least 90% of the monomeric residues comprising two geminal chelating groups, each chelating group being independently a group according to formula (I): TIFF2025510507000002.tif9170, R 1 and R 2 are independently selected from the group consisting of a negative charge and H, "-" indicates an internal bond in a monomer residue, and the chelating groups according to formula (I) constitute at least 90% of the chelating groups in the nanostructure.

[0011] The term "two geminal chelating groups" means two chelating groups separated by one carbon atom, ie, the two chelating groups are attached to the same carbon atom.

[0012] Importantly, the present disclosure relates to a plurality of spherical nanostructures having a defined dispersity. Moreover, the spherical nanostructures described herein can be used as the "core" or "central portion" of a coated nanostructure. Such a plurality of coated nanostructures also have a low dispersity. Several advantages, some of which are newly discovered, are associated with the low dispersity. As shown in Example 6, the optimal particle size for tumor delivery is on the order of 30 nm. Thus, the lower the dispersity of the coated nanostructures, as long as the average diameter is on the order of 30 nm, the better the tumor delivery. It is advantageous for the plurality of nanostructures to have a low dispersity, since the dispersity of the core nanostructures is transferred to the dispersity of the coated nanostructures. Also, a low dispersity leads to better economics due to reduced losses during the production of the coated nanostructures, because if the dispersity is high, the coated nanostructures outside the desired range need to be filtered out.

[0013] As noted above, the plurality of spherical nanostructures have a dispersity of 1 to 1.8. Dispersity may be measured by DLS, as defined below, or by other methods known in the art. Nanostructures with such low dispersity are particularly useful for producing coated nanostructures that can be used for in vivo applications such as imaging and radiotherapy.

[0014] The dispersity may be from 1 to 1.5, from 1 to 1.3, or from 1.1 to 1.35, such as less than 1.3.

[0015] The dispersity of the core nanostructures of the nanostructures according to the present disclosure translates to the dispersity of the coated nanostructures (discussed below), and in particular, the lower the dispersity of the coated nanostructures, the better the delivery to the tumor.

[0016] The nanostructures may have a volume average hydrodynamic diameter of 13 to 90 nm, such as 13 to 50 nm, such as 13 to 30 nm, such as 14 to 25 nm, such as 15 to 22 nm, such as 16 to 20 nm. Thus, the volume average hydrodynamic diameter may be 17 to 19 nm, such as 18 nm.

[0017] Nanostructures according to the present disclosure are small enough to leak through imperfect capillaries and diffuse through the intracellular matrix to deliver radioactivity to tumor cells.

[0018] The "average number of bonds from each monomer residue" is the average number of bonds from a monomer to the polymer backbone, i.e., to other monomers.

[0019] The polymer network may be amorphous.

[0020] The polymer backbone may be a homopolymer of a single monomer or a copolymer of two or more different monomers, and preferably has a random branching and crosslinking pattern, as opposed to the regular branching pattern in, for example, dendrimers. When the polymer backbone is a copolymer, the nanostructure comprises a polymer with random ordering.

[0021] The average number of bonds from each monomer residue may be within the range of 3.5 to 5.9, such as 3.7 to 5.5, such as 4.0 to 5.0, such as 4.5. The higher the number of bonds from each monomer residue, the better the storage stability and in vivo stability. Furthermore, the higher the degree of crosslinking, the more the number of chelate phosphonate groups (-PO(OR 1 )(OR 2 A higher density of nanostructures is obtained in which the chelates are located closer to each other, which is believed to result in higher chelate stability.

[0022] As noted above, the nanostructures contain between 10% and 25% silicon by weight. By weight of silicon, we mean the percentage of silicon in a dried sample of the nanostructure. A drying procedure is provided below in Example 11. In some examples, the nanostructures contain between 13% and 18% silicon by weight.

[0023] As noted above, at least 90% of the monomer residues have from 5 to 11 carbon atoms. Preferably, at least 95%, such as at least 99%, of the monomer residues have from 7 to 9 carbon atoms.

[0024] As stated above, at least 90% of the monomer residues contain two geminal chelating groups according to formula (I) as defined above. Preferably, at least 92%, such as at least 95%, such as at least 97%, such as at least 99%, such as 100%, of the monomer residues contain two chelating groups according to formula (I) as defined above.

[0025] Chelating groups according to formula (I) may constitute at least 95%, such as at least 99%, of the chelating groups in the nanostructure.

[0026] The spherical chelating polymer nanostructures according to the present disclosure can serve as intermediates in the manufacture of coated nanostructures having applications in radioisotope therapy and cancer diagnostics, and are particularly suitable to act as the core portion of coated nanostructures having applications in total body radiation therapy and cancer imaging.

[0027] Nanostructures according to the present disclosure are bioinert because biodegradation would cause undesirable and uncontrolled loss of radioisotopes from the nanostructures, which can cause radiation damage in vital organs such as the liver and kidneys.

[0028] Nanostructures according to the present disclosure can serve as intermediates for the manufacture of nanocarriers or nanomaterials that exceed the threshold of causing damage and / or being lost from the body by being excreted through the kidney. At the same time, nanostructures and coated nanostructures according to the present disclosure are small enough (having diameters of less than 90 nm and less than 100 nm, respectively) to leak through imperfect capillaries and diffuse through the intracellular matrix to deliver radioactivity to tumor cells. Thus, although by no means definitive or definitive, the EPR effect is believed in many cases to be the basis for the advantageous tumor delivery properties of materials derived from nanostructures according to the present disclosure.

[0029] According to one embodiment the dispersity is between 1 and 1.5, such as between 1 and 1.3, such as between 1.1 and 1.35, such as less than 1.3.

[0030] According to one embodiment, at least 90% of the monomer residues when incorporated into the polymer backbone are residues according to formula (II): TIFF2025510507000003.tif9170 In the formula, each R 1 and R 2 is independently selected from the group consisting of a negative charge and H, and each R 3 are independently selected from the group consisting of a negative charge, H, and a covalent bond to the polymer backbone, and at least three R 3 is the bond to the polymer backbone and n is an integer from 1 to 5.

[0031] At least three R's 3 In nanostructures according to the present disclosure having less than three R 3 Such nanostructures have better storage and in vivo stability due to a higher degree of cross-linking between monomers than the corresponding nanostructures in which the chelating phosphonate groups (-PO(OR) are attached to the polymer backbone. Furthermore, the higher degree of cross-linking allows the chelating phosphonate groups (-PO(OR)) to be bonded to the polymer backbone. 1 )(OR 2 A higher density of nanostructures is obtained in which the chelates are located closer to each other, which is believed to result in higher chelate stability.

[0032] R 3 At least four, such as at least five, such as six, of the groups may represent bonds to the polymer backbone.

[0033] R 3 At least four of the groups may be bonds to the polymer backbone.

[0034] In some instances, R 3 At least five, such as six, of the groups may be bonds to the polymer backbone.

[0035] In one embodiment, n = 3. Such nanostructures have been demonstrated to be particularly efficient.

[0036] In one specific embodiment, at least three R 3 The group is the bond to the polymer backbone and n=3.

[0037] In one specific embodiment, at least four R 3 The group is the bond to the polymer backbone and n=3.

[0038] In one specific embodiment, at least five R 3 The group is the bond to the polymer backbone and n=3.

[0039] In one specific embodiment, all six R 3 The group is the bond to the polymer backbone and n=3.

[0040] The nanostructures may further include a coating, which contributes to the biocompatibility of the nanostructures.

[0041] Typically, the coated nanostructures described herein have a volume average hydrodynamic diameter of from 18 to 100 nm, such as from 20 to 50 nm, such as from 25 to 35 nm.

[0042] Preferably, the coating adds at least 5 nm, such as 5-25 nm, such as 10-20 nm, such as 15 nm, to the diameter of the nanostructure. In other words, the thickness of the coating is at least 2.5 nm, such as 2.5-12.5 nm, such as 5-10 nm, such as 7.5 nm.

[0043] The coating contributes to the biocompatibility of the nanostructures.

[0044] Preferably, the coating contains hydrophilic groups, which impart water solubility, biocompatibility, and stability against aggregation.

[0045] Thus, the coating may be a hydrophilic polymer coating, such as a coating comprising polyethylene glycol (PEG), a polyoxazoline, or a peptoid. Preferably, each polyethylene glycol chain comprises 10 to 150 ethylene glycol units, such as 20 to 100 ethylene glycol residues, such as 30 to 50 ethylene glycol residues, such as 45 ethylene glycol residues.

[0046] The coating may include coating monomer residues that include one or more polyethylene glycol chains and one or more silicon atoms linked via an organic linker. Multiple ethylene glycol units linked together are also referred to as polyethylene glycol chains or PEG chains.

[0047] Preferably, the coating comprises a coating monomer residue comprising two silicon atoms and two polyethylene glycol chains, each polyethylene glycol chain comprising 20-100 ethylene glycol units.

[0048] Specifically, the coating may include a coating monomer residue that includes one or more polyethylene glycol chains and one or more silicon atoms linked via an organic linker. The organic linker may be a hydrocarbon. The organic linker may also include an ether linkage. The silicon atom in the monomer may be present in a reactive siloxane group, such as -Si(OEt)3, -Si(OMe)3, or -SiCl3.

[0049] When the coating includes a coating monomer residue that includes a silicon atom, the coating monomer residue bonds to the remainder of the nanostructure via a siloxane bond.

[0050] The coating can be grafted onto the nanostructures via reaction of the nanostructures with a coating monomer that contains a reactive siloxane group, such as -Si(OEt)3, -Si(OMe)3, or -SiCl3.

[0051] The preferred coating monomer is (m-PEG x OCH2)2C]-CH2CH2CH2-Si(OEt)3], where m is an abbreviation for methyl and x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45 ethylene glycol residues.

[0052] Another preferred coating monomer is m-PEG. x -CH2CH2CH2-Si(OEt)3, where m is an abbreviation for methyl and x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45 ethylene glycol residues.

[0053] Another preferred coating monomer is 1-(ω-methyl-(ethyleneoxy) x -methyl)-3,5-bis(3-(triethoxysilyl)propyloxy)benzene, where x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45, as well as 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy) x-methyl)heptane, in which x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45.

[0054] According to a second aspect, a pharmaceutical composition is disclosed comprising a plurality of spherical nanostructures comprising a coating according to the present disclosure. Preferably, the hydrophilic groups of the coating are as described above.

[0055] The pharmaceutical composition may be in the form of a liquid solution.Preferably, the liquid solution is an aqueous solution.In one embodiment, the aqueous solution has a pH of less than 3.5.

[0056] The pharmaceutical composition may further comprise a liquid, such as water.

[0057] The pharmaceutical composition may further comprise at least one antioxidant and / or at least one cryoprotectant.

[0058] The spherical nanostructures of the pharmaceutical composition may further comprise one or more radioisotopes. Suitable one or more radioisotopes are described below.

[0059] The pharmaceutical composition according to the second aspect may be a pharmaceutical composition for use as a medicament.

[0060] According to a third aspect, there is provided a pharmaceutical composition for use in the treatment and / or imaging of cancer, the pharmaceutical composition comprising a plurality of spherical nanostructures comprising a coating according to the present disclosure, the spherical nanostructures further comprising one or more radioisotopes. Preferably, the hydrophilic groups of the coating are as described above.

[0061] The imaging may be PET imaging or SPECT imaging.

[0062] The radioisotope is actinium-225( 225 Ac), copper-62( 62 Cu), Copper-64( 64 Cu), Copper-67( 67Cu), Gallium-67( 67 Ga), Gallium-68( 68 Ga), Holmium-166( 166 Ho), Indium-111 ( 111 In), Pb-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188( 188 Re), Rubidium-82 ( 82 Rb), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Technetium-99m ( 99m Tc 3+ ), Thallium-201( 201 Tl), thorium-227( 227 Th), Yttrium-86( 86 Y), Yttrium-90 ( 90 Y), and zirconium-89 ( 89 Zr), and combinations thereof. Thus, more than one radioisotope may be present in a pharmaceutical composition for use in imaging and / or treating cancer.

[0063] Specifically, the therapeutic radioisotope is actinium-225( 225 Ac), copper-64( 64 Cu), Copper-67( 67 Cu), Holmium-166( 166 Ho), lead-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188( 188 Re), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Thorium-227( 227 Th), and Yttrium-90 ( 90Y), and combinations thereof. Thus, more than one radioisotope may be present in a pharmaceutical composition for use in treating cancer.

[0064] Specifically, the radioisotope for imaging is copper-62( 62 Cu), Copper-67( 67 Cu), Gallium-67( 67 Ga), Gallium-68( 68 Ga), Indium-111 ( 111 In), Lutetium-177( 177 Lu), Rhenium-186( 186 Re), Rubidium-82 ( 82 Rb), Technetium-99m ( 99m Tc 3+ ), Thallium-201( 201 Tl), Yttrium-86( 86 Y), and zirconium-89 ( 89 Zr), and combinations thereof. Thus, more than one radioisotope may be present in a pharmaceutical composition for use in imaging.

[0065] A suitable radioisotope for PET imaging is copper-62( 62 Cu), Gallium-68( 68 Ga), Rubidium-82( 82 Rb), Yttrium-86( 86 Y), and zirconium-89 ( 89 Zr), and combinations thereof. Thus, more than one radioisotope may be present in a pharmaceutical composition for use in PET imaging.

[0066] The radioisotope suitable for SPECT imaging is gallium-67( 67 Ga), Indium-111 ( 111 In), Technetium-99m ( 99m Tc 3+ ), Lutetium-177( 177 Lu), and Thallium-201 ( 201Tl), and combinations thereof. Thus, more than one radioisotope may be present in a pharmaceutical composition for use in SPECT imaging.

[0067] In one specific embodiment of the pharmaceutical composition, the nanostructure comprises a coating as described above, wherein at least 90% of the monomer residues in the central portion of the nanostructure are residues according to formula (II): TIFF2025510507000004.tif9170 In the formula, each R 1 and R 2 is independently selected from the group consisting of a negative charge and H, and each R 3 are independently selected from the group consisting of a negative charge, H, and a covalent bond to the polymer backbone, and at least three R 3 is the bond to the polymer backbone and n is 3. Specifically, R 3 At least four of the groups are bonds to the polymer backbone.

[0068] Preferably, the coating comprises a coating monomer residue comprising two silicon atoms and two polyethylene glycol chains, each polyethylene glycol chain comprising 20-100 ethylene glycol units.

[0069] According to a fourth aspect, there is provided a method for purifying 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane, the method comprising the steps of: (a) providing a solution of impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in a polar aprotic solvent; (b) separating the solution of step (a) from insoluble matter; (c) concentrating the solution obtained in step (b) thereby obtaining a residue; (d) dissolving the residue obtained in step (c) in a non-polar solvent; (e) separating the solution obtained in step (d) from insoluble matter; (f) removing water from the solution obtained in step (e); (g) concentrating the dried solution obtained in step (f) to obtain a second residue; and (h) distilling the residue obtained in step (g) by short path, pass-through vacuum distillation. and (i) recovering a pass-through fraction from step (h) comprising purified 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane.

[0070] The steps may be performed in the following order: (a), (b), (c), (d), (e), (f), (g), (h), (i).

[0071] The precipitation steps (steps (a) and (d)) are advantageous in removing oligomeric materials which might otherwise plug the distillation equipment.

[0072] The aprotic solvent in step (a) may be a nitrile, a ketone, an ester, or a polar ether.

[0073] Examples of suitable nitriles are acetonitrile and propionitrile.

[0074] Examples of suitable ketones are acetone and methyl ethyl ketone.

[0075] Examples of suitable esters are ethyl acetate and isopropyl acetate.

[0076] Examples of suitable polar ethers are THF (tetrahydrofuran) and Me-THF (methyl-tetrahydrofuran).

[0077] Specifically, the aprotic solvent in step (a) can be acetonitrile. Impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane may be dissolved in acetonitrile at a concentration of 5% (wt / vol) to 20% (wt / vol), such as 10% (wt / vol), such as 7% (wt / vol) to 15% (wt / vol), where (w / v) indicates weight / volume.

[0078] Step (b) may be carried out by filtration.

[0079] Alternatively, step (b) may be carried out by settling and decanting, followed by filtration.

[0080] Step (c) and / or step (g) may be carried out by evaporation of the solvent.

[0081] The non-polar solvent in step (d) can be a cyclic or acyclic hydrocarbon, or a mixture of hydrocarbons.

[0082] Examples of suitable cyclic hydrocarbons are cyclohexane and cycloheptane.

[0083] Examples of suitable acyclic hydrocarbons are pentane, hexane, and heptane.

[0084] The non-polar solvent in step (d) may be heptane. The residue obtained in step (c) may be dissolved in heptane at a concentration of 5% (wt / vol) to 20% (wt / vol), such as 10% (wt / vol), such as 7% (wt / vol) to 15% (wt / vol), where (w / v) indicates weight / volume.

[0085] Step (e) may be carried out by filtration.

[0086] Alternatively, step (e) may be carried out by settling and decanting.

[0087] Step (f) may be carried out by drying the solution obtained in step (e) over a desiccant, for example using a molecular sieve such as a 4 Å molecular sieve. In other words, step (f) may be carried out by drying the solution obtained in step (e) over an activated molecular sieve, followed by filtration, if desired. The solvent may be removed by evaporation. If a molecular sieve is used in step (f), step (g) may be carried out by separating the solution from the molecular sieve, followed by evaporating the solvent.

[0088] Step (h) of the short path pass-through vacuum distillation may include setting the temperature of the heating element to a temperature of 150° C. to 190° C., such as 160° C. to 180° C., or such as 165° C. to 175° C., and passing the crude product through the apparatus. Low boiling impurities, characterized by lack of any structural features such as silyl groups, may then be removed and recovered as a distillate, while the purified product is retained.

[0089] Step (h) may be carried out multiple times until sufficient purity is achieved.

[0090] In an optional second step of short-path pass-through vacuum distillation, the heating elements are set to a higher temperature, such as 170°C to 190°C, and the once purified product is passed through the apparatus again. The product is then vaporized and collected as the distillate, with the non-volatiles being retained. This second step is advantageous because the production of many silanes, such as 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, can involve a platinum-catalyzed hydrosilylation step and can contain unacceptable amounts of platinum residues, which are non-volatile and are removed in the second step.

[0091] In one embodiment of the process, the polar aprotic solvent of step (a) is acetonitrile and the solution of step (a) has a concentration of non-pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in the range of 25 g / L to 250 g / L; and / or the non-polar solvent of step (d) is a lower alkane and the solution of step (d) has a concentration of the residue obtained in step (c) in the range of 25 g / L to 250 g / L; and / or the short path pass-through vacuum distillation of step (h) is carried out at a temperature in the range of 150° C. to 190° C. and a pressure in the range of 0.1 mbar to 1 mbar.

[0092] Preferably, the solution of step (a) has a concentration of non-pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in the range of 50 g / L to 200 g / L, more preferably 65 g / L to 150 g / L, even more preferably 75 g / L to 125 g / L, and most preferably 100 g / L.

[0093] Preferably, the non-polar solvent in step (d) is heptane.

[0094] Preferably, the solution of step (d) has a concentration of the residue obtained in step (c) in the range of 50 g / L to 200 g / L, more preferably 65 g / L to 150 g / L, even more preferably 75 g / L to 125 g / L, and most preferably 100 g / L.

[0095] Preferably, the short path pass-through vacuum distillation of step (h) is carried out at a temperature in the range of 150° C. to 190° C., preferably 160° C. to 180° C., and at a pressure in the range of 0.1 mbar to 1 mbar.

[0096] In specific embodiments of the process, the polar aprotic solvent of step (a) is acetonitrile and the solution of step (a) has a concentration of non-pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in the range of 75 g / L to 125 g / L; and / or the non-polar solvent of step (d) is heptane and the solution of step (d) has a concentration of the residue obtained in step (c) in the range of 75 g / L to 125 g / L; and / or the short path pass-through vacuum distillation of step (h) is carried out at a temperature in the range of 160° C. to 180° C. and a pressure in the range of 0.1 mbar to 1 mbar.

[0097] According to a fifth aspect, there is provided a use of 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane purified by a method according to the present disclosure for producing a plurality of spherical nanostructures according to the present disclosure.

[0098] According to a sixth aspect, there is provided a method for producing a plurality of spherical nanostructures according to the present disclosure, comprising the steps of: (a) providing a solution comprising a monomer in a mixture of water and a lower alcohol, the monomer being according to formula (II): TIFF2025510507000005.tif9170 In the formula, each R 1 and R 2 is independently selected from the group consisting of lower alkyl and aryl; 3 is independently selected from the group consisting of lower alkyl and aryl, and n is an integer from 1 to 5; and (b) subjecting the solution of step (a) to a temperature of 110-160° C. for a duration such that the growth rate of the nanostructures is significantly slower than the initial growth rate.

[0099] Preferably, R 1 and R 2 is lower alkyl, such as containing 1 to 8 carbon atoms. More preferably, R 1 and R 2 is -CH3.

[0100] Preferably, R 3The group is a lower alkyl, such as one having 1 to 8 carbon atoms. More preferably, R 3 The group is -CH2-CH3.

[0101] Preferably, n=3.

[0102] In a particularly preferred embodiment, R 1 and R 2 is -CH3, R 3 The group is -CH2-CH3, where n=3.

[0103] In step (b), the temperature may be from 115 to 145°C, for example from 125 to 140°C.

[0104] In step (b), the duration may be from 30 to 300 hours, for example from 40 to 250 hours, such as from 45 to 225 hours, such as from 48 to 200 hours. In certain cases, the duration may be even shorter, such as 25 hours, 20 hours, 15 hours, 10 hours or 5 hours.

[0105] In a preferred embodiment, in step (b), the duration is 45 to 50 hours.

[0106] Preferably, in step (b), the solution of step (a) is subjected to a temperature of 125° C. for 200 hours, or to a temperature of 140° C. for 48 hours.

[0107] Preferably, in step (b), the temperature is 140° C. and the heating time is 45 to 50 hours.

[0108] In one embodiment, the monomer concentration is 20-85 mM, such as 30-80 mM, such as 35-75 mM, such as 40-70 mM, such as 45-65 mM.

[0109] In another embodiment, the monomer concentration is 30-85 mM, such as 35-80 mM, such as 40-75 mM, such as 45-70 mM, such as 50-65 mM.

[0110] In another embodiment, the monomer concentration is 35 to 85 mM.

[0111] In one embodiment, the monomer concentration is 20-85 mM, such as 30-80 mM, such as 35-75 mM, such as 40-70 mM, and the reflux temperature is at least 140° C. Preferably, in this embodiment, the reaction time is 40-140 hours, such as 40-120 hours, such as 40-100 hours, such as 40-80 hours, such as 40-60 hours, such as 40-55 hours, preferably 45-50 hours.

[0112] In another embodiment, the monomer concentration is 30-85 mM, such as 35-80 mM, such as 40-75 mM, such as 45-70 mM, and the reflux temperature is greater than or equal to 125° C. Preferably, in this embodiment, the reaction time is greater than 250 hours, such as greater than 300 hours, such as greater than 400 hours.

[0113] Optionally, the method further comprises the step of (c) allowing the solution of step (b) to cool to ambient temperature.

[0114] Optionally, the method includes a first step of purifying the monomer according to a method according to the present disclosure.

[0115] Preferably, the monomer has a purity of more than 80%, more preferably more than 85%, more preferably more than 90%, even more preferably more than 95%, especially more than 96%. In such a case, the particle size of the nanostructures produced will plateau at a given particle size. When this plateau is reached, the degree of crosslinking will be as high as possible, and the phosphonate ester will be essentially completely hydrolyzed or hydrolyzed to a high degree. In addition, the use of monomers of such purity will result in a narrower particle size distribution of the nanostructures produced.

[0116] The monomer may be 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane, preferably purified according to the method according to the present disclosure.

[0117] The mixture of water and a lower alcohol may be a mixture of 5 to 50% (volume / volume), such as 5 to 22% (volume / volume), such as 6 to 20% (volume / volume), such as 7 to 18% (volume / volume), such as 8 to 15% (volume / volume), such as 9 to 12% (volume / volume), such as 10 to 11% (volume / volume), preferably 5 to 25% (volume / volume) of water in the lower alcohol, where (vol / vol) indicates volume / volume and the lower alcohol has 1 to 8 carbon atoms.

[0118] Preferably, the lower alcohol is selected from the group consisting of ethanol, 1-propanol, 2-propanol, or 1,2-propanediol, 1,3-propanediol, and ethylene glycol, or mixtures thereof.

[0119] Suitable solvent mixtures are water / ethylene glycol in suitable ratios such as 50%-95% ethylene glycol, or 80%-95% ethylene glycol, or 88-92% ethylene glycol, i.e. 5-50% (v / v), such as 5-20% (v / v), such as 8-12% (v / v), water in ethylene glycol.

[0120] Heating may be carried out in a sealed pressure vessel or at atmospheric pressure under reflux.

[0121] The temperature in step (b) may be 115-145°C, such as 120-145°C, such as 125-145°C, such as 130-145°C, such as 135-145°C, or 140°C.

[0122] The minimum duration of step (b) varies with temperature, such that a temperature of 125° C. requires a heating duration of at least 195 hours, and a temperature of 140° C. requires a heating duration of at least 48 hours. Preferably, a duration longer than the minimum duration is used.

[0123] Preferably, the heating time is from 46 to 49 hours, such as from 47 to 48 hours.

[0124] The fabricated nanostructures can be coated, preferably with a coating that contains hydrophilic groups.

[0125] The advantage of this method is that a subsequent step of chromatographic purification of the produced nanostructures is usually not required.

[0126] The solution provided in step (a) may be provided by dissolving a monomer having a purity of more than 80% in a mixture of water and a lower alcohol. Preferably, the purity of the monomer is more than 85%, or more than 90%, or more than 95%, or more than 96%. Preferably, the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane, preferably purified as described herein.

[0127] The lower alcohol may be an alcohol containing 1 to 8 carbon atoms. Preferably, the alcohol is ethylene glycol.

[0128] Preferably, R 1 and R 2 is lower alkyl, such as containing 1 to 8 carbon atoms. More preferably, R 1 and R 2 is -CH3.

[0129] Preferably, R 3 The group is a lower alkyl, such as one having 1 to 8 carbon atoms. More preferably, R 3 The group is -CH2-CH3.

[0130] Preferably, n=3.

[0131] Preferably, R 1 and R 2 is -CH3, R 3 The group is -CH2-CH3.

[0132] In a particularly preferred embodiment, R 1 and R 2is -CH3, R 3 The group is -CH2-CH3, where n=3.

[0133] Thus, preferably the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane having a purity of greater than 90%, optionally purified according to the method according to the present disclosure.

[0134] Thus, preferably, the monomer in step (a) is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane having a purity of more than 90%, the monomer concentration is 30-40 mM, the solvent mixture is 10% water in ethylene glycol, and in step (b) the temperature is 140° C. and the heating time is 45-50 hours. Preferably, the heating time is 46-49 hours, such as 47-48 hours.

[0135] Optionally, the 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane has been purified according to the method according to the present disclosure.

[0136] The heating time may be from 46 to 49 hours, such as from 47 to 48 hours.

[0137] According to a seventh aspect, there is provided the use of a plurality of spherical nanostructures according to the present disclosure and / or a product of a method according to the present disclosure as an intermediate in the production of a plurality of coated spherical nanostructures.

[0138] According to an eighth aspect, there is provided the use of a plurality of spherical nanostructures according to the present disclosure and / or a product of a method according to the present disclosure as an intermediate in the manufacture of a pharmaceutical product. Preferably, the spherical nanostructures comprise a coating. Preferably, the coating comprises hydrophilic groups. Preferably, the coating is as described above.

[0139] According to a ninth aspect, there is provided the use of a pharmaceutical composition comprising a plurality of spherical nanostructures comprising a coating according to the present disclosure as a carrier of a radioisotope, preferably the coating comprises hydrophilic groups.

[0140] Other objects, features, and advantages of the present disclosure will become apparent from the following detailed description, from the experimental data, and from the appended claims. It is noted that the present disclosure relates to all possible combinations of features.

[0141] In general, all terms used in the claims should be interpreted according to their ordinary meaning in the art, unless expressly stated otherwise herein. Any reference to "a / an / the [component, means, step, etc.]" should be interpreted in an open-ended manner as referring to at least one example of said component, means, step, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless expressly stated otherwise.

[0142] As used herein, the term "comprising" and variations of this term are not intended to exclude other additives, components, integers, or steps.

[0143] Definition of Terms As used herein, the term "nanostructure" refers to entities whose overall particle size is in the nano range, i.e., 100 nm or less. As used herein, the term excludes structures that typically have an inorganic core and an organic coating, often referred to as "core-shell nanoparticles" or simply "nanoparticles."

[0144] As used herein, the term "spherical" is intended to describe a shape whose minor axis is equal to or greater than half of its major axis, i.e., the length of the longest axis passing through the center (centre of gravity) of the structure is equal to or less than twice the length of the shortest axis passing through the same point. For a non-limiting illustration of this definition, see Figure 1.

[0145] As used herein, the term "spherical nanostructures" refers to nanostructures as discussed above that have an essentially spherical morphology or shape, which is meant to exclude shapes such as flakes, rods, tubes, toroids, chains, and ribbons.

[0146] As used herein, the term "hydrodynamic diameter" refers to the diameter of a hypothetical hard sphere diffusing at the same rate as the nanostructure in solution, i.e., the diameter of an equivalent hard sphere calculated from the diffusion coefficient according to the Stokes-Einstein equation. This term is also known as the "Stokes diameter" or "Stokes-Einstein diameter". Hydration and shape are included in the behavior of the sphere. The diffusion coefficient is then calculated from time-dependent light scattering data obtained, for example, by dynamic light scattering (DLS). Other technical methods for measuring the diffusion coefficient of nanostructures are known to those skilled in the art and may be used instead. In such cases, the measurements should be referenced against DLS measurements. As a comparison, bovine serum albumin has been measured to have a hydrodynamic diameter of 6.9 nm by DLS in saline (150 mM NaCl) at room temperature at pH 7. Depending on whether number average, volume average, or scattering intensity average is used, the calculated values ​​may vary slightly. The volume average is generally the most useful since it indicates what the nanostructure particle size is throughout the material. The mean diameters referred to herein mean the volume average when measured in saline or 8% ethylene glycol in saline (vol / vol) at 25°C.

[0147] As used herein, the term "DLS" is an acronym for Dynamic Light Scattering, a particle size measurement technique, which may also be referred to as Photon Correlation Spectroscopy or Quasi-Elastic Light Scattering. DLS diameters given herein and in the claims, unless otherwise specified, refer to the average of the volume-weighted peaks of a sample measured at 25°C in an aqueous solution of ionic strength equivalent to 150 mM NaCl, also referred to as saline, or in 8% ethylene glycol (volume / volume) in saline. In other words, the hydrodynamic diameters specified herein refer to the average of the volume-weighted peaks of a sample measured by DLS at 25°C in an aqueous solution of ionic strength equivalent to 150 mM NaCl, also referred to as saline, or in 8% ethylene glycol (volume / volume) in saline.

[0148] As used herein, SEC-ELSD is an acronym for Size Exclusion Chromatography with Evaporative Light Scattering Detection.

[0149] As used herein, HPLC-ELSD is an acronym for High Pressure Liquid Chromatography with Evaporative Light Scattering Detection.

[0150] As used herein, the term "AFM" is an acronym for atomic force microscopy.

[0151] As used herein, the term "ICP-OES" is an acronym for Inductively Coupled Plasma - Optical Emission Spectrometry. ICP-OES is a technique used to determine the elemental composition in a sample.

[0152] A "monomer" is a molecule that can be covalently linked to other molecules of the same type (and, if desired, other types of molecules) to form polymers, i.e., macromolecules composed of multiple monomer residues.

[0153] The term "monomer residue" refers to the atoms from one monomer unit that has been incorporated into a larger polymer. Depending on how the monomers are linked, all of the atoms may be retained or some may be lost during bond formation.

[0154] By "crosslinking" we mean the connection between two different chains in a polymer. It is usually formed by the reaction of a multifunctional monomer (i.e., a crosslinker) that is added during the formation of the polymer. Crosslinks can also be introduced, for example, by radiation treatment, chemical means, or heat. For the materials of the present disclosure, which are network polymers of monomers with multiple branching capabilities, the usual expression of crosslinking degree becomes somewhat inappropriate. For simplicity, we only describe the average number of bonds between monomers. For example, if a monomer can form six bonds with other molecules, and on average three of them are filled, we avoid the term crosslinking degree and describe that there are "on average three bonds with other monomers," or sometimes "on average three bonds out of six possible with other monomers."

[0155] The term "crosslinked" refers to the structure formed after at least one crosslink has been formed.

[0156] A "branch point" is a location in a network polymer where a polymer chain branches into two or more branches.

[0157] As used herein, the term "polymer backbone" refers to a covalently bonded group of atoms that forms a network structure with multiple crosslinks. Such a polymer backbone is formed by linking suitable monomers and / or oligomers (i.e., molecular complexes consisting of several monomer residues) through covalent bonds. Some examples of monomers include styrene, propylene, ethylene, tetrafluoroethylene, trifluoroethylene, difluoroethylene, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, acrylamide, methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate, H2N-(CH2) p -COOH (p is 1-10), 3-aminobenzoic acid, 4-aminobenzoic acid, N-vinylpyrrolidone, and silicone precursors such as (CH3COO)2Si(CH3)2. Some examples of polymer backbones are terephthalic acid + 1,4 diaminobenzene, terephthalic acid + ethylene glycol, and HCOO-(CH2). p COOH+H2N-(CH2) qIt is formed from a corresponding pair of monomers such as -NH2 (p and q are independently 1 to 10). Oligomers having 2 to 10 linked monomer units can be used as precursors. Some examples of oligomers that are different from the linked groups of monomers listed above are cyclic or polycyclic silanes such as hexamethylcyclotrisiloxane, 2,4,6,8-tetramethylcyclotetrasiloxane, and decamethylcyclopentasiloxane. Some examples of crosslinkers are N,N'-methylenebis(acrylamide), O,O'-methylenebis(acrylic acid), epichlorohydrin, divinylbenzene, 1,3-divinyltetramethyldisiloxane, 1,3-phenylene diisocyanate, 3,3''-biphenyltetracarboxylic dianhydride, 1,4-butanediol divinyl ether, tetraethoxysilane, oligosilicates such as metasilicates or silsequioxanes, organosilanes such as bis(triethoxysilyl)methane, bis(triethoxysilyl)ethane, bis(triethoxysilyl)propane, bis(triethoxysilyl)butane, methyltriethoxysilane, ethyltriethoxysilane, and propyltriethoxysilane.

[0158] The polymer backbone constitutes the backbone of the nanostructures according to the present disclosure. Such nanostructures may be coated as described herein, in which case the polymer backbone constitutes the central portion of the coated nanostructure. Those skilled in the art will appreciate that the random nature of the polymerization process will result in materials with many similar, but in most cases not identical, mixtures of branching patterns, crosslinking locations, and molecular weights.

[0159] The term "chelating group" refers to a chemical group that can compete well with water for electrostatic binding of a positively charged ion. A single chelating group does not bind very strongly, but when multiple chelating groups surround a positively charged ion, a synergistic binding enhancement occurs. This is called chelation.

[0160] The expression "positioned to allow chelation" means that several chelating groups as defined above are positioned so that a synergistic strengthening of the binding of positively charged ions can occur. This can be obtained by statistical means, when a large number of chelating groups are incorporated into a random polymer, with a density such that at least some of them are in close proximity and can bind to the same positively charged ion, or by incorporating preformed units in which chelating groups are already present in close proximity. An example of the latter is the known chelating agent DOTA (dodecanetetraacetic acid).

[0161] As used herein, the terms "covalently attached," "covalently linked," and "covalently bound" are synonymous and have the meaning known to those of skill in the art.

[0162] As used herein, the term "independently selected" means that each of the different components mentioned preceding the term is selected from the group that follows the term independently or separately from the selection of the other mentioned components.

[0163] The term "geminal bisphosphonate group" refers to two phosphonate groups separated by one carbon atom, i.e., the phosphonate groups are attached to the same carbon atom. Compounds containing such geminal bisphosphonate groups are often referred to as 1,1-bisphosphonates (or 1,1-diphosphonates). The phosphonate group in the geminal bisphosphonate group may be substituted.

[0164] The term "radionuclide" means an unstable form of a chemical element that undergoes radioactive decay resulting in the emission of alpha, beta, and / or gamma rays.

[0165] As used herein, the expression "radionuclide for imaging and / or radiotherapy" refers to actinium-225 ( 225 Ac), copper-62( 62 Cu), Copper-64( 64 Cu), Copper-67(67 Cu), Gallium-67( 67 Ga), Gallium-68( 68 Ga), Holmium-166( 166 Ho), Indium-111 ( 111 In), Pb-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188( 188 Re), Rubidium-82 ( 82 Rb), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Technetium-99m ( 99m Tc 3+ ), Thallium-201( 201 Tl), thorium-227( 227 Th), Yttrium-86( 86 Y), Yttrium-90 ( 90 Y), and zirconium-89 ( 89 The expression "radionuclide for imaging and / or radiotherapy" also encompasses combinations of two or more of the abovementioned radionuclides.

[0166] As used herein, the expression "radionuclide for imaging" refers to copper-62 ( 62 Cu), Copper-67( 67 Cu), Gallium-67( 67 Ga), Gallium-68( 68 Ga), Indium-111 ( 111 In), Lutetium-177( 177 Lu), Rhenium-186( 186 Re), Rubidium-82 ( 82 Rb), Technetium-99m ( 99m Tc 3+ ), Thallium-201( 201 Tl), Yttrium-86( 86 Y), and zirconium-89 ( 89The expression "radionuclide for imaging" also encompasses combinations of two or more of the abovementioned radionuclides.

[0167] As used herein, the expression "radionuclide for PET imaging" refers to copper-62 ( 62 Cu), Gallium-68( 68 Ga), Rubidium-82( 82 Rb), Yttrium-86( 86 Y), and zirconium-89 ( 89 The expression "radionuclide for PET imaging" also encompasses combinations of two or more of the abovementioned radionuclides.

[0168] As used herein, the expression "radionuclide for SPECT imaging" refers to gallium-67 ( 67 Ga), Indium-111 ( 111 In), Technetium-99m ( 99m Tc 3+ ), Lutetium-177( 177 Lu), and Thallium-201 ( 201 Tl). The expression "radionuclide for SPECT imaging" also encompasses combinations of two or more of the abovementioned radionuclides.

[0169] As used herein, the expression "radionuclide for radiotherapy" refers to actinium-225 ( 225 Ac), copper-64( 64 Cu), Copper-67( 67 Cu), Holmium-166( 166 Ho), lead-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188( 188 Re), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Thorium-227( 227 Th), and Yttrium-90 (90 The expression "radionuclide for radiotherapy" also encompasses combinations of two or more of the abovementioned radionuclides.

[0170] As used herein, the expression "radionuclide for PET imaging and radiotherapy" refers to actinium-225 ( 225 Ac), copper-62( 62 Cu), Copper-64( 64 Cu), Copper-67( 67 Cu), Gallium-68( 68 Ga), Holmium-166( 166 Ho), lead-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188( 188 Re), Rubidium-82 ( 82 Rb), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Thorium-227( 227 Th), Yttrium-90( 90 Y), and zirconium-89 ( 89 The expression "radionuclide for PET imaging and radiotherapy" also encompasses combinations of two or more of the abovementioned radionuclides.

[0171] As used herein, the expression "radionuclide for SPECT imaging and radiotherapy" refers to actinium-225 ( 225 Ac), copper-64( 64 Cu), Copper-67( 67 Cu), Gallium-67( 67 Ga), Holmium-166( 166 Ho), Indium-111 ( 111 In), Pb-212( 212 Pb), Lutetium-177( 177 Lu), Radium-223 ( 223 Ra), Rhenium-186( 186 Re), rhenium-188(188 Re), Samarium-153( 153 Sm), Strontium-89 ( 89 Sr), Technetium-99m ( 99m Tc 3+ ), Thallium-201( 201 Tl), thorium-227( 227 Th), and Yttrium-90 ( 90 The expression "radionuclide for SPECT imaging and radiotherapy" also encompasses a combination of two or more of the abovementioned radionuclides.

[0172] As used herein, the term "bioinert" refers to a material that is biocompatible, i.e., non-harmful to mammals and mammalian cells, and at the same time, stable to degradation in the human body for a period of one week or more (less than 10% degradation).

[0173] As used herein, the term "oxysilane" refers to any compound in which one or more oxygen atoms are bonded to a silicon atom. Non-limiting examples include: The file is TIFF2025510507000006.tif32170.

[0174] As used herein, the term "organosilane" means an organic compound that contains one or more carbon-silicon bonds.

[0175] As used herein, the term "alkoxysilane" means any compound that contains one or more carbon-oxygen-silicon moieties.

[0176] As used herein, the terms "siloxane bond," "siloxane linkage," and "siloxane network" refer to moieties that contain Si-O-Si.

[0177] The terms "hydrocarbon" and "hydrocarbon chain" are used herein to denote an organic residue composed of hydrogen and carbon. A hydrocarbon may be fully saturated or may contain one or more unsaturations. A hydrocarbon according to the present disclosure may contain any number of carbon atoms from 1 to 50.

[0178] As used herein, the term "alkyl" refers to a straight or branched chain, fully saturated (no double or triple bonds) hydrocarbon group. As used herein, an alkyl group can have 1 to 15 carbon atoms. Typical alkyl groups include, but are in no way limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl, hexyl, and the like.

[0179] As used herein, the term "lower alkyl" means an alkyl having 1 to 8 carbon atoms.

[0180] As used herein, the term "lower alcohol" means an alcohol having from 1 to 8 carbon atoms.

[0181] As used herein, the term "low boiling alcohol" means an alcohol having a boiling point below 160°C.

[0182] As used herein, the term "lower alkane" means a straight or branched chain, fully saturated (no double or triple bonds) hydrocarbon having from 1 to 8 carbon atoms. When the term is used in reference to a solvent, it means a straight or branched chain, fully saturated (no double or triple bonds) hydrocarbon having from 4 to 8 carbon atoms.

[0183] Numeric ranges: whenever used herein, unless otherwise specified, a numerical range such as "1 to 8" or "1-8" refers to each integer within the given range, for example, "1 to 8 carbon atoms" and "1-8 carbon atoms" means that an alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to 8 carbon atoms. However, there are some exceptions that will be apparent to those skilled in the art. In particular, whenever a range is given herein for a molar ratio, such as the Si / P molar ratio, diameter or particle size, pH, duration, concentration, osmolality, or temperature of a nanostructure, the range includes all decimals within the range, including the upper and lower limits.

[0184] As used herein, the term "alkoxy" refers to the formula -OR, where R is lower alkyl, such as methoxy, ethoxy, n-propoxy, 1-methylethoxy (isopropoxy), n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy, amyloxy, iso-amyloxy, etc. Alkoxy groups in accordance with the present disclosure may be optionally substituted.

[0185] As used herein, the term "aryl" refers to a carbocyclic (i.e., all carbon) ring or two or more fused rings (i.e., rings sharing two adjacent carbon atoms) having a completely delocalized pi-electron system. Examples of aryl groups include, but are not limited to, benzene, naphthalene, and azulene. Aryl groups according to the present disclosure may be optionally substituted, such as, for example, phenoxy, naphthalenyloxy, azulenyloxy, anthracenyloxy, naphthalenylthio, phenylthio, and the like. Aryloxy may be optionally substituted.

[0186] As used herein, the term "conjugate" refers to a molecular entity that is a fluorescent marker, a dye, a spin label, a radioactive marker, a peptide, a ligand for a biological receptor, a chelate, an enzyme inhibitor, an enzyme substrate, an antibody, or an antibody-related structure.

[0187] The term "coated nanostructures" (or nanostructures having a coating) is used to describe materials that can be produced from the nanostructures of the present disclosure by the addition of one or more layers of additional materials. Often, such coated nanostructures are intended for use in radioisotope therapy.

[0188] As used herein, the term "coating" refers to a layer of material applied to a surface to impart one or more properties to the surface. Often, the coating is covalently attached to the surface. Often, the surface is a nanostructured surface. Often, the properties imparted to the surface include inertness, such as bioinertness. The term "coating" can also refer to the process of applying a coating to a surface, and the term "coat" can be used as a verb meaning "to apply a coating to." It will generally be clear to one of ordinary skill in the art which form of the term "coating" is to be used in a particular case.

[0189] The term "dispersity" is used in situations where the term polydispersity was previously used. For most applications, it is important that the particle size distribution around the mean value is as narrow as possible, i.e., a low dispersity. For a sample with perfectly uniform particle size, the dispersity is 1; for a non-uniform sample, the dispersity is greater than 1. Dispersity can be calculated in different ways, M w / M n or equivalently, M v / M n As a ratio of M w is the weight average molecular weight, M n is the number average molecular weight, M v is the volume average molecular weight. In this specification, the inventors follow the recommendation by the International Union of Pure and Applied Chemistry (Pure Appl. Chem., Vol. 81, No. 2, pp. 351-353, 2009. doi:10.1351 / PAC-REC-08-05-02) to determine the degree of dispersion of the nanostructure sample. Similarly, TIFF2025510507000007.tif5170 Define it as TIFF2025510507000008.tif6170, d v is the volume mean diameter as measured by DLS, and d n is the number average diameter as measured by DLS. Another way to express the dispersity of a material is to compare it to a known particle size standard. As a non-limiting example illustrated here, a suitable particle size standard could be bovine serum albumin (BSA), or thyroglobulin, or empty cowpea mosaic virus (CPMV) VLPs.

[0190] As used herein, the term "molecular weight" refers to the molecular weight of a compound having a specific molecular structure, or the weight-average molecular weight, also called mass-average molar mass or weight-average molar mass, of a compound that contains a polymeric portion, and the number of monomers of the polymeric portion varies between different individual molecules.Thus, the molecular weight of a compound having a specific molecular structure is the molecular weight calculated based on the number and nature of atoms of the compound, or the molecular weight measured, for example, by mass spectrometry.The molecular weight of a compound that contains a polymeric portion refers to the weight-average molecular weight, also called mass-average molar mass or weight-average molar mass, which can be determined, for example, by gel filtration chromatography or size exclusion chromatography (SEC). More specifically, the weight average molecular weight may be determined according to ISO 16014-1:2019 and ISO 16014-5:2019 ("Determination of average molecular weight and molecular weight distribution of polymers using size-exclusion chromatography"), or according to ISO 16014-1:2019 in combination with any of ISO 16014-2:2019 through ISO 16014-4:2019. Alternatively, the weight average molecular weight may be determined by SEC and confirmed using liquid chromatography-mass spectrometry (LC-MS) or high performance liquid chromatography (HPLC).

[0191] As used herein, the term "growth rate" or "rate of growth" refers to the first derivative of the nanostructure particle size with respect to time. For convenience, the rate of growth is often approximated as the change in the nanostructure particle size between two measurements, such as the change in the mean hydrodynamic diameter, Δd, divided by Δt, the time elapsed between the two measurements. The particle size of the nanostructures may be determined by any of a number of methods known to those skilled in the art, such as DLS or SEC. The unit of measurement for the growth rate will depend on the method used to determine the particle size, but units such as nm / hour may be used when DLS is used to determine the particle size, or minutes / hour when SEC is used to determine the particle size.

[0192] As used herein, the term "resin" is defined as an insoluble organic material.

[0193] As used herein, the term "Tris" means tris(hydroxymethyl)aminomethane.

[0194] As used herein, the term (w / w) stands for weight / weight.

[0195] As used herein, the term (w / v) stands for weight / volume.

[0196] As used herein, the terms "vol / vol" or "v / v" stand for volume / volume.

[0197] By way of example, embodiments of the present teachings will now be described with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0198] [Figure 1] FIG. 1 is an explanatory diagram of a spherical shape. [Diagram 2]FIG. 2 shows how chelating groups (illustrated as "U") in a network polymer (represented by the thick black curve) are distributed to form ion-binding sites of various binding strengths. [Diagram 3] FIG. 3 shows the 1H NMR spectra of nanostructures boiled for a long time (upper chart) and for a short time (lower chart). [Figure 4] FIG. 4 shows the 31P NMR spectra of long-boiled and short-boiled nanostructures (from bottom to top: short boil with 1H-decoupling, short boil without 1H-decoupling, long boil with 1H-decoupling, long boil without 1H-decoupling) and shows how the phosphonate ester present in the short-boiled nanostructures (bottom two charts) hydrolyzes to form only one phosphonate peak in the long-boiled nanostructures (top two charts). [Diagram 5] FIG. 5 shows A) HPLC chromatograms of crude 7-bis-(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane with a purity of 54% and B) HPLC chromatograms of purified 7-bis-(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane with a purity of 97%; C) overlay of details of A and B to show relative amounts, with the crude material shown as a thin line and the purified material as a thick line. [Figure 6] Figure 6 shows the SEC chromatogram of the nanostructures prepared according to Example 1B. The average particle size (mean diameter) of the nanostructures is 18.2 nm. The retention time (tR) is in minutes. The three thin light gray peaks are CPMV, tR approx. 8.28 min, thyroglobulin, tR approx. 9.04 min, and BSA, tR approx. 10.05 min, respectively. [Figure 7] Figure 7 is an AFM image of the nanostructures made according to Example 1B. Individual nanostructures meet the definition of a spherical shape. Some aggregates of nanostructures are also visible. [Figure 8] FIG. 8 is a schematic of a manufacturing method for producing nanostructures according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0199] The present disclosure relates to spherical nanostructures, methods for purifying monomers used in the production of such nanostructures, as well as methods for producing such nanostructures, and specific uses of such nanostructures.

[0200] Certain aspects and embodiments of the disclosure are described in detail below.

[0201] Spherical Nanostructures A plurality of spherical nanostructures according to the present disclosure can be characterized by their average hydrodynamic diameter and dispersity. Other useful measurements can include average molecular weight and density. The molecular weight of a given spherical nanostructure can be calculated as the product of the volume and density of the nanostructure, calculated according to geometrical formulas known in the art.

[0202] The range of particle sizes of nanostructures according to the present disclosure is limited from the bottom by their ability to chelate radioisotopes with high affinity and maintain their binding state for many days after administration to the body. Example 4 below shows that there is a correlation between the particle size of nanostructures according to the present disclosure and their chelation strength. The chelation strength is considered to be sufficient for particle sizes greater than 13 nm in diameter, especially for particle sizes greater than 15 nm.

[0203] The upper particle size limit is determined by the ability of the coated nanostructures derived from the spherical nanostructures according to the present disclosure to penetrate from the bloodstream into tumor tissue in the organism. Due to the high diffusion resistance in tissue, it has been found to be more advantageous to use spherical nanostructures at the lower end of the feasible particle size range, such as 13-25 nm diameter, such as 16-20 nm, as precursors to the coated nanostructures. The diffusion resistance depends on the nanostructure particle size, and for entities with diameters of more than 100 nm, the diffusion resistance is found to be too high and the dose delivered locally to the tumor is too small to be useful for many clinical purposes.

[0204] When used for imaging or therapy, the nanostructures preferably include a coating as described herein. The biodistribution of coated nanostructures according to the present disclosure was investigated (Example 6). The data presented in Example 6 indicates that the optimal particle size of the coated nanostructures is around 30 nm in diameter. It is estimated that the particle size of the coated nanostructures should be 100 nm or less, preferably 90 nm or less, more preferably 60 nm or less, and even more preferably 35 nm or less. The upper limit for the core nanostructures (uncoated nanostructures) of the present disclosure is 90 nm, since the coating adds at least 5-10 nm to the diameter. Thus, nanostructures according to the present disclosure are less than 90 nm, such as less than 70 nm, such as less than 50 nm, such as less than 30 nm, such as less than 25 nm, such as less than 22 nm, such as less than 20 nm.

[0205] In one embodiment, nanostructures of the present disclosure having an average particle size (diameter) of 18 nm have 95% of the population between the protein BSA and the virus-like particle CPMV as measured by SEC-ELSD.

[0206] Example 7 and FIG. 7 describe several nanostructures of the present disclosure with an average particle size (diameter) of 18.2 nm by DLS, with 1.6% of the peak area in the SEC-ELSD chromatogram exceeding the CPMV standard and 2.8% below the BSA standard.

[0207] Example 1 describes how to select conditions to produce nanostructures of the present disclosure within a given particle size range.

[0208] The nanostructures of the present disclosure comprise a polymeric backbone of monomeric residues, at least 90% of which contain two geminal chelating groups, each chelating group independently having the formula (I), -PO(OR 1 )(OR 2 ) in which R 1 and R 2 are independently selected from the group consisting of a negative charge and H, with "-" indicating an internal bond in a monomer residue.

[0209] The polymer backbone may be a homopolymer of a single monomer, or a copolymer of two or more different monomers.

[0210] The polymer backbone can in principle be constructed from a large number of known monomers, as can be found in any textbook on polymer chemistry.

[0211] Specifically, in a preferred embodiment, the nanostructures of the present disclosure comprise polymers with random branching and crosslinking patterns, as opposed to macromolecules such as dendrimers or cascade polymers such as arborols, or proteins, all of which have well-defined molecular structures and essentially all of the molecular entities are identical. The advantage of this approach is that it is possible to produce nanostructures with minimum particle sizes as low as 13 nm in a cost-effective, reliable, and relatively simple manner. While it is possible to reach the desired minimum particle size in nanostructures with well-defined molecular entities, doing so is very costly and cumbersome. An example is, for example, PAMAM-G10, which is believed to be the largest dendrimer commercially available, which is described as having a hydrodynamic diameter of 13.5 nm, costing approximately 4,000 euros for a 100 mg research sample (Sigma-Aldrich, product number 536776), and only reaching the lower end of the desired particle size range of 13-90 nm for nanostructures according to the present disclosure. The cost of producing the nanostructures of the present disclosure is expected to be less than 1% of the above prices. Moreover, a particular advantage of the disclosed techniques is that chromatographic purification is usually not required.

[0212] In specific embodiments where the nanostructure comprises a polymer with random branching and crosslinking patterns, the number of bonds between monomer residues is unusually high for such polymers. In such cases, the number of bonds between monomer residues is on average more than 2 bonds per monomer, or more than 3 bonds per monomer. Higher bond numbers such as 4-5 bonds, or less than but close to 6, may also be contemplated. It will be apparent to one skilled in the art that even when monomers with crosslinking or branching potential are used as monomers for making nanostructures according to the present disclosure, some residual groups with crosslinking or branching potential will remain in the structure of the central portion, since not all of the potentials will actually be fulfilled.

[0213] In general, it is difficult to precisely determine the average number of bonds between monomer residues in nanostructures according to the present disclosure, but it is constrained to some extent by information from elemental composition, density measurements, NMR, and AFM, and it is clear that the number of bonds between monomer residues is very high, as discussed above.

[0214] In one embodiment, the nanostructure comprises a homopolymer in which there are six potential bonding groups in the monomer, with three to five of those groups actually forming bonds with other monomer residues.

[0215] In another embodiment, the average number of bonds between monomer residues is between 3 and 5.9.

[0216] Preferably, at least 90% of the monomer residues are residues according to formula (II): TIFF2025510507000009.tif9170, each R 1 and R 2 is independently selected from the group consisting of a negative charge and H, and each R 3 are independently selected from the group consisting of a negative charge, H, and a covalent bond to the polymer backbone, and at least three R 3 is the bond to the polymer backbone and n is an integer from 1 to 5.

[0217] Preferably, R 3At least three of the groups are bonds to the polymer backbone.

[0218] Preferably, n=3.

[0219] Preferably, three R 3 The group is the bond to the polymer backbone and n=3.

[0220] Preferably, four R 3 The group is the bond to the polymer backbone and n=3.

[0221] Preferably, five R 3 The group is the bond to the polymer backbone and n=3.

[0222] Preferably, all six R 3 The group is the bond to the polymer backbone and n=3.

[0223] Preferably, all R 3 The groups are independently selected from the group consisting of a negative charge, H, or a bond to the polymer backbone.

[0224] Preferably, all R 3 The groups are independently selected from the group consisting of a negative charge, H, or a bond to the polymer backbone, and n=3.

[0225] Typically, there are at least 200 chelating groups in each nanostructure, arranged to allow chelation of one or more multivalent cations.

[0226] The chelating groups may be randomly distributed throughout the nanostructure and rely on chance for an arrangement that allows chelation of multivalent cations (see FIG. 2). If chance is relied upon, it is preferable to incorporate a large excess of chelating groups into the nanostructure to increase the probability of forming clusters of chelating groups with high chelating capacity.

[0227] As mentioned above, the chelating groups present in the nanostructures of the present disclosure are groups according to formula (I) as defined above. When incorporated into the polymer backbone, particularly as geminal phosphonates, and allowed to bind multivalent cations, these chelating groups bind cations strongly. Example 4 shows how nanostructures containing geminal bisphosphonates compete favorably with the strong chelating agent EDTA.

[0228] Preferably, the phosphonate groups are essentially completely hydrolyzed to the acid form and then ionized to some degree, ranging from partially to completely, depending on the pH value of the surrounding medium.

[0229] It has been found that when the phosphonate groups are partially present in ester form, the nanostructures bind weaker to the metal ions.

[0230] The nanostructures containing phosphonate groups described herein bind the multivalent cations best at neutral or basic pH, indicating that it is the anionic form of the hydrolyzed phosphonate that is at least partially, and possibly, or even completely, responsible for binding the metal ion.

[0231] It is advantageous if the phosphonate is primarily or completely hydrolyzed to the phosphonic acid when incorporated into the nanostructure. Example 8 and Figure 4 show NMR data that confirms that the phosphonate is essentially completely hydrolyzed.

[0232] In one embodiment, the phosphonate, when present in the nanostructure, is hydrolyzed to a great extent, such as greater than 50%, or greater than 90%, or greater than 95%, to phosphonic acid.

[0233] It may be contemplated that not only phosphonate esters or acids, but also phosphonic acid amides may be used as part of the material or as starting materials.

[0234] In another embodiment, the dried sample of the nanostructure has a density of 1.4 to 1.68 g / cm 3 etc., 1.5~1.67g / cm 3 etc., 1.6~1.65g / cm 3 1.3 to 1.7 g / cm 3 has a density of

[0235] The very high density of the dried sample of nanostructures from Example 1 (1.469 g / cm 3 ) is in accordance with the more conventional density of phosphonates (typically around 1.1 g / cm 3 ), in contrast to the typically very high density of phosphonic acids (1.3-2.0 g / cm 3 )

[0236] Coated spherical nanostructures In some embodiments, the nanostructures include a coating. The coating contributes to the biocompatibility of the nanostructures. Preferably, the coating is a hydrophilic coating. Typically, the coated nanostructures described herein have an average hydrodynamic diameter of 18 to 100 nm, such as 20 to 50 nm, such as 25 to 35 nm.

[0237] The coating may comprise polyethylene glycol (PEG). Each polyethylene glycol chain may comprise 10 to 150 ethylene glycol residues, such as 30 to 50 ethylene glycol residues, such as 45 ethylene glycol residues, preferably 20 to 100 ethylene glycol residues.

[0238] Preferably, the coating comprises a coating monomer residue comprising two silicon atoms and two polyethylene glycol chains, each polyethylene glycol chain comprising 20-100 ethylene glycol units.

[0239] In a specific embodiment, the coating comprises a coating monomer residue that comprises one or more polyethylene glycol chains and one or more silicon atoms linked via an organic linker. The organic linker can be a hydrocarbon. The organic linker can also include an ether bond. The silicon atom in the monomer can be present in a reactive siloxane group, such as -Si(OEt)3, -Si(OMe)3, or -SiCl3.

[0240] When the coating includes a coating monomer residue that includes a silicon atom, the coating monomer residue bonds to the remainder of the nanostructure via a siloxane bond.

[0241] The coating can be grafted onto the nanostructures via reaction of the nanostructures with a coating monomer that contains a reactive siloxane group, such as -Si(OEt)3, -Si(OMe)3, or -SiCl3.

[0242] The preferred coating monomer is [(m-PEG x OCH2)2C]-CH2CH2CH2-[Si(OEt)3], where m is an abbreviation for methyl and x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45 ethylene glycol residues.

[0243] Another preferred coating monomer is m-PEG. x -CH2CH2CH2-Si(OEt)3, where m is an abbreviation for methyl and x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45 ethylene glycol residues.

[0244] Another preferred coating monomer is 1-(ω-methyl-(ethyleneoxy) x -methyl)-3,5-bis(3-(triethoxysilyl)propyloxy)benzene, where x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45, as well as 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy) x-methyl)heptane, in which x is an integer from 10 to 150, such as 20 to 100, such as 30 to 50, such as 45.

[0245] Pharmaceutical compositions comprising coated spherical nanostructures A pharmaceutical composition comprising a plurality of spherical nanostructures further comprising a coating in accordance with the present disclosure is preferably formulated as a solution.

[0246] Typically, when used for imaging and / or cancer treatment, the spherical nanostructure further comprises a radioisotope. Depending on the application, different radioisotopes are used. The composition may comprise a nanostructure that comprises a single radioisotope or two or more different types of radioisotopes. Radioisotopes, also referred to as radionuclides, suitable for different applications are listed above.

[0247] In one embodiment, the alkoxysilanes are separated by 1 to 10 carbon atoms or 3 to 9 carbon atoms.

[0248] In another embodiment, the alkoxysilanes are separated by 7 carbon atoms.

[0249] In a preferred embodiment, the polymer backbone is derived from 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane. The polymer backbone may be formed by hydrolytic condensation polymerization.

[0250] In another preferred embodiment, the polymer backbone is derived from 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane having a purity of greater than 80%, or greater than 85%, or greater than 90%, or greater than 95%, or greater than 96%.

[0251] When nanostructures are formed by linking multiple monomers into a polymer network, the residues of the monomers are referred to as monomer residues: they still retain the basic covalent bonding pattern of the original free monomers, but the groups directly involved in the linkages have been modified by the formation of the linkages.

[0252] Purification method for 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane As discussed below, the purity of the monomers affects the quality of the nanostructures produced by the methods disclosed below (Example 1).

[0253] As discussed below, when nanostructures are produced by the methods disclosed below, the use of higher purity monomers results in higher quality nanostructures.

[0254] Therefore, methods have been developed to purify 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane to very high purity, such as greater than 80%, or greater than 85%, or greater than 90%, or greater than 95%, or greater than 96%.

[0255] This method is suitable for moisture-prone, reactive, high-boiling, heat-sensitive oils in large-scale production, such as several kilos in an industrial environment. Notably, all standard purification methods are not suitable for such materials. Chromatography on silica is poor due to the reactivity of triethoxysilane, and reversed-phase chromatography on large scale is poor due to the need for an aqueous mobile phase. The same is true for extraction. Crystallization does not work for oils, and the material is too heat-sensitive to withstand the long heating conditions of vacuum distillation (as shown in Example 3).

[0256] The method for purifying 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane of the present disclosure includes the steps of: (a) providing a solution of impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in a polar aprotic solvent; (b) separating the solution of step (a) from insoluble matter; (c) concentrating the solution obtained in step (b), thereby obtaining a residue; (d) dissolving the residue obtained in step (c) in a non-polar solvent; (e) separating the solution obtained in step (d) from insoluble matter; (f) removing water from the solution obtained in step (e); (g) concentrating the dried solution obtained in step (f) to obtain a second residue; (h) subjecting the residue obtained in step (g) to short-path pass-through vacuum distillation; and (i) recovering the pass-through fraction from step (h) comprising purified 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane.

[0257] The aprotic solvent in step (a) may be a nitrile, such as acetonitrile and propionitrile; a ketone, such as acetone and methyl ethyl ketone; an ester, such as ethyl acetate and isopropyl acetate; or a polar ether, such as THF (tetrahydrofuran) and Me-THF (methyltetrahydrofuran). In a preferred embodiment, the aprotic solvent in step (a) is acetonitrile.

[0258] Specifically, step (a) may be carried out by dissolving crude 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane in acetonitrile. The non-pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane may be dissolved in acetonitrile at a concentration of 5% (wt / vol) to 20% (wt / vol), such as 10% (wt / vol), such as 7% (wt / vol) to 15% (wt / vol), where (w / v) indicates weight / volume.

[0259] The separation step (b) may be carried out, for example, by filtration, or by settling and decantation.

[0260] Step (c) may be carried out by evaporation.

[0261] The non-polar solvent in step (d) can be a cyclic or acyclic hydrocarbon, or a mixture of hydrocarbons.

[0262] In step (d), the residue obtained in step (c) may be dissolved in an alkane.

[0263] In step (d), the residue obtained in step (c) may be dissolved in a lower alkane.

[0264] Examples of suitable cyclic hydrocarbons are cyclohexane and cycloheptane.

[0265] Examples of suitable acyclic hydrocarbons are pentane, hexane, and heptane. Specifically, in step (d), the residue obtained in step (c) may be dissolved in heptane. The residue obtained in step (c) may be dissolved in heptane at a concentration of 5% (wt / volume) to 20% (wt / volume), such as 10% (wt / volume), such as 7% (wt / volume) to 15% (wt / volume), (w / v) indicates weight / volume).

[0266] The separation step (e) may be carried out, for example, by filtration, or by settling and decantation.

[0267] In step (f), the water may be removed by evaporation or by drying the solution obtained in step (e) over a desiccant such as 4 Å molecular sieves. If molecular sieves are used, step (g) is carried out by first separating the solution from the molecular sieves.

[0268] The short path pass-through vacuum distillation of step (h) is preferably carried out at a temperature in the range of 150°C to 190°C, such as 160°C to 180°C or 165°C to 175°C, with falling film vacuum removal of impurities.

[0269] The precipitation steps (steps (a) and (d)) are advantageous for removing oligomeric substances which might otherwise clog the distillation equipment. Notably, in the case of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, it was found that this compound decomposes rapidly, even under vacuum, at the temperatures required for boiling (Example 3), making conventional vacuum distillation impractical.

[0270] To solve this difficult purification problem, a two-stage process was developed that involves selective precipitation of impurities followed by falling film distillation. In this particular method, the material is exposed to high temperatures for only a few seconds, too short for thermal degradation to occur. Several other versions of the broader concept of "short path distillation", which involves short residence times at high temperatures, are also suitable, including wiped film distillation methods.

[0271] To remove lower boiling point impurities, in step (h), the intermediate purity mixture is passed through a distillation apparatus to vaporize the impurities.

[0272] Falling film distillation has the advantage of being a technique that can be used from laboratory scale to production plant scale.

[0273] The distillation can be carried out in two alternative ways, involving one step or two steps. In the first step, the temperature of the heating element is set to a temperature such as 150°C to 165°C and the crude product is passed through the apparatus. Low boiling impurities, characterized by lack of any structural features such as silyl groups, are then removed and collected as a distillate, and the purified product is retained. In an optional second step, the heating element is set to a higher temperature such as 170°C to 190°C and the once purified product is passed through the apparatus. The product is then vaporized and collected as a distillate, and the non-volatiles are retained. This second step is advantageous because the production of many silanes, such as 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, can involve a platinum catalyzed hydrosilylation step and can contain unacceptable amounts of platinum residues. These are the non-volatiles that are removed in the second step.

[0274] In a specific embodiment, 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is purified in the following order: in step (a), the crude material is dissolved in acetonitrile, and insoluble matter is separated by filtration (step (b)), followed by evaporation of the solvent (step (c)); in step (d), the resulting material is dissolved in a lower alkane, and insoluble matter is separated by filtration (step (e)); in step (f), water is removed by molecular sieves (step (f)), and the molecular sieves are removed by filtration, followed by evaporation of the solvent (step (g)); in step (h), falling film distillation is performed under vacuum while heating the heating element to 150° C.-175° C., and the concentrate is recovered.

[0275] In another specific embodiment, 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is purified in the following order: in step (a), the crude material is dissolved in acetonitrile at a concentration of 7% (wt / vol) to 15% (wt / vol), the insoluble material is separated by precipitation and decantation followed by filtration (step (b)), followed by evaporation of the solvent (step (c)), in step (d), the resulting material is dissolved in heptane at a concentration of 7% (wt / vol) to 15% (wt / vol), the insoluble material is separated by precipitation and decantation (step (e)), followed by drying over activated molecular sieves, followed by removal of the molecular sieves by filtration (step (f)), followed by evaporation of the solvent (step (g)), followed by falling film distillation under vacuum with a heating element at 165° C. to recover the concentrate (step (i)) in step (h).

[0276] In another specific embodiment, 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is purified in the following order: in step (a), the crude material is dissolved in acetonitrile at a concentration of 10% (w / v), followed by separation of the insoluble material by precipitation and decantation followed by filtration (step (b)), followed by evaporation of the solvent (step (c)), in step (d), the resulting material is dissolved in heptane at a concentration of 10% (w / v), followed by separation of the insoluble material by precipitation and decantation followed by filtration (step (e)), followed by drying over activated molecular sieves followed by removal of the molecular sieves by filtration (step (f)), followed by evaporation of the solvent (step (g)), followed by falling film distillation under vacuum with the heating element at 165° C. to recover the concentrate (step (i)) in step (h).

[0277] Alternatively, 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane can be prepared by (i) dissolving the crude material in heptane at a concentration of 10% (wt / vol), as in (d) above, (ii) isolating the insoluble matter by precipitation and decantation followed by filtration (as in step (e) above), followed by (iii) evaporating the solvent (as in step (g) above), followed by (iv) dissolving the resulting material in acetonitrile at a concentration of 10% (wt / vol), as in step (a) above, and (v) precipitation. and decantation followed by separation of the insoluble material by filtration (as in step (b) above), followed by (vi) drying over activated molecular sieves followed by filtration to remove the molecular sieves (as in step (f) above), followed by (vii) evaporation of the solvent (as in step (c) above), followed by (viii) falling film distillation under vacuum with the heating element heated to 165° C. (as in step (h) above), and (ix) recovery of the concentrate (as in step (i) above).

[0278] To purify the impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane, it is envisaged to use only the short-path pass-through distillation used in step (h), especially when the impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane contains only small amounts of polymeric impurities. However, it has been found that when known methods for the synthesis of 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane are used, oligomeric impurities are always present in the impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane.

[0279] As explained above, step (h) may include the further step of purifying the 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane by heating the heating element above 185° C. to perform falling film distillation under vacuum and recovering the distillate. In such a case, the resulting purified material, 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, has a reduced concentration of inorganic impurities.

[0280] One of the impurities present in non-pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is a by-product that forms during the manufacture of the monomer. HPLC analysis of a crude preparation of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane indicates a purity of 54%, and FIG. 5A shows an HPLC chart of such a sample. FIG. 5B shows a sample of the material that has been purified to 97% according to the method described above (see Example 2 for details). The improved purity is evident. This is an important advantage when 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is subsequently used to manufacture nanostructures according to the present disclosure.

[0281] 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane purified as described herein can be used to produce a plurality of spherical nanostructures in accordance with the present disclosure.

[0282] Method for producing a plurality of spherical nanostructures A method for producing a plurality of spherical nanostructures according to the present disclosure is shown generally in Figure 8. It has been found that this method, even when carried out on a large scale, results in nanostructures having a particular particle size and dispersity, of a quality suitable for use in imaging and radiotherapy.

[0283] Briefly, the method for producing a plurality of spherical nanostructures according to the present disclosure involves dissolving monomers (step 001) in a water / solvent mixture (002) and heating the solution (003) for an extended period of time (Figure 8).

[0284] In detail, the method comprises: (a) providing a solution comprising a monomer in a mixture of water and a lower alcohol, the monomer being according to formula (II); TIFF2025510507000010.tif9170In the formula, Each R 1 and R 2 is independently selected from the group consisting of lower alkyl and aryl; and Each R 3 is independently selected from the group consisting of lower alkyl and aryl; and n is an integer from 1 to 5; The process and (b) subjecting the solution of step (a) to a temperature of 110-160° C. for a duration such that the growth rate of the nanostructures is significantly lower than the initial growth rate; Includes.

[0285] Step (a) corresponds to steps 001 and 002 in FIG. 8, and step (b) corresponds to step 003.

[0286] Preferably, R 1 and R 2 is -CH3, R 3 The group is -CH2-CH3, where n=3.

[0287] In step (b), the temperature may be from 115 to 145°C, for example from 125 to 140°C.

[0288] In step (b), the duration may be from 30 to 300 hours, for example from 40 to 250 hours, such as from 45 to 225 hours, such as from 48 to 200 hours. In certain cases, the duration may be even shorter, such as 25 hours, 20 hours, 15 hours, 10 hours, or 5 hours.

[0289] In a preferred embodiment, in step (b), the duration is 45 to 50 hours.

[0290] Preferably, in step (b), the solution of step (a) is subjected to a temperature of 125° C. for 200 hours, or to a temperature of 140° C. for 48 hours.

[0291] Preferably, in step (b), the temperature is 140° C. and the heating time is 45 to 50 hours.

[0292] Optionally, the method further comprises the step of (c) allowing the solution of step (b) to cool to ambient temperature.

[0293] When nanostructures are formed by linking multiple monomers into a polymer network, the residues of the monomers are referred to as monomer residues: they still retain the basic covalent bonding pattern of the original free monomers, but the groups directly involved in the linkages have been modified by the formation of the linkages.

[0294] In the resulting nanostructures, the monomer residues are incorporated into the polymer backbone through Si-O-Si bonds, and the silicon atoms are silicon atoms of the structure according to formula (II).

[0295] The chelating group contains a geminal bisphosphonate group, ie, two phosphonate groups attached to the same carbon atom.

[0296] It is envisioned to mix two, three, or several different polymer backbones produced by the methods of the invention with any combination of chemically compatible monomers, either by mixing the monomers prior to polymerization or by grafting one polymer onto another.

[0297] The degree of polymerization (average number of monomer residues), or alternatively, molecular weight, of nanostructures produced by the methods disclosed herein can be precisely controlled by manipulating process parameters to obtain products of desired particle size. Examples of such parameters are described in Example 1. Expressing particle size in terms of degree of polymerization by describing molecular weight rather than hydrodynamic diameter is less useful, but is another way to conceptualize the structure. The degree of polymerization is included as a reference rather than as a limitation. For example, for nanostructures with a diameter of 17.5 nm derived from 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane by hydrolytic condensation polymerization according to the methods described herein, the density of the nanostructures is 1.469 g / cm. 3 The estimated degree of polymerization is about 6400 monomers and the molecular weight is about 2.5 MDa. The degree of polymerization can be measured by mass spectrometry, gel filtration, or dynamic light scattering.

[0298] In the case of impure starting materials, i.e., monomers with a purity less than 80%, the particle size of the produced nanostructures continues to grow indefinitely, as evidenced by the formation of precipitates, resulting in a broader particle size distribution (Example 10).

[0299] Alternatively, monomers of a certain purity may be used as starting materials, such as having a purity of more than 80%, preferably more than 85%, more preferably more than 90%, even more preferably more than 95%, especially more than 96%.

[0300] Solutions of nanostructures produced from such monomers may optionally be subjected to a series of size selection steps to remove undesirably large or small entities and reduce the degree of dispersion, such size selection steps being described in more detail below.

[0301] When the monomeric silane is sufficiently pure, such as having a purity of more than 80%, preferably more than 85%, more preferably more than 90%, even more preferably more than 95%, especially more than 96%, the particle size of the nanostructure produced will plateau at a given particle size, which depends on the reaction conditions. When this plateau is reached, the degree of crosslinking is as high as possible, and the phosphonate ester is essentially completely hydrolyzed or highly hydrolyzed. This is important in the application of the nanostructure in nanomaterial-based radioisotope therapy and imaging products, since the product of complete hydrolysis, bisphosphonic acid, is the most chelating form of phosphonate (see Example 5).

[0302] Preferably, the purity of the silane monomer is 80% or more, such as 85% or more, more preferably, the purity of the silane monomer is 90% or more, and even more preferably, the purity of the silane monomer is 95%, especially more than 96% or more. Such high purity can be achieved by the purification methods described herein.

[0303] Bis(trialkoxy)silanes bearing phosphonate groups, i.e., R 3 Silanes in which the groups are lower alkyl have been found to be particularly useful in forming nanostructures in accordance with the present disclosure.

[0304] Preferably, R 1 and R 2 is independently selected from the group consisting of lower alkyl, i.e., alkyl having 1 to 8 carbon atoms, more preferably selected from the group including methyl, ethyl, and propyl, and even more preferably, R 1 and R 2 is methyl.

[0305] Preferably, R 3 The groups are independently selected from the group consisting of lower alkyl, i.e., alkyl having 1 to 8 carbon atoms, more preferably selected from the group including methyl, ethyl, and propyl, and even more preferably, R 3The group is an ethyl group.

[0306] Preferably, n=3.

[0307] Preferably, R 1 and R 2 is methyl, R 3 The group is an ethyl group.

[0308] Preferably, R 1 and R 2 is methyl, R 3 The group is an ethyl group and n=3.

[0309] 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane has been found to be a suitable monomer, especially when the purity is greater than 80%, or greater than 85%, or greater than 90%, or greater than 95%, or greater than 96% as measured by HPLC-ELSD. High purity increases the predictability of the polymerization process. High purity can be achieved by the purification methods disclosed herein.

[0310] Preferably, at least 50%, such as at least 90%, of the monomer residues are 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane.

[0311] The mixture of water and a lower alcohol may be a mixture of 5 to 50% (volume / volume), such as 5 to 22% (volume / volume), such as 6 to 20% (volume / volume), such as 7 to 18% (volume / volume), such as 8 to 15% (volume / volume), such as 9 to 12% (volume / volume), such as 10 to 11% (volume / volume), preferably 5 to 25% (volume / volume) of water in the lower alcohol, the lower alcohol having 1 to 8 carbon atoms.

[0312] Preferably, the lower alcohol is selected from the group consisting of ethanol, 1-propanol, 2-propanol, or 1,2-propanediol, 1,3-propanediol, and ethylene glycol, or mixtures thereof.

[0313] In one embodiment, the mixture of water and lower alcohol is a mixture of 5-25% (volume / volume) water in ethanol, such as 5-22% (volume / volume), such as 6-20% (volume / volume), such as 7-18% (volume / volume), such as 8-15% (volume / volume), such as 9-12% (volume / volume), such as 10-11% (volume / volume).

[0314] In another embodiment, the mixture of water and a lower alcohol is a mixture of 5-25% (volume / volume) water, such as 5-22% (volume / volume), such as 6-20% (volume / volume), such as 7-18% (volume / volume), such as 8-15% (volume / volume), such as 9-12% (volume / volume), such as 10-11% (volume / volume) in 1-propanol.

[0315] In a further embodiment, the mixture of water and lower alcohol is a mixture of 5-25% (volume / volume) water in 2-propanol, such as 5-22% (volume / volume), such as 6-20% (volume / volume), such as 7-18% (volume / volume), such as 8-15% (volume / volume), such as 9-12% (volume / volume), such as 10-11% (volume / volume).

[0316] In yet another embodiment, the mixture of water and lower alcohol is a mixture of 5-25% (volume / volume) water, such as 5-22% (volume / volume), such as 6-20% (volume / volume), such as 7-18% (volume / volume), such as 8-15% (volume / volume), such as 9-12% (volume / volume), such as 10-11% (volume / volume) in 1,2-propanediol.

[0317] In a further embodiment, the mixture of water and lower alcohol is a mixture of 5-25% (v / v), such as 5-22% (v / v), such as 6-20% (v / v), such as 7-18% (v / v), such as 8-15% (v / v), such as 9-12% (v / v), such as 10-11% (v / v) water in 1,3-propanediol.

[0318] In another embodiment, the mixture of water and a lower alcohol is a mixture of 5-25% (volume / volume) water, such as 5-22% (volume / volume), such as 6-20% (volume / volume), such as 7-18% (volume / volume), such as 8-15% (volume / volume), such as 9-12% (volume / volume), such as 10-11% (volume / volume), in ethylene glycol.

[0319] As used herein, 90.0% (vol / vol) aqueous ethylene glycol means a mixture of 90.0% (vol / vol) ethylene glycol and 10.0% (vol / vol) water.

[0320] In one embodiment, the mixture of water and lower alcohol is a mixture of 5-25% water in ethylene glycol.

[0321] In a further embodiment, the mixture of water and lower alcohol is a mixture of 18-22% water in ethylene glycol.

[0322] In another embodiment, the mixture of water and lower alcohol is a mixture of 9-11% water in ethylene glycol.

[0323] Suitable solvent mixtures are water / ethylene glycol in suitable ratios such as 50%-95% ethylene glycol, or 80%-95% ethylene glycol, or 88-92% ethylene glycol, i.e. 5-50% (v / v), such as 5-20% (v / v), such as 8-12% (v / v), water in ethylene glycol.

[0324] Heating may be carried out in a sealed pressure vessel or at atmospheric pressure under reflux.

[0325] If low boiling alcohols are used, it may be necessary to operate in a closed pressure vessel to achieve the desired reaction temperature.

[0326] In step (b), the temperature may be from 110 to 160° C. for up to 10 days.

[0327] The temperature in step (b) may be from 120 to 145°C, such as from 120 to 140°C.

[0328] The minimum duration of step (b) varies with temperature, such that a temperature of 125° C. requires a heating duration of at least 195 hours, and a temperature of 140° C. requires a heating duration of at least 48 hours. Preferably, a duration longer than the minimum duration is used.

[0329] The minimum duration of step (b) is characterized by the growth rate of the nanostructures after the minimum duration being significantly lower than the growth rate at the start of the reaction.

[0330] It will be apparent to one skilled in the art that, based on the growth rate at the end of step (b) and the particle size of the nanostructures at the end of step (b), it is possible to determine whether the growth rate is significantly lower than the initial growth rate, even without first measuring the initial growth rate.

[0331] In one embodiment, the growth rate of the nanostructures at the end of step (b) is much slower, such as more than 10 times slower, or more than 20 times slower, or even more than 30 times slower, than at the beginning of step (b).

[0332] In another embodiment, the growth rate of the nanostructures at the end of step (b) is essentially zero.

[0333] In a further embodiment, the conditions of step (b) are a temperature of 125° C. and a duration of 200 to 500 hours.

[0334] In yet another embodiment, the conditions of step (b) are a temperature of 140° C. and a duration of 40 to 200 hours.

[0335] Notably, the silane starting material is sensitive to moisture and will slowly form oligomers when exposed to moisture, for example, through contact with the atmosphere or glassware. The presence of such oligomers will cause variability in the reaction rate and the final particle size and particle size distribution of the nanostructures produced (Example 9). Therefore, measures should be taken to avoid exposing the monomers to moisture. Such measures are known to those skilled in the art.

[0336] High quality nanostructures of a given particle size from 13 to 90 nm, such as 13 to 50 nm, or 14 to 25 nm, or 15 to 22 nm, or 16 to 20 nm, can be produced by the methods disclosed above. It is envisioned that the methods disclosed above can be used to produce nanostructures of smaller or larger particle sizes.

[0337] Exemplary conditions are described in Example 1. The industrial and economic advantages of the process described herein are that it uses only solvents that are environmentally friendly and fairly non-toxic.

[0338] In one embodiment, the monomer concentration is 20-85 mM, such as 30-80 mM, such as 35-75 mM, such as 40-70 mM, such as 45-65 mM.

[0339] In another embodiment, the monomer concentration is 30-85 mM, such as 35-80 mM, such as 40-75 mM, such as 45-70 mM, such as 50-65 mM.

[0340] In another embodiment, the monomer concentration is 35 to 85 mM.

[0341] In one embodiment, the monomer concentration is 20-85 mM, such as 30-80 mM, such as 35-75 mM, such as 40-70 mM, and the reflux temperature is at least 140° C. Preferably, in this embodiment, the reaction time is 40-140 hours, such as 40-120 hours, such as 40-100 hours, such as 40-80 hours, such as 40-60 hours, such as 40-55 hours, preferably 45-50 hours.

[0342] In another embodiment, the monomer concentration is 30-85 mM, such as 35-80 mM, such as 40-75 mM, such as 45-70 mM, and the reflux temperature is greater than or equal to 125° C. Preferably, in this embodiment, the reaction time is greater than 250 hours, such as greater than 300 hours, such as greater than 400 hours.

[0343] In a specific embodiment, the monomer concentration is 25-85 mM, the solvent mixture is 20% (v / v) water in ethylene glycol, the reflux temperature is 125° C., and the reaction time is greater than 250 hours.

[0344] In another specific embodiment, the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, the monomer concentration is 25-85 mM, the solvent mixture is 80% v / v ethylene glycol in water (i.e., 20% v / v water in ethylene glycol), the reflux temperature is 125° C., and the reaction time is greater than 250 hours.

[0345] In another specific embodiment, the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, the monomer concentration is 30-40 mM, the solvent mixture is 10% (vol / vol) water in ethylene glycol, the reflux temperature is 140° C., and the reaction time is about 48 hours.

[0346] In another specific embodiment, the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, the monomer concentration is 34-36 mM, the solvent mixture is 10% (v / v) water in ethylene glycol, the reflux temperature is 140° C., and the reaction time is about 48 hours.

[0347] In a further specific embodiment, the monomer is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, the monomer concentration is 34-36 mM, the solvent mixture is 10% (vol / vol) water in ethylene glycol, the reflux temperature is 140° C., and the reaction time is greater than 48 hours.

[0348] If desired, the solution of nanostructures may be subjected to a series of size selection steps to remove undesirably large (004) or small (005) entities to reduce dispersion. Steps 004 and 005 of Figure 8 may be performed in any order and may be repeated any number of times in any order. Starting materials and residual solvent may also be removed from the reaction mixture at this stage.

[0349] Importantly, if the purity of the starting material (ie, monomer) is greater than 80%, a size selection step may not be required.

[0350] Ultrafiltration is the preferred method of size selection, especially when used in a form commonly referred to as tangential flow filtration. Other ultrafiltration methods such as spin filters or dialysis may be used, but are less amenable to scale-up.

[0351] Preferably, undesirably large nanostructures and / or aggregates are removed by passing the solution through a filter having relatively large pores (004). The preferred nominal cutoff for such filters is 0.2 μm. Alternatively, the nominal cutoff for such filters is 1000 kDa, 500 kDa, or 300 kDa.

[0352] In step (005), the desired material may be collected on a filter with a smaller pore size. Preferred pore sizes in step 005, given as nominal cutoff values, are 300 kDa, 100 kDa, 50 kDa, 30 kDa, or 10 kDa, except that if a 300 kDa filter is used in step 005, the filter used in step 004 must have larger pores. It should be noted that the nanostructures in this state have reactive surfaces, and excessively high concentrations should be avoided in any size selection step, otherwise the nanostructures may irreversibly aggregate. Such high concentrations can be avoided by ensuring that the volume remains essentially constant during the filtration process.

[0353] In step 005, the material may be washed in portions with a solvent, such as water, to further remove any unreacted monomer or unwanted residual solvent from steps 001, 002, or 003.

[0354] Nanostructures in the desired size range may be selected by size exclusion chromatography (also called gel filtration).

[0355] Uses of spherical nanostructures according to the present disclosure Nanostructures according to the present disclosure can be used as precursors to, or as intermediates in, the manufacture of other materials.

[0356] Use as intermediates in the production of coated nanostructures One such use is as an intermediate in the manufacture of coated nanostructures. The coating may be a polyethylene glycol (PEG) coating. Typically, the average hydrodynamic diameter of the final coated nanostructures may be 18-100 nm, or 20-50 nm, or 25-35 nm.

[0357] The coated nanostructures can be used for imaging or radiation therapy.

[0358] In particular, such coated nanostructures may be used as intravenous imaging and / or radiotherapy agents, and preferably are incorporated into a composition suitable for such use, such as a liquid composition.

[0359] In one embodiment, the nanostructures according to the present disclosure are used as intermediates for the manufacture of pharmaceuticals comprising PEG (polyethylene glycol) coated nanostructures suitable for carrying radioisotopes for imaging and / or radiotherapy.

[0360] Example 6 describes how coated nanostructures according to the present disclosure can be produced that have properties compatible with pharmaceutical products. Such nanostructures can be used for tumor imaging and therapy. When used, radioisotopes are incorporated into the nanostructures. The radioisotopes can be incorporated into the nanostructures prior to delivery to the clinic or immediately prior to injection into a patient.

[0361] Use as an intermediate in the manufacture of pharmaceuticals Another application is the use of nanostructures according to the present disclosure as intermediates in the manufacture of pharmaceuticals, which may be used in imaging and / or radiation therapy.

[0362] Preferably, the nanostructures are coated nanostructures as described above.

[0363] When used, radioisotopes are incorporated into the nanostructures, which may be incorporated into the nanostructures prior to delivery to the clinic or immediately prior to injection into a patient.

[0364] Use as a carrier for radioisotopes Nanostructures according to the present disclosure may therefore be used as carriers of radioisotopes. EXAMPLES

[0365] Examples of different embodiments of the present disclosure are described below.

[0366] General experimental conditions Materials, reagents, and solvents were obtained from commercial sources and used without further purification unless otherwise noted. Solvents were of reagent grade or similar unless otherwise noted.

[0367] 1,7-Bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane was prepared according to published procedures (WO2013041623A1, Example 3).

[0368] HPLC (high pressure liquid chromatography) of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane was performed on a Hewlett Packard Series 1100 equipped with an Agilent Poroshell 120 EC-C18 3.0 x 50 mm column eluting at 0.7 ml / min with an oven temperature of 40 °C, a DAD detector recording at 220 nm, and an ELSD detector (ELSD settings: 36 °C, 1.4 L N2 / min, gain = 8, impactor on).

[0369] HPLC (high pressure liquid chromatography) of all other compounds was performed on a Hewlett Packard Series 1100 equipped with an Agilent Poroshell 120 EC-C18 4.6 x 50 mm column, a DAD detector recording at 220 nm, and an ELSD detector (ELSD settings: 40 °C, 1.4 L N2 / min, gain = 4, impactor on) using a non-linear gradient starting from 43% acetonitrile in water at 1 ml / min with an oven temperature of 40 °C.

[0370] SEC was performed on a Younglin Instrument YL9100 equipped with an Agilent Bio SEC-5 1000 Å column eluting at 1.2 ml / min at ambient temperature, a DAD detector recording at 220 nm, 280 nm, and 560 nm, and an ELSD detector (ELSD settings: 60° C., 1.2 L N2 / min, gain=4).

[0371] DLS was measured using a Malvern Instruments Zetasizer Nano ZEN3600 and processed using the general process settings in the Zetasizer software.

[0372] The term "PES" is an acronym for polyethersulfone.

[0373] The term "GF / A Filter" is an abbreviation for Glass Microfiber Filter, Grade GF / A.

[0374] The term "RPM" is an acronym for Revolutions Per Minute.

[0375] As used herein, the term "PTFE" is an acronym for polytetrafluoroethylene.

[0376] Example 1 - Synthesis of nanostructures Three different variants of the method for producing spherical nanostructures according to the present disclosure are disclosed below ("Method 1", "Method 2" and "Method 3"). The process parameters, such as the concentration and purity of the monomers, the nature of the solvent as well as the reaction time, differ between these different variants.

[0377] Method 1 represents a method carried out at atmospheric pressure suitable for large scale synthesis of nanostructures. Method 2 represents a method in a closed vessel at pressures above 1 atmosphere suitable for small scale synthesis of nanostructures. Method 3 is a reference method outside the scope of this disclosure in which the nanostructures are harvested before they achieve a stable particle size and before the phosphonate ester and alkoxysilane are fully hydrolyzed.

[0378] Example 1A. Representative example of "Method 1" (long-term boiling) A 1 liter jacketed reactor was fitted with a mechanical stirrer, temperature probe and a reflux condenser with the top connected to a vacuum-nitrogen manifold. The reactor was charged with 16.3 g of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, 97% purity, and 748.3 g of 90.0% (volume / volume) aqueous ethylene glycol. The solution was degassed. With stirring, the mantle temperature was increased to 146° C. over 25 minutes, during which the solution became clear. After 25 minutes at the set mantle temperature, a gentle reflux was obtained. The reaction mixture was held at reflux for 47.5 hours and then cooled to 20° C. Samples were taken for DLS after 45 and 47 hours of reflux, giving average diameters of 18.1 and 18.2 nm, respectively. Average diameter=18.2 nm; TIFF2025510507000011.tif5170, [P](ICP-OES)=69mM, [Si](ICP-OES)=74mM

[0379] Example 1B. Representative example of "Method 2" (long boiling) A 250 ml bomb vial was charged with 7.91 g of 96% pure 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane and 182.5 ml of 80% (volume / volume) aqueous ethylene glycol. The solution was degassed and placed under a nitrogen atmosphere. The bomb vial was sealed and heated in an oil bath at 125° C. for 264 hours. The solution was filtered through a glass fiber filter. Mean diameter=17.5 nm. TIFF2025510507000012.tif6170, [P](ICP-OES)=136mM, [Si](ICP-OES)=154mM

[0380] Example 1C. Representative example of "Method 3" (short boiling) - a reference method outside the scope of this disclosure In a round bottom flask, 4.53 g of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane of estimated purity 90% was mixed with 667 μl of a 23 mg / ml solution of rhodamine isothiocyanate in ethylene glycol, 71 ml ethylene glycol, and 17.9 ml water. The solution was degassed and 12 ml aliquots were placed in sealed reaction vials. The reaction vials were heated in a preheated (125° C.) oil bath for 43 hours. Mean diameter=15.5 nm. TIFF2025510507000013.tif6170, [P](ICP-OES)=164mM, [Si](ICP-OES)=165mM

[0381] Examples 1D-1Z Further experiments were also carried out in which the process parameters of the three variants mentioned above were varied.

[0382] The results of Experiments 1A to 1Z are shown in Table 1. TIFF2025510507000014.tif254161

[0383] As can be seen from Table 1, the hydrodynamic diameter of the nanostructures can be controlled by controlling the monomer concentration at the start of the synthesis, as was done in Method 1 (1A, 1Q-1W) or Method 2 (1B, 1D-P). In addition, the hydrodynamic diameter of the nanostructures can also be controlled by controlling the concentration of water in the reaction medium (1X-1Z).

[0384] Example 2 - Purification of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane A dry 2 liter 3-neck round bottom flask was charged with 107 g of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane with an estimated purity of 54%. Anhydrous acetonitrile (1070 ml) was added with vigorous stirring. After 30 minutes of vigorous stirring, the stirring rate was reduced to approximately 40 RPM and allowed to stand overnight. The solution was cannulated through a 0.2 μm PTFE filter and the solvent removed under vacuum to give 98.9 g of a pale yellow oil.

[0385] The resulting oil was mixed with heptane (1000 ml), resulting in the immediate formation of a sticky precipitate. The supernatant was decanted into a new flask, the precipitate was washed with heptane, and the washings were added to the supernatant. The solution was gently stirred overnight, after which the clear supernatant was decanted. The solution was dried over fresh activated molecular sieves with gentle shaking on a shaking table for 8 days, then filtered first through a glass fiber filter and finally through a cannula through a 0.2 μm PTFE filter. The solvent was removed in vacuo to give 74 g of a clear oil.

[0386] 61.5 g of the resulting oil was subjected to falling film distillation using a homemade distillation apparatus similar to that sold by Sigma Aldrich (e.g., Sigma Aldrich catalog number Z156604, provided by Merck KGaA, Darmstadt, Germany) at a pressure of 1.3 mbar with a heating element heated to 160° C. at an addition rate of approximately 10 ml / h to obtain 44 g of concentrate, which was identified by HPLC-ELSD as 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane with a purity of 97%.

[0387] Example 3 - Unsuccessful Attempt at Vacuum Distillation of 1,7-Bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane - Reference Method Outside the Scope of This Disclosure A 50 ml two-neck round bottom flask equipped with a distillation head, Liebig condenser, and receiving flask was charged with 4.6 g of crude 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane. An oil pump vacuum (0.1 mbar) was applied and the distillation flask was gradually heated in an oil bath from 40° C. to a temperature of 210° C. The maximum internal temperature reached was 142° C. No product was collected in the receiving flask and the residue in the distillation flask was very dark brown and not suitable for use as a starting material for nanostructures.

[0388] Thus, it was demonstrated that crude 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane cannot be purified using conventional vacuum distillation.

[0389] Example 4 – Chelation strength of coated nanostructures with different particle sizes by EDTA competitive chelation test Nanostructures were synthesized by methods according to the present disclosure (the "extended boiling" method detailed in Example 1 yielded nanostructures of 7.1 nm, 12.5 nm, 17.5 nm, and 23 nm in specimens 4A, 4B, 4C, and 4D, respectively).

[0390] The test articles were coated with metal ions (M) such as yttrium (Y) or lutetium (Lu) using a procedure similar to that used in Example 6 below. 3+) was loaded onto the nanostructures. The metal ion loaded nanostructures were then diluted with 50 mM Tris buffer (pH 7.4) to a concentration of 0.2 mM yttrium or lutetium. A 2 mM ethylenediaminetetraacetic acid (EDTA) solution was prepared in 50 mM Tris buffer at pH 7.5 for testing with a 10 molar equivalent excess of EDTA relative to the metal ion bound to the nanostructures, or a 1 mM EDTA solution was prepared for testing with a 5 molar equivalent excess of EDTA relative to the metal ion bound to the nanostructures. 280 μL of the diluted metal ion loaded nanostructures was mixed with 280 μL of the prepared EDTA solution and left at room temperature for 1 hour (1hRT) or at 37°C for 24 hours (24h37C). After incubation, 50 μL of the mixture was removed and labeled XXX-pre (XXX=selected id, pre=pre-filtration). The remaining mixture was placed in a 0.5 ml Amicon 3 kDa spin filter and centrifuged at 12000 x g for 15 min. The permeate was labeled as XXX-post (post = after filtration). The metal ion concentrations of samples xxx-pre and xxx-post were determined by ICP-OES. The percentage of nanostructure-bound metal ions remaining was called metal ion stability % and calculated using the following formula: The obtained value was called the chelating strength of the nanostructure, and the higher this value, the stronger the chelating strength of the nanostructure. TIFF2025510507000015.tif15170TIFF2025510507000016.tif72170

[0391] As can be seen from Table 2, coated nanostructures synthesized by the method according to the present disclosure having chelating centers smaller than 13 nm have significantly weaker chelating strengths compared to coated nanostructures having chelating centers larger than 13 nm.

[0392] Example 5 - Comparison of chelating strength of nanostructures boiled for short and long periods Nanostructures were synthesized in a similar manner to Examples 1B and 1C, resulting in nanostructures of 12.4 nm, 12.5 nm, 17.8 nm, and 17.5 nm for samples 5A, 5B, 5C, and 5D, respectively. Samples 5B and 5D were synthesized in a similar manner to Example 1B, and samples 5A and 5C were synthesized in a similar manner to Example 1C.

[0393] The test articles were coated with metal ions (M) such as yttrium (Y) or lutetium (Lu) using a procedure similar to that used in Example 6 below. 3+ ) was loaded onto the nanostructures. The metal ion loaded nanostructures were then diluted with 50 mM Tris buffer (pH 7.4) to a concentration of 0.2 mM yttrium or lutetium. A 2 mM ethylenediaminetetraacetic acid (EDTA) solution was prepared in 50 mM Tris buffer at pH 7.5 for testing with a 10 molar equivalent excess of EDTA relative to the metal ion bound to the nanostructures, or a 1 mM EDTA solution was prepared for testing with a 5 molar equivalent excess of EDTA relative to the metal ion bound to the nanostructures. The greater the excess of EDTA, the more severe the test. 280 μL of the diluted metal ion loaded nanostructures were mixed with 280 μL of EDTA solution and incubated at room temperature for 1 hour. After incubation, 50 μL of the mixture was removed and labeled XXX-pre (XXX=selected id, pre=pre-filtration). The remaining mixture was placed in a 0.5 ml Amicon 3 kDa spin filter and centrifuged at 13.4 kRPM (=12,000×g) for 15 minutes. The permeate was labeled as XXX-post (post = after filtration). The metal ion concentrations of samples xxx-pre and xxx-post were determined by ICP-OES. The percentage of nanostructure-bound metal ions remaining was called metal ion stability % and calculated using the following formula: The obtained value is a measure of the chelating strength of the nanostructures, and the higher the value, the stronger the chelating strength of the nanostructures. TIFF2025510507000017.tif17170TIFF2025510507000018.tif72170

[0394] Table 3 shows that metal ion-loaded long boiling nanostructures synthesized by the method according to the present disclosure (detailed in Example 1A or 1B) have better metal ion stability compared to nanostructures of the same size produced by short boiling method 1C, demonstrating the superior chelating strength of the nanostructures of the present disclosure.

[0395] Example 6 – Biodistribution studies of coated nanostructures in a tumor-bearing mouse model Representative Preparation of Test Article: Test Article C Nanostructures were synthesized using a procedure similar to that of Example 1B using a 95 mM solution of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, resulting in nanostructures with a diameter of 23.0 nm. To prepare coated nanostructures, a 10 ml sample of the resulting nanostructure solution (nominal 0.95 mmol of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane) was placed in a vial and heated to 100° C. in an oil bath. After 20 min, 809 mg of bis(triethoxysilyl)methane (2.38 mmol, 2.5 equivalents relative to 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane) was added with vigorous stirring. Heating was maintained for 4 h with gentler stirring. Average diameter 25.7 nm

[0396] A 1.025 mL sample of the resulting nanostructure solution (nominal 0.097 mmol of 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane) was diluted to 7.5 mL with 80% (vol / vol) aqueous ethylene glycol in a two-neck round-bottom flask fitted with a reflux condenser at the vertical end connected at the top to a vacuum-nitrogen manifold and the side end plugged with a septum. This solution was heated in a preheated 110° C. oil bath for 10 min, after which 200 μL of a 50% (wt / wt) solution of 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy)45-methyl)heptane in anhydrous dioxane heated to 40° C. was added. An additional 805 μl of the warm 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy)45-methyl)heptane solution was added via syringe pump at a rate of 43 μl / hr. After a total of 48 hours, the solution was allowed to cool to ambient temperature.

[0397] The nanostructure solutions from two identical batches were combined, diluted to 50 ml with water, and filtered through a 0.2 μm polyethersulfone (PES) syringe filter. The resulting solution was diluted to 800 ml with water and concentrated to approximately 20 ml using a tangential flow filtration device with a nominal cutoff of 300 kD. The dilution-concentration procedure was repeated a total of five times, after which the solution was further concentrated to 11.3 ml with a spin filter with a nominal cutoff of 300 kD. Mean diameter = 35.3 nm, [P](ICP-OES) = 28 mM

[0398] A 4 ml sample of the resulting nanostructure solution (112 μmol P) was treated with 228 μl of a 19.7 mM LuCl3 solution (4.5 μmol Lu) and heated to 60° C. for 1 h, after which 1.269 ml of 1 M Tris buffer (pH=7.47) was added. After an additional 2 h at 60° C., the solution was filtered through a 0.2 μm PES syringe filter.

[0399] A 3.47 ml sample of the resulting nanostructure solution was mixed with 3.80 ml saline and 140 μl of 99 mM CaCl2 solution, after which the pH was adjusted to 7.2 with 12 μl of 1 M NaOH solution. The solution was diluted to a total volume of 7.5 ml with saline and then filtered through a 0.2 μm PES syringe filter.

[0400] Average diameter (DLS)=36.0nm, [P](ICP-OES)=9.9mM, [Si](ICP-OES)=46mM, [Lu](ICP-OES)=0.39mM

[0401] Test samples A and B Test specimens A and B were similarly prepared starting from 37 mM and 65 mM 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane solutions, respectively. Test item A: Average diameter (DLS)=21.3nm, [P](ICP-OES)=8.9mM, [Si](ICP-OES)=48mM, [Lu](ICP-OES)=0.39mM Test sample B: average diameter (DLS) = 27.7 nm, [P] (ICP-OES) = 8.7 mM, [Si] (ICP-OES) = 41 mM, [Lu] (ICP-OES) = 0.39 mM

[0402] Distribution in the body The tissue distribution of the test articles was investigated after intravenous injection in tumor-bearing mice. The injectable test articles were analyzed by ICP-OES for lutetium, silicon, and phosphorus content. The lutetium values ​​obtained represent the total amount of lutetium injected (i.e., 100%). Each test article was administered intravenously at 2 μmol Lu / kg and 5 ml / kg. The animals were divided into four groups per test article (n=5 mice / group) and the groups were sacrificed at 6, 24, 48, and 168 hours after injection. Three animals served as control animals and were not dosed. At the end of the experimental period, blood samples were taken and plasma was prepared by removing blood cells. After termination, organs were removed (liver, tumor, and thigh muscle). Plasma and digested tissue samples were analyzed by ICP-OES for lutetium (shown in Table 4) and silicon (data not shown) content. Table 4 shows the distribution of injected lutetium at different times after injection of the test article. TIFF2025510507000019.tif113170

[0403] As can be seen from Table 4, the coated nanostructures according to the present disclosure are long circulating, i.e., have a long plasma half-life. In addition, a significant proportion of the nanostructures are seen to be distributed in the tumor, demonstrating that the nanostructures according to the present disclosure are suitable for use in pharmaceutical compositions and for use in imaging and / or cancer therapy.

[0404] Example 7 – SEC chromatogram vs. DLS The nanostructures according to Example 1A, with a mean diameter of 18.2 nm based on DLS measurements, were also analyzed by size exclusion chromatography (SEC). The peak apex and particle size distribution were determined by comparison with reference proteins or protein complexes of known particle size.

[0405] Reference protein standards: bovine serum albumin, 66 kDa, thyroglobulin from bovine thyroid gland (Thyro-bov), 667 kDa, empty cowpea mosaic virus (CPMV) VLP, 4360 kDa

[0406] The chromatogram in Figure 6 shows that the nanostructures (bold line) show a bell-shaped peak, and that the nanostructures peak apex is located near Thyro-bov (19.4 nm by DLS). 95.6% of the nanostructures peak area is between BSA (6.9 nm by DLS) and CPMV (29.1 nm by DLS), 1.6% of the nanostructures peak area is above CPMV, and 2.8% of the peak area is below BSA. The 2.8% portion is mainly residue of the starting monomer.

[0407] Example 8 – NMR of nanostructures boiled for short and long periods NMR spectra were recorded at 25° C. on a Varian Unity Inova 500 MHz spectrometer equipped with a Z-spec DBG500-5EF 5 mm dual broadband gradient probe.

[0408] 1 H spectra were recorded with an excitation pulse of 5.7 μs (corresponding to a flip angle of 45°), an observation time of 1.0 s, and a repeat delay of 5.0 s, collecting four transients, at a spectral width of i) 200 kHz with 400 k data points or ii) 12 kHz with 24 k data points. Shimming was performed by gradient shimming against the solvent hydrogen signal. 31 P NMR spectra were recorded with 2k data points, collecting 64 transients with a pulse width of 4.9 μs, an observation time of 0.02 s, a repetition delay of 1.0 s, and a spectral width of 506 kHz. Spectra were recorded both with and without proton decoupling.

[0409] Samples of nanostructures synthesized as in Examples 1C "short boiling" and 1B "long boiling" were transferred to D2O and analyzed by NMR.

[0410] Nanostructures by short-term and long-term boiling 1The H NMR is shown in Figure 3. The long boiled nanostructures show a very broad spectrum indicating a higher degree of cross-lining.

[0411] Nanostructures by short-term and long-term boiling 31 P NMR is shown in Figure 4. The long boiled sample shows a single peak indicating that there is only one phosphonate present, presumably the fully hydrolyzed phosphonate, in contrast to the short boiled sample which shows a more complex shape indicating partial hydrolysis.

[0412] Example 9 - Synthesis of nanostructures using low purity 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane - Reference method outside the scope of this disclosure A 25 mL three-neck round-bottom flask equipped with a reflux condenser at the center neck connected at its top to a vacuum-nitrogen manifold and with a glass stopper at the side neck was charged with 720 mg of crude 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane of 80% purity and 14.7 mL of 80% (vol / vol) aqueous ethylene glycol. The solution was degassed and then heated to gentle reflux in an oil bath. After 44 hours of reflux, a 16.2 nm diameter and high dispersity were obtained. The nanostructure TIFF2025510507000020.tif5170 was obtained.

[0413] Another reaction set up similarly using the same batch of crude 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane produced a highly disperse 1,2-dichloro-2,3-dichloro-1,3-dichloro-2,4-dichloro-2,5-dichloro-1,3-dichloro-2,5-dichloro-2,6 ... The nanostructure TIFF2025510507000021.tif5170 was obtained.

[0414] This demonstrates that impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane is not suitable for the synthesis of nanostructures according to the present disclosure.

[0415] Example 10 - AFM image showing spherical shape of nanostructures according to the present disclosure Nanostructures made according to Example 1B with an average particle size of 19.1 nm were subjected to atomic force microscope (AFM) analysis. AFM Model: Fast Scan Asyst Tip: SSS-NCHR-10 (2 nm), spring constant 10 to 100 N / m Imaging mode: Tapping mode with peak force instead of cantilever amplitude as feedback gain

[0416] Silicon wafers were ultrasonically cleaned in acetone for 2 min, then blown dry with N2 gas. They were sonicated in 2-propanol for an additional 2 min, after which the wafers were blown dry again with N2 gas. The nanostructures were diluted in 10 mM ammonium bicarbonate [(NH4)HCO3] aqueous solution to a phosphorus concentration of 16 μM, and then a 10 μl droplet was placed on the cleaned silicon wafer. The droplet on the wafer was dried on a hot plate at 40 °C for 10 min, and the nanostructures were subjected to atomic force microscopy (AFM) analysis.

[0417] The results are shown in Figure 7, which shows that the individual nanostructures meet the definition of a spherical shape.

[0418] Example 11 – Modeling nanostructure composition from elemental analysis The nanostructure according to Example 1A was freeze-dried and subsequently subjected to combustion elemental analysis after further drying at 120° C. overnight. The results were as follows: C: 24.17%, H: 5.37%, Si: 15.42%, P: 14.81%. Modeling was performed in Excel according to the following method: Suspected molecular components were added to their relative molar contributions. The main component 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane was set to 1 and the molecular weight was set to 362 g / mol, which is the molecular weight of the hypothetical fully cross-linked and fully hydrolyzed version. Water was then added to formally break the cross-links, since Si-O-Si + H2O→SiOH + HOSi. NMR showed that the structure contained about 4 wt% ethylene glycol, which was also added. The elemental contributions of each molecular component were then calculated and the percentages of each element were calculated and compared to the experimental values. The penalty function of the deviation (sum of absolute values ​​of the difference between the model value and the calculated value) is minimized by adjusting the fractions. In this case, only the water and ethylene glycol contents need to be optimized. The best fit to the combustion data was obtained with a molar ratio of 1:0.39:0.01 for 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, ethylene glycol, and water, respectively, corresponding to a bond number of 5.9 between the monomers. This indicates that the nanostructures have the intended composition, with a very high bond number between the monomers.

[0419] Example 12 - Determining nanostructure powder density The freeze-dried nanostructures from Example 1A were suspended in a series of mixtures of heptane and dibromomethane with different densities. The suspensions were centrifuged at 13,000 RPM for 5 minutes to observe whether the nanostructures precipitated, floated, or were suspended. If the density was higher than the heptane-dibromomethane mixture, the particles precipitated, if the density was lower than the heptane-dibromomethane mixture, the particles floated, and if the density was similar to the respective heptane-dibromomethane mixture, the particles remained suspended. The nanostructures precipitated in heptane-dibromomethane solvent mixtures up to a density of 1.561 g / mL and floated in solvent mixtures with a density of 1.736 g / mL. The average of these two densities, 1.649, was therefore taken as the estimated density of the nanostructures. Since bisphosphonic acids are much denser than the corresponding esters, the high density indicates complete hydrolysis of the phosphonate esters.

[0420] TIFF2025510507000022.tif39170

[0421] Example 13a: 4,4-bis(ω-methyl-(ethyleneoxy) 45 Synthesis of (Methyl)-hepta-1,6-diene Diallylpropanediol (22 g, 0.1411 mol) was dissolved in anhydrous toluene (2.61 L) and cooled in an ice bath. When the internal temperature was below 10° C., NaH (23.7 g, 0.593 mol, 60% in mineral oil, 4.2 eq) was added in three portions while maintaining the temperature below 10° C. The slurry was then stirred at room temperature for 60 min, followed by m-PEG in anhydrous toluene (2.61 L). 45To an azeotropically dried solution of -OTs (1.071 kg, 0.9877 mmol, 3.5 equiv) was added at 0°C under N2. The reaction mixture was heated to reflux overnight and stirred under N2. The reaction was monitored by HPLC and upon completion, the temperature was reduced to 15°C and the reaction was quenched by dropwise addition of H2O (70 ml). The pH of the crude reaction mixture was adjusted to 5-7 with 1.0 M HCl (100 ml). The crude reaction mixture was divided into two equal portions for practical reasons and the two portions were extracted separately. Each half of the crude mixture was diluted with H2O (7.14 L). The temperature was increased to 60°C and NaCl (540 g) was added. The mixture was then stirred for 45 min and extracted three times with EtOAc (2.1 L). To the remaining aqueous phase, NaCl (200 g) was added and the mixture was extracted again three times with EtOAc (2.1 L). The last three extracted fractions had acceptable product purity (HPLC) and were dried over MgSO4, filtered through dual GF / A filters, and the solvent was evaporated. The resulting residues were pooled, dissolved in H2O (2.0 L), and the pH was adjusted to pH 8 with 0.8 M aqueous NaHCO3 (100 ml). The aqueous phase was extracted three times with DCM (dichloromethane) (500 mL). The organic phase was dried over MgSO4, filtered, and evaporated to give a white residue.

[0422] Therefore, the extraction process was repeated for the other half of the crude mixture, and the final products of both extractions were pooled together with the products of another similarly sized batch synthesized in the same manner to obtain 4,4-bis(ω-methyl-(ethyleneoxy) 45 -methyl)-hepta-1,6-diene (758 g, yield 66.36%, purity 96.8% (HPLC-ELSD)). 1 H NMR(400MHz,CDCl3)δ5.80(m,2H),5.03(m,4H),3.70-3.60(s,540H),3.37(s,6H),3.22(s,4H),2.04(d,4H)

[0423] Example 13b: 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy) 45 Synthesis of (Methyl)heptane 4,4-Bis(ω-methyl-(ethyleneoxy) 45 To an azeotropically dried solution of 1,2-dimethyl-2,4-hexanedione (714 g, 0.172 mol) was added triethoxysilane (1117 g, 6.88 mol, 40 equiv.) under nitrogen at 22° C. Karstedt's catalyst (25.34 ml, 2% in xylene, 1.14 mmol, 0.0066 equiv.) was added in 1 mL portions via syringe over 30 min resulting in an exotherm of ≦2° C. The reaction mixture was stirred overnight at 22° C. under nitrogen.

[0424] The reaction is analyzed for the disappearance of an olefinic proton. 1 The reaction was monitored by H-NMR. The solvent was then evaporated and the excess silane was removed by co-evaporation with anhydrous toluene (2.5 L) for a total of four times. The residue was then redissolved in toluene (4.2 L), degassed with three vacuum / nitrogen cycles, and stirred with activated SIR-200 resin (175 g) at 60 °C for three days. The solution was filtered from the resin, the resin was washed with toluene (3 x 2.8 L), and the collected fractions were filtered through a double GF / A filter, pooled, the solvent was evaporated to give 1,7-bis(triethoxysilyl)-4,4-bis(ω-methyl-(ethyleneoxy) 45 (-methyl)-heptane was obtained in quantitative yield as a white solid (783.2 g, ≧99%, purity 94.4% (HPLC-ELSD)). 1 H NMR(400MHz,C6D6)δ3.71(q,12H),3.70-3.40(s,400H),3.52(s,4H),3.35(s,6H),1.68(m,4H),1.59(m,4H),1.23(t,18H),0.79(t,4H)

[0425] Example 14. Hydrodynamic size distribution of several nanostructure samples. TIFF2025510507000023.tif6170, and comparison with polydispersity index (PDI) Nanostructure samples with different dispersions were analyzed by DLS, and the dispersion of each sample was TIFF2025510507000024.tif5170 and the polydispersity index (PDI) was calculated (shown in Table 5). TIFF2025510507000025.tif101170

[0426] From Table 5, It can be seen that TIFF2025510507000026.tif5170 and PDI are correlated, and that both parameters represent the breadth of the size distribution of the nanostructure population. However, a simple, monotonic conversion between the two does not allow a good fit to the data. It can be concluded that TIFF2025510507000027.tif5170 and PDI capture different aspects of the shape of the particle size distribution.

Claims

1. a plurality of spherical nanostructures, the plurality of spherical nanostructures having a dispersity of 1 to 1.8; the nanostructures have a volume average hydrodynamic diameter of 13 nm to 90 nm; each nanostructure comprises a polymeric backbone of monomer residues, the average number of bonds from each monomer residue is in the range of from 3.0 to less than 6.0, the linkages between said monomer residues are Si—O—Si, each nanostructure comprises 10% to 25% silicon by weight, at least 90% of said monomer residues have 5 to 11 carbon atoms, and at least 90% of said monomer residues comprise two geminal chelating groups, each chelating group independently being a group according to formula (I); During the ceremony, R １ and R ２ is independently selected from the group consisting of a negative charge and H; and "-" indicates an internal bond of said monomer residue, and the chelating groups according to formula (I) constitute at least 90% of the chelating groups in the nanostructure; Multiple spherical nanostructures.

2. 10. The plurality of nanostructures of claim 1, wherein the dispersity is between 1 and 1.5, such as between 1 and 1.3, such as between 1.1 and 1.35, such as less than 1.

3.

3. at least 90% of the monomer residues are residues according to formula (II); During the ceremony, Each R １ and R ２ is independently selected from the group consisting of a negative charge and H; Each R ３ are independently selected from the group consisting of a negative charge, H, and a covalent bond to the polymer backbone, and at least three R ３ is a bond to the polymer backbone, and n is an integer from 1 to 5; A plurality of nanostructures according to claim 1 or 2.

4. The R ３ 4. The plurality of nanostructures of claim 3, wherein at least four of the groups are bonds to the polymer backbone.

5. 4. The plurality of spherical nanostructures of claim 3, wherein n=3.

6. The plurality of spherical nanostructures of claim 1 , wherein the nanostructures further comprise a coating, preferably the coating comprises hydrophilic groups.

7. A pharmaceutical composition comprising a plurality of spherical nanostructures according to claim 6.

8. 10. A pharmaceutical composition for use in treating and / or imaging cancer, comprising a plurality of spherical nanostructures according to claim 6, said spherical nanostructures further comprising a radioisotope.

9. 1. A method for purifying 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane, the method comprising: (a) providing a solution of impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in a polar aprotic solvent; (b) separating the solution of step (a) from insoluble matter; (c) concentrating the solution obtained in step (b), thereby obtaining a residue; (d) dissolving the residue obtained in step (c) in a non-polar solvent; (e) separating the solution obtained in step (d) from insoluble matter; (f) removing water from the solution obtained in step (e); (g) concentrating the solution obtained in step (f) to obtain a second residue; (h) subjecting the residue obtained in step (g) to short-path pass-through vacuum distillation; and (i) recovering the pass-through fraction from step (h) comprising purified 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane; A purification method comprising:

10. - the polar aprotic solvent of step (a) is acetonitrile and the solution of step (a) has a concentration of impure 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane in the range of 25 g / L to 250 g / L; and / or - the non-polar solvent of step (d) is a lower alkane and the solution of step (d) has a concentration of the residue obtained in step (c) in the range of 25 g / L to 250 g / L / L; and / or - the short-path pass-through vacuum distillation of step (h) is carried out at a temperature in the range of from 150°C to 190°C and a pressure in the range of from 0.1 mbar to 1 mbar; 10. The method of claim 9.

11. Use of 1,7-bis(triethoxysilyl)-4,4-bis(dimethoxyphosphonato)heptane purified according to claim 9 for producing a plurality of spherical nanostructures according to claim 1.

12. 2. A method for producing a plurality of spherical nanostructures according to claim 1, comprising: (a) providing a solution comprising a monomer in a mixture of water and a lower alcohol, said monomer being a monomer according to formula (II): {(OR １ )(OR ２ )PO} ２ -(C){(CH ２ ) ｎ Si(OR ３ ) ３ }{(CH ２ ) ｎ Si(OR ３ ) ３ } (II) During the ceremony, Each R １ and R ２ is independently selected from the group consisting of lower alkyl and aryl, and Each R ３ is independently selected from the group consisting of lower alkyl and aryl, and n is an integer from 1 to 5; The process and (b) subjecting the solution of step (a) to a temperature of 110-160°C for a duration such that the growth rate of the nanostructures is significantly lower than the initial growth rate; A manufacturing method comprising:

13. 13. The method of claim 12, wherein the solution provided in step (a) is provided by dissolving a monomer having a purity greater than 80% in a mixture of water and a lower alcohol.

14. 14. The method of claim 12 or 13, wherein the monomer in step (a) is 1,7-bis(triethoxysilyl)-4,4-bis(dimethylphosphonato)heptane, the concentration of the monomer is 30 to 40 mM, the solvent mixture is 10% water in ethylene glycol, and in step (b), the temperature is 140° C. and the heating time is 45 to 50 hours.

15. 13. Use of the plurality of spherical nanostructures of claim 1 and / or the product of the method of claim 12 as an intermediate in the production of a plurality of spherical coated nanostructures.

16. 13. Use of the plurality of spherical nanostructures of claim 1 and / or the product of the method of claim 12 as an intermediate in the manufacture of a pharmaceutical product.

17. Use of the pharmaceutical composition according to claim 7 as a carrier for a radioisotope.

Images