Method for synthesizing zeolite nanoparticles in a saline phosphate buffer and associated nanoparticles, suspensions, pharmaceutical composition and uses

Abstract

The present invention relates to a method for synthesizing nanoparticles consisting of or comprising at least one zeolite nanocrystal according to which: - a first composition / solution 1 containing an aluminum source and a source of an ion of an alkali metal M, in particular Na, is prepared; a second composition / solution 2 comprising a silicon source and a source of an ion of an alkali metal M, in particular Na, is prepared, said solutions 1 and 2 being free of any organic structuring agent; - the two compositions / solutions 1 and 2 are mixed; - the mixture is crystallized; and - said nanoparticles thus formed are optionally separated. According to the invention, said first composition / solution 1 and said second composition / solution 2 are both constituted of said source and of an alkaline phosphate buffer (PBS). The present invention also relates to the nanoparticles obtained and compositions containing them.

Description

[0001] PROCESS FOR THE SYNTHESIS OF ZEOLITE NANOPARTICLES IN A SALINE PHOSPHATE BUFFER - NANOPARTICLES, SUSPENSIONS, PHARMACEUTICAL COMPOSITION AND ASSOCIATED USES

[0002] Technical field

[0003] The present invention relates to a process for synthesizing zeolite nanoparticles, the nanoparticles thus obtained, suspensions of these nanoparticles in water or PBS buffer as well as a pharmaceutical composition and a combination product containing these nanoparticles.

[0004] These nanoparticles can be used in the medical field, in particular for the treatment of hypoxic solid tumors.

[0005] State of the art

[0006] Zeolites are a class of crystalline microporous materials. They are formed by a three-dimensional arrangement of TO4 (T= Si, Al or other heteroatoms) bonded to each other by sharing an oxygen atom. In aluminosilicate zeolites, the presence of ACGU ions 5 ' gives the framework negative charges which must be compensated by so-called compensating cations (alkaline or alkaline-earth), such as Na + , K + , That 2+ , Sr 2+in order to maintain electrical neutrality. The vacant space is defined by the aluminosilicate framework formed by these three-dimensional chains. The vacant spaces in the tetrahedral crystal lattice are connected to each other and occupied by alkali ions and water molecules. Dehydration of zeolites removes the water molecules present. Zeolites also have a microporous network formed by cavities, channels connecting the cavities and pores connecting the channels or cavities with the outside. Zeolites can be natural or synthetic. There are currently more than 250 types of zeolites.

[0007] W02015 / 101800 A describes a method for synthesizing faujasite nanocrystals (FAU-type zeolites), faujasite single crystals, and a method for synthesizing a colloidal suspension of these nanocrystals. The faujasite nanocrystals have a size ranging from 5 to 400 nm, a Si / Al molar ratio ranging from 1 to 2.5, and a Si / Na molar ratio of 1.1 to 1.5. The total pore volume (total pore volume) ranges from 0.50 to 1.5 cm 3 / g. WO 2019 / 030200 A1 describes FAU and EMT type zeolite nanocrystals for which sodium ions have been replaced by Fe or Gd ions and which can be loaded with gaseous dioxygen. These nanocrystals can be used for the diagnosis and treatment of brain tumors, including glioblastoma. The publication by Anfray et al "Nanosized zeolites as a gas delevery platfrom in a glioblasma model" describes a suspension of FAU type nanozeolites in water. The zeolite nanocrystals described in these documents are synthesized in water, which limits their medical uses. Indeed, over the long term and at high concentrations, these nanocrystals are likely to cause allergy-type problems. Technical problem to be solved

[0008] An aim of the present invention is therefore to propose new zeolite nanoparticles which can be used in the diagnosis and / or treatment of certain pathologies, in particular solid brain tumors.

[0009] Another aim of the invention is to propose a new method for synthesizing such nanoparticles.

[0010] Another aim of the invention is to provide colloidal suspensions of these nanoparticles.

[0011] Another aim of the invention is to provide zeolite nanoparticles which have reduced toxicity and / or exhibit an improved oxygen adsorption and / or release capacity.

[0012] Summary of the invention

[0013] A first aspect of the invention relates to a method for synthesizing nanoparticles consisting of or comprising at least one zeolite nanocrystal according to which:

[0014] - a first composition / solution 1 is prepared containing a source of aluminum and a source of an ion of an alkali metal M, in particular Na;

[0015] - a second composition / solution 2 is prepared comprising a source of silicon and a source of an ion of an alkali metal M, in particular Na, said compositions / suspensions 1 and 2 being free of any organic structuring agent;

[0016] - compositions / solution 1 and 2 are mixed and the mixture is left stirring, - the mixture is crystallized at a temperature greater than or equal to 50°C; and

[0017] - the said nanoparticles thus formed are possibly separated,

[0018] Characteristically, according to the invention said first composition / solution 1 and said second composition / suspension 2 are each a composition / solution consisting of said source and an aqueous buffer (PBS), which consists of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4, 1.76 mM / L of KH2PO4 and having a pH equal to 7.2 and said mixture of solutions 1 and 2 has the following molar composition (I):

[0019] X1 M2O : yAI2O3: 10SiO2: z PBS (I) in which 2.8 <x1 < 8,8, 0,3 <y< 1 ,5 et 40 <z< 300.

[0020] The method of the invention is simple to implement and makes it possible to obtain zeolite nanoparticles forming a stable colloidal suspension in PBS. Preferably, solutions 1 and 2 are prepared.

[0021] Depending on the method of implementation, it is sometimes necessary to heat the mixture of PBS buffer and other reagents to obtain a clear or limpid suspension.

[0022] With regard to temperatures, the first composition / solution 1 can be prepared at room temperature. The second composition / solution is prepared, for example, at a temperature below 30°C and in particular equal to 25°C. The mixing of the two compositions / solutions can advantageously be carried out at a temperature equal to or greater than 0°C and equal to or less than 30°C and in particular equal to 0°C. Then, the mixture must be left stirring at a temperature equal to or greater than 0°C and equal to or less than 30°C and in particular equal to 25°C for at least 2 hours and in particular 24 hours. The mixture can be crystallized at a temperature greater than or equal to 50°C.

[0023] Detailed description

[0024] The aluminum source may be chosen from any aluminum source capable of providing monomeric oxyhydroxide species. For the purposes of the present invention, "any aluminum source capable of providing monomeric oxyhydroxide species" means that this aluminum source does not provide polymeric aluminum oxyhydroxide species and makes it possible to dissolve all the aluminum in the clear aqueous solution 1. In particular, the aluminum source may be chosen from alumina, hydrated alumina, aluminum powder, Al, Al2(SO4)3, aluminum hydroxide AI(OH)3, sodium aluminate (NaAlCh), potassium aluminate (KAIO2) and kaolin clays.

[0025] The silicon source can be chosen from any silicon source capable of providing monomeric or Si2-Sie oxyhydroxide species. Thus, the quantity of [SiOOH] units nlarger is limited in the composition / suspension 2. In particular, the silicon source may be chosen from silica hydrogel, silicic acid, colloidal silica, fumed silica, tetraalkyl orthosilicates, silica hydroxides, precipitated silica, silica fume and clays. Colloidal silica is preferred in all embodiments of the method of the invention.

[0026] The source of alkali metal M can be chosen in particular from a source of Na and a source of K. The hydroxides of these two alkali metals are preferred as sources of alkali metal.

[0027] According to a particular embodiment, M = Na, said source of aluminum is aluminum powder, solutions 1 and 2 are prepared and before crystallizing said mixture of solutions 1 and 2, it is dehydrated under vacuum and the remaining solid fraction is then crystallized at a temperature greater than or equal to 30°C and less than or equal to 100°C and in particular equal to 50°C for a duration equal to or greater than 6 hours and equal to or less than 30 hours and in particular equal to 25 hours.

[0028] According to a particular variant, 5 <x1 < 8.8, 0,3 <y< 1 ,5 et 40 <z< 200 et selon une variante plus particulière x1 = 8,3 , y =1 , 1 et z = 55,6.

[0029] FAU type zeolite nanoparticles are thus obtained. It should be noted that the method of the invention also allows the direct production of suspensions of zeolite nanoparticles in PBS.

[0030] Advantageously, the purification of said nanoparticles is carried out using a membrane, in particular a dialysis membrane. The operation of this method is simple, inexpensive, generally carried out using commercially available membranes (dialysis membrane), and it also saves water. This technique also allows the PBS to be preserved in the nanoparticles.

[0031] A second aspect of the invention relates to a method for manufacturing a colloidal suspension of nanoparticles, according to which nanoparticles are synthesized according to the method of the invention and said synthesized nanoparticles are dispersed in optionally sterile water or in an optionally sterile aqueous buffer solution consisting of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4 and 1.76 mM / L of KH2PO4 and having a pH equal to 7.2. A suspension of zeolite nanoparticles in water or in PBS is thus obtained. In the case of a suspension in water, the zeolite nanoparticles are dispersed, having been previously filtered in order to remove the PBS.

[0032] The present invention also relates to a nanoparticle consisting of or comprising a zeolite nanocrystal and obtainable according to the method of the invention. According to the invention, said zeolite is an aluminosilicate of the FAU type and it contains PBS ions, i.e. Na ions + , K + , H2PO4 2 ; HPCU' HsO + and Cl' and possibly water molecules. These ions are arranged on the surface of the crystal lattice and / or in the interstices of the crystal lattice and / or in the pore network of the particle. The surface of the crystal lattice can be the surface of the particle. The Na ions + and K + , in particular can be found in the interstices of the crystal lattice as compensation ions. Said nano zeolite can advantageously contain at least two species of the aforementioned ions. Depending on the pH, it can contain different quantities of the HPCU ions 2', H3O+, FhPCU'. These ions, whatever they are, are located in its porous network and / or on its surface and / or in the interstices of its crystal network and / or on the surface of the crystal network, which can correspond to the surface of the particle.

[0033] The inventors have demonstrated that nanoparticles synthesized in PBS saline buffer are less cytotoxic and therefore likely to be better accepted by the body.

[0034] PBS has the same salt concentration as the human body; it also contains the dihydrogen phosphate / hydrogen phosphate pair, which helps maintain blood pH in the body. Without the inventors being bound to this explanation, it would seem that certain ions of the PBS contained in the crystal lattice and / or in the porous lattice and / or on the surface of the nanoparticle can stabilize the nanoparticles and prevent them from degrading in the biological environment, thereby reducing their toxicity potential. In addition, the ions of the PBS can also regulate the charge on the surface of the nanoparticles, which can influence their behavior and interaction with biological cells and tissues. The nanoparticles obtained according to the method of the invention thus avoid or reduce the allergy phenomena described above. The nanoparticle may be a nanocrystal.

[0035] This nanocrystal may have an average diameter greater than or equal to 10 nm and less than or equal to 100 nm and in particular equal to 30 nm. According to a particular embodiment, the zeolite has the following chemical composition:

[0036] | Na69.79K6.O6 (H2O)211.85| (Sil23.09Al66.59O384) (H).

[0037] The number of moles of water is determined by thermogravimetric analysis. The number of Na, K, Si, and Al atoms is determined by ICP, and the number of moles of oxygen is determined from the number of moles of metals using the stoichiometry of the formula.

[0038] Regardless of the embodiment, the nanoparticle of the invention may have a total pore volume greater than or equal to 0.4 cm 3 / g and less than or equal to 1.5 cm 3 / g and / or a specific surface area SBET greater than or equal to 200 m 2 / g and less than or equal to 1000 m 2 / g.

[0039] According to a particular variant, said nanoparticle has a total pore volume (cavity + pores + channels) greater than or equal to 0.6 cm 3 / g and less than or equal to 1.3 cm 3 / g to and in particular equal to 0.93 cm 3 / g and / or a specific surface area SBET greater than or equal to 300 m 2 / g and less than or equal to 800 m 2 / g and in particular equal to 600 or 428 m 2 / g. This nanocrystal can have the chemical formula (II)

[0040] The porous network of the zeolite of the invention extends in the three directions of space

[0041] According to a fourth aspect of the invention, it relates to a nanoparticle as mentioned above which further contains, in the cavities of its crystal lattice, cations of a metal chosen from Fe, Gd, Cu and Ce and in particular in an amount greater than or equal to 0.2% by mass and less than or equal to 5% by mass and / or a gas contained in its pore volume and chosen from oxygen, nitrogen, carbon dioxide and mixtures thereof. Some of these nanoparticles can be used in diagnosis (the Gd, Fe ions serving in particular as labeling ions) in particular in magnetic resonance imaging (MRI) and in treatment when they are loaded with oxygen. Indeed, they then provide oxygen which they deliver into the cells and thus increase the reactivity of the cells of solid cancerous tumors to anticancer agents.

[0042] According to another aspect of the invention, it relates to a suspension comprising or consisting of the nanoparticles of the invention and a dispersant chosen from water, a buffer consisting of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4, 1.76 mM / L of KH2PO4 and having a pH equal to 7.2 (PBS), alcohols and mixtures thereof.

[0043] According to another aspect, the present invention relates to a pharmaceutical composition containing as contrast agent or pharmaceutically active agent nanoparticles according to the invention, optionally suspended in a dispersant.

[0044] The quantity of nanoparticles is the quantity suitable to obtain a therapeutic effect or to obtain a contrast allowing diagnosis.

[0045] The dispersant is chosen from pharmaceutically acceptable solvents, in particular water, PBS, alcohols and their mixtures.

[0046] The composition of the invention can be administered orally, mucosally (in particular intranasally) or parenterally.

[0047] The present invention also relates to a nanoparticle according to the invention, for its use as a medicament, in particular for the treatment of hypoxic solid cerebral tumors and in particular glioblastoma, or as a diagnostic agent, in particular as a contrast agent in MRI.

[0048] The present invention also relates to a combination product comprising or consisting of the pharmaceutical composition of the invention or the suspension according to the invention and an anticancer agent, for their simultaneous or delayed administration. The nanoparticles according to the invention preferably contain oxygen in their porous network and are optionally suspended in a pharmaceutically acceptable dispersant. The dispersant is preferably chosen from water, PBS and mixtures thereof. The anticancer agent and the pharmaceutical composition of the combination product of the invention may be administered simultaneously or in a delayed manner, the anticancer agent being advantageously administered first. The anticancer agent may be chosen from temozolomide® (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo [4.3.0]nona-2,7,9-triene-9-carboxamide methazolastone), doxorubicin (8S,10S)-10-(4-amino-5-hydroxy-6-methyl-tetrahydro-2H-pyran-2-yloxy)-6,8, 11 -trihydroxy-8-(2-hydroxyacetyl)-1 -methoxy-7,8,9, 10-tetrahydrotetracene- 5,12-dione)., cisplatin (cis-diamminedichloroplatinum(ll)).

[0049] Definitions

[0050] The term "average size" designates, within the meaning of the invention, the average size (in number or in intensity) measured by dynamic light scattering. The average size corresponds to the diameter of the sphere which scatters at the same speed as that of the particle being measured. The fundamental size distribution obtained by DLS is an intensity distribution. The operating conditions are as defined in the remainder of the application.

[0051] For the purposes of the invention, the term “nanoparticle” designates any solid particle with a maximum dimension of less than 100 nm. It may be a single crystal or an aggregate of crystals.

[0052] The term PBS refers to phosphate buffered saline which is an aqueous solution of NaCl (0.137 M), KCl (0.0027 M), sodium phosphate dibasic (0.01 M) and potassium phosphate monobasic (0.0018 M). Its pH is 7.2.

[0053] The term "FAU-type nanoparticle" means nanoparticles comprising or consisting of a single crystal of FAU-type zeolite.

[0054] The term "FAU-type zeolite" refers to an aluminosilicate that crystallizes in a face-centered cubic system. According to the invention, the terms include FAU X-type zeolites for which the Si / Al molar ratio is greater than or equal to 1 and less than or equal to 1.5 and FAU Y-type zeolites for which the Si / Al molar ratio is greater than or equal to 1.5 and less than or equal to 2.6. Thus, a chemical formula of a FAU-type zeolite nanocrystal is INa a Kb (H2O) C I(AI X Sii92-xO384), Na ions + and K + being present so as to ensure the electrical neutrality of the nanocrystal. Water molecules may be absent from the nanocrystal.

[0055] The term "clear suspension" means an aqueous suspension having substantially the same refractive index as water, i.e., a refractive index of approximately 1.333 ± 0.030, measured under standard conditions.

[0056] The terms "pore volume" or "pore network" refer to the set formed by the cavities, the channels connecting these cavities to each other and the pores which connect the channels and cavities to the exterior of the nanoparticle.

[0057] The term "pharmaceutically active" means an agent which confers curative or preventive therapeutic properties to the composition which contains it and which, if it has harmful side effects, does not outweigh the curative and / or preventive effects.

[0058] The term "pharmaceutically acceptable" means any agent that can be ingested, injected or brought into contact with the skin and mucous membranes without generating an adverse effect or without generating an adverse effect of such magnitude that it disrupts the patient's state of health. The term "composition" means any homogeneous or inhomogeneous mixture of at least two compounds that may be in different physical states; the term composition thus includes, in particular, solutions, suspensions and dispersions.

[0059] Brief description of the figures

[0060] The characteristics and advantages of the invention will appear on reading the following description based on the appended figures, among which:

[0061] - Fig. 1 represents the size distribution of the Na-FAU-PBS nanoparticles of the invention, the nanoparticles are dispersed in a PBS solution;

[0062] - Fig. 2A represents images obtained by scanning electron microscope of nanoparticles (nanocrystals) of Na-FAU-PBS and Gd-FAU-PBS type with a scale of 500 nm and Fig. 2B represents images obtained by scanning electron microscope of nanoparticles (nanocrystals) of Na-FAU-PBS type with a scale of 100 nm and 40 nm;

[0063] - Fig. 3 represents the quantity of adsorbed nitrogen as a function of the relative pressure obtained under the operating conditions described below for the Na-FAU-PBS type nanoparticles;

[0064] - Fig. 4 represents a comparison of the viability of U87-MG cells exposed to two colloidal suspensions of nanoparticles containing respectively 10 pg / mL and 100 pg / mL of Na-FAU-Water or Gd-FAU-Water nanoparticles with that obtained for the same concentrations of Na-FAU-PBS and Gd-FAU-PBS nanoparticles;

[0065] - Fig. 5 represents on the left the percentage of hemolysis as a function of the dose of nanoparticles (in pg / mL) of the Na-FAU and Gd-FAU type synthesized with water or PBS;

[0066] - Fig. 6A represents the change in the oxygen concentration in the water obtained by bringing into contact Na-FAU-Water and Gd-FAU-Water particles, previously loaded with O2 and Fig. 6B the change in the oxygen concentration in the PBS obtained by bringing into contact with Na-FAU-PBS and Gd-FAU-PBS particles of the invention and previously loaded with O2;

[0067] EXAMPLES

[0068] SYNTHESIS AND CHARACTERIZATION OF NANOPARTICLES

[0069] The raw materials used in the following examples are listed below: - Sodium hydroxide (Sigma Aldrich, 98%)

[0070] - Potassium hydroxide (Sigma Aldrich, 90%)

[0071] - Aluminum hydroxide (type A2100, Alfa Aesar, 76.5% by mass AI(OH)3, 23.5% by mass H2O)

[0072] - Aluminum powder (325 mesh, Alfa Aesar 99.5%)

[0073] - Colloidal silica (SiCh (Ludox HS-30, 30 wt.% SiC>2, pH=9.5-10.2 Sigma Aldrich)

[0074] - Colloidal silica (SiCh (Ludox SM-30, 30 wt.% SiC>2, pH=9.7-10.3 Sigma Aldrich)

[0075] - Gadolinium nitrate Gd(NOs)3, 6H2O (Aldrich, 99.9%)

[0076] - Phosphate buffered saline (PBS) (Sigma Aldrich, pH=7.15-7.25)

[0077] These starting reagents were used as received from the manufacturers, without further purification.

[0078] Analysis methods used and operating conditions

[0079] The different zeolite materials obtained in the examples were characterized on different size scales.

[0080] Scanning and transmission electron microscopy (SEM / TEM) imaging:

[0081] The morphology of the nanoparticles was examined by scanning electron microscopy (SEM) using a Tescan Mira I LMH device at a voltage of 20 kV.

[0082] Transmission electron microscopy (TEM): Colloidal suspensions were sonicated for 15 minutes, then 2 to 3 drops of fine particle suspensions were dried on 300 mesh copper electron microscope grids coated with carbon film. Images were obtained using a FEI Tecnai G2 30 microscope (Vacc = 300 kV, LaB6).

[0083] Dynamic Light Scattering (DLS) Analysis:

[0084] The hydrodynamic diameters of the zeolite material in the different suspensions were determined with a Malvern Zetasizer Nano instrument. The surface charge of the samples was determined by measuring the zeta potential of the suspensions. The analyses were carried out on samples after purification with a solid concentration of 1% by weight dispersed in a PBS solution at pH = 7.2. The backscattering geometry (scattering angle 173°, HeNe laser with an output power of 3 mW at a wavelength of 632.8 nm) allows measurements at a high sample concentration, since complete penetration of the incident light through the sample is not necessary. Chemical analysis by ICP-MS (inductively coupled plasma mass spectrometry)

[0085] The chemical composition of the zeolite samples was characterized by inductively coupled plasma mass spectrometry using Agilent Technologies 7900 equipment. The samples were prepared according to the following procedure: (i) 50 mg of zeolite sample was dissolved in 3 mL of hydrofluoric acid (HF) (Sigma-Aldrich 40-45%), (ii) a 0.5 mL solution (HNO3 / HCl equals 1:3 v / v) was added and then the mixture was heated at 110 °C for 1 h in a polytetrafluoroethylene (PTFE) bottle (100 mL), and subsequently (iii) 96.5 mL of distilled water and 2 g of boric acid (H3BO3) were added. The obtained solution was stirred overnight to facilitate the dissolution of boric acid. Finally, 10 mL of the suspension was diluted 10 times with distilled water before analysis.

[0086] Example 1: Synthesis of FAU-type nanocrystals in PBS solution (Na-FAU-PBS)

[0087] The colloidal suspension of FAU was synthesized hydrothermally from the molar composition cited with reference to the first mode of implementation of the process of the invention.

[0088] A solution A of aluminum powder is prepared by dissolving 2.3 g of NaOH in 3 g of PBS followed by slow addition of 0.29 g of aluminum powder.

[0089] Silicate solution B was prepared by mixing 10 g of colloidal silica (LUDOX® HS-30) with 1.1 g of NaOH and 1 g of PBS. This cloudy solution (suspension B) was heated for 6-7 min in an oven at 100°C to be transformed into a clear solution. Solution B was then added dropwise to solution A under a temperature of 0-3°C and rapid stirring, and then the mixture was aged for 24 h at room temperature.

[0090] The initial molar composition of the mixture is as follows:

[0091] 8.3Na2O: 1.1 AI2O3: 10SiO2: 55.6 (PBS)

[0092] The resulting mixture is dehydrated by lyophilization and then crystallized for 25 hours in an oven at 50°C. The suspension is purified by dialysis membrane (Visking Dialysis Tubing, Code No. - DTV.12000.08 Size No.8 (25.4mm, 30m), Molecular Weight 12-14000 Daltons), until a pH of 7.2 is reached. 60 - 75 mL (1.6 to 1.9 g) of a colloidal suspension containing 2.5% by mass of Na-FAU type zeolite nanocrystals in PBS are obtained. The nanoparticles contain PBS ions in their porous network and, as an alkali ion intercalated in the network, Na ions. + and K + The final suspensions were sonicated for 2 h.

[0093] The crystal yield ranges from 53 to 63% (the crystal yield is defined as the mass of product obtained X 100 / mass of SiCh contained in solution B. Chemical formula of the Na-FAU-PBS zeolite nanocrystal obtained by ICP:

[0094] | Na69.79K6.O6 (H2O)211.85| (Sil23.09Al66.59O384)

[0095] The formula in parentheses corresponds to the crystal lattice, between the bars are the number of moles of compensation ions and the number of moles of water.

[0096] Example 2: Synthesis of colloidal suspensions of nanoparticles according to the invention A given quantity of each of the types of nanoparticles of Example 1 was dispersed in 10 mL of PBS under sonication for 2 hours. Colloidal solutions containing respectively 1%, 2%, 3% and 4% by mass of Na-FAU-PBS type nanoparticles dispersed in PBS are obtained.

[0097] These nanoparticles are stable in colloidal suspension at room temperature for at least one week.

[0098] Example 3: Synthesis of zeolite nanoparticles charged with metal ions

[0099] 5 mL of each of the two colloidal suspensions obtained in Example 2, each containing 2.5% by mass of nanoparticles, were added separately to 25 mL of a solution of gadolinium (III) nitrate hexahydrate (Gd(NO3)3.6H2O) with a concentration of 0.03 mM). The suspension was then kept stirring at room temperature for 1 h. This ion exchange process was carried out twice. The final suspension was then washed 3 times with PBS to finally obtain a suspension of Gd-FAU-PBS zeolite in PBS and therefore at pH=7.2. Example 4: Incorporation of dioxygen and / or CO2 into the porous network of nanoparticles

[0100] Each of the colloidal aqueous suspensions obtained in Example 2 or Example 3 was then bubbled with O2, CO2 or carbogen at a flow rate of 800 mL / min for 30 minutes.

[0101] This produces nanoparticles whose porous network is at least partially filled with O2 and / or CO2.

[0102] Example 5: Morphological characterization of the nanoparticles obtained in Examples 1, 2 and 4. Scanning / transmission electron microscopy (SEM) / (TEM) were used to determine the morphology and size of the synthesized Na-FAll-PBS and Gd-FAU-PBS nanoparticles.

[0103] The curve giving the size distribution of nanoparticles dispersed in PBS is shown in Fig. 1 for Na-FAU-PBS nanoparticles.

[0104] For Na-FAU-PBS type nanoparticles, the hydrodynamic size of nanoparticle aggregates in PBS solution measured by DLS is between 50-200 nm. It is found that this is a mono-dispersed population.

[0105] Scanning electron microscopy images of Na-FAU-PBS or Gd-FAU-PBS zeolite nanoparticles (see Fig. 2A) show nanoparticles with a quasi-spherical shape with a homogeneous size distribution and TEM transmission electron microscopy images (see Fig. 2B) show nanoparticles (nanocrystals) with an average size of 30 nm.

[0106] In addition, high-resolution transmission electron microscopy images show that the nanoparticles are highly crystalline. These are nanoparticles each formed from a single nanocrystal.

[0107] Example 6: Chemical analysis of Na-FAU nanoparticles

[0108] The chemical formula of the zeolite material of Na-FAU-PBS and Gd-FAU-PBS type nanoparticles is as follows (determined by ICP):

[0109] | Na69.79K6.O6 (H2O)21 1.85| (Sil 23.09Al66.59O384)

[0110] I Na63.92K2.33Gd2.44 (H2O)l 65.49| (Sil 23.26Al67.13O384)

[0111] The formula in parentheses corresponds to the crystal tetrahedral lattice, between the bars are the number of moles of compensating cations and the number of moles of water.

[0112] Example?: Determination of porosity by adsorption / desorption of nitrogen

[0113] The porosity of the Na-FAU-PBS and Gd-FAU-PBS zeolites synthesized in the above examples was characterized by nitrogen gas adsorption / desorption measurements.

[0114] The textural properties of the nanoparticles obtained in Examples 1, 2 and 4 were determined by the nitrogen adsorption / desorption isotherms measured at a temperature of -196°C using a “Micromeritics 3Flex” surface characterization device. All samples were degassed at 250°C under vacuum overnight before analysis. The external surface area of ​​the zeolite nanoparticles and the micropore volume of the zeolite nanoparticles were evaluated by the t-plot method.

[0115] Nitrogen adsorption / desorption measurements for both zeolites resulted in hybrid isotherms of type I and IV according to the IUPAC classification (see Fig. 3). The measurement of the SBET specific surface area, the total pore volume and the micropore volume of the zeolite nanoparticles are grouped in Table 1 below. A micropore is defined as a pore smaller than 0.08 mm.

[0116] Table 1

[0117] Table 2 below lists the chemical composition of the Na-FAU-PBS and Gd-FAU-PBS nanoparticles of the invention.

[0118] Table 2

[0119] The pharmacological properties of the nanoparticles of the invention were studied. The results are shown in the following examples.

[0120] Example 8: Toxicity test on human cell line.

[0121] The cells used were derived from a human glioblastoma cell line, U87-MG, purchased from American Type Culture Collection (ATCC). The cells were cultured in DMEM 1 g / L glucose (Sigma-Aldrich) supplemented with 10% fetal bovine serum (Eurobio), 2 mM glutamine (Sigma-Aldrich), and penicillin (100 U / mL) / streptomycin (100 pg / mL) (Sigma-Aldrich). The cells were maintained in culture at 37°C with 5% CO2 and 95% humidity. Cell viability was assessed 72 h after exposure to zeolite nanoparticles with the WST-1 assay (Roche) according to the manufacturer's instructions.

[0122] The results are visible in Figure 4 5. This figure also shows the percentage of cell viability with exposure to nanoparticles synthesized in water instead of PBS. It can be seen that for the Na-FAU-PBS, Gd-FAU-PBS nanoparticles of the invention, the percentage of viable cells is higher than for nanoparticles synthesized from the same mixture but with water instead of PBS (Na-FAU-Water, Gd-FAU-Water).

[0123] Example 9: Red blood cell viability test.

[0124] To confirm the absence of toxicity of the nanoparticles of the invention, red blood cells were exposed to increasing concentrations of nanoparticles according to the invention (from examples 1, 2 and 4). The results are visible in Fig. 5. It can be seen that for the nanoparticles synthesized in water, the maximum percentage of hemolysis is 1.85% for the Na-FAU-Water nanoparticles and 1.19% for the Gd-FAU-Water nanoparticles. This percentage decreases to 0.408% and 0.590% for the Na-FAU-PBS and Gd-FAU-PBS particles, respectively.

[0125] Furthermore, in the presence of a large amount of nanoparticles (500 pg / mL), the highest percentage of hemolysis obtained for Gd-FAU-Water nanoparticles is 2%. It drops to 1% for Gd-FAU-PBS nanoparticles.

[0126] These results confirm that the use of PBS during the synthesis of nanoparticles decreases their toxicity.

[0127] Example 10: Study of oxygen release by zeolitic nanoparticles in aqueous and hypoxic conditions.

[0128] A hypoxia chamber (IN VIV02 500™, 3M) was used to achieve a stable and precisely controlled gas composition of the atmosphere with an accuracy of 0.1% O2 by adjusting the amount of N2. The PBS solution (Sigma-Aldrich) was equilibrated with the gas mixture contained in the hypoxia chamber for 1 h before the experiment. A closed tube containing 12 mL of PBS equilibrated at 37°C and a dissolved oxygen sensor (SevenGo (Duo) pro™ / OptiOx™, Mettler Toledo) were used inside the hypoxia chamber. Before the experiment, the baseline was established by measuring the oxygen content of the PBS for 30 min.

[0129] The nanoparticles of the examples of the different types and previously loaded with oxygen were then added to the system and the dissolved oxygen in the PBS solution was continuously measured for 1 h. The results are visible in Fig. 6A and 6B. It can be seen that the Gd-FAU-PBS nanoparticles of the invention previously loaded with oxygen exhibit a better release of oxygen compared to the nanoparticles prepared in water (Gd-FAU-Water). In addition, the release kinetics is also increased, which is of interest for in vivo use. The release of oxygen is accelerated after 30 min, which is of considerable interest for in vivo use, the particle having time to reach the brain and deliver oxygen there. Concerning the Na-FAU-PBS nanoparticles, it can be seen that the release kinetics of oxygen is slower compared to Na-FAU-Water.

Claims

Claims 1. Process for the synthesis of nanoparticles consisting of or comprising at least one zeolite nanocrystal according to which: - a first composition / solution 1 is prepared containing a source of aluminum and a source of an ion of an alkali metal M, in particular Na; - a second composition / solution 2 is prepared comprising a source of silicon and a source of an ion of an alkali metal M, in particular Na, said compositions / solutions 1 and 2 being free of any organic structuring agent; - mix compositions / solutions 1 and 2 and leave the mixture stirring, - the mixture is crystallized at a temperature greater than or equal to 50°C; and - optionally separating said nanoparticles thus formed, characterized in that said first composition / solution 1 and said second composition / solution 2 each consist of said source and an aqueous buffer consisting of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4, 1.76 mM / L of KH2PO4 and having a pH equal to 7.2 (PBS) and in that said mixture of said compositions / suspensions 1 and 2 has the following molar composition (I): XI M2O : YAI2O3 : 10SiO2: Z PBS (I) in which 2.8 <X1 < 8,8, 0.3 <Y< 1 ,5, 40 <Z<300.

2. Method according to claim 1, characterized in that M=Na, in that said source of aluminum is aluminum powder, in that before crystallizing said mixture of said compositions / solutions 1 and 2, it is dehydrated under vacuum and in that the remaining solid fraction is then crystallized at a temperature greater than or equal to 30°C and less than or equal to 100°C and in particular equal to 50°C for a duration equal to or greater than 6 hours and equal to or less than 30 hours and in particular equal to 25 hours.

3. Method according to any one of claims 1 and 2, characterized in that M= Na and in that 5 <x1 < 8.8, 0,3 <y< 1 ,5 et 40 <z< 200 et en particulier x1 = 8,3, y =1 ,1 et z = 55,6.

4. Method according to any one of the preceding claims, characterized in that said nanoparticles are separated by membrane filtration.

5. Nanoparticle consisting of or comprising at least one zeolite nanocrystal and obtainable according to the method of any one of claims 1 to 4, characterized in that said zeolite is an aluminosilicate of FAU type and in that it contains Na ions + , K + , HPO4 2 ; HsCT, H2PO4 and Cl'.

6. Nanoparticle according to claim 5, characterized in that said nanocrystal has the following formula (II): INa69.79K6.06 (H2O)2i i.85| (Sii23.09Al66.59O384) (II) or the following formula INa63.92K2.33Gd2.44 (H2O)l65.49| (Sil23.26Al67.13O384) 7. Nanoparticle according to claim 5 or 6, characterized in that it has a total pore volume greater than or equal to 0.4 cm 3 / g and less than or equal to 1.5 cm 3 / g and / or a specific surface area SBET greater than or equal to 200 m 2 / g and less than or equal to 1000 m 2 / g.

8. Nanoparticle according to any one of claims 5 to 7, characterized in that it further contains in its crystal lattice cations of a metal chosen from Fe, Gd, Cu and Ce and in particular in an amount greater than or equal to 0.2% by mass and less than or equal to 5% by mass and / or a gas contained in its pore volume and chosen from oxygen, nitrogen, carbon dioxide and their mixtures.

9. Suspension comprising or consisting of nanoparticles according to any one of claims 5 to 8 and a dispersant chosen from water, a buffer consisting of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4, 1.76 mM / L of KH2PO4 and having a pH equal to 7.2, alcohols and their mixtures.

10. Pharmaceutical composition containing as contrast agent or pharmaceutically active agent nanoparticles according to any one of claims 5 to 8, optionally suspended in a dispersant or the suspension according to claim 9.

11. Pharmaceutical composition according to claim 10, characterized in that said dispersant is chosen from water, a buffer consisting of water and 137 mM / L of NaCl, 2.7 mM / L of KCl, 10 mM / L of Na2HPO4, 1.76 mM / L of KH2PO4 and having a pH equal to 7.2, alcohols and their mixtures.

12. Combination product characterized in that it comprises or consists of the pharmaceutical composition according to claim 10 or 11 or the suspension according to claim 9 and an anticancer agent for their simultaneous or delayed administration.

13. Use of the nanoparticle according to any one of claims 5 to 8 as a medicament, in particular for the treatment of solid tumors, in particular of the brain, in particular glioblastoma.

14. Use of the nanoparticle according to any one of claims 5 to 8 as a contrast agent, in particular in magnetic resonance imaging (MRI).

15. Use of the suspension according to claim 9, in particular in PBS, as a medicament, in particular for the treatment of solid tumors, in particular of the brain, in particular glioblastoma.

16. Use of the suspension according to claim 9, in particular in PBS, for its use as a contrast agent, in particular in magnetic resonance imaging (MRI).

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