Method for making magnetite nanoparticles stabilised by biocompatible polymer having functional formyl groups

FIELD: medicine, pharmaceutics.

SUBSTANCE: invention can be used for creation of magnetic-susceptible sorbents applicable in medicine. A method for making magnetite nanoparticles stabilised by a biocompatible polymer having available functional formyl groups, involves preparation of magnetite of two mixed salts of ferrous iron and ferric iron adsorbed in polymeric matrixes, and modification of end groups of polymer. Magnetite is produced by coprecipitation in an alkaline medium of two mixed salts of ferrous iron and ferric iron, and at least one polymer selected from a number: chitosan, polyvinyl alcohol, block copolymer of polystyrene and polyethylene oxide. The weight relation of polymers in the composite makes 4 to 46 wt %. The produced composite is dispersed, processed in an aqueous solution of glutaraldehyde and washed. All the operations are combined with continuous ultrasound exposure.

EFFECT: invention allows producing multiuseable steady magnetite nanoparticles.

3 cl, 2 dwg, 1 tbl, 5 ex

 

The present invention relates to the field of obtaining magnetospirillum sorbents and can be used for monitoring and diagnosis of epidemic infections, such as tuberculosis.

Modern research in the field of nanomaterials bear witness to the promise in the use of magnetospirillum composite materials in medicine, biology and diagnosis of epidemic infectious diseases.

For existing methods of obtaining magnetospirillum composites using magnetite (Fe3O4), including iron(3+) and iron(2+), the main problems are: production of nano-sized particles of magnetite, preventing agglomeration of the nanoparticles of magnetite in the process of selection, the creation of a stable composition of the magnetic particles of the sorbent, which carries on its outer surface reactive group suitable for immobilization of biological objects, such as antibodies.

Affordable way to prevent agglomeration of the nanoparticles with the formation of larger aggregates is to stabilize the magnetite nanoparticles in electrically neutral polymer, poly-or polyanionic matrix, forming stable compounds with magnetite. Polymer matrix assumes the absence of its direct chemical interaction with magnetica, that allows it to retain its magnetic properties in the process of further use when creating bionanocomposites based on it. The resulting spatial structure of the polymer prevents aggregation of the magnetite particles, allowing the particles of the specified size.

The matrix, for its part, must have the ability to bind to biological macromolecules, in particular antibodies, i.e. it must surface to be modified with the introduction of active chemical groups.

A method of obtaining particles of magnetite stabilized with chitosan and treated with glutaraldehyde to immobilize pullulanase used for hydrolysis of pullulan and amylopectin (Zhang Lianying, Photochemical preparation of magnetic beads for immobilization of pullunase, Biochemical Engineering Journal, 2009, v.46(1), 83-87).

The method includes the following stages: a) obtaining particles of magnetite using ferric chloride(3+) and sodium sulfite as a reducing agent in the presence of excess ammonia, b) surface modification of magnetite solution of hydrochloric acid salt of chitosan in the presence of N,N'-methylene-bis-acrylamide as a cross-linking agent in the presence of hydrogen peroxide and irradiation with ultraviolet light at a pH of 5.5 in) modification of particles with glutaraldehyde.

This method is quite time-consuming, and its main disadvantage is used the e hydrogen peroxide, which leads to the depolymerization of chitosan (C.Q.Qin, Effect of hydrogen peroxide treatment on the molecular weight and structure of chitosan. Polymer Degradation and Stability, 2002, v.76, 211-218), education regenerating chitooligosaccharides in the complex and, as a consequence, the reduction of iron(3+) iron(2+), which leads to rapid destruction of the composite and not allow the use of such composites repeatedly.

Also known is a method of obtaining magnetic microspheres based on chitosan for use as a sorbent. The method includes the following stages: a) preparation of a mixture of magnetite in a solution of chitosan in 5% acetic acid; b) emulsifying the mixture in mineral oil with addition of petroleum ether and emulsifier with vigorous stirring; C) adding glutaraldehyde and stirring the emulsion prior to the formation of microspheres; d) separation of the microspheres with a size of 1-5 μm (1000-5000 nm), washing them from the oil with petroleum ether (Emir Baki Dekba, Magnetic chitosan microspheres: preparation and characterization. Reactive and Functional Polymers, 2002, v.50(3), 225-232).

However, this method is time consuming, requires the use of flammable substances and is suitable only for obtaining large particles, which reduces the effectiveness of their use, because the microparticles have a smaller ratio of surface/weight than the nanoparticles.

The closest analogue of the present invention is a method of obtaining a composite is s granules based on chitosan for use in medicine with the goal of immobilization of biological objects. The method includes the following stages: 1) preparation of magnetite (Fe3O4) adding ammonia to a solution of salts of Fe(3+) and Fe(2+); 2) dispersing the obtained magnetite in alcohol; 3) adding acetic acid derivative of chitosan and its dispersion under the action of ultrasound; 4) separating and washing compositions and eventually obtaining nanometer granule magnetic chitosan composites for medical applications. (CN 101129339 (A)A61K 9/16, publ. 2008-02-27).

However, this method has a number of disadvantages, such as: (a) in this method particles of magnetite cover stabilizer (chitosan) only from the surface with the content of chitosan in the composite is not more than 2% by weight; b) as a result of the low content of stabilizer stability of the composite insufficient for repeated use; b) stabilizing the surface layer is non-uniform and destroyed by the action of acids and oxidizing agents; d) the absence of the stabilizer inside the composite leads to its high density relative to the density of physiological aqueous solutions and quick samosatene particles of a composite of aquatic environments, causing no need for such bystrorassasyvayuschikhsya particles have magnetic properties; d) the absence of active groups on the surface of the granules.

The present invention solves the task is to create sustainable magnetite nanoparticles stabilized biocompatible polymer, are reusable.

The problem is solved by a method for production of composite nanoparticles of magnetite stabilized biocompatible polymer having available functional formyl group, including the production of magnetite from a mixture of salts of divalent or trivalent iron adsorbed in the polymer matrices with subsequent modification of the polymer. The novelty of the method lies in the fact that obtaining magnetite adsorbed in the polymer matrices, carry out joint deposition in an alkaline medium a mixture of salts of divalent or trivalent iron and at least one polymer selected from the range of: chitosan, polyvinyl alcohol, copolymer, block copolymers of polystyrene and polyethylene oxide, to obtain composite particles with a weight content of polymers from 4 to 46 wt.%, then the resulting composite is dispersed and carry out its modification with glutaraldehyde, in this case, all operations are performed under continuous ultrasound exposure. The term "composite" here we understand magnetite, glucouse these polymers as in its internal part and the external surface.

To obtain the final product with the highest specific magnetization weight content of the polymer in the mixture is from 4 to 18 wt.%.

Joint precipitation of sm is si salts of divalent or trivalent iron and polymer in an alkaline medium with the recovery of salts of iron to magnetite allows to simplify the technology of obtaining particles of magnetite, stable polymer matrix with simultaneous increase of their stability.

While the preferred deposition condition is the use of an aqueous solution of ammonia, which allows the use of easily detachable alkaline solutions.

The technical result achieved by the implementation of the proposed method allows to solve the problem due to:

1) getting activated composite particles capable of covalently bind biologically active substances and affinity ligands due to the presence of reactive formyl groups on the surface and the weight of the composite;

2) reduce the specific gravity of the composite and the achievement of its increased stabilization in aqueous media;

3) increasing the stability of the composite particles in the processes reusable.

The proposed method, these effects are achieved through a synergistic effect of one or two polymers of the above range to be included in the composite particles of the polymer/magnetite, and allow you to create the internal structure of the composite, ensuring the stability of magnetite in time. This effect could not be predicted from the previously known in the scientific literature information and patent data. The treatment with glutaraldehyde helps to reinforce the internal structure of the composite, chemically link the polymers in the composite covalent bonds and to ensure the availability of reactive formyl groups on the surface of the particles.

When interacting composite with glutaraldehyde occurs simultaneous modification and cross-linking of the polymer layer on the hydroxyl and amino groups. The presence listed in the proposed invention the polymer and aldehyde groups in the complex is confirmed by the method of IR-spectroscopy. Thus, the IR spectrum of the composite are the strongest absorption band 593-595 nm, attributed to magnetite, as well as a strong band in the range of 1036-1149 cm-1characteristic C-O-C vibrations fragments of 1,4-polysaccharides, band 1641 cm-1(amide II). The IR spectrum of the modified glutaraldehyde composite, in addition to the above absorption bands, contained intensive band 1659 cm-1typical of aliphatic Schiff bases, and the band at 1713 cm-1(C=O), typical for aliphatic aldehydes.

The resulting aldehyde (formyl) group quantitatively determined by the method based on the use of mercaptoethanol. The method of determining the content of aldehyde groups in the composite using mercaptoethanol based on known quantitative reaction of the aldehyde groups with mercaptoethanol in water by the reaction:

-SNO+HSCH2CH2OH→-CH(OH)SCH2CH2OH

For analysis of the obtained product is taken 3 samples, 2 ml of the dispersion. The first portion add 0.1 ml Merck is toetenel, maintain for 1 hour, and then washed with water collecting using a permanent magnet. Then this product and the other two portions of the dispersion is dried first freeze, and then in a vacuum of 1-2 mm Hg at 60°C. In the first portion to determine the sulfur content of the elemental analysis. The sulfur content directly correlates with the content of aldehyde groups. The second portions define the content of the solid residue by the gravimetric method and carbon, iron, and nitrogen by the method of elemental analysis. The composition of the composite is calculated according to elemental analysis.

Magnetic properties of samples were investigated using vibrating sample magnetometer type Fonera. The specific magnetization of the composite ranged from 47 to 70 Gauss·cm3/g (see table 1).

Figure 1 shows an image transmission electron microscopy (TEM) of magnetite particles adsorbed in the matrix of chitosan.

Figure 2 shows the TEM image of magnetite particles adsorbed in the matrix mixture of chitosan and blockcopolymer of polystyrene and polyethylene oxide.

The table shows the properties of the composite, depending on the composition of the starting components.

These examples suggest, but do not exhaust the invention.

Example 1. Getting the magnetite nanoparticles stabilized by chitosan.

Dissolve 1.4 g of Fe2(SO4)3 ·9H2O and 0.9 g of FeSO4·12H2O in 25 ml deionized water and add 1.2 ml of 2% solution of chitosan. Then add an excess of concentrated ammonia. After that, collect the magnetic composite and washed with water collecting using a permanent magnet.

The resulting composite is treated with an aqueous solution of glutaraldehyde and washed again, collecting particles of the composite using a permanent magnet. All operations are performed under continuous ultrasound exposure with a frequency of 22 kHz.

Figure 1 shows using TEM particles of magnetite adsorbed in the matrix of chitosan. As can be seen in figure 1, the magnetite particles adsorbed in the matrix of chitosan, weakly aggregated among themselves, have a fairly narrow dispersion and the particle size of magnetite are 5-10 nm.

The content of aldehyde (formyl) groups in the composite is 4 µmol/mg, specific magnetization of the composite 69,0 Gauss·cm3/year

The table shows data about the changing properties of the composite, depending on the composition of the starting components.

As can be seen from the table, the specific magnetization of magnetite composites shows that it decreases with the increasing content of polymers and reducing the magnetite content in the complex. To obtain the highest specific surface magnetization option is of magnetite should be conducted with a reduced number of polymers (4-18%). Composites with increased content of the polymers can also find their application because they have a higher content of functional groups, and greater resilience. However, an excess content of polymer in the composite is higher than 46%, although increases the content of formyl group, but at the same time leads to an unacceptable reduction of the magnetic susceptibility and reduce the resistance of the composite.

Example 2. Getting the magnetite nanoparticles stabilized by chitosan and polyvinyl alcohol.

Dissolve 1.4 g of Fe2(SO4)3·9H2O and 0.9 FeSO4·12H2O in 25 ml deionized water and add 0.6 ml of 2% solution of chitosan and 0.6 ml of 2% solution of polyvinyl alcohol. Then add an excess of concentrated ammonia. After that, collect the magnetic composite and washed with water collecting using a permanent magnet.

The resulting composite is treated with an aqueous solution of glutaraldehyde and washed again, collecting particles of the composite using a permanent magnet.

All operations are performed under continuous ultrasound exposure with a frequency of 22 kHz.

The content of aldehyde (formyl) groups in the composite is 4 µmol/mg, specific magnetization of the composite 70,0 Gauss·cm3/year

Example 3. Getting the magnetite nanoparticles stabilized by chitosan and bloxom what limera of polystyrene and polyethylene oxide.

Dissolve 1.4 g of Fe2(SO4)3·9H2O and 0.9 g of FeSO4·12H2O in 25 ml deionized water and add 1.2 ml of 2% solution of chitosan and 4.2 ml of 2% solution of blockcopolymer of polystyrene and polyethylene oxide. Then under the simultaneous effect of ultrasound add an excess of concentrated ammonia. After that, collect the magnetic composite and washed with water collecting using a permanent magnet.

The resulting composite is treated with an aqueous solution of glutaraldehyde and washed again, collecting particles of the composite using a permanent magnet.

All operations are performed under continuous ultrasound exposure with a frequency of 22 kHz.

Figure 2 is using PAM magnetite particles adsorbed in the matrix mixture of chitosan and block copolymers of polystyrene and polyethylene oxide. As can be seen in figure 2, the magnetite particles adsorbed in the matrix of chitosan and block copolymers of polystyrene and polyethylene oxide have a size of from 5 to 10 nm, and some reach the value of 20 nm.

The content of aldehyde (formyl) groups in the composite is 9 µmol/mg, specific magnetization of the composite 47,0 Gauss·cm3/year

Example 4. Getting the magnetite nanoparticles stabilized by polyvinyl alcohol.

Dissolve 1.4 g of Fe2(SO4)3·9H2O and 0.9 g of FeSO4·N2About 25 ml of ionizovannoi water and add to 5.4 ml of a 2% solution of polyvinyl alcohol. Then add an excess of concentrated ammonia. After that, collect the magnetic composite and washed with water collecting using a permanent magnet.

The resulting composite is treated with an aqueous solution of glutaraldehyde and washed again, collecting particles of the composite using a permanent magnet.

All operations are performed under continuous ultrasound exposure with a frequency of 22 kHz.

The content of aldehyde (formyl) groups in the composite is 9.5 µmol/mg, specific magnetization of the composite 47,2 Gauss·cm3/year

Example 5 Obtaining nanoparticles of magnetite stabilized blockcopolymers of polystyrene and polyethylene oxide.

Dissolve 1.4 g of Fe2(SO4)3·9H2O and 0.9 g of FeSO4·12H2O in 25 ml deionized water and add to 10.4 ml of 2% solution of blockcopolymer of polystyrene and polyethylene oxide. After that, collect the magnetic composite and washed with water collecting using a permanent magnet.

The resulting composite is treated with an aqueous solution of glutaraldehyde and washed again, collecting particles of the composite using a permanent magnet.

All operations are performed under continuous ultrasound exposure with a frequency of 22 kHz.

The content of aldehyde (formyl) groups in the composite is 2 μmol/mg, specific magnetization of the components of the ITA 37,0 Gauss·cm 3/year

Further increase in the content of the polymer leads to the reduction of the magnetization.

As seen from the above examples when compared to the prototype, the resistance of the composite manufactured according to our proposed method increases dramatically (4-40 times), and the content of functional formyl groups in 2-12 times.

The method of obtaining the magnetite nanoparticles stabilized biocompatible polymer having functional formyl group
The weight of the polymer, wt.%Mass of Fe3O4, wt.%The content of formyl groups, mEq/gThe stability of the composite, the dayThe specific saturation magnetization, 20°C, Gauss·cm3/g
2 (prototype)9800,2571,0
4964,5169,0
4964,51 70,0
188210,0546,3
18829,0547,0
18829,56to 47.2
36642,01037,0
46562,51527,7
50502,71019,0

1. The method of obtaining the magnetite nanoparticles stabilized biocompatible polymer having available functional formyl group, including the production of magnetite from a mixture of salts of divalent or trivalent iron adsorbed in the polymer matrix, with subsequent modification of the end groups of the polymer, characterized in that the receiving magnetite adsorbed in the polymer matrices together to carry out the deposition in an alkaline medium a mixture of salts of divalent or trivalent iron, and at least one polymer selected from the range of: chitosan, polyvinyl alcohol, copolymer, block copolymers of polystyrene and polyethylene oxide, the weight content of the polymer in the composite from 4 to 46 wt.%, then the resulting composite is dispersed, treated with an aqueous solution of glutaraldehyde and washed, with all operations carried out under continuous ultrasound exposure.

2. The method according to claim 1, characterized in that to obtain the final product with the highest specific magnetization weight content of the polymer in the mixture is from 4 to 18 wt.%.

3. The method according to claim 1, characterized in that the deposition of a mixture of salts of divalent or trivalent iron and polymers carried out by adding an aqueous solution of ammonia.



 

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4 cl, 3 dwg

FIELD: metallurgy.

SUBSTANCE: invention refers to manufacturing method of nanoparticles of metallic silver with diameter of 1 to 100 nm and average diameter of 20 to 40 nm, which are characterised with monodispersion, stability during more than 12 months, in wide range of concentrations. Method involves preparation of water solution of silver salt, which contains 0.01 to 20 wt % of soluble silver salt; preparation of water solution of reducing agent, which contains 0.01 to 20 wt % of the compound of group of tannins; mixing of the above water solutions in order to perform the reaction between them, separation of mother solution from silver nanoparticles obtained in the above reaction. At that, the above reaction is performed by mixing those solutions and pH control in the value range of 10.5 to 11.5. Obtained particles can be repeatedly dispersed in various media, such as water, alkydal and phenol resins, cellulose nitrate, polyurethane resin, vinyl and acrylic compounds, alcohols and in many organic materials and polymers, such as high-density and low-density polyethylenes, nylon, acrylonitrile-butadiene-styrene resin and/or their mixtures.

EFFECT: obtaining nanoparticles of metallic silver, which are characterised with monodispersion, stability during more than 12 months in wide value range of concentrations.

20 cl, 5 dwg

FIELD: medicine, pharmaceutics.

SUBSTANCE: declared invention refers to chemical-pharmaceutical industry, and concerns a method for preparing a solid oral dosage form which contains a poorly soluble and/or poorly mouldable drug substance and a hydrophylic polymer. The method is implemented by using an extruder with an added unstable plasticiser in the form of a liquefied gas or a supercritical fluid, e.g. such as a supercritical carbon dioxide. The unstable plasticiser is added to accelerate material processing.

EFFECT: unstable plasticiser is used to reduce viscosity of the mould mixture, and/or improved solubility of the drug substance.

9 cl, 2 ex

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