JP2006321763A - Biocompatibilie nanoparticle and method for production of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide biocompatible nanoparticles encapsulating a medicinal substance with a high rate irrespective of the medicinal substance is hydrophilic or hydrophobic, and to provide a method for producing the same. <P>SOLUTION: The invention relates to the biocompatible nanoparticles 1 comprising a hydrophilic polymer block 3 thrusting to the surface of the particle and forming a shell part 5, and a hydrophobic polymer block 2 locating at a core section 6 to form a core shell structure. The leak out of the hydrophilic component 7 to a poor solvent is suppressed by a mutual action with the hydrophilic polymer block 3 and the hydrophilic component 7 is encapsulated in the shell part 5 of the nanoparticles 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to biocompatible nanoparticles in which a bioactive component is encapsulated in a biocompatible polymer.

  When drug therapy is performed, the drug usually gets absorbed and decomposed in the body, or spreads widely throughout the body, that is, other than the affected part (organ, tissue, cell, pathogen, etc.). Is said to be a trace of the dose. In other words, it was not possible to artificially control whether the drug could reach the affected area. On the other hand, when the drug dose is determined by calculating backward from the amount of drug that should reach the affected area, the dose becomes very large, and the possibility of developing side effects increases.

  In general, it is ideal that a drug is allowed to act in the required amount at the required site at the required time. Therefore, a technique for suppressing excessive drug administration by preventing the drug from being absorbed and decomposed until it reaches the affected area, a so-called drug delivery system (hereinafter referred to as DDS) has been devised and has been actively studied in recent years. DDS is a technology that wraps a drug in a film (carrier), effectively and intensively sends the drug to the target affected area without being absorbed or decomposed in the middle, and releases the drug in the affected area. This has the merit of not only enhancing the therapeutic effect of the drug, but also reducing side effects.

  The technology that is the center of DDS is a technology that wraps a minute amount of drug with a biocompatible polymer to make nanoparticles of about several tens of nanometers that can pass through minute holes in capillaries. These drug-containing nanoparticles deliver the drug stably and reliably to the target affected area, and control the release rate (sustained release) of the drug according to the type of polymer and the elapsed time after administration. The drug can be released at the point of time, and it is highly effective not only for use as an injection or oral preparation but also for externally used drugs that have heretofore been difficult to penetrate deeply into the skin.

  The biocompatible polymer as the material constituting the nanoparticles is preferably a biocompatible polymer that has low irritation and toxicity to the living body, is biocompatible, and decomposes and metabolizes after administration. Moreover, it is preferable that it is the particle | grain which releases the drug to include continuously and gradually. As such a material, for example, a polylactic acid / glycolic acid copolymer (hereinafter referred to as PLGA) is preferably used. It is known that PLGA can contain a drug and can be stored for a long time while maintaining the efficacy of the drug. Furthermore, it is considered that sustained release in units of several days to one month can be performed from the characteristics of PLGA hydrolysis and long-term half-life.

  Patent Document 1 discloses a method for producing drug-containing nanoparticles by a multiple emulsion method in which a drug is encapsulated in a carrier composed of a biodegradable polymer and the release of the drug can be adjusted. An example using PLGA is described. In Patent Document 2, by encapsulating a pyridone carboxylic acid compound in PLGA, the encapsulation rate is improved and stable sustained release is realized, and the drug concentration in the blood or affected area can be maintained for a long period of time. A microcapsule formulation is disclosed.

  Such nanoparticles are generally produced using a spherical crystallization method in which a drug solution dissolved in a good solvent is dropped into a poor solvent that is difficult to dissolve the drug under stirring to precipitate drug crystals. Is done. In the spherical crystallization method, nanoparticles can be formed by a physicochemical method, and the resulting nanoparticles are almost spherical, so there is no need to consider the problem of residual catalyst or raw material compounds from homogeneous nanoparticles. It can be formed easily. However, when an aqueous phase is used as a poor solvent, a hydrophilic drug having high water solubility generally diffuses into the poor solvent along with the diffusion of the good solvent during crystallization. However, it has been difficult to encapsulate hydrophilic drugs in nanoparticles at a high encapsulation rate.

  Patent Document 3 discloses a drug using PLGA having a polyalkylene glycol moiety on the surface as a biodegradable polymer in order to obtain particles that are difficult to be purified from the bloodstream by macrophages and capable of adjusting the drug release rate. Although the contained nanoparticles are disclosed, there is no suggestion that the encapsulation rate of the hydrophilic drug is increased, and no specific method for improving the encapsulation rate is described.

  On the other hand, in Patent Document 4, a bioactive polypeptide is dispersed in an organic solvent solution of a biodegradable polymer and zinc oxide, and then the organic solvent is removed to increase the encapsulation rate of the bioactive polypeptide. Patent Document 5 discloses a method for producing a releasable drug by adding a water-miscible organic solvent or a volatile salt to an aqueous solution of a biodegradable polymer and freeze-drying to increase the encapsulation rate of a bioactive polypeptide. In addition, methods for producing sustained-release drugs are disclosed, and the use of PLGA as a biodegradable polymer is also described.

However, although the methods of Patent Documents 4 and 5 can improve the encapsulation rate of a physiologically active polypeptide in PLGA, there is no description that it can be applied to hydrophilic drugs other than polypeptides, and encapsulation of hydrophilic drugs in general. It was not enough as a way to increase the rate.
Japanese Patent Laid-Open No. 2002-20269 JP 2003-300088 A2 Japanese National Patent Publication No. 9-504042 JP-A-10-231252 JP-A-11-322631

  In view of the above problems, the present invention aims to provide biocompatible nanoparticles with an increased encapsulation rate inside the nanoparticles regardless of whether the drug to be encapsulated is hydrophilic or hydrophobic. And Another object of the present invention is to provide a method for producing biocompatible nanoparticles that is simple, low-cost, and has low environmental impact.

  In order to achieve the above object, a first configuration of the present invention includes a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, and the hydrophobic polymer block is a core. A biocompatible nanoparticle having a core-shell structure located on the side and having the hydrophilic polymer block located on the shell side, wherein a hydrophilic bioactive component is encapsulated in the hydrophilic polymer block Nanoparticles.

  Further, the second configuration of the present invention is composed of a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, and the hydrophobic polymer block is located on the shell side, A biocompatible nanoparticle having a core-shell structure in which a hydrophilic polymer block is located on the core side, wherein the hydrophilic bioactive component is encapsulated in the hydrophilic polymer block.

  According to a third configuration of the present invention, in the biocompatible nanoparticle having the above configuration, the hydrophilic bioactive component is amphiphilic, and the amphiphilic bioactive component is combined with the hydrophobic polymer block and the hydrophobic polymer block. It is characterized by being enclosed in both hydrophilic polymer blocks.

  The fourth configuration of the present invention is characterized in that, in the biocompatible nanoparticle having the above configuration, a hydrophobic bioactive component is further encapsulated in the hydrophobic polymer block as the bioactive component.

  According to a fifth configuration of the present invention, in the biocompatible nanoparticle having the above configuration, the hydrophobic polymer block is composed of a lactic acid / glycolic acid copolymer, and the hydrophilic polymer block is composed of polyethylene glycol. It is characterized by.

  According to a sixth configuration of the present invention, in the biocompatible nanoparticle having the above configuration, the polyethylene glycol has a molecular weight of 5,000 or more and 10,000 or less.

  A seventh configuration of the present invention is characterized in that the biocompatible nanoparticles having the above configuration are used for non-injection applications.

  The eighth configuration of the present invention is characterized in that the biocompatible nanoparticles having the above configuration are combined.

  In the ninth configuration of the present invention, vitamins or vitamin derivatives are complexed with the biocompatible nanoparticles having the above configuration.

  In the tenth configuration of the present invention, a sugar alcohol is complexed with the biocompatible nanoparticles having the above configuration.

  According to an eleventh aspect of the present invention, a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, and a hydrophilic bioactive component are added to an organic solvent and, if necessary, the organic solvent. A dissolution step that dissolves in water and a solution obtained by the dissolution step is added to the aqueous phase to form biocompatible nanoparticles in which the bioactive component is encapsulated in a hydrophilic polymer block located at least on the shell side And a nanoparticle forming step for forming a nanoparticle-containing solution and a solvent distilling step for distilling off the organic solvent from the nanoparticle-containing solution.

  According to a twelfth configuration of the present invention, a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, and a hydrophilic bioactive component are added with an organic solvent and, if necessary. A dissolution step that dissolves in water and a solution obtained by the dissolution step is added to the oil phase to form biocompatible nanoparticles in which the bioactive component is encapsulated in a hydrophilic polymer block located at least on the core side And a nanoparticle forming step for forming a nanoparticle-containing solution and a solvent distilling step for distilling off the organic solvent from the nanoparticle-containing solution.

  According to a thirteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having the above configuration, the aqueous phase is a polyvinyl alcohol aqueous solution.

  According to a fourteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having the above-described configuration, the oil phase is glycerin triester.

  According to a fifteenth aspect of the present invention, in the method for producing biocompatible nanoparticles having the above structure, a polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is less than 0.5% by weight.

  According to a sixteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having the above-described configuration, the method further includes a removal step of removing polyvinyl alcohol from the nanoparticle-containing solution after the solvent distillation step. It is said.

  According to a seventeenth aspect of the present invention, in the method for producing biocompatible nanoparticles having the above structure, the polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is 0.1 wt% or more and 10 wt% or less. .

  According to an eighteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having the above-described configuration, in the dissolution step, a hydrophobic bioactive component is further dissolved in an organic solvent, whereby the hydrophilic bioactivity is increased. A component is encapsulated in at least a hydrophilic polymer block, and the hydrophobic bioactive component is characterized in that it forms biocompatible nanoparticles encapsulated in at least a hydrophobic polymer block.

  According to a nineteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having the above configuration, the organic solvent is a mixed solution of acetone and ethanol.

  In addition, the twentieth configuration of the present invention is the method for producing biocompatible nanoparticles having the above-described configuration, further comprising a compounding step of compounding the nanoparticles after the solvent evaporation step or the removal step. It is a feature.

  According to a twenty-first configuration of the present invention, in the method for producing biocompatible nanoparticles having the above-described configuration, one or more of sugar alcohol, vitamins and vitamin derivatives are combined with the nanoparticles in the combining step. It is characterized by letting.

  According to a twenty-second configuration of the present invention, in the method for producing biocompatible nanoparticles having the above-described configuration, the complexing step is performed by lyophilization.

  According to the first configuration of the present invention, in the core-shell structured biocompatible nanoparticle composed of a block copolymer in which a hydrophobic polymer block and a hydrophilic polymer block are bonded, the hydrophilic polymer block located on the shell side is hydrophilic. By encapsulating a bioactive component, a biocompatible nanoparticle in which a hydrophilic bioactive component that was difficult to encapsulate by a spherical crystallization method was encapsulated at a high encapsulation rate when a hydrophobic polymer was used. Provided.

  Further, according to the second configuration of the present invention, in the core-shell structured biocompatible nanoparticle comprising a block copolymer in which a hydrophobic polymer block and a hydrophilic polymer block are bonded, the hydrophilic polymer block located on the core side By encapsulating the hydrophilic bioactive component in the container, the hydrophilic bioactive component is encapsulated at a high encapsulation rate, and along with the degradation of the hydrophobic polymer block located on the shell side, the bioactive component is retained for a long period of time. A biocompatible nanoparticle that can be gradually released is provided.

  Further, according to the third configuration of the present invention, in the biocompatible nanoparticle of the first or second configuration, when the bioactive component is amphiphilic, the bioactive component is hydrophilic with the hydrophobic polymer block. By encapsulating in both polymer blocks, the encapsulation rate in the nanoparticles can be improved regardless of the degree of hydrophilicity of the bioactive component.

  According to the fourth configuration of the present invention, in the biocompatible nanoparticle of any one of the first to third configurations, a hydrophobic bioactive component is further converted into a hydrophobic polymer block as a bioactive component. Encapsulation results in biocompatible nanoparticles capable of simultaneously encapsulating various bioactive components regardless of whether they are hydrophilic or hydrophobic.

  Further, according to the fifth configuration of the present invention, in the biocompatible nanoparticle of any one of the first to fourth configurations, a block copolymer that is distributed industrially as a biocompatible polymer, , By using a polyethylene glycol-PLGA copolymer in which the hydrophobic polymer is composed of lactic acid / glycolic acid copolymer and the hydrophilic polymer is composed of polyethylene glycol, it has excellent encapsulation performance of hydrophilic bioactive components Biocompatible nanoparticles can be provided at low cost.

  According to the sixth configuration of the present invention, in the biocompatible nanoparticles of the fifth configuration, the molecular weight of polyethylene glycol is 5,000 or more and 10,000 or less, so that a hydrophilic bioactive component is obtained. The encapsulating rate is further improved, and handling at the time of production of the polyethylene glycol-PLGA copolymer is facilitated.

  Further, according to the seventh configuration of the present invention, by using the biocompatible nanoparticles having any one of the first to sixth configurations for non-injection applications, it can be sufficiently permeated to an orally administered agent or deep into the skin. Even when used as a topical drug that is difficult to apply, it penetrates well into the body and exhibits high medicinal effects.

  Further, according to the eighth configuration of the present invention, the biocompatible nanoparticles having any one of the first to seventh configurations are combined, so that the handling is easy when filling the container, and the biocompatible nanoparticle is reused when used. It becomes a dispersible aggregated particle.

  Further, according to the ninth configuration of the present invention, in the biocompatible nanoparticle of the eighth configuration, by combining the sugar alcohol with the nanoparticle, the dispersibility and heat resistance of the combined nanoparticle are increased. As a result, the re-leakage of the bioactive component once encapsulated from the nanoparticle surface can be prevented.

  Further, according to the tenth configuration of the present invention, in the biocompatible nanoparticle having the above-described eighth or ninth configuration, a vitamin or a vitamin derivative is combined with the nanoparticle, thereby being encapsulated in the nanoparticle. The effects of the bioactive ingredient and the effects of vitamins and vitamin derivatives complexed with the nanoparticles act synergistically to express a more remarkable medicinal effect.

  According to the eleventh or twelfth configuration of the present invention, the biocompatible polymer to which the hydrophobic polymer block and the hydrophilic polymer block are bound, and the hydrophilic bioactive component are added to the organic solvent and, if necessary. After dissolving in water, the resulting solution is added to an aqueous or oil phase to form biocompatible nanoparticles in which at least a bioactive component is encapsulated in a hydrophilic polymer block to form a nanoparticle-containing solution, Biocompatible nanoparticles with high encapsulating rate of hydrophilic bioactive ingredients and little variation in encapsulating rate and average particle size by distilling organic solvent from nanoparticle-containing solution to produce biocompatible nanoparticles Particles can be produced easily and at low cost.

  According to the thirteenth configuration of the present invention, in the method for producing biocompatible nanoparticles according to the eleventh configuration, polyvinyl alcohol is attached to the nanoparticle surface by using an aqueous polyvinyl alcohol solution as the aqueous phase. In addition to improving redispersibility in water after drying, biocompatible nanoparticles that are highly safe for the human body and have a low environmental load can be produced.

  According to the fourteenth configuration of the present invention, in the method for producing biocompatible nanoparticles of the twelfth configuration, by using glycerin triester as the oil phase, the hydrophilic bioactive component is glycerin triester. Rather than diffusing into it, it interacts nonhydrophobically with the hydrophilic polymer block and is encapsulated in the core of the nanoparticle with a high encapsulation rate.

  According to the fifteenth configuration of the present invention, in the method for producing biocompatible nanoparticles of the thirteenth configuration, the polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is less than 0.5% by weight. As in the case of using a polyvinyl alcohol aqueous solution having a concentration, the removal step of washing the nanoparticles by centrifugal separation or the like to remove excess polyvinyl alcohol is not necessary, so that the manufacturing process and time can be reduced.

  According to the sixteenth configuration of the present invention, in the method for producing biocompatible nanoparticles of the thirteenth configuration, after the solvent distillation step, a removal step of removing polyvinyl alcohol from the nanoparticle-containing solution is further performed. By providing, after forming nanoparticles using a high-concentration polyvinyl alcohol aqueous solution, surplus polyvinyl alcohol can be removed, and the encapsulation rate of the bioactive component encapsulated in the nanoparticles can be stabilized. .

  According to the seventeenth configuration of the present invention, in the method for producing biocompatible nanoparticles of the sixteenth configuration, the polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is 0.1 wt% or more and 10 wt% or less. Thus, the viscosity of the aqueous solution can be maintained in an appropriate range for the diffusion of the organic solvent.

  Moreover, according to the 18th structure of this invention, in the manufacturing method of the biocompatible nanoparticle of the said 11th thru | or 17th structure, in addition to a hydrophilic bioactive component, a hydrophobic bioactive component Is dissolved in an organic solvent to produce biocompatible nanoparticles in which a hydrophilic bioactive component is encapsulated in at least a hydrophilic polymer block and a hydrophobic bioactive component is encapsulated in at least a hydrophobic polymer block, Biocompatible nanoparticles having both high entrapment ratios of hydrophilic and hydrophobic bioactive ingredients and small variations in entrapment ratios and average particle diameters can be produced easily and at low cost.

  According to the nineteenth configuration of the present invention, in the method for producing biocompatible nanoparticles having any one of the eleventh to eighteenth configurations, a mixture of acetone and ethanol having good volatility is used as the organic solvent. Then, by adding these distillation steps later, it is possible to eliminate the residual organic solvent in the nanoparticles, to produce nanoparticles with a low risk of adverse effects on the human body, and to reduce the burden on the environment.

  According to the twentieth configuration of the present invention, in the method for producing biocompatible nanoparticles according to any one of the eleventh to nineteenth configurations, by providing a complexing step for complexing the nanoparticles, the container It is easy to handle at the time of filling, and can be combined into redispersible aggregated particles at the time of use.

  According to the twenty-first configuration of the present invention, in the method for producing biocompatible nanoparticles of the twentieth configuration, in the complexing step, one of sugar alcohol, vitamins and vitamin derivatives is combined with the nanoparticles. Combining the above can further improve the dispersibility, heat resistance and medicinal properties of the composite nanoparticles.

  According to the twenty-second configuration of the present invention, in the method for producing biocompatible nanoparticles of the above-described twentieth or twenty-first configuration, the complexing step is performed by freeze-drying, so that the nanoparticles can be compounded well. And can be carried out efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the structure of a block copolymer used in the present invention, and FIG. 2 is a schematic diagram showing the structure of biocompatible nanoparticles according to the first embodiment of the present invention. The biocompatible nanoparticle 1 is formed by agglomerating a large number of block copolymers 4 in which a hydrophobic polymer block 2 and a hydrophilic polymer block 3 are bonded, and an emulsion in water using an aqueous phase as a poor solvent. When prepared by the method, as shown in FIG. 1, the hydrophilic polymer block 3 protrudes from the particle surface to form an outer shell portion (shell portion) 5, and the hydrophobic polymer block 2 is located inside the particle (core portion) 6. Forming a core-shell structure.

  Since the hydrophilic polymer block 3 has a high ability to attract and hold water molecules, the shell portion 5 from which the hydrophilic polymer block 3 protrudes attracts water molecules in a poor solvent to form a hydrated phase. The hydrophilic bioactive component (hereinafter referred to as hydrophilic component) 7 diffuses into the poor solvent along with the diffusion of the organic solvent (good solvent) during nanoparticle crystallization, but interacts with the hydrophilic polymer block 3. Therefore, it is considered that leakage into the poor solvent is suppressed, and encapsulation of the nanoparticles 1 in the shell portion 5 becomes possible.

  Therefore, in the biocompatible nanoparticles of the present invention, the entrapment ratio of hydrophilic bioactive components that were difficult to encapsulate by the spherical crystallization method is improved. Particles can be produced easily and at low cost. In addition, when the hydrophilicity of the hydrophilic component 7 is weakened, the interaction with the hydrophilic polymer block 3 is also weakened, and the encapsulation rate in the shell portion 5 is reduced, but conversely, due to the interaction with the hydrophobic polymer block 2 Since the core part 6 is also encapsulated, a high encapsulation rate is ensured for the entire nanoparticle even if the hydrophilic component 7 is amphiphilic.

  Here, if the molecular weight of the whole block copolymer 4 is equal, when the molecular weight of the hydrophilic polymer block 3 in the block copolymer 4 is small, the core occupying in the nanoparticles 1 as shown in FIG. The ratio of the part 6 increases, the ratio of the shell part 5 decreases, and the amount of the hydrophilic component 7 enclosed decreases. On the other hand, when the molecular weight of the hydrophilic polymer block 3 is large, as shown in FIG. 3B, the proportion of the core portion 6 occupying in the nanoparticle 1 becomes small, the proportion of the shell portion 5 becomes large, and the hydrophilic component 7 The amount of inclusion increases.

  When the molecular weight of the hydrophobic polymer block 2 is equal, the size of the core portion 6 depends on the molecular weight of the hydrophobic polymer block 2 as shown in FIGS. 4 (a) and 4 (b). 4 (b) where the molecular weight of the hydrophilic polymer block 3 is large, the shell portion 5 is larger than that in FIG. 4 (a) where the molecular weight of the hydrophilic polymer block 3 is small. The amount of the hydrophilic component 7 enclosed increases. Accordingly, the encapsulation amount of the hydrophilic component 7 increases in proportion to the molecular weight of the hydrophilic polymer block 3.

  The biocompatible block copolymer 4 used in the present invention is desirably a biocompatible one that has low irritation and toxicity to the living body, is biocompatible, and is decomposed and metabolized after administration. Moreover, it is preferable that it is the particle | grain which releases the drug to include continuously and gradually. As such a material, a PEG-PLGA copolymer in which the hydrophobic polymer block 2 is composed of a polylactic acid / glycolic acid copolymer (PLGA) and the hydrophilic polymer block 3 is composed of polyethylene glycol (PEG). Can be suitably used.

  The molecular weight of PLGA is preferably in the range of 5,000 to 200,000, and more preferably in the range of 15,000 to 25,000. The composition ratio of lactic acid and glycolic acid may be 1:99 to 99: 1, but glycolic acid is preferably 0.333 with respect to lactic acid 1. PLGA having a lactic acid and glycolic acid content in the range of 25 wt% to 65 wt% is preferably used because it is amorphous and soluble in an organic solvent such as acetone.

  As the molecular weight of PEG, a molecular weight in the range of 1,000 to 20,000 can be used, but as described above, the encapsulation rate of the hydrophilic component increases in proportion to the molecular weight of PEG. The molecular weight is preferably 3,000 or more, and more preferably 5,000 or more. On the other hand, when the molecular weight of PEG exceeds 10,000, handling at the time of manufacture of a PEG-PLGA copolymer becomes difficult.

  Accordingly, the molecular weight of PEG is more preferably in the range of 5,000 to 10,000. As will be described later, since the release rate of the hydrophilic component increases with the increase in the molecular weight of PEG, the molecular weight of PEG depends on the hydrophilicity of the encapsulated bioactive component and the required degree of sustained release. What is necessary is just to select suitably.

  Examples of the hydrophobic polymer block 2 other than PLGA include polyglycolic acid (PGA), polylactic acid (PLA), polyaspartic acid and the like. In addition, these copolymers are aspartic acid / lactic acid copolymer (PAL), aspartic acid / lactic acid / glycolic acid copolymer (PALG), polyamides, polycarbonates, polyalkylenes such as polyethylene, polypropylene or copolymers or mixtures thereof. Etc.

  Examples of the hydrophilic polymer block 3 other than PEG include polyalkylene glycols such as polypropylene 1,2-glycol and polypropylene 1,3-glycol, polypyrrolidone, dextran, polyvinyl alcohol, cellulose and other polysaccharides, and peptides or proteins or These copolymers or mixtures are mentioned. By subjecting these hydrophobic polymer block 2 and hydrophilic polymer block 3 to block copolymerization by a conventionally known method, the biocompatible block copolymer 4 used in the present invention can be obtained.

  Examples of the block copolymer 4 include a diblock copolymer in which the hydrophobic polymer block 2 and the hydrophilic polymer block 3 are linearly bonded as shown in FIG. 1, and the hydrophobic polymer block 2 or the hydrophilic polymer block. A triblock copolymer in which the other polymer block is bonded to both ends of 3, a multiblock copolymer in which a plurality of diblocks or triblock copolymers are bonded, or the like can be used.

  Examples of the hydrophilic component 7 included in the biocompatible nanoparticle of the present invention include genes such as plasmid DNA, peptides, proteins such as interferon (α, β, γ), calcitonin, insulin, gastrin, prolactin, and adrenal cortex stimulation. Hormones (ACTH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), follicle stimulating hormone (FSH) and other hormones, interleukins, blood growth factors, growth factors and other intercellular signal transmitters (cytokines), Arnica Extract, Hypericum extract, Hydrolyzed conchiolin, Kina extract, Clara extract, Sage extract, Clove extract, Cordyceps extract, Peppermint extract, Hop extract, Dipotassium glycyrrhetinate, β-glycyrrhetinic acid, Eugon extract, Rosemary extract, Buttonpi extract, Herbal ingredients such as bow extract, carrot extract, royal jelly extract, chamomile extract, sensu extract, assembly extract, red pepper tincture, ginger tincture, toki extract, safflower extract, chimpi extract, cephalanthin, water soluble drugs such as croconazole hydrochloride, neticonazole hydrochloride, Examples include water-soluble vitamins such as vitamin C. In addition, any one of the above-mentioned biologically active ingredients may be encapsulated, but in particular, if a plurality of ingredients having different efficacy and action mechanisms are encapsulated, the pharmaceutical effect is expected to be enhanced by the synergistic effect of each ingredient. it can.

  FIG. 5 is a schematic view showing the structure of biocompatible nanoparticles according to the second embodiment of the present invention. Portions common to FIG. 2 are denoted by the same reference numerals and description thereof is omitted. In this embodiment, the hydrophilic component 7 is encapsulated in the shell part 5 of the nanoparticle 1 by interaction with the hydrophilic polymer block 3, and a hydrophobic bioactive component (hereinafter referred to as a hydrophobic component) 8 is: The core portion 6 is sealed by the interaction with the hydrophobic polymer block 2.

  That is, by using a block copolymer 4 in which a hydrophobic polymer block 2 and a hydrophilic polymer block 3 are bonded as a base polymer, the bioactive component is effective regardless of whether it is hydrophilic or hydrophobic. It becomes possible to enclose plural kinds of components having different action mechanisms in the particles. As the hydrophobic component 8, conventionally known fat-soluble biologically active components such as fat-soluble vitamin derivatives such as ascorbyl tetrahexyl decanoate and tocopherol acetate can be used.

  The biocompatible nanoparticle of the present invention is not particularly limited as long as it has an average particle diameter of less than 1,000 nm. However, when applied to an external medicine, the average particle is used to enhance the penetration effect into the deep part of the skin. The diameter is preferably 300 nm or less. In general, the size of skin cells is 15,000 nm, and the skin cell spacing varies between shallow and deep skin, but is considered to be about 70 nm. Therefore, it is preferable because the nanoparticles have very high permeability to the skin.

  On the other hand, the smaller the particle size of the nanoparticles, the lower the encapsulation rate, and it is said that foreign substances up to about 45 nm are swallowed by cells due to cell phagocytosis (phagocytosis: swallowing). Therefore, by using nanoparticles as small as 50 nm or more and as small as possible, penetration into the cell interval can be expected without undergoing cell phagocytosis.

  The nanoparticles obtained as described above can be formed into aggregated particles that can be redispersed when powdered by freeze drying or the like (can be combined). Moreover, even if it combines by applying a compressive force and a shearing force by a fluid bed dry granulation method or a dry mechanical particle composite method (for example, by Mechano Fusion System AMS (manufactured by Hosokawa Micron Corporation)), it is separated again. Can be integrated where possible. Thus, before use, the nanoparticles are aggregated particles that are easy to handle, and when used, they become composite particles that return to the nanoparticles by touching moisture and restore characteristics such as high reactivity.

  When the encapsulated bioactive component is water-soluble, once the encapsulated bioactive component leaks to the nanoparticle surface, it is re-dissolved in the surrounding water. When this water is removed by freeze-drying or the like, the bioactive component is reduced by that amount, and the encapsulation rate varies. Therefore, it is preferable to combine organic or inorganic substances so that they can be redispersed and to dry them together with the nanoparticles without removing the water in which the biologically active component is dissolved. For example, by applying sugar alcohol or sucrose, it is possible to effectively prevent variation in the encapsulation rate, and sugar alcohol or the like can be used as an excipient to improve the handleability of the nanoparticles. Examples of the sugar alcohol include mannitol, trehalose, sorbitol, erythritol, maltose, xylitol, etc. Among them, trehalose is particularly preferable.

  In addition, by combining drugs such as vitamins and provitamins on the surface of the composite particles (nanocomposites), the composites are separated from the components that are released slowly from the nanoparticles. A fast-acting drug that dissolves from the particle surface can act. By adopting such a configuration, the nanoparticles can be given quicker permeability (fast-acting penetration action). Moreover, by having the drug contained in the nanoparticle and the compounded drug, the nanoparticle has both the fast-acting effect and the slow-acting effect. In addition, it is more preferable that the compound to be conjugated is water-soluble because it dissolves quickly and exhibits a fast-acting effect.

Drugs to be attached to the surface of the composite particles include vitamin A, vitamin B, vitamin C, vitamin D, vitamin E, vitamin F, vitamin K, vitamin P, vitamin U, carnitine, ferulic acid, γ-oryzanol, α- Ribolic acid, orotic acid and their components or derivatives, retinol acetate, riboflavin acetate, pyridoxine dioctanoate, L-ascorbic acid dipalmitate, L-ascorbic acid-2-sodium sulfate, L-ascorbic acid phosphate Ester, DL-tocopherol-L-ascorbic acid diester dipotassium, pantothenyl ethyl ether, D-pantothenyl alcohol, acetyl pantothenyl ethyl ether, ergocalciferol, cholecalciferol, dl-α-tocopherol acetate, nicoti Acid -α- tocopherol, vitamin or vitamin derivatives such as succinic acid -α- tocopherol, or water-soluble pro-vitamins, e.g. ascorbyl phosphate Mg, ascorbic acid glucoside, panthenol (water-soluble vitamin B _5), L-cysteine Etc.

  In addition, when the biocompatible nanoparticle of the present invention is used as a transdermal drug, the surface of the nanoparticle may be combined with chitosan that enhances mucoadhesion, or phospholipid (lecithin / phosphatidylcholine) may be combined. Skin affinity may be increased. In addition, by combining polyethylene glycol (PEG), it becomes easier to dissolve in water, and the permeability to the skin can be improved. Furthermore, by combining talc, the slipperiness of the particles can be improved and the feeling on the skin can be enhanced.

  The composite particles produced in this way can penetrate into the skin as it is attached to the skin as it is and have the effect of transporting the contained or attached drug to the deep part of the skin. Produces good permeability. However, PLGA is hydrolyzed when mixed with moisture, and the transport performance of the composite particles is lost in a short time. Therefore, when using as such an emulsion, a container in which the emulsion and powder are filled and stored in separate containers adjacent to each other and the partition between the containers can be removed immediately before use to mix the emulsion and powder. Is preferably used.

  The method for producing the biocompatible nanoparticle of the present invention is not particularly limited as long as it is a method capable of processing a target substance into particles having a particle diameter of less than 1,000 nm. It is highly preferred to use the method. Spherical crystallization is a method in which spherical crystal particles can be designed and processed by directly controlling their physical properties by controlling the crystal generation and growth process in the final process of compound synthesis. The spherical crystallization method can be divided into a spherical granulation method (SA method) and an emulsion solvent diffusion method (ESD method) depending on the generation / aggregation mechanism of crystals to be crystallized.

  The SA method is a method of forming a spherical granulated crystal by precipitating drug crystals using two kinds of solvents. Specifically, first, a poor solvent that hardly dissolves the target drug and a good solvent that can dissolve the drug well and can be mixed and diffused in the poor solvent are prepared. Then, the drug solution dissolved in the good solvent is dropped into the poor solvent with stirring. At this time, the drug crystals are precipitated in the system by utilizing the shift of the good solvent to the poor solvent and the decrease in solubility due to the temperature effect or the like.

  Furthermore, when a small amount of liquid (liquid cross-linking agent) that has affinity for the drug and is not miscible with the poor solvent is added to the system, the liquid cross-linking agent is liberated. And a bridge | crosslinking is formed between crystals and a crystal | crystallization begins to aggregate non-randomly by interfacial tension and capillary force. This state is called a funicular state.

  When a mechanical shearing force is further applied to the system in the funicular state, the agglomerated crystals are consolidated into a substantially spherical granulated product. This state is called a capillary state. A final granulated crystal is formed by randomly combining the granulated materials in a capillary state (nanoparticle forming step).

  The ESD method is also a method using two types of solvents, but unlike the SA method, it is a method in which an emulsion is formed and then the drug is crystallized in a spherical shape by utilizing mutual diffusion between a good solvent and a poor solvent. is there. Specifically, first, a drug solution dissolved in a good solvent (an organic solvent and water added if necessary) is dropped into a poor solvent under stirring. At this time, since the drug and the good solvent have affinity, the transition of the good solvent to the poor solvent is delayed, and emulsion droplets are formed. Then, due to the cooling of the emulsion droplets and the mutual diffusion of the good solvent and the poor solvent, the solubility of the drug in the emulsion droplet decreases, and the spherical crystal particles of the drug precipitate and grow while maintaining the shape of the emulsion droplet. To do.

  After preparing a nanoparticle-containing solution by the spherical crystallization method, the organic solvent which is a good solvent is distilled off under reduced pressure (solvent distillation step) to obtain a drug-containing nanoparticle powder. Then, the obtained powder is compounded as it is or by freeze-drying or the like as necessary (compositing step) to form composite particles, which are then filled into a container to form drug-containing nanoparticles.

  The type of the good solvent and the poor solvent, and the type of the liquid cross-linking agent are determined according to the type of the bioactive component to be encapsulated and are not particularly limited. Since it is used as a raw material for drugs that act on the human body, it is necessary to use a material that is highly safe for the human body and has a low environmental impact.

  Examples of such a poor solvent include water or water to which a surfactant is added. For example, a polyvinyl alcohol aqueous solution to which polyvinyl alcohol is added as a surfactant is preferably used. In addition, when the excess polyvinyl alcohol remains, the process (removal process) of removing polyvinyl alcohol by centrifugation etc. is provided after a solvent distillation process. Examples of surfactants other than polyvinyl alcohol include lecithin, hydroxymethylcellulose, hydroxypropylcellulose, and the like. Examples of good solvents include halogenated alkanes, which are low-boiling and poorly water-soluble organic solvents, acetone, methanol, ethanol, ethyl acetate, diethyl ether, cyclohexane, benzene, toluene and the like. For example, a mixture of acetone and ethanol A liquid is preferably used.

  The concentration of the polyvinyl alcohol aqueous solution, or the mixing ratio of acetone and ethanol, the conditions at the time of crystal precipitation and the method of applying mechanical shearing force are not particularly limited, and the type of the target drug and the spherical granulated crystals It may be determined appropriately according to the particle size (in the case of the present invention, nano-order), etc., but the higher the concentration of the polyvinyl alcohol aqueous solution, the better the adhesion of the polyvinyl alcohol to the nanoparticle surface, and the re-dispersion in water after drying On the other hand, when the concentration of the polyvinyl alcohol aqueous solution exceeds a predetermined level, the viscosity of the poor solvent increases and adversely affects the diffusibility of the good solvent. Therefore, although depending on the polymerization degree and saponification degree of polyvinyl alcohol, when a removal step is provided after the nanoparticle formation step, it is preferably 0.1% by weight or more and 10% by weight or less, more preferably about 2%. In addition, when not providing a removal process, it is preferable to set it as 0.5 weight% or less.

  FIG. 6 is a schematic view showing the structure of biocompatible nanoparticles according to the third embodiment of the present invention. Portions common to FIGS. 2 and 5 are denoted by the same reference numerals and description thereof is omitted. Nanoparticles 1 of the present embodiment are prepared by an emulsion-in-oil method using an oil phase as a poor solvent. As shown in FIG. 6, the hydrophobic polymer block 2 protrudes from the particle surface to form a shell portion 5. The hydrophilic polymer block 3 is located in the core portion 6. That is, it has a core-shell structure opposite to that of the first and second embodiments.

  In the production of nanoparticles by the emulsion-in-oil method, since the oil phase is used as a poor solvent, the diffusion rate of good solvents (acetone, ethanol, water, etc.) during crystallization is delayed compared to the underwater emulsion method. Therefore, the hydrophilic component 7 remains in the core portion 6 and is sealed by interacting with the hydrophilic polymer block 3 before diffusing into the poor solvent. As a result, the drug release behavior is expected to be different from the nanoparticles of the first and second embodiments in which the hydrophilic component 7 is enclosed in the shell portion 5, and the sustained release of the hydrophilic component 7 over a longer period of time is expected. Will be possible. In addition, about the kind of block copolymer 4 to be used, and the hydrophilic component 7 included in the nanoparticle 1, it is the same as that of 1st Embodiment.

  In addition to the hydrophilic component 7, a hydrophobic component can be encapsulated in the biocompatible nanoparticle of the present embodiment as in the second embodiment. In that case, the hydrophobic component is enclosed in the shell portion 5 in which the hydrophobic polymer blocks 2 are aggregated in a matrix. The emulsion-in-oil method is the same as the underwater emulsion method except that an oil phase (glycerin triester, etc.) is used as a poor solvent, so the explanation is omitted, but if necessary, a surfactant is added to the oil phase. Alternatively, a washing step for washing the oil phase adhering to the nanoparticle surface and a nanoparticle resuspension step may be provided. In addition, as in the first and second embodiments, nanoparticles can be combined to improve handling.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.

  The manufacturing method of the biocompatible nanoparticle of this invention was examined. Block copolymer of polyethylene glycol (PEG) and lactic acid / glycolic acid copolymer (PLGA) (molecular weight of PEG 5,000, molecular weight of PLGA 15,000, lactic acid / glycolic acid = 75/25, manufactured by BPI) 4 g Was dissolved in 80 mL of acetone, and a solution in which 1 g of caffeine was dissolved in 5 mL of purified water was added thereto and mixed uniformly to obtain a good solvent. 100 mL of 0.2% by weight aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co., Ltd.) was used as a poor solvent.

  The good solvent was added dropwise at a constant rate (4 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 4 hours while stirring at 100 rpm under reduced pressure. Thereafter, freeze-drying was performed over about 1 day. As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle size of 280 nm was obtained. The encapsulation rate of caffeine in the particles (weight percent of caffeine with respect to PLGA weight) was determined by HPLC to be 9%.

  Block copolymer of polyethylene glycol (PEG) and lactic acid / glycolic acid copolymer (PLGA) (molecular weight of PEG 5,000, molecular weight of PLGA 15,000, lactic acid / glycolic acid = 75/25, manufactured by BPI) 4 g Was dissolved in 80 mL of acetone, and a solution in which 1 g of caffeine was dissolved in 5 mL of purified water was added thereto and mixed uniformly to obtain a good solvent. 100 mL of 0.2% by weight aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co., Ltd.) was used as a poor solvent.

  The good solvent was added dropwise at a constant rate (4 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 4 hours while stirring at 100 rpm under reduced pressure. Thereafter, a solution prepared by dissolving 8 g of trehalose (manufactured by Hayashibara) in 50 mL of purified water as an excipient was added, and after pre-freezing (cooled at −40 ° C. for 25 minutes), freeze-drying was performed for about 1 day. As a result of measurement by a dynamic light scattering method, composite particles having an average particle diameter of 220 nm and good redispersibility in water were obtained.

Comparative Example 1

  As a comparison with Example 1, PLGA (molecular weight: 15,000, lactic acid / glycolic acid = 75/25) was used in place of the block copolymer of PEG and PLGA, and particles were prepared under the same conditions as in the above preparation method. It was. The preparation method is shown below.

  4 g of lactic acid / glycolic acid copolymer (PLGA; molecular weight 15,000, lactic acid / glycolic acid = 75/25, manufactured by Wako Pure Chemical Industries) and 1 g of caffeine are dissolved in 80 mL of acetone, and then 40 mL of ethanol is added and mixed. Solvent was used. As a poor solvent, 100 mL of a 0.4% by weight aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co., Ltd.) was used. The good solvent was added dropwise at a constant rate (4 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 4 hours while stirring at 100 rpm under reduced pressure. After pre-freezing (cooling at −40 ° C. for 25 minutes), lyophilization was performed for about 1 day. As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle diameter of 460 nm was obtained. When the encapsulation rate of caffeine in the particles was quantified by HPLC, it was about 1%.

  As the base polymer, the molecular weight and composition ratio of lactic acid / glycolic acid copolymer (PLGA) are the same (PLGA molecular weight 15,000, lactic acid / glycolic acid = 75/25), but the molecular weight of polyethylene glycol (PEG) is different. (PEG molecular weight: 6,000, 8,000, 10,000) Using three types of PEG and PLGA block copolymers (manufactured by BPI), particles were prepared in the same manner as in Example 1 above. . As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle size of 100 to 3,000 nm was obtained.

  By HPLC, the encapsulation rate and introduction rate of caffeine in the particles (weight percent of caffeine in the particles relative to the weight of caffeine at the time of charging) were quantified, and the results are shown in Table 1 together with Example 1 and Comparative Example 1. And shown in FIG.

  As shown in Table 1, the caffeine encapsulation rates were 9%, 11%, and 17% in order of increasing molecular weight of PEG (molecular weight of PEG 5,000, 6,000, 8,000, 10,000), respectively. The introduction rates were 36%, 44%, 68%, and 88%, respectively. On the other hand, in Comparative Example 1 using PLGA instead of the block copolymer of PEG and PLGA, the encapsulation rate of caffeine was 1% and the introduction rate was as low as 4%. Further, as is clear from FIG. 7, the encapsulation rate of caffeine increases in proportion to the molecular weight of PEG, and in order to obtain an encapsulation rate of about 10% or more, the molecular weight of PEG is set to 5,000 or more. It can be said that it is preferable to do.

  Ascorbyl phosphate Mg (VCPMg) -encapsulated nanoparticles, which are water-soluble vitamin C derivatives, were prepared by the same operation using the same base polymer as in Example 1 above. The preparation method is shown below.

  Block copolymer of polyethylene glycol (PEG) and lactic acid / glycolic acid copolymer (PLGA) (molecular weight of PEG 5,000, molecular weight of PLGA 15,000, lactic acid / glycolic acid = 75/25, manufactured by BPI) 4 g Was dissolved in 80 mL of acetone, and then a solution prepared by dissolving 1 g of ascorbyl phosphate Mg (manufactured by Nikko Chemicals) in 8 mL of purified water was added and mixed uniformly to obtain a good solvent. 100 mL of 0.2% by weight aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co., Ltd.) was used as a poor solvent.

  The good solvent was added dropwise at a constant rate (4 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 4 hours while stirring at 100 rpm under reduced pressure. After pre-freezing (cooling at −40 ° C. for 25 minutes), lyophilization was performed for about 1 day. As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle size of 170 nm was obtained. The encapsulation rate of ascorbyl phosphate Mg in the particles (weight percent of ascorbyl phosphate Mg with respect to the PLGA weight) was quantified by HPLC to be 8%.

  As the base polymer, the molecular weight and composition ratio of lactic acid / glycolic acid copolymer (PLGA) are the same (PLGA molecular weight 15,000, lactic acid / glycolic acid = 75/25), but the molecular weight of polyethylene glycol (PEG) is different. (PEG molecular weights 6,000, 8,000, 10,000) Particles were prepared in the same manner as in Example 4 above, using three types of PEG and PLGA block copolymers (manufactured by BPI). . As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle size of 50 to 4,000 nm was obtained.

  The amount of ascorbyl phosphate Mg (VCPMg) contained in the particles and the introduction rate (weight percentage of ascorbyl phosphate Mg in the particles with respect to the weight of ascorbyl phosphate Mg at the time of charging) were quantified by HPLC. The results are shown in Table 2 and FIG. Regarding particles (Comparative Example 2) prepared under the same conditions as in Comparative Example 1 above, using PLGA (molecular weight 15,000, lactic acid / glycolic acid = 75/25) instead of the block copolymer of PEG and PLGA. The results are also shown.

  As shown in Table 2, in Examples 4 and 5, the encapsulation rate of VCPMg was 8 in order of increasing molecular weight of PEG (molecular weight of PEG 5,000, 6,000, 8,000, 10,000), respectively. %, 10%, 16%, and 19%, and VCPMg introduction rates were 32%, 40%, 64%, and 76%, respectively. On the other hand, in Comparative Example 2 using PLGA instead of the block copolymer of PEG and PLGA, the encapsulation rate of VCPMg was 2% and the introduction rate was as low as 8%. Further, as apparent from FIG. 8, the encapsulation rate of VCPMg increases in proportion to the molecular weight of PEG, and in order to obtain an encapsulation rate of about 10% or more, the molecular weight of PEG is set to 5,000 or more. It can be said that it is preferable.

  Block copolymer of polyethylene glycol (PEG) and lactic acid / glycolic acid copolymer (PLGA) (molecular weight of PEG 5,000, molecular weight of PLGA 15,000, lactic acid / glycolic acid = 75/25, manufactured by BPI) 4 g Was dissolved in 100 mL of acetone. 1 g of ascorbyl phosphate Mg (manufactured by Nikko Chemicals) and 0.6 g of ascorbyl tetrahexyldecanoate (manufactured by Nikko Chemicals) which is a fat-soluble vitamin C derivative (VC-IP) were dissolved in 8 mL of purified water and 40 mL of ethanol, respectively. The solution was added and mixed uniformly to make a good solvent. As a poor solvent, 100 mL of a 0.4% by weight aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co., Ltd.) was used.

  The good solvent was added dropwise at a constant rate (4 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 4 hours while stirring at 100 rpm under reduced pressure. After pre-freezing (cooling at −40 ° C. for 25 minutes), lyophilization was performed for about 1 day. As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle diameter of 180 nm was obtained. The encapsulation rate of ascorbyl phosphate Mg and ascorbyl tetrahexyldecanoate in the particles (weight percent of ascorbyl phosphate Mg and ascorbyl tetrahexyldecanoate relative to the PLGA weight) was quantified by HPLC. The results were 6.3% and 6.0%, respectively. Met.

  As the base polymer, the molecular weight and composition ratio of lactic acid / glycolic acid copolymer (PLGA) are the same (PLGA molecular weight 15,000, lactic acid / glycolic acid = 75/25), but the molecular weight of polyethylene glycol (PEG) is different. (PEG molecular weight: 6,000, 8,000, 10,000) Using three types of PEG and PLGA block copolymers (manufactured by BPI), particles were prepared in the same manner as in Example 6 above. . As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle size of 50 to 3,000 nm was obtained.

  By HPLC, the encapsulation rate and introduction rate of ascorbyl phosphate Mg (VCPMg) and ascorbyl tetrahexyldecanoate (VC-IP) in the particles (VCPMg and VC-IP in the particles relative to the weight of VCPMg and VC-IP at the time of charging) Weight percent) was quantified, and the results are shown in Table 3 and FIG. Regarding particles (Comparative Example 3) prepared using PLGA (molecular weight 15,000, lactic acid / glycolic acid = 75/25) instead of the block copolymer of PEG and PLGA, under the same conditions as in Comparative Example 1 above. The results are also shown.

  As shown in Table 3, in Examples 6 and 7, in the order of decreasing molecular weight of PEG (molecular weight of PEG 5,000, 6,000, 8,000, 10,000) Encapsulation rates were 6.3%, 8.1%, 13.4%, and 18.3%, respectively, and VCPMg introduction rates were 25.2%, 32.4%, 53.6%, and 73.2%, respectively. It became. On the other hand, the encapsulation rate of VC-IP, which is a fat-soluble drug, was about 6%, and the introduction rate was constant at 40%. In Comparative Example 3 using PLGA instead of the block copolymer of PEG and PLGA, the encapsulation rate of VC-IP was 8.0% and the introduction rate was 53%. It was 1% and the introduction rate was 0.4%.

  From this result, it is necessary to use a PEG-PLGA copolymer as a base polymer in order to produce nanoparticles encapsulating both the hydrophilic component VCPMg and the hydrophobic component VC-IP. confirmed. Further, as shown in FIG. 9, since the VCPMg has a higher encapsulation rate in proportion to the molecular weight of PEG, it is enclosed in the shell portion 5 (see FIG. 4) that increases in proportion to the molecular weight of PEG, and VC-IP Since the encapsulation rate is almost constant regardless of the molecular weight of PEG, it is presumed that it is encapsulated in the core portion 6 (see FIG. 4) having the same size regardless of the molecular weight of PEG.

  Block copolymer of polyethylene glycol (PEG) and lactic acid / glycolic acid copolymer (PLGA) (molecular weight of PEG 5,000, molecular weight of PLGA 15,000, lactic acid / glycolic acid = 75/25, manufactured by BPI) 1 g Was dissolved in 20 mL of acetone, and then a solution prepared by dissolving 250 mg of ascorbyl phosphate Mg (manufactured by Nikko Chemicals) in 2 mL of purified water was added and uniformly mixed to obtain a good solvent. A glycerin triester (caprylic acid / capric acid triglyceride, Nikko Chemicals) solution (250 mL) containing 2% by weight of HGCR (hexaglycerin condensed ricinoleic acid ester, Nikko Chemicals) was used as a poor solvent.

  The good solvent was added dropwise at a constant speed (2 mL / min) while stirring the poor solvent at 40 ° C. and 400 rpm. After stirring for 5 minutes after completion of dropping, the organic solvent was distilled off in 2 hours while stirring at 100 rpm under reduced pressure. The obtained suspended nanospheres in oil were centrifuged (20,000 rpm, −20 ° C., 15 minutes). After removing the supernatant, in order to wash the triester on the particle surface, n-hexane was added, and the suspension was resuspended by ultrasonic waves, followed by centrifugation. After removing the supernatant, the pellet was completely dried, resuspended in 50 mL of a 2 wt% aqueous solution of polyvinyl alcohol (PVA403, manufactured by Kuraray Co.), and centrifuged again. The supernatant was removed and the pellet was resuspended in purified water. The obtained suspension was pre-frozen (cooled at −40 ° C. for 25 minutes) and then freeze-dried over about 1 day.

  As a result of measurement by a dynamic light scattering method, a lyophilized powder having an average particle diameter of 550 nm was obtained. When the encapsulation rate of ascorbyl phosphate Mg in the particles (weight percent of ascorbyl phosphate Mg with respect to the PLGA weight) was quantified by HPLC, it was 12.7%.

  Using the caffeine-containing nanoparticles prepared in Example 1 and Example 3, the release pattern of the water-soluble drug was investigated. As a test method, 100 mg of each nanoparticle was immersed in a 37 ° C. phosphate buffer (pH = 7.4), and the amount of caffeine released (mg) after a predetermined time elapsed was quantified by HPLC. The results are shown in FIG.

  As is clear from FIG. 10, the caffeine-encapsulated nanoparticles of the present invention all have a high caffeine release rate until the fifth day after the start of the test, and thereafter the release rate becomes slow. From this result, in the initial stage, PEG located in the shell part of the particle takes in the surrounding moisture and forms a hydrated layer, and caffeine encapsulated near the surface of the shell part is rapidly released, and then PLGA The hydrolysis of PLGA and the dissociation of the block copolymer linked that the PEG chain gradually dissociates and caffeine encapsulated in the deep part of the shell part or the core part is gradually released. It is inferred that it exhibits a release behavior.

  Moreover, the initial release amount of caffeine increases as the molecular weight of PEG increases. This is thought to be because the proportion of the shell portion increases in proportion to the molecular weight of PEG, so the amount of caffeine enclosed in the shell portion increases and the amount of caffeine released in the initial stage increases. It is done.

  The biocompatible nanoparticle of the present invention has a core-shell structure composed of a block copolymer to which a hydrophobic polymer block and a hydrophilic polymer block are bonded, and encapsulates a hydrophilic bioactive component in the hydrophilic polymer block. When a hydrophobic polymer such as PLGA is used as a base polymer, a hydrophilic bioactive component that has been difficult to encapsulate by the spherical crystallization method can be encapsulated at a high encapsulation rate. In addition, by selecting whether the hydrophilic polymer block is located on the shell side or the core side in the core-shell structure, the sustained release property of the biologically active ingredient can be controlled.

  In addition, when the bioactive component is amphiphilic, since it is encapsulated in both the hydrophobic polymer block and the hydrophilic polymer block, a high encapsulation rate is ensured for the entire nanoparticle. Furthermore, since the hydrophobic bioactive component is encapsulated in the hydrophobic polymer block, it becomes a biocompatible nanoparticle capable of simultaneously encapsulating various bioactive components regardless of hydrophilicity or hydrophobicity.

  Further, as the block copolymer, it is preferable to use an inexpensive PEG-PLGA copolymer which is also distributed industrially. In addition, the entrapment ratio of the hydrophilic bioactive ingredient is increased in proportion to the molecular weight of PEG, and the release rate is also increased. However, by setting the molecular weight of PEG to 5,000 or more and 10,000 or less, hydrophilic bioactive ingredients can be obtained. While increasing the encapsulation rate of the active ingredient, handling during production of the PEG-PLGA copolymer is facilitated.

  In addition, if biocompatible nanoparticles are combined by freeze-drying or the like, aggregated particles that are easy to handle at the time of filling into a container are obtained. Furthermore, by combining sugar alcohols and vitamins with the nanoparticles, the dispersibility and heat resistance of the combined nanoparticles are improved, and even if the bioactive component to be encapsulated is water-soluble, it is once encapsulated. Leakage of components to the particle surface can be prevented. Moreover, by having the drug contained in the nanoparticle and the compounded drug, the nanoparticle has both the fast-acting effect and the slow-acting effect.

  Moreover, the manufacturing method of the biocompatible nanoparticle of this invention which forms a nanoparticle using a spherical crystallization method can use either an aqueous phase or an oil phase as a poor solvent. When an aqueous phase is used as a poor solvent, hydrophilic bioactive components are enclosed in a hydrophilic polymer block located on the shell side, and when an oil phase is used, enclosed in a hydrophilic polymer block located on the core side. The A polyvinyl alcohol aqueous solution is suitably used as the aqueous phase, and glycerin triester is suitably used as the oil phase.

  In addition, by setting the concentration of the polyvinyl alcohol aqueous solution to a low concentration of 0.5% by weight or less, it is not necessary to wash the nanoparticles by centrifugation or the like, so that labor and time can be reduced, which is advantageous in production. On the other hand, when a nanoparticle is formed using a high concentration polyvinyl alcohol aqueous solution and then the aqueous solution is subjected to solid-liquid separation by centrifugation or the like to remove excess polyvinyl alcohol adhering to the nanoparticle surface, It is possible to stabilize the entrapment rate of the bioactive component encapsulated in the particles. At this time, by setting the concentration of the polyvinyl alcohol aqueous solution to 0.1 wt% or more and 10 wt% or less, the viscosity of the poor solvent can be suppressed to an extent that does not affect the diffusion of the good solvent.

  In addition, since a mixed solution of acetone and ethanol, which has little influence on the human body and the environment, is used as a good solvent, it is highly safe as a raw material for a drug that directly acts on the human body. If the compounding step is performed by freeze-drying, the nanoparticles can be compounded satisfactorily and efficiently.

These are the schematic diagrams which show the structure of the block copolymer used for this invention. These are the schematic diagrams which show the structure of the biocompatible nanoparticle which concerns on 1st Embodiment of this invention. These are the schematic diagrams which show the relationship between the molecular weight of a hydrophilic polymer block in case the molecular weight of a block copolymer is equal, and a core-shell structure. These are schematic diagrams showing the relationship between the molecular weight of the hydrophilic polymer block and the core-shell structure when the molecular weight of the hydrophobic polymer block is equal. These are the schematic diagrams which show the structure of the biocompatible nanoparticle which concerns on 2nd Embodiment of this invention. These are the schematic diagrams which show the structure of the biocompatible nanoparticle which concerns on 3rd Embodiment of this invention. These are graphs showing the relationship between the molecular weight of polyethylene glycol and the encapsulation rate of caffeine. These are graphs showing the relationship between the molecular weight of polyethylene glycol and the encapsulation rate of VCPMg. These are graphs showing the relationship between the molecular weight of polyethylene glycol and the encapsulation rate of VCPMg and VC-IP. These are graphs showing the relationship between the molecular weight of polyethylene glycol and the release rate of caffeine from the nanoparticles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Biocompatible nanoparticle 2 Hydrophobic polymer block 3 Hydrophilic polymer block 4 Block copolymer 5 Shell part 6 Core part 7 Hydrophilic component 8 Hydrophobic component

Claims (22)

It consists of a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, wherein the hydrophobic polymer block is located on the core side and the hydrophilic polymer block is located on the shell side Biocompatible nanoparticles forming a core-shell structure,
A biocompatible nanoparticle comprising a hydrophilic bioactive component encapsulated in the hydrophilic polymer block. It consists of a block copolymer in which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bonded, wherein the hydrophobic polymer block is located on the shell side and the hydrophilic polymer block is located on the core side Biocompatible nanoparticles forming a core-shell structure,
A biocompatible nanoparticle comprising a hydrophilic bioactive component encapsulated in the hydrophilic polymer block.   The hydrophilic bioactive component is amphiphilic, and the amphiphilic bioactive component is encapsulated in both the hydrophobic polymer block and the hydrophilic polymer block. The biocompatible nanoparticle according to 2.   The biocompatible nanoparticle according to any one of claims 1 to 3, wherein a hydrophobic bioactive component is further encapsulated in the hydrophobic polymer block as the bioactive component.   The living body according to any one of claims 1 to 4, wherein the hydrophobic polymer block is composed of a lactic acid / glycolic acid copolymer, and the hydrophilic polymer block is composed of polyethylene glycol. Compatible nanoparticles.   The biocompatible nanoparticle according to claim 5, wherein the polyethylene glycol has a molecular weight of 5,000 or more and 10,000 or less.   The biocompatible nanoparticle according to any one of claims 1 to 6, which is used for non-injection applications.   A biocompatible nanoparticle, wherein the biocompatible nanoparticle according to any one of claims 1 to 7 is complexed.   The biocompatible nanoparticle according to claim 8, wherein a sugar alcohol is complexed with the biocompatible nanoparticle.   The biocompatible nanoparticle according to claim 8 or 9, wherein a vitamin or a vitamin derivative is complexed with the biocompatible nanoparticle. A dissolution step of dissolving a block copolymer to which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bound, and a hydrophilic bioactive component in an organic solvent and optionally added water;
The solution obtained by the dissolution step is added to an aqueous phase to form biocompatible nanoparticles in which the bioactive component is encapsulated in a hydrophilic polymer block located at least on the shell side to form a nanoparticle-containing solution. A particle forming step;
A solvent distillation step of distilling off the organic solvent from the nanoparticle-containing solution;
A method for producing biocompatible nanoparticles, comprising: A dissolution step of dissolving a block copolymer to which a biocompatible hydrophobic polymer block and a biocompatible hydrophilic polymer block are bound, and a hydrophilic bioactive component in an organic solvent and optionally added water;
The solution obtained by the dissolution step is added to an oil phase to form biocompatible nanoparticles in which the bioactive component is enclosed in a hydrophilic polymer block located at least on the core side to form a nanoparticle-containing solution. A particle forming step;
A solvent distillation step of distilling off the organic solvent from the nanoparticle-containing solution;
A method for producing biocompatible nanoparticles, comprising:   The method for producing biocompatible nanoparticles according to claim 11, wherein the aqueous phase is an aqueous polyvinyl alcohol solution.   The method for producing biocompatible nanoparticles according to claim 12, wherein the oil phase is glycerin triester.   The method for producing biocompatible nanoparticles according to claim 13, wherein the polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is less than 0.5 wt%.   The method for producing biocompatible nanoparticles according to claim 13, further comprising a removal step of removing polyvinyl alcohol from the nanoparticle-containing solution after the solvent distillation step.   The method for producing biocompatible nanoparticles according to claim 16, wherein the polyvinyl alcohol concentration in the aqueous polyvinyl alcohol solution is 0.1 wt% or more and 10 wt% or less.   In the dissolving step, the hydrophilic bioactive component is further encapsulated in at least a hydrophilic polymer block by further dissolving the hydrophobic bioactive component in an organic solvent, and the hydrophobic bioactive component is at least a hydrophobic polymer. The method for producing biocompatible nanoparticles according to any one of claims 11 to 17, wherein biocompatible nanoparticles encapsulated in a block are formed.   The method for producing biocompatible nanoparticles according to any one of claims 11 to 18, wherein the organic solvent is a mixed solution of acetone and ethanol.   The biocompatible nanoparticle according to any one of claims 11 to 19, further comprising a compounding step of compounding the nanoparticles after the solvent distillation step or the removal step. Manufacturing method.   21. The method for producing biocompatible nanoparticles according to claim 20, wherein in the complexing step, at least one of sugar alcohol, vitamins and vitamin derivatives is complexed with the nanoparticles.   The method for producing biocompatible nanoparticles according to claim 20 or 21, wherein the complexing step is performed by freeze-drying.

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