Double-layer microparticles for colon-selective drug delivery, comprising photocrosslinkable fructooligosaccharide, and preparation method therefor

Abstract

The present invention provides a preparation method for double-layer microparticles for colon-selective drug delivery, the method comprising the steps of: preparing a photocrosslinkable fructooligosaccharide by reacting a hydroxyl group present in fructooligosaccharide with glycidyl methacrylate so as to substitute the hydroxyl group with a methacryloyl group; forming drug-loaded fructooligosaccharide microparticles by, in a first microfluidic chip of a microfluidic control system, moving an aqueous solution comprising the photocrosslinkable fructooligosaccharide, a photocrosslinking agent, a photocatalyst, and a drug to a core flow, and moving soybean oil to a sheath flow, thereby forming an emulsion, and then photocrosslinking same by irradiating same with ultraviolet rays; and preparing microparticles having a double-layer structure by, in a second microfluidic chip, moving the drug-loaded fructooligosaccharide microparticles to a core flow, and moving an alginic acid solution to a sheath flow, thereby forming an emulsion, and then reacting same with a calcium chloride solution so as to form an alginic acid hydrogel layer.

Description

Bilayer microparticles for selective colon drug delivery containing photocrosslinkable fructooligosaccharides and methods for manufacturing the same

[0001] The present invention relates to a bilayer microparticle for selective colon drug delivery comprising a photocrosslinkable fructooligosaccharide and a method for manufacturing the same. More specifically, the invention relates to a method for manufacturing a photocrosslinkable fructooligosaccharide by reacting the hydroxyl group of the fructooligosaccharide with glycidyl methacrylate to substitute it with a methacryloyl group, and to manufacturing a bilayer microparticle having a bilayer structure consisting of a first layer composed of a photocrosslinked fructooligosaccharide and a second layer composed of an alginate hydrogel by simultaneously combining a microfluidic control system and a photocrosslinking method, and to a bilayer microparticle for selective colon drug delivery manufactured by the same.

[0002]

[0003] Selective colonic drug delivery plays an important role in the delivery of proteins and therapeutic peptides, as well as in the delivery of drugs for the treatment of colon-related diseases. To effectively deliver drugs to the colon, the drugs must be protected from the harsh environment and absorption of the upper gastrointestinal tract and controlled to selectively release the drugs within the colon. Selective colonic drug delivery methods are being applied in the treatment of various diseases, such as Crohn's disease, ulcerative colitis, colon cancer, and amoebic infections. In particular, as issues regarding inflammation and side effects associated with drug delivery via injection are emerging, research on selective colonic drug delivery methods that can efficiently deliver drugs through oral administration is becoming increasingly active.

[0004] Materials used for selective colonic drug delivery need to be biodegradable and protect the drug from the upper gastrointestinal environment and absorption to enhance drug delivery efficiency within the colon. Currently, widely used colonic drug delivery materials are polysaccharide-based natural materials such as chitosan and alginate; while these materials offer the advantages of excellent biocompatibility and degradation by colonic microorganisms, they also have the following limitations. In the case of chitosan, it carries a positive charge in low pH environments, leading to easy dissolution or swelling in gastric fluid, which poses a risk of premature drug release in the upper gastrointestinal tract. Additionally, microparticles made solely of alginate exhibit pH-dependent solubility but struggle to maintain sufficient mechanical strength during gastrointestinal transit and suffer from low drug loading efficiency. Furthermore, existing synthetic polymer-based systems are difficult to selectively degrade in the colon and may generate toxic byproducts after biodegradation, limiting their long-term use. Moreover, most existing systems consist of a single-layer structure, which fails to adequately protect the drug from the low pH of the upper gastrointestinal tract and the attack of digestive enzymes.

[0005] Fructooligosaccharides are oligosaccharides composed of 2 to 10 fructose units linked together. They exist in nature in onions, asparagus, chicory, and other plants and are widely known as prebiotics. Fructooligosaccharides reach the large intestine without being broken down by human digestive enzymes and improve the gut microbiome by acting as a selective nutrient source for beneficial bacteria, such as Bifidobacterium and Lactobacillus, that inhabit the colon. Due to these characteristics, fructooligosaccharides offer several advantages as selective drug delivery materials for the colon. These include the ability to be selectively degraded by specific microorganisms in the colon to release drugs, excellent biocompatibility, non-toxicity, and additional health benefits by serving as a nutrient source for beneficial bacteria after degradation, as well as ease of chemical modification due to the presence of multiple hydroxyl groups. However, fructooligosaccharides themselves are difficult to form polymer networks due to their low molecular weight and high water solubility, and appropriate chemical modification is required to impart drug loading and sustained-release properties.

[0006] Photocrosslinking is a technology that generates radicals through the action of a photocatalyst by irradiating ultraviolet or visible light, and these radicals initiate double bonds of methacrylate or acrylate functional groups to form a three-dimensional network structure. Photocrosslinking technology offers several advantages: it is advantageous for loading heat-sensitive drugs as it has a short reaction time and proceeds at room temperature; it allows for precise control of crosslinking density by adjusting the irradiation time and intensity, thereby controlling the drug release rate; it allows for the preservation of the activity of biological drugs such as proteins and peptides by carrying out the reaction in an aqueous solution without using organic solvents; and it enables the mass production of uniform microparticles by combining photocrosslinking with a microfluidic control system.

[0007] The bilayer structure provides multi-stage protection and controlled release functions in drug delivery systems; the inner layer serves to encapsulate the drug and release it upon degradation by microorganisms in the large intestine, while the outer layer protects the inner layer and the drug from the low pH and digestive enzymes of the upper gastrointestinal tract. The alginate hydrogel exhibits pH-dependent solubility characteristics and is stable in gastric juice, but can implement a two-stage release mechanism in which it gradually swells and degrades as it moves through the small and large intestines, exposing the inner core, and subsequently, the exposed fructooligosaccharide core is degraded by microorganisms in the large intestine, thereby finally releasing the drug.

[0008] Microfluidic control systems are a technology capable of producing particles of uniform size by precisely controlling fluid flow through micrometer-scale channels. By controlling core and sheath flow, monodisperse emulsions are formed, which can then be photocrosslinked or ionically crosslinked to produce microparticles. Compared to conventional bulk emulsification or spray drying methods, microfluidic control systems offer advantages such as a narrow particle size distribution and excellent reproducibility, the ability to continuously produce particles with complex structures like core-shell and multilayer structures, the ability to precisely control particle characteristics by controlling process parameters in real time, and low drug loss and high loading efficiency.

[0009] As discussed above, there is a need for bilayer microparticles that can effectively protect the drug from the harsh environment of the upper gastrointestinal tract while selectively degrading and releasing the drug in the colon as a selective drug delivery system. Additionally, there is a need for a technology that modifies the hydroxyl groups of fructooligosaccharides into photocrosslinkable functional groups to form a polymer network and impart drug loading and sustained-release characteristics. Furthermore, there is a need for a manufacturing process that combines microfluidic control systems with photocrosslinking technology to mass-produce bilayer microparticles of uniform size and excellent reproducibility. Finally, there is a demand for a natural material-based drug delivery system that offers excellent biocompatibility, is non-toxic, and provides additional health benefits such as promoting the growth of beneficial bacteria in the colon. However, to date, no technology has been reported for manufacturing bilayer microparticles for selective drug delivery in the colon by modifying fructooligosaccharides into photocrosslinkable materials and combining them with alginate. Accordingly, the present invention aims to solve the above technical problem by providing a method for producing photocrosslinkable fructooligosaccharides by reacting the hydroxyl groups of fructooligosaccharides with glycidyl methacrylate to substitute them with methacryloyl groups, and then producing microparticles for selective colon drug delivery with a double-layer structure by photocrosslinking them using a microfluidic control system and then coating them with an alginate hydrogel.

[0010]

[0011] The present invention aims to enable effective treatment of colon-related diseases such as Crohn's disease, ulcerative colitis, and colon cancer by a method for manufacturing a bilayer microparticle for selective colon drug delivery comprising a photocrosslinkable fructooligosaccharide according to one embodiment of the present invention and by the bilayer microparticle manufactured thereby effectively protecting the drug from the harsh environment of the upper gastrointestinal tract and selectively degrading it by microorganisms in the colon to release the drug.

[0012] Another objective of the present invention is to provide a manufacturing method that can mass-produce microparticles with a uniform size and a double-layer structure by substituting the hydroxyl group of fructooligosaccharide with a methacryloyl group to impart photocrosslinkable properties and using a microfluidic control system.

[0013] Another objective of the present invention is to provide a natural material-based drug delivery system that is biocompatible, non-toxic, and offers additional health benefits as a prebiotic that promotes the growth of beneficial bacteria in the large intestine, along with a drug delivery function.

[0014]

[0015] The objectives of the present invention are not limited to those mentioned above, and other unmentioned objectives will be clearly understood by those skilled in the art from the description below.

[0016]

[0017] A method for preparing a bilayer microparticle for selective colon drug delivery comprising a photocrosslinkable fructooligosaccharide according to one aspect of the present invention for solving the above technical problem provides a method for preparing a photocrosslinkable fructooligosaccharide by reacting a hydroxyl group present in the fructooligosaccharide with glycidyl methacrylate and substituting the hydroxyl group with a methacryloyl group.

[0018] Here, the above reaction can be carried out through an epoxide ring-opening reaction or an ester exchange reaction.

[0019] Here, the reaction may further include being carried out in the presence of dimethylaminopyridine in a dimethyl sulfoxide solvent.

[0020] Here, the reaction may further include being carried out at a temperature of 25°C to 30°C for 10 to 14 hours.

[0021] The present invention provides a photocrosslinkable fructooligosaccharide prepared by the above method, characterized in that it is biodegradable by microorganisms inhabiting the large intestine.

[0022] Here, the microorganism may further include Bifidobacterium longum or Lactobacillus acidophilus.

[0023] The present invention provides a microparticle for selective colon drug delivery having a double-layer structure comprising: a first layer comprising a photocrosslinkable fructooligosaccharide, a photocrosslinking agent, and a photocatalyst; and a second layer comprising an alginate hydrogel, wherein the first layer is surrounded by the second layer.

[0024] Here, the photocrosslinking agent may further be polyethylene glycol diacrylate, and the photocatalyst may be lithium phenyl-2,4,6-trimethylbenzoylphosphinate.

[0025] Here, the diameter of the microparticle may further include 65㎛ to 70㎛.

[0026] The present invention provides a method for manufacturing microparticles for selective colon drug delivery, comprising: a step of forming drug-supported fructooligosaccharide microparticles by photocrosslinking by irradiating ultraviolet rays, after forming an emulsion, by moving an aqueous solution containing photocrosslinkable fructooligosaccharide, a photocrosslinking agent, a photocatalyst, and a drug in a first microfluidic chip of a microfluidic control system by moving the aqueous solution containing the photocrosslinkable fructooligosaccharide, a photocrosslinking agent, a photocatalyst, and a drug in a core flow and moving soybean oil in a sheath flow; and a step of manufacturing a double-layered microparticle by forming an alginate hydrogel layer by reacting the drug-supported fructooligosaccharide microparticles in a second microfluidic chip by moving the aqueous solution containing the drug in a core flow and moving the alginate solution in a sheath flow to form an emulsion and then reacting it with a calcium chloride solution.

[0027]

[0028] A method for preparing a bilayer microparticle for selective drug delivery to the colon containing a photocrosslinkable fructooligosaccharide according to one embodiment of the present invention and the bilayer microparticle prepared thereby can effectively protect the drug from the low pH environment and digestive enzymes of the upper gastrointestinal tract and selectively degrade the drug by specific microorganisms such as Bifidobacterium and Lactobacillus residing in the colon, thereby increasing the therapeutic efficiency of colon-related diseases such as Crohn's disease, ulcerative colitis, and colon cancer.

[0029] The double-layer microparticles of the present invention can be mass-produced with uniform size and excellent reproducibility using a microfluidic control system, and the drug loading efficiency is higher than normal, so the loss of expensive biological drugs such as proteins and therapeutic peptides can be minimized.

[0030] The photocrosslinkable fructooligosaccharide of the present invention has excellent biocompatibility and is non-toxic. After being degraded in the large intestine, it is utilized as a nutrient source for beneficial bacteria, thereby providing additional health benefits as a prebiotic that improves the intestinal microbial community, and thus can simultaneously exhibit the effect of promoting intestinal health along with drug delivery.

[0031] The manufacturing method of the present invention can complete the reaction within a short time at room temperature using photocrosslinking technology, is environmentally friendly as it does not use organic solvents, and can preserve the activity of heat-sensitive proteins and peptide drugs, so it can be applied as a biological drug delivery system for various types.

[0032]

[0033] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0034]

[0035] Figure 1 shows a reaction for synthesizing a photocrosslinkable fructooligosaccharide by conjugating glycidyl methacrylate (GMA) to fructooligosaccharide (FOS), including (a) the result of confirming the substitution of a hydroxyl group to a methacrylate functional group through a colorimetric test, and (b) the result of confirming the introduction of a methacrylate functional group through ATR-FTIR analysis.

[0036] Figure 2 shows the results of an in vivo test confirming the colon-targeted drug delivery function of FOS-GMA and alginate-based bilayer microparticles, including (a) a schematic diagram showing the operating principle of the bilayer microparticles, (b) a mouse dissection photograph, (c) a photograph confirming the detection of the drug (cardiogreen) in the cecum and colon 8 hours after oral administration, and (d) a fluorescence microscope image.

[0037] Figure 3 illustrates the development of a drug delivery system for FOS-GMA-based microparticles and the confirmation of their microbial-dependent degradation function, including (a) the development of a drug delivery system for FOS-GMA microparticles via a microfluidic chip and the optimization of microparticle generation conditions via photocrosslinking (including the chemical structures of FOS-GMA, photocrosslinking agent (PEGDA), and photocatalyst (LAP)), (b) actual operation photographs of a microparticle manufacturing device using an air pressure control pump system (ELVEFLOW) and a pressure supply device, (c) optical microscope images of the manufactured FOS-GMA microparticles (average diameter: 65–70 μm, uniform spherical shape), and (d) results of a microbial-dependent degradation test of FOS-GMA-based microparticles (in vitro degradation test protocol using Lactobacillus acidophilus and a graph of bacterial growth rate (CFU / ml) over time).

[0038] FIG. 4 is a schematic diagram of the overall research strategy for the development of a FOS-GMA / alginate bilayer formulation, comprising: (a) a first layer (1st shell): a process of reacting the hydroxyl groups of fructooligosaccharides with GMA to substitute them with methacryloyl groups (including epoxide ring-opening reaction mechanism and ester exchange reaction mechanism), (b) a photo-crosslinking polymerization process of FOS-GMA (photo-cross-linking and radical polymerization through UV-light irradiation), and (c) a second layer (2nd shell): a process of forming an outer layer through ionic cross-linking of alginate.

[0039] FIG. 5 shows the manufacturing process and structural characteristics of a drug delivery system using FOS-GMA and alginate, including (a) the process of forming a first layer (FOS-GMA-based microparticle) through microfluidic chip A, (b) the process of coating a second layer (alginate layer) through microfluidic chip B, (c) a cross-sectional schematic diagram and microscopic image of the double-layer structure, and (d) a graph showing the measurement results of shell thickness, FOS-GMA microparticle diameter, and total microparticle diameter.

[0040]

[0041] The objectives and effects of the present invention, and the technical configurations for achieving them, will become clear by referring to the embodiments described in detail below in conjunction with the accompanying drawings. In describing the present invention, if it is determined that a detailed description of known functions or configurations may unnecessarily obscure the essence of the invention, such detailed description will be omitted. Furthermore, the terms described below are defined with consideration of their function in the present invention, and these may vary depending on the intentions or practices of the user or operator.

[0042] However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Therefore, such definition should be based on the content throughout this specification.

[0043] The term "Fructooligosaccharides (FOS)" used in this invention refers to oligosaccharides in which about 2 to 10 fructose units are combined. They exist in nature in onions, asparagus, chicory, etc., and are widely known as prebiotics. Fructooligosaccharides reach the large intestine without being broken down by the digestive enzymes of the human body, and have the function of improving the intestinal microbial community by acting as a selective nutrient source for beneficial bacteria such as Bifidobacterium and Lactobacillus inhabiting the large intestine. The fructooligosaccharides having methacrylate functional groups mentioned in the description of this invention have a structure in which some of the hydroxyl groups present in the structure of the fructooligosaccharides are converted into methacrylates, as shown in Formula 1 below.

[0044]

[0045]

[0046]

[0047] The term "photo-crosslinking" used in the present invention refers to a technique in which radicals are generated by the action of a photocatalyst through irradiation with ultraviolet (UV) or visible light, and these radicals initiate double bonds of methacrylate or acrylate functional groups to form a three-dimensional network structure. The photo-crosslinking has the advantage of preserving the activity of biological drugs such as proteins and peptides, as the reaction time is short, it proceeds at room temperature, and the reaction can be carried out in an aqueous solution without using organic solvents.

[0048] The term "microfluidic system" used in this invention refers to a technology capable of producing particles of uniform size by precisely controlling the flow of fluid through micrometer-scale channels. The microfluidic system is used to manufacture microparticles by controlling core flow and sheath flow to form a monodisperse emulsion, and then photocrosslinking or ionic crosslinking the emulsion. Compared to conventional bulk emulsification or spray drying methods, it offers the advantages of a narrow particle size distribution, excellent reproducibility, and the ability to continuously produce particles with complex structures, such as core-shell structures and multilayer structures.

[0049] The term "double layer structure" used in the present invention refers to a structure composed of an inner layer and an outer layer, wherein the inner layer serves to carry a drug and release the drug upon decomposition by microorganisms in the large intestine, and the outer layer serves to protect the inner layer and the drug from the low pH and digestive enzymes of the upper gastrointestinal tract. The present invention provides a microparticle having a double layer structure composed of a first layer (inner layer, core) made of photocrosslinked fructooligosaccharide and a second layer (outer layer, shell) made of alginate hydrogel.

[0050] The term "colon-selective drug delivery" used in the present invention refers to a drug delivery method in which an orally administered drug is not released in the upper gastrointestinal tract but reaches the large intestine and selectively releases the drug. This drug delivery method is useful for the treatment of colon-related diseases such as Crohn's disease, ulcerative colitis, and colon cancer.

[0051] The term "methacryloyl group" used in the present invention refers to a functional group derived from methacrylic acid that includes a carbon-carbon double bond and is capable of participating in a photocrosslinking reaction. In the present invention, photocrosslinkable properties are imparted by reacting the hydroxyl group of fructooligosaccharide with glycidyl methacrylate (GMA) to substitute it with a methacryloyl group.

[0052] The term "epoxide ring-opening reaction" used in the present invention refers to a reaction mechanism in which the epoxide ring of GMA is opened and reacts with the hydroxyl group of fructooligosaccharide to form an ester bond and introduce a methacryloyl group. The above reaction is carried out in the presence of a catalyst, and in the present invention, dimethylaminopyridine (4-Dimethylaminopyridine, DMAP) is used as the catalyst.

[0053] The term "transesterification reaction" used in the present invention refers to a reaction mechanism in which the ester functional group of GMA directly undergoes a transesterification reaction with the hydroxyl group of fructooligosaccharide to introduce a methacryloyl group. The above reaction is a reaction pathway that can be used in conjunction with an epoxide ring-opening reaction to produce the photocrosslinkable fructooligosaccharide of the present invention.

[0054]

[0055] The present invention will be described in detail below.

[0056]

[0057] The present invention relates to a method for producing a photocrosslinkable fructooligosaccharide by reacting the hydroxyl group of the fructooligosaccharide with glycidyl methacrylate (GMA) to substitute it with a methacryloyl group, as shown in FIG. 4, forming a first layer by photocrosslinking the fructooligosaccharide through a microfluidic control system, and then forming a second layer by coating it with an alginate hydrogel.

[0058] As shown in FIG. 2, the double-layer microparticles of the present invention have the characteristic of effectively protecting the drug from the low pH environment and digestive enzymes of the upper gastrointestinal tract, reaching the large intestine, and selectively degrading the drug by microorganisms residing in the large intestine.

[0059]

[0060] - Preparation of photocrosslinkable fructooligosaccharides

[0061] (1) Reaction mechanism

[0062] As shown in FIG. 4(a), the photocrosslinkable fructooligosaccharide of the present invention is prepared by reacting the hydroxyl group present in fructooligosaccharide (FOS) with glycidyl methacrylate (GMA) to substitute it with a methacryloyl group.

[0063]

[0064] The above reaction can proceed through the following two mechanisms:

[0065]

[0066] a) Epoxide ring-opening mechanisms: A mechanism in which the epoxide ring of GMA opens and reacts with the hydroxyl group of fructooligosaccharide to form an ester bond and introduce a methacryloyl group.

[0067] b) Transesterification mechanisms: A mechanism in which the ester functional group of GMA directly undergoes a transesterification reaction with the hydroxyl group of fructooligosaccharide to introduce a methacryloyl group.

[0068]

[0069] (2) Synthesis method

[0070] 7.5 g (2.56 mmol) of fructooligosaccharide is placed in a 2-neck round-bottom flask under a nitrogen atmosphere and completely dissolved in 30 ml of dimethyl sulfoxide (DMSO). 1.093 g (7.69 mmol) of glycidyl methacrylate (GMA), purified with an inhibitor remover column to remove hydroquinone, is added. Then, 475 mg (3.88 mmol) of dimethylaminopyridine (DMAP) is added as a catalyst, and the reaction mixture is stirred at 26.5°C for 12 hours.

[0071] After the reaction is complete, 240 μl of 35–37% hydrochloric acid (HCl) is added to inactivate DMAP. The product is extracted using 150 ml of ethanol, and impurities in the supernatant are removed by centrifuging at 1,500 rpm for 2 minutes. The product is dissolved in 30 ml of deionized distilled water, 150 ml of ethanol is added, and the purification process of removing the supernatant by centrifugation (1,500 rpm, 2 minutes) is repeated 5 times.

[0072] Finally, a mixture of purified fructooligosaccharides having methacryloyl groups and ethanol is dried in a glass Petri dish to obtain photocrosslinkable fructooligosaccharides.

[0073]

[0074] (3) Structure verification

[0075] As shown in Figure 1 (a), it can be confirmed through a colorimetric test that the hydroxyl group was substituted with a methacrylate functional group. After carrying out the reaction to substitute the hydroxyl group present in fructooligosaccharide with a methacrylate functional group, a colorimetric test was performed on samples after 0 and 12 hours of reaction time, and a significant color reaction was observed after 12 hours of reaction.

[0076] In addition, as shown in Fig. 1(b), the ATR-FTIR analysis results show 1700-1710cm -1 A characteristic peak of the carbonyl group (C=O) of the ester bond was observed, confirming the successful introduction of a methacrylate functional group into the fructooligosaccharide. Additionally, at 3000–3700 cm⁻¹ -1 The peak of the hydroxyl group (-OH) decreased in the region of 800–1200 cm⁻¹. -1 Characteristic peak of glycosidic bonds in the region and 1300–1500 cm⁻¹ -1 A CCH deformation vibration peak derived from a methacrylate functional group was identified in the region.

[0077]

[0078] C. Manufacturing of double-layered microparticles

[0079] (1) Overview of the manufacturing process

[0080] As illustrated in FIG. 5, the double-layer microparticles of the present invention are manufactured through a continuous process using two microfluidic chips. The process is characterized by a continuous double-layer formation process in which photocrosslinkable fructooligosaccharide microparticles (first layer) are formed on a first microfluidic chip (A in FIG. 5), and an alginate hydrogel layer (second layer) is coated on a second microfluidic chip (B in FIG. 5).

[0081]

[0082] (2) Formation of the first layer (fructooligosaccharide microparticles)

[0083] Figure 3 illustrates the development of drug delivery systems using FOS-GMA-based microparticles and the verification of their microbial-dependent degradation function, comprising: (a) the development of drug delivery systems using FOS-GMA microparticles via a microfluidic chip and the optimization of microparticle generation conditions through photocrosslinking, including the chemical structural formulas of fructooligosaccharide conjugated with glycidyl methacrylate (FOS-GMA), the photocrosslinking agent polyethylene glycol diacrylate (PEGDA), and the photocatalyst lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP); (b) photographs of the actual apparatus for the microparticle manufacturing process using an air pressure regulating pump system (LIVEFLOW system) and a pressure supply device of a microfluidic control system, including two photographs showing the operation of the microfluidic chip and three pressure regulating vessels that independently control the pressures of core flow and sheath flow; and (c) optical microscope images of the manufactured FOS-GMA microparticles with an average diameter of 65–70 μm. (d) results of an in vitro test to confirm the microbial-dependent degradation function of FOS-GMA-based microbeads, which includes a schematic of an experimental protocol on the left in which FOS-GMA microbeads are added to a Lactobacillus acidophilus culture medium, cultured for 5 hours, separated with a 0.2 μm cell strainer, and CFU (Colony Forming Units) are measured, and a graph on the right showing the bacterial growth rate (CFU / ml) according to time (0h, 1h, 3h, 5h) and results comparing the difference in bacterial growth patterns between the group with added FOS-GMA microbeads (W / FOS-GMA microbeads, red circle) and the control group (W / O FOS-GMA microbeads, black square).

[0084] FIG. 5 shows the manufacturing process and structural characteristics of a drug delivery system using FOS-GMA and alginate, including (a) the process of forming a first layer (FOS-GMA-based microparticle) through microfluidic chip A, (b) the process of coating a second layer (alginate layer) through microfluidic chip B, (c) a cross-sectional schematic diagram and microscopic image of the double-layer structure, and (d) a graph showing the measurement results of shell thickness, FOS-GMA microparticle diameter, and total microparticle diameter.

[0085] Referring to FIGS. 3 and 5, as shown in FIGS. 3 (a), (b) and FIGS. 5 (a), a photocrosslinking solution is prepared by completely dissolving 70.645 mg of photocrosslinkable fructooligosaccharide, 264.81 μl (0.5 mmol) of polyethylene glycol diacrylate (PEGDA) as a photocrosslinking agent, and 33.67 mg (0.1 mmol) of lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photocatalyst in 5 ml of deionized distilled water.

[0086] Using the first microfluidic chip of the microfluidic control system, the photocrosslinking solution is moved through a pneumatic control pump at a core flow rate (flow rate: 50 μl / min), and soybean oil is moved at a sheath flow rate (flow rate: 200 μl / min) to form an emulsion.

[0087] As shown in Fig. 4(b), photocrosslinking is carried out by irradiating the formed emulsion with ultraviolet light of a wavelength of 365 nm for 13 seconds. The photocatalyst (LAP) absorbs UV light to generate radicals, and these radicals initiate the double bonding of methacrylate functional groups to form a three-dimensional network structure together with the photocrosslinking agent (PEGDA). Through this, photocrosslinked fructooligosaccharide microparticles with a diameter of 65 to 70 μm are prepared.

[0088]

[0089] (3) Formation of the second layer (alginate hydrogel layer)

[0090] As shown in Fig. 5(b), the previously prepared photocrosslinked fructooligosaccharide microparticles and soybean oil mixture is transferred in the second microfluidic chip at a core flow rate (flow rate: 50 μl / min). At the same time, a 4 wt% alginate solution dissolved in 5 ml of deionized distilled water is transferred at a sheath flow rate (flow rate: 100 μl / min) to form an emulsion in which the fructooligosaccharide microparticles are surrounded by the alginate solution.

[0091]

[0092] As shown in Fig. 4(c), the formed emulsion is immersed for 30 minutes in a 50 mM calcium chloride solution dissolved in 30 ml of deionized distilled water to induce ionic cross-linking of alginate. Calcium ions (Ca 2+ A rigid hydrogel layer is formed by combining with the carboxyl group of alginate to form an "egg-box" structure.

[0093]

[0094] After the reaction is complete, the microparticles are recovered, washed three times with deionized distilled water, and dried to obtain bilayer microparticles for selective colon drug delivery containing photocrosslinkable fructooligosaccharides.

[0095]

[0096] D. Structural characteristics of double-layered microparticles

[0097] (1) Confirmation of double-layer structure

[0098] As shown in Fig. 5(c), the manufactured microparticle has a distinct double-layer structure, and has a structure in which a first layer (core) composed of photocrosslinked fructooligosaccharide is completely surrounded by a second layer (shell) composed of alginate hydrogel.

[0099]

[0100] The double-layer structure was confirmed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations, and the average diameter of the first layer was measured to be 65.3±2.1μm, and the thickness of the second layer (alginate shell) was measured to be 8.5±1.2μm. Therefore, the total diameter of the microparticles was approximately 82.3μm.

[0101]

[0102] (2) Particle size distribution

[0103] As shown in FIG. 3(c) and FIG. 5(d), the double-layer microparticles produced using a microfluidic control system exhibit a very uniform size distribution.

[0104]

[0105] When 100 microparticles were randomly selected and their sizes were measured using an optical microscope and dynamic light scattering (DLS), the average diameter of the microparticles was 67.8 ± 2.5 μm, and more than 90% of the particles were distributed within the range of 65 to 70 μm. This demonstrates the excellent reproducibility and uniformity of the manufacturing process using a microfluidic control system.

[0106]

[0107] By controlling the core flow rate and sheath flow rate of the microfluidic chip, microparticles within a target size range (65–70 μm) can be precisely manufactured.

[0108]

[0109] (3) Composition analysis

[0110] Fourier transform infrared spectroscopy (FT-IR) analysis revealed the C=O stretching vibration peak of the methacrylate functional group in the first layer (1700-1710 cm⁻¹). -1 The characteristic peaks of ) and PEGDA were confirmed. In the second layer, the carboxyl group peak characteristic of alginate (1600-1630 cm⁻¹) was observed. -1 A shift in the COO- peak due to ) and calcium ion crosslinking was observed.

[0111]

[0112] E. Selective drug delivery function in the large intestine

[0113] (1) Biodegradability check

[0114] As shown in Figure 3 (d), FOS-GMA-based microparticles are degraded in a time-dependent manner by microorganisms inhabiting the large intestine.

[0115]

[0116] As a result of performing an in vitro degradation test using Bifidobacterium longum and Lactobacillus acidophilus, the weight of microparticles decreased by about 65% in the Bifidobacterium longum culture after 48 hours, and by about 58% in the Lactobacillus acidophilus culture.

[0117]

[0118] As shown in graph (d) of Figure 3, when comparing the bacterial growth rates of the control group (W / FOS-GMA microbeads, red dots) and the FOS-GMA microbeads (W / O FOS-GMA microbeads, black squares) upon the addition of FOS-GMA microbeads, it was confirmed that the FOS-GMA microbeads decompose over time and promote bacterial growth.

[0119]

[0120] When cultured in a control medium without microorganisms, the weight loss was less than 5% even after 48 hours, confirming that the biodegradation of microparticles is selectively carried out by specific microorganisms in the large intestine.

[0121]

[0122] (2) In vivo drug delivery efficacy

[0123] As shown in Figure 2, double-layer microparticles loaded with indocyanine green (ICG) were orally administered to a mouse model, and the organ distribution was confirmed by dissecting after 8 hours.

[0124] Figure 2(a) shows the operating principle of a double-layer microparticle, which remains stable in the upper gastrointestinal tract, but when it reaches the colon, the second layer is gradually degraded according to pH changes, and finally, the first layer is degraded by microorganisms in the colon to release the drug.

[0125] As shown in Figures 2(b) and 2(c), microparticles were observed in mostly intact form in the stomach and small intestine, but the breakdown of microparticles and the release of ICG were observed in the cecum and colon. In particular, fluorescence of cardiogreen was clearly detected in the cecum and colon 8 hours after oral administration.

[0126] In the fluorescence microscope image (d) of Figure 2, a strong ICG fluorescence signal (purple) was detected in the colon tissue, confirming that the microparticles were selectively degraded in the colon to release the drug.

[0127] (3) pH stability comparison

[0128] As a result of comparing microparticles composed solely of a fructooligosaccharide monolayer with the double-layer microparticles of the present invention, the monolayer microparticles decomposed by more than 50% within 30 minutes in a gastric fluid (pH 1.2) environment, whereas the double-layer microparticles maintained an intact form of more than 95% even after 2 hours. This demonstrates that the second layer of the alginate hydrogel effectively protects the drug and the first layer from the upper gastrointestinal environment.

[0129]

[0130] B. Optimization of manufacturing conditions

[0131] (1) Change of reaction conditions

[0132] In the production of photocrosslinkable fructooligosaccharides, even when the reaction temperature was controlled to 25°C and the reaction time was changed to 14 hours, the product could be obtained with a yield of 91%. Additionally, the reaction temperature can be raised to 30°C, but in this case, the reaction time can be shortened to 10 hours.

[0133]

[0134] (2) Change of light irradiation conditions

[0135] When the irradiation time of 365 nm wavelength ultraviolet light was shortened to 10 seconds during the photocrosslinking stage, the degree of photocrosslinking was slightly lower, but there was no problem with the formation of fine particles. Conversely, when the irradiation time was extended to 15 seconds, a more robust network structure was formed.

[0136]

[0137] (3) Change in alginate concentration

[0138] When the concentration of the alginate solution was increased to 5 wt%, the shell thickness of the formed double-layer microparticles increased to about 12 μm, and pH stability improved. Conversely, when the concentration was reduced to less than 4 wt%, the shell thickness decreased, and the protective effect was somewhat reduced.

[0139]

[0140] (4) Change of calcium chloride conditions

[0141] When the concentration of the calcium chloride solution was adjusted to 40 mM and the reaction time was shortened to 20 minutes, the degree of crosslinking of the alginate layer decreased slightly, but there was no hindrance to the formation of double-layer microparticles. When the calcium chloride concentration was increased to 60 mM and the reaction time was extended to 40 minutes, a more robust alginate layer was formed.

[0142]

[0143] D. Industrial Applicability of the Invention

[0144] The bilayer microparticle for selective colon drug delivery comprising photocrosslinkable fructooligosaccharide according to the present invention has the following advantages:

[0145]

[0146] First, using a microfluidic control system, uniformly sized microparticles (65–70 μm) can be mass-produced, and the manufacturing process exhibits excellent reproducibility.

[0147]

[0148] Second, through its double-layered structure, it effectively protects the drug from the harsh environment of the upper gastrointestinal tract (low pH, digestive enzymes) and selectively breaks down the drug by microorganisms in the large intestine to release it.

[0149]

[0150] Third, fructooligosaccharides provide additional health benefits by acting as prebiotics to promote the growth of beneficial bacteria in the gut.

[0151]

[0152] Fourth, the drug loading efficiency (82%) is high through photocrosslinking, and drug loss is minimized, making it advantageous for the delivery of expensive protein and peptide drugs.

[0153]

[0154] Therefore, the double-layer microparticles of the present invention can be utilized as a drug delivery system for the treatment of colon-related diseases such as Crohn's disease, ulcerative colitis, and colon cancer, and can also be applied to the oral delivery of proteins and therapeutic peptides.

[0155]

[0156] The embodiments of the present invention will be described in detail below.

[0157]

[0158] Examples

[0159] Example 1: Preparation of Photocrosslinkable Fructooligosaccharides

[0160]

[0161] Fructooligosaccharide methacrylation via epoxide ring-opening reaction

[0162]

[0163] 7.5 g (2.56 mmol) of fructooligosaccharide was placed in a 2-neck round-bottom flask under a nitrogen atmosphere and completely dissolved in 30 ml of dimethyl sulfoxide (DMSO). 1.093 g (7.69 mmol) of glycidyl methacrylate (GMA), purified with an inhibitor remover column to remove hydroquinone, was added. Subsequently, 475 mg (3.88 mmol) of dimethylaminopyridine (DMAP) was added as a catalyst, and the reaction mixture was stirred at 26.5°C for 12 hours to carry out the epoxide ring-opening reaction.

[0164] After the reaction was complete, 240 μl of 35–37% hydrochloric acid (HCl) was added to inactivate DMAP. The product was extracted using 150 ml of ethanol, and impurities in the supernatant were removed by centrifuging at 1,500 rpm for 2 minutes. The product was dissolved in 30 ml of deionized distilled water, 150 ml of ethanol was added, and the purification process of removing the supernatant by centrifugation (1,500 rpm, 2 minutes) was repeated 5 times. Finally, the mixture of the purified fructooligosaccharide containing a methacryloyl group and ethanol was dried in a glass Petri dish to obtain 7.2 g of the compound (photocrosslinkable fructooligosaccharide).

[0165]

[0166] Example 1-1: Methacrylization of fructooligosaccharides via ester exchange reaction

[0167]

[0168] 10 g (3.42 mmol) of fructooligosaccharide was dissolved in 40 ml of DMSO under a nitrogen atmosphere. 1.8 g (12.68 mmol) of purified GMA and 620 mg (5.07 mmol) of DMAP were added, and the transesterification reaction was carried out by stirring at 28°C for 10 hours. 9.4 g of photocrosslinkable fructooligosaccharide was obtained by purification in the same manner as in Example 1.

[0169]

[0170] Example 2: Preparation of bilayer microparticles for colon-selective drug delivery

[0171]

[0172] Step 1: Formation of photocrosslinkable fructooligosaccharide microparticles

[0173]

[0174] A photocrosslinking solution was prepared by completely dissolving 70.645 mg of the photocrosslinkable fructooligosaccharide prepared in Example 1, 264.81 μl (0.5 mmol) of polyethylene glycol diacrylate (PEGDA) as a photocrosslinking agent, and 33.67 mg (0.1 mmol) of lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photocatalyst in 5 ml of deionized distilled water.

[0175] Using the first microfluidic chip of the microfluidic control system, the photocrosslinking solution was moved via a pneumatic control pump at a core flow rate (flow rate: 50 μl / min), and soybean oil was moved via a sheath flow rate (flow rate: 200 μl / min) to form an emulsion. Photocrosslinking was performed by irradiating the formed emulsion with ultraviolet light of a wavelength of 365 nm for 13 seconds, thereby producing photocrosslinked fructooligosaccharide microparticles with a diameter of 65–70 μm. As shown in Figures 3 (a) and 3 (b), microparticles were produced using the microfluidic control system and a pneumatic pump. Here, FOS-GMA, PEGDA, and LAP are all biocompatible materials, and are either FDA-approved medical materials or materials known to be safe for in vivo use.

[0176] The microfluidic control system described above is connected to an air pressure regulating pump system, and precisely controls the flow velocities of the core and sheath flows by independently supplying pressure to each fluid vessel through ELVEFLOW software. Through this system, it is possible to continuously produce microparticles of uniform size with excellent reproducibility.

[0177]

[0178] Step 2: Formation of the alginate hydrogel layer

[0179]

[0180] In the second microfluidic chip, the mixture of photocrosslinked fructooligosaccharide microparticles prepared in Step 1 and soybean oil was transferred via core flow (flow rate: 50 μl / min). At the same time, a 4 wt% alginate solution dissolved in 5 ml of deionized distilled water was transferred via sheath flow (flow rate: 100 μl / min) to form an emulsion in which the fructooligosaccharide microparticles were surrounded by the alginate solution.

[0181] The formed emulsion was immersed in a 50 mM calcium chloride solution dissolved in 30 ml of deionized distilled water for 30 minutes to induce ionic crosslinking of alginate. After the reaction was complete, the microparticles were recovered, washed three times with deionized distilled water, and dried to obtain bilayer microparticles for selective colon drug delivery containing photocrosslinkable fructooligosaccharides.

[0182]

[0183] Example 3: Preparation of drug-loaded double-layer microparticles

[0184] In Step 1 of Example 2, 5 mg (0.1 mmol) of indocyanine green (ICG) was additionally added as a model drug when preparing the photocrosslinking solution. Bilayer microparticles for selective colon drug delivery loaded with indocyanine green were prepared by proceeding in the same manner as in Example 2. As a result of measuring the drug loading efficiency using a fluorescence spectrometer, a high loading efficiency of 82% was confirmed.

[0185]

[0186] Example 4: Example of changing reaction conditions

[0187] Example 4-1: Change in reaction temperature and time

[0188]

[0189] Photocrosslinkable fructooligosaccharides were prepared by adjusting the reaction temperature to 25°C and changing the reaction time to 14 hours in the method of Example 1. The yield was 91%.

[0190]

[0191] Example 4-2: Change in light irradiation time

[0192]

[0193] In Step 1 of Example 2, the experiment was conducted by changing the UV irradiation time at a wavelength of 365 nm to 10 seconds. Although the degree of photocrosslinking was slightly lower, there was no problem with the formation of fine particles.

[0194]

[0195] Example 4-3: Change in alginate concentration

[0196]

[0197] In step 2 of Example 2, the concentration of the alginate solution was changed to 5 wt%. The shell thickness of the formed double-layer microparticles increased to about 12 μm, and pH stability was improved.

[0198]

[0199] Example 4-4: Change in calcium chloride concentration and reaction time

[0200]

[0201] In Step 2 of Example 2, the concentration of the calcium chloride solution was adjusted to 40 mM, and the reaction time was shortened to 20 minutes. Although the degree of crosslinking of the alginate layer decreased slightly, there was no hindrance to the formation of double-layer microparticles. When the calcium chloride concentration was increased to 60 mM and the reaction time was extended to 40 minutes, a more robust alginate layer was formed.

[0202]

[0203] Comparative Example 1: Conditions with unidentified reaction mechanism

[0204] Fructooligosaccharides and GMA alone were reacted in DMSO solvent at 26.5°C for 12 hours without DMAP. Since the reaction hardly proceeded, the methacryloyl group substitution rate was confirmed to be less than 5%, and photocrosslinking was impossible.

[0205]

[0206] Example 5: Analysis of Structural Characteristics of Double-Layered Microparticles

[0207] 5-1. Verification of Double-Layer Structure

[0208]

[0209] Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations were performed to analyze the structure of the double-layer microparticles prepared in Example 2. After freezing the microparticles with liquid nitrogen and crushing them, cross-sectional observations were performed, confirming a clear double-layer structure. The inner core (first layer) was composed of photocrosslinked fructooligosaccharides, and the outer shell (second layer) was composed of alginate hydrogel.

[0210]

[0211] The average diameter of the first layer was 65.3 ± 2.1 μm, and the thickness of the second layer (alginate shell) was measured to be 8.5 ± 1.2 μm. Therefore, the total diameter of the microparticles was approximately 82.3 μm.

[0212]

[0213] 5-2. Composition Analysis

[0214]

[0215] Fourier transform infrared spectroscopy (FT-IR) analysis revealed the C=O stretching vibration peak of the methacrylate functional group in the first layer (1700-1710 cm⁻¹). -1 The characteristic peaks of ) and PEGDA were confirmed. In the second layer, the carboxyl group peak characteristic of alginate (1600-1630 cm⁻¹) was observed. -1 The shift of the COO- peak due to ) and calcium ion crosslinking was observed.

[0216]

[0217] As a result of X-ray photoelectron spectroscopy (XPS) analysis, carbon (C 1s) and oxygen (O 1s) peaks derived from fructooligosaccharide, along with lithium (Li 1s) and phosphorus (P 2p) peaks derived from the photocatalyst, were detected in the first layer. In the second layer, calcium (Ca 2p) peaks were clearly observed along with carbon and oxygen peaks derived from alginate, confirming the composition of the double-layer structure.

[0218]

[0219] Example 6: Analysis of microparticle size

[0220] 6-1. Measurement of Particle Size Distribution

[0221]

[0222] One hundred double-layer microparticles prepared by the method of Example 2 were randomly selected, and their particle sizes were measured using an optical microscope and dynamic light scattering (DLS).

[0223]

[0224] As a result of the measurement, the average diameter of the microparticles was 67.8 ± 2.5 μm, and more than 90% of the particles were distributed within the range of 65 μm to 70 μm. This demonstrates the reproducibility and uniformity of the manufacturing process using a microfluidic control system.

[0225]

[0226] 6-2. Particle Size Control According to Process Conditions

[0227]

[0228] Microparticles of various sizes were fabricated by controlling the core flow velocity and sheath flow velocity of a microfluidic chip:

[0229]

[0230] Core flow 40μl / min, sheath flow 250μl / min: Average diameter 58.2μm

[0231]

[0232] Core flow 50 μl / min, sheath flow 200 μl / min: average diameter 67.8 μm (Example 2 conditions)

[0233]

[0234] Core flow 60μl / min, sheath flow 180μl / min: Average diameter 76.5μm

[0235]

[0236] Through this, it was confirmed that microparticles within a target size range (65–70 μm) can be precisely manufactured using a microfluidic control system.

[0237]

[0238] Example 7: Confirmation of Biodegradability of Microparticles

[0239] 7-1. In vitro biodegradability test

[0240]

[0241] To confirm the biodegradability of the double-layer microparticles prepared in Example 2 by microorganisms in the large intestine, an in vitro degradation test was performed using Bifidobacterium longum and Lactobacillus acidophilus.

[0242] Microparticles were added to the culture medium in which each strain was cultured, and weight loss over time was measured while incubating at 37°C. In the Bifidobacterium longum culture medium, the weight of the microparticles decreased by approximately 65% ​​after 48 hours, and in the Lactobacillus acidophilus culture medium, it decreased by approximately 58%.

[0243] When cultured in a control medium without microorganisms, the weight loss was less than 5% even after 48 hours, confirming that the biodegradation of microparticles is selectively carried out by specific microorganisms in the large intestine.

[0244] Specifically, a culture medium (inoculation) containing Lactobacillus acidophilus was prepared and pre-cultured for 5 hours (After 5hr), after which the groups were divided into two. When adding the samples, 200 mg of FOS-GMA micro beads were added to each group (Sample 1), while the other group was cultured without FOS-GMA microparticles as a control (Only Lactobacillus acidophilus). The OD values ​​were measured while culturing with the same amount, and after 5 hours of incubation, the microparticles were removed using a 0.2 μm cell strainer, after which the CFU (Colony Forming Units) of Lactobacillus acidophilus were measured. The bead size was confirmed to be 64 ± 5-12 μm.

[0245]

[0246] 7-2. In vivo biodegradability test

[0247]

[0248] The ICG-loaded bilayer microparticles prepared in Example 3 were orally administered to a mouse model, and the organ distribution was confirmed by dissecting after 8 hours.

[0249] While microparticles were observed in mostly intact form in the stomach and small intestine, the breakdown of microparticles and the release of ICG were observed in the cecum and large intestine. Fluorescence measurements revealed a strong ICG fluorescence signal in the large intestine tissue, confirming that the microparticles selectively degrade and release the drug within the large intestine.

[0250]

[0251] Comparative Example 2: Comparison of single-layer microparticles

[0252] Microparticles composed solely of a fructooligosaccharide monolayer were prepared and compared with the bilayer microparticles of Example 2. The monolayer microparticles decomposed by more than 50% within 30 minutes in a gastric fluid (pH 1.2) environment, whereas the bilayer microparticles maintained an intact form of more than 95% even after 2 hours. This demonstrates that the second layer of the alginate hydrogel effectively protects the drug and the first layer from the upper gastrointestinal environment.

[0253]

[0254] The present specification and drawings disclose preferred embodiments of the present invention. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the present invention and to aid in understanding the invention, and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present invention are possible.

Claims

1. A method for producing a photocrosslinkable fructooligosaccharide by reacting a hydroxyl group present in the fructooligosaccharide with glycidyl methacrylate to replace the hydroxyl group with a methacryloyl group.

2. In Paragraph 1, A method for producing photocrosslinkable fructooligosaccharides, characterized in that the above reaction is carried out through an epoxide ring-opening reaction or an ester exchange reaction.

3. In Paragraph 1, A method for producing photocrosslinkable fructooligosaccharides, characterized in that the above reaction is carried out in the presence of dimethylaminopyridine in a dimethyl sulfoxide solvent.

4. In Paragraph 3, A method for producing photocrosslinkable fructooligosaccharides, characterized in that the above reaction is carried out at a temperature of 25°C to 30°C for 10 to 14 hours.

5. A photocrosslinkable fructooligosaccharide produced by the method of any one of claims 1 to 4, characterized in that it is biodegradable by microorganisms inhabiting the large intestine.

6. In Paragraph 5, A photocrosslinkable fructooligosaccharide characterized in that the microorganism is Bifidobacterium longum or Lactobacillus acidophilus.

7. A microparticle for selective colon drug delivery having a double-layer structure comprising: a first layer comprising a photocrosslinkable fructooligosaccharide, a photocrosslinking agent, and a photocatalyst of claim 5; and a second layer comprising an alginate hydrogel, wherein the first layer is surrounded by the second layer.

8. In Paragraph 7, Microparticles for selective colon drug delivery, characterized in that the photocrosslinking agent is polyethylene glycol diacrylate and the photocatalyst is lithium phenyl-2,4,6-trimethylbenzoylphosphinate.

9. In Paragraph 7, Microparticles for selective colon drug delivery, characterized in that the diameter of the microparticles is 65㎛ to 70㎛.

10. A method for manufacturing microparticles for selective colon drug delivery, comprising: a step of forming drug-supported fructooligosaccharide microparticles by photocrosslinking by irradiating ultraviolet rays, after forming an emulsion, by moving an aqueous solution containing the photocrosslinkable fructooligosaccharide, photocrosslinking agent, photocatalyst, and drug of claim 5 in a first microfluidic chip of a microfluidic control system by moving the aqueous solution containing the drug-supported fructooligosaccharide in a core flow and moving the soybean oil in a sheath flow to form an emulsion, and then forming a double-layered microparticle by reacting it with a calcium chloride solution to form an alginate hydrogel layer in a second microfluidic chip.

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