JPH0456660B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a capsule body containing an unstable functional substance and a method for producing the same, and more specifically, a capsule body containing an unstable functional substance, and more specifically, a capsule body containing an unstable functional substance, and more specifically, a capsule body that utilizes a gel film formed by contacting a polyanionic polysaccharide or a salt thereof with a soluble chitin derivative. The present invention relates to the capsule body and its manufacturing method. Conventional technology Conventionally, as a method for manufacturing capsule bodies, a mixture of a fluid (core liquid) constituting the core of the capsule body and a polyvalent metal salt such as a calcium salt is added to alginate or low methoxyl pectin or a mixture thereof. A method of forming a gel film by contacting with a solution of a mixture (Japanese Patent Publication No. 48-16183), an aqueous solution containing a de-N-acetylated product of carboxylmethyl chitin or a carboxylmethyl chitin salt,
A method for producing capsule bodies by dropping, stirring, and dispersing an organic acid in an aqueous anhydride solution such as a mixture of acetic anhydride and acetic acid (Japanese Patent Application Laid-open No. 55-90503)
etc. are known. However, these known methods have the following drawbacks in encapsulating unstable functional substances, such as animal cells that produce useful substances. The ionic strength of the liquid (core liquid) that makes up the core of the capsule body is too high. A rapid change in the hydrogen ion concentration of the core fluid is observed during the capsule formation process.
There is a risk that the substance involved in capsule membrane formation contained in the core liquid and the unstable functional substance may directly interact, causing the functionality to disappear or be inhibited.
Due to the high viscosity of the liquid inside the capsule, it is difficult to uniformly spread the substance inside the capsule. Problems to be Solved by the Invention In view of the above-mentioned problems with capsules produced by conventionally known methods, the inventors have studied capsules particularly suitable for unstable functional substances, and have found the following: When a solution of a chitin derivative such as chitosan is brought into contact with a solution of a polyanionic polysaccharide or its salt, an excellent gel film is formed even under biologically mild conditions, and in this case, it is possible to form an excellent gel film even under biologically mild conditions. When a droplet of a solution containing a stable functional substance coated with a solution of the polyanionic polysaccharide or its salt is encapsulated by contacting with a solution of the chitin derivative, it participates in capsule formation with the functional substance. The present invention was developed based on the knowledge that the interaction between the capsule and the substance used in the capsule becomes extremely weak, and the viscosity of the core liquid within the capsule also becomes extremely low. Therefore, an object of the present invention is to provide a capsule body that can encapsulate an unstable functional substance without impairing the functional properties of the substance, and a method for producing the same. The present invention will be explained in detail below. Structure of the Invention The capsule body according to the present invention is characterized by coating small droplets of a fluid containing an unstable functional substance with a fluid mainly composed of a polyanionic polysaccharide, a salt thereof, or a mixture thereof. The coated droplet is encapsulated as a core in a gel film formed by contacting the droplet with a solution of a soluble chitin derivative. Furthermore, the method for manufacturing the capsule body according to the present invention is characterized in that a fluid containing an unstable functional substance is extruded from an inner cylindrical nozzle of a double cylindrical nozzle to form small droplets, and the droplets are formed into small droplets. In the formation process, a fluid mainly composed of a polyanionic polysaccharide, a salt thereof, or a mixture thereof is extruded from an outer cylinder nozzle disposed parallel to the outside of the inner cylinder nozzle. coating the droplets that form;
The resulting coated droplets are then contacted with a solution of a soluble chitin derivative to form a gel film. The polyanionic polysaccharide or salt thereof used in the present invention is a polysaccharide or a salt thereof that forms a polyanionic polymer in an aqueous solution, and examples thereof include low methoxyl pectin, carrageenan, carboxymethyl cellulose, sodium alginate, chondroitin sulfate, and heparin. . These polysaccharides can be used alone or as a mixture. In addition, the soluble chitin derivative used in the present invention is
Chitin, which is originally an insoluble substance, is chemically treated to increase its reaction activity, and chitosan, which is obtained by deacetylating chitin, is a typical example. Incidentally, chitin is N contained in the carapace of crabs, krill, insects, etc., the cell walls of microorganisms, and mushrooms.
- It is a linear homopolysaccharide in which acetyl-D-glucosamine is β (1 → 4) linked, and is abundantly produced in nature, but it is an unused natural resource that cannot be used as it is because of its inactivity. It can be said. However, chitin derivatives such as chitosan obtained by deacetylating chitin become soluble in dilute acids and have reactive activity. That is, chitosan has a structural unit represented by the following general formula (), It is positively charged due to the amino group in the formula, has chitosan molecules as a polycationic polymer, and exhibits reactive activity. Means for Solving the Problems In the present invention, a fluid containing an unstable functional substance is formed into droplets, and during the formation process, the polyanionic polysaccharide, its salt, or a mixture thereof is used as the main material. A coated droplet is created by contacting the formed droplet with a fluid that coats the formed droplet. The production of the coated droplets may be carried out, for example, using an apparatus such as that shown in the accompanying figures. First, a fluid containing an unstable functional substance and a fluid mainly composed of a polyanionic polysaccharide, its salt, or a mixture thereof were prepared, and the former fluid 2 was divided into two fluids as shown in the attached diagram. By supplying the latter fluid 1 to the cylindrical nozzle 4 of the cylindrical body having a cylindrical nozzle and extruding it, and supplying the latter fluid 1 to the nozzle 3 of the outer cylinder and extruding it, the inner cylinder nozzle 4
The droplets of fluid 2 formed at the outlet of the nozzle 3 of the barrel become covered by the fluid 1 from the outlet of the nozzle 3 of the barrel. Coating with the droplets can be carried out in a continuous manner by controlling the diameters of the inner and outer nozzles of the cylindrical body and the flow rates of the fluids supplied to these nozzles. In the present invention, the coated droplets prepared as described above are then contacted with a solution of a soluble chitin derivative. This contact is preferably carried out by dropping the coated droplet into the solution with slow stirring. Due to the above contact, a charged crosslinking reaction, that is, a crosslinking bond, occurs between the polyanionic polysaccharide in the coating layer of the droplet and the chitosan in the solution, producing a gel-like substance and forming a film as a capsule body. become. At this time, once the gel film is formed, the solution contained in the film and constituting the core does not gel substantially at all, so that the desired capsule body can be obtained. This phenomenon occurs because once a gel film is formed as described above, the polyanionic polymer and chitosan molecules in the solution (i.e. core liquid) contained in the film can no longer pass through the film, and the above reaction is delayed. This is thought to be due to the fact that it stops progressing in the core liquid. In the present invention, a polyanionic polysaccharide, a salt thereof, or a mixture thereof is used in preparing the solution used as the fluid constituting the core of the capsule body.
It is appropriate to prepare an aqueous solution containing 0.3 to 1.0% by weight, and it is particularly preferable to use carboxymethylcellulose as the polyanionic polysaccharide from the viewpoint of forming a gel film. The chitosan solution with which the above aqueous solution is brought into contact is suitably one dissolved in a weak acid such as acetic acid to a concentration of 0.5 to 1.0% by weight. Effects of the Invention As described above, in the present invention, the gel film of the capsule body can be formed in a short time under extremely mild conditions, that is, biologically mild conditions, without using organic solvents. , unstable biological substances, functional substances, and various other additives depending on the intended use of the capsule can be added to and dispersed in the fluid constituting the core of the capsule. Therefore, it is possible to provide a capsule body containing various useful substances in the core liquid. In addition, the present invention enables encapsulation by forming a gel film in one step.
It can be said that this method is advantageous in terms of production compared to the known encapsulation method that utilizes salt crosslinking between a polyanion and a polycation as seen in No. 197031. Furthermore, in the present invention, by controlling the formation conditions of the gel film of the capsule body, it is possible to change the membrane permeability of the gel film, so it is also possible to impart a fractionation function to the film of the capsule body. Become. As described above, the present invention provides a capsule body that is suitable for encapsulating unstable functional substances in a short period of time using easily available raw materials, and can be produced easily and in a short time, and that can be used for a wide range of applications. There are benefits it can offer. EXAMPLES The present invention will be explained in more detail with reference to Examples below. Example A monoclonal anti-human lactoferrin antibody-producing hybridoma was used as an unstable functional substance. Add this to DMEM to 4×10 ⁴ cells/ml.
Disperse in a medium (containing 10% serum) and add it to (A
liquid). Meanwhile, using carboxymethylcellulose as polyanionic polysaccharide, 0.5% by weight of it
An aqueous solution (solution B) was prepared. The above-mentioned liquid A is supplied to the inner cylinder nozzle 4 of the double cylindrical nozzle shown in the attached figure, and liquid B is supplied to the outer cylinder nozzle 3, and the liquid A is supplied at the outlet of these nozzles.
A droplet of liquid was formed and the droplet was coated with liquid B. For reference, 2 used for forming and coating the droplets above.
The diameters of the inner and outer nozzles of the heavy cylindrical nozzle and the flow rates of the liquids A and B supplied to these nozzles are shown in the table below.

[Table] Next, the coated droplets formed in this way were
A capsule body was prepared by dropping it into a 0.7% by weight chitosan solution. The survival of the antibody protein-producing hybridoma in the core fluid of the capsule body thus obtained was confirmed, and its proliferation was further confirmed 4 days later. The capsule body had a diameter of 3 to 4 mm and was transparent, and the thickness of the capsule film was 2 to 3 μm when observed using a scanning electron microscope. In addition, this capsule body also had high mechanical strength, and the concentration of carboxymethyl cellulose in the core liquid of the capsule body was reduced to 0.1 to 0.2% by weight.

[Brief explanation of drawings]

The attached figure illustrates the apparatus used in the present invention to form droplets of a fluid containing labile functional substances and to coat the droplets with a fluid based on a polyanionic polysaccharide. This is what I did. In the figure, 1...Fluid mainly composed of polyanionic polysaccharide, 2...Fluid containing unstable functional substance, 3...Outer tube nozzle, 4...Inner tube nozzle.

Claims (1)

[Scope of Claims] 1 Coated droplets of a fluid containing an unstable functional substance coated with a fluid containing a polyanionic polysaccharide, a salt thereof, or a mixture thereof, and a coated droplet of a soluble chitin derivative. A capsule body containing an unstable functional substance, which is made of a gel film formed by contact with a solution and has a core of air-covered droplets. 2 A fluid containing an unstable functional substance is extruded from the inner cylindrical nozzle of a double cylindrical nozzle to form droplets, and in the process of forming the droplets, a polyanionic polysaccharide or a salt thereof or a mixture thereof is extruded. Covering the formed droplets with the fluid by extruding a fluid mainly composed of from an outer cylinder nozzle disposed parallel to the outside of the inner cylinder nozzle,
A method for producing a capsule body containing an unstable functional substance, characterized in that the coated droplets obtained are then brought into contact with a solution of a soluble chitin derivative to form a gel film.