JP6249885B2 - Microneedle structure and method for producing microneedle structure - Google Patents

Description

  The present invention relates to a master mold made of a high-precision mold, and injection molded into a mold using the master mold to create a mold, and a microneedle structure and a method of manufacturing the microneedle structure using the mold .

  Currently, in the medical field, medical devices using microneedles, which are extremely small needles for injecting drugs into the body through the skin of the human body, are known.

  Patent Document 1 discloses a conventional microneedle device 110 as shown in FIG. 7 (the same as FIG. 3 of Patent Document 1). This microneedle device 110 is a structure in which a plurality of needle-like protrusions 112 are formed integrally with a substrate 111 on a flat substrate 111, and the needle-like protrusions 112 are formed on the skin of a living body including a human body. An invention is disclosed in which a drug can be injected into the body through a fluid conduit 115 provided therein by puncturing.

  Patent Document 2 discloses a method and an apparatus for manufacturing a microneedle sheet having an array of microneedles at a low manufacturing cost and a high yield without performing heating during manufacturing.

JP2013-94224A JP2008-6178

  The microneedle sheet of Patent Document 2 is disclosed in which a master mold is created using a photolithographic photoresist, and a stamper (mold) is created with a resin to produce a microneedle sheet. As described above, a general microneedle creation method is to create a master mold using a photolithographic technique, create a mold for a resin product, and then pour resin and chemicals into the mold to create a microneedle. The method is known.

  However, the conventional planar production method using photolithography has a problem in that a product having insufficient microneedle altitude, needle tip angle, and appearance shape accuracy is insufficient. In addition, in the case of microneedles with insufficient accuracy, there is a possibility that the needle-like projection 112 as shown in FIG. 7 is difficult to puncture the skin.

  Therefore, the present invention uses a master mold made of a high-precision mold and a fluororesin (Teflon (registered trademark)) as a mold, so that the manufacturing method of a high-precision microneedle structure can be fitted to the human skin ( It is an object of the present invention to provide a microneedle structure in which microneedles can be arranged so as to be able to be adapted, and drug injection into a more effective affected area can be performed.

According to the present invention, a method for manufacturing a microneedle structure includes forming a plurality of cone-shaped needle protrusions that pierce skin having different heights into a master mold by metal processing and releasing the master mold from the master mold. A material is injected by injection molding to form a mold having needle recesses with different depths and diameters corresponding to the plurality of needle protrusions, and the needle recesses are filled with a drug, and the volume varies depending on the height and diameter. A plurality of conical microneedles that pierce the skin are formed, a flexible base member is formed so as to cover the microneedles, and the micros are disposed at a central portion of the base member and an outer edge portion outside thereof. by varying the volume of the needle and arranged to mix different the microneedles of volume in accordance with the human body shape, with pierce the microneedles into the skin, said base The and forming a micro-needle structure in contact with the skin.

In the method for manufacturing a microneedle structure according to the present invention, the microneedles are characterized in that a plurality of microneedles having different volumes , appearance shapes, and tip angles are molded on a base member.

In the method for producing a microneedle structure according to the present invention, the microneedle is characterized in that the whole is solidified and molded, or is hollowed with a resin , and the hollow portion is filled with the drug.

In the method of manufacturing a microneedle structure according to the present invention, the drug is characterized by filling and molding different drugs for each of a plurality of microneedles having different volumes and different external shapes and tip angles. .

  In the method of manufacturing a microneedle structure according to the present invention, the microneedle has a height H of 100 μm to 600 μm, a tip angle θ of 20 ° to 60 °, an external shape of a cone shape, a triangular pyramid shape, It is characterized by being a quadrangular pyramid, a hexagonal pyramid, or a two-stage cone.

The microneedle structure according to the present invention includes a plurality of cone-shaped needle protrusions that are individually formed on a master mold by metal processing and pierce skin having different volumes depending on the height and diameter , and releasability from the master mold. Corresponding to the plurality of needle protrusions formed by injecting the material into the mold by injection molding, the needle recesses having different depths and diameters , and the height and diameter of the volume formed by filling the needle recesses with a medicine A plurality of cone-shaped microneedles that pierce different skins, and a flexible base member so as to cover the microneedles, and are arranged at a central portion of the base member and an outer edge portion outside thereof. and with different volumes of microneedles, placed in a mix of different said microneedles of volume, with pierce the microneedles into the skin, the said base member Characterized in that characterized in that formed on the structure for fixing the peel.

The microneedle of the microneedle structure according to the present invention is characterized in that a plurality of microneedles having different volumes and different external shapes and tip angles are molded on a base member.

The microneedle of the microneedle structure according to the present invention is characterized in that the whole is coagulated and molded, or formed hollow with a resin and filled with the drug.

  According to the present invention, by creating a master mold with a high-precision mold and using a fluororesin as a mold, it is possible to make the height, appearance shape, tip angle, etc. of each microneedle uniform, Accurate microneedles and microneedle structures can be created.

  In addition, according to the present invention, a master mold can be created with a high-precision mold, so that a plurality of microneedles having different heights, appearance shapes, tip angles, and the like can be created with high precision.

  In addition, according to the present invention, a plurality of types of microneedles having different heights, appearance shapes, tip end angles, and the like can be provided on the microneedle structure, and the arrangement of the microneedles is inserted into the skin. An easy arrangement pattern can be selected.

  Further, according to the present invention, since different types of microneedles such as height, appearance shape, and tip angle suitable for the drug filled in the microneedles can be provided on the microneedle structure, An effective microneedle arrangement pattern can be selected.

  Further, according to the present invention, since the medicine to be filled can be changed depending on the type of the microneedle, the microneedle becomes a mark of the medicine, and medical errors can be reduced.

  Further, according to the present invention, since the microneedle can solidify and mold the drug, the microneedle itself can be dissolved in the body as a drug.

It is a flowchart which shows the manufacturing process of the microneedle which concerns on embodiment of this invention, and a microneedle structure. It is a figure which shows the master type | mold and casting_mold | template which concern on embodiment of this invention. It is a figure which shows the use condition of the microneedle structure which concerns on embodiment of this invention. Fig.4 (a) is a figure which shows the shape of the microneedle which concerns on embodiment of this invention. (B) is a figure which shows the other shape of a microneedle. It is a figure which shows the use condition of the microneedle of multiple shapes in the microneedle structure which concerns on embodiment of this invention. FIG. 6 (a) is a diagram showing a use state in which a plurality of microneedles are mixed in the microneedle structure according to the embodiment of the present invention. FIG. 6B is a sectional view taken along line A-A ′ in FIG. It is a figure which shows the use condition of the microneedle structure which concerns on the conventional invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 1 thru | or FIG. 3, the manufacturing method of the microneedle and microneedle structure which concern on this invention is demonstrated. FIG. 1 is a flowchart showing manufacturing steps of a microneedle and a microneedle structure according to an embodiment of the present invention. FIG. 2 is a view showing a master mold and a mold according to the embodiment of the present invention. FIG. 3 is a view showing a microneedle structure manufactured by the manufacturing process according to the present invention.

As shown in FIG. 2, the master mold 20 is made of a high-precision mold, and is a male mold for making the mold of the microneedle and the microneedle structure of the present invention. The needle convex part 21 with a highly accurate angle of the part is provided.
In the master mold 20, a needle convex portion 21 that becomes a prototype of the microneedle 11 is formed with high accuracy by mold processing. In manufacturing the microneedle 11, the accuracy of the master die 20 greatly affects the accuracy of the microneedle 11. The raw material of the master mold 20 is preferably stainless steel.

Conventionally, in master mold molding, a master mold is molded by molding an original plate using a photolithographic technique and silicon molding a male mold.
However, in master mold molding using photolithography technology, the original drawing of the design drawing cannot be copied with high accuracy according to the design document when printing or developing on the male photosensitive material, or there is sufficient master mold to mold from the male mold. In some cases, the accuracy of the microneedles that are finally produced from a mold obtained by performing the plating process on the master mold and removing silicon from the master mold subjected to the plating process may not be sufficient. Further, there may be a case where sufficient accuracy cannot be obtained due to, for example, the case where plating of the cast mold is not stable. For example, a microneedle structure formed by arranging a plurality of microneedles in which the height, appearance shape (cone, triangular pyramid, etc.) of the microneedles, and the side tilt angles of the microneedles are uneven due to individual differences. Inferior accuracy may occur and variations may occur. Such a microneedle with inferior accuracy has a problem that it is difficult to pierce the skin and the drug may not be sufficiently injected.

  Therefore, in the present invention, the male needle convex portion 21 of the master mold 20 is processed with high precision by metal processing and molded, so that the molding is performed with higher precision than the conventional silicon master mold. Can do.

  The needle convex portion 21 can perform highly accurate mold processing by computer control. Accordingly, the master die 20 performs the processing by taking in the design drawing data created by CAD (computer aided design) software into the control device of the machine tool. In the present invention, the die machining by the machine tool is to cut out (form) the needle convex portion 21 from the metal lump of the raw material of the master die 20.

  The microneedle 11 finally created using the master mold 20 has a desired height, external shape (cone, triangular pyramid, etc.), side inclination angle, etc., and one or more microneedles 11 are uniformly formed. Molded with high accuracy. The microneedle 11 can be smoothly stabbed into the skin. Further, since the microneedles 11 are uniform, the microneedle structure 10 provided with a plurality of microneedles 11 can also be formed with high accuracy.

Also, in conventional photolithography technology, fine patterns are transferred to the substrate by performing multiple processes such as exposure and development on the substrate, and determining and changing the array pattern is a design process. Of course, redesigning the figure took a lot of steps. In the present invention, it is possible to easily determine and change the arrangement pattern by CAD software, and design the arrangement of the microneedles 11 on the microneedle structure 10 as shown in FIGS. The figure can be easily designed and loaded into the machine tool control equipment for processing.
Furthermore, in the die machining by a machine tool, the surface roughness of the microneedle 11 can be suppressed and the specularity can be improved, so that the surface of the microneedle 11 can be formed more smoothly than in the prior art.

  The mold 30 is a prototype for forming the microneedles 11, and a needle recess 31 for forming the microneedles 11 is formed. The raw material of the mold 30 is preferably a fluororesin or glass material that is a releasable material.

In the conventional mold, a silicon mold prototype that is injection-molded from a master mold is molded, and plating is performed on the mold prototype, and an internal silicon mold prototype is extracted, leaving a plated portion as a mold. The plating, which is a raw material of the mold, sometimes includes materials such as nickel that are undesirable for the human body.
However, the fluororesin and glass material of the raw material of the present invention have chemical resistance / corrosion resistance, non-adhesiveness, low friction characteristics, electrical characteristics, nonflammability, heat resistance / cold resistance, etc. And has an effect of preventing contact of impurities.

Moreover, since it has corrosion resistance and hardness as compared with the conventional silicon mold, it is possible to prevent the dispersion (non-uniformity) of the solid of the microneedles 11 due to wear of the mold 30 during mass production of the microneedles. Moreover, since the lifetime of the casting_mold | template 30 is long, it is excellent also in economical efficiency.
Moreover, since the microneedle 11 can be smoothly taken out from the needle recessed part 31 by the fluororesin and glass raw material which are mold release properties, damage to the microneedle 11 can be prevented.

  The needle recess 31 is a depression formed by injection molding from the needle protrusion 21 and is filled with a drug, resin (polylactic acid) or the like, and becomes a prototype for molding the microneedle 11. As described above, since it is molded from a fluororesin or glass material that is a releasable material, when removing the microneedle 11 from the needle recess 31, the frictional resistance of the needle recess 31 is reduced, so that at the time of removal. Can be prevented. Since injection molding is a general technique, a description thereof is omitted.

  FIG. 3 is a view showing the microneedle structure 10 manufactured by the manufacturing method of the present invention. The microneedle structure 10 includes a plurality of microneedles 11 having a needle shape and a base member 15 that serves as a base of the microneedles 11.

  The microneedle 11 is a needle-shaped structure that enters the skin by puncturing the tip of the living body. The microneedle 11 in the present invention is preferably manufactured with high accuracy, and the height H of the microneedle 11 is preferably 100 μm to 600 μm, and the tip angle θ of the microneedle 11 is preferably in the range of 20 ° to 60 °. The microneedle 11 is preferably made of a substance obtained by coagulating a drug itself to be injected into the human body, or a material such as a resin that melts when entering the human body, such as polylactic acid. In the present invention, explanation will be made using polylactic acid as a resin, but it is needless to say that other resins that are harmless to the human body may be used. Therefore, the microneedle 11 according to the present invention melts in the human body, and the microneedle 11 itself disappears after use. In addition, although the microneedle 11 by this invention is demonstrated with the material to melt | dissolve, it can also shape | mold so that a chemical | medical agent may be inject | poured from a hollow needle using the material which does not melt | dissolve.

  The shape of the microneedle 11 can be easily punctured according to the firmness and position of the skin, and the appearance shape can be conical, triangular pyramid, quadrangular pyramid, hexagonal pyramid, two-stage depending on the efficacy and application of the drug. It can be molded in a conical shape or the like.

  As shown in FIG. 3, the base member 15 is a base of the microneedles 11, and a plurality of microneedles 11 are formed on the top thereof. The size of the base member 15 may be appropriately selected and determined depending on the number of microneedles 11, the interval, the range of the affected area of the skin, and the like, and the specific size is not uniquely determined. Moreover, the space | interval P between the microneedle 11 and the adjacent microneedle 11 is a 100 micrometer pitch or more. The material of the base member 15 is preferably a product obtained by coagulating the drug itself, or polylactic acid, as with the microneedle 11.

<Microneedle manufacturing method>
Next, the manufacturing process of the microneedle will be described with reference to FIG. Further, description will be made using a fluororesin as a releasable material.
As shown in FIGS. 1 and 2, the master mold 20 (shown in FIG. 2) is formed with high accuracy by mold processing (step S1). The design drawing data of the microneedle 11 created by the CAD software is taken into the control device of the machine tool, and the needle convex portion 21 of the master die 20 is molded by the operation of the machine tool.

  Next, the raw material fluororesin melted at a temperature of about 400 degrees in an injection molding machine (not shown) is injection-molded with respect to the master mold 20 (step S2). A mold 30 is created by this injection molding (step S3).

Next, a drug is filled in the needle recess 31 of the mold 30 created in the above process (step S4), and the microneedle structure 10 including the microneedle 11 and one or more microneedles 11 is molded.
The drug filled in the needle recess 31 is a drug used for the affected part of the skin, such as hyaluronic acid, a vaccine, and the like.

Next, the base member 15 is filled with polylactic acid (PLA) so as to sufficiently cover the upper part of the medicine filled in the needle recess 31 of the mold 30 shown in FIG. By doing so, the needle recess 31 is covered with a lid, and the base member 15 is formed. The thickness of the base member 15 may be a thickness that can be appropriately selected, and is not particularly limited.

  Next, the base member 15 made of the drug, polylactic acid or the like filled in step S4 is solidified (step S5). The mold 30 is cooled or dried according to a predetermined temperature, humidity, etc. of the drug and polylactic acid. In the present invention, the filling of the medicine is to put the medicine directly into the needle recess 31, and as will be described later, the needle recess 31 is partially filled with polylactic acid to form the appearance of the microneedle 11, and to the inside. Creating a hollow part and putting a medicine in the hollow part.

Then, the base member 15 made of the solidified drug and polylactic acid is removed from the mold 30 (step S6). The microneedle structure 10 shown in FIG. 3 is formed by carefully removing the microneedle 11 from the needle recess 31.
As described above, the microneedle structure 10 having no variation in the accuracy of the microneedles 11 and high quality and uniform quality can be produced.

[Microneedle material example 1]
In step S4 described above, the microneedle structure 10 was created by filling the needle recess 31 with a drug and filling the base member 15 with polylactic acid. When this microneedle structure 10 is affixed to the human body, the plurality of microneedles 11 are melted in the human body, and only the unmelted portion of the base member 15 remains after use.

[Microneedle material example 2]
In step S4 described above, the needle recess 31 and the base member 15 may be filled with the medicine, and the entire microneedle structure 10 including the microneedle 11 and the base member 15 may be made of the medicine. In this case, the base member 15 is suitable for the purpose of bringing the drug into contact with the skin of the human body and penetrating the drug from the skin surface. All of the microneedle structure 10 is melted and no dust is left behind.

[Microneedle material example 3]
In step S4 described above, the needle recess 31 may be partially filled with polylactic acid, a hollow portion may be created inside the microneedle 11, and the hollow portion may be filled with a drug.
In this case, when the base member 15 is affixed to the human body, the polylactic acid of the microneedle 11 is melted, and the drug penetrates into the hollow portion of the microneedle 11 from there. After use, only the portions of the microneedle 11 and the base member 15 that have not been melted remain.

<Microneedle variations>
As described above, the microneedle structure 10 can be manufactured by producing the uniform microneedle 11 with high precision and no individual variation. In addition, it is possible to create a variation of the microneedle 11 as a uniform microneedle 11 with high precision and no variation among individuals.

FIG. 4A shows conical microneedles 11l, 11m, and 11s having different heights and diameters. These microneedles can be used differently depending on the amount of drug, the depth of penetration into the skin, and the degree of penetration into the skin.
FIG. 4B shows 11lw, 11mw, and 11sw having the same height as the microneedles 11l, 11m, and 11s of FIG. 4A and having different diameters and increased volumes as external shapes. For example, although the height of the microneedle 11m is necessary, when it is desired to increase the amount of the drug, the diameter can be increased and the volume of the drug can be increased. As shown in FIG. 4 (b), the volume of the microneedle 11 without changing the position of the tip of the microneedle 11 with respect to the skin, with respect to the cone-shaped microneedle 11 in a state where the height is positioned with respect to the skin, That is, the amount of drug solution injected into the affected area can be adjusted.

  Here, as shown in FIG. 3, the base member 15 is made of a thin material as a whole and has flexibility, but the surface of the base member 15 is formed as a flat surface as a whole. The microneedle structure 10 formed on the upper surface of the base member 15 also has a uniform height, appearance shape, and the like. On the other hand, each part of the human body to which the microneedle structure 10 is attached has not only a flat surface but also an uneven surface, a curved surface shape, etc. (hereinafter referred to as a bent surface). Therefore, it is desirable that the microneedle structure 10 is more appropriately brought into contact with the bending surface of the human body to cause the human skin.

  Therefore, according to the present invention, the microneedles 11l, 11m, and 11s having different sizes can be molded with the same accuracy as the microneedle 11 as shown in FIG.

  Therefore, the present inventor arranges the microneedles 11 of a plurality of sizes on the base member 15 according to the shape of the human body, so that the microneedles 11 can be easily stuck even if the skin is a curved surface. The effect of further treatment can be obtained by adjusting the amount of the drug according to the size and shape of the microneedle.

<Example 1 of microneedle arrangement>
As shown in FIG. 5, the microneedle structure 10a has microneedles 11l, 11m, and 11s having different sizes arranged on a base member 15a.

  As shown in FIG. 5, the smallest microneedle 11s is disposed at the center on the base member 15a, the medium-sized microneedle 11m is disposed on the concentric circle, and the large microneedle is disposed on the outer concentric circle. 11l is arranged. By arranging the large microneedles 11l that are easy to pierce the human skin on the outermost side, the base member 15a can be easily fixed to the human skin. In addition, the arrangement is effective when the administration of the drug is small in the center and the drug is increased in the outer edge.

  Conversely, the largest microneedle 11l is arranged at the center, the medium microneedle 11m is arranged on the concentric circle, and the small microneedle 11s is arranged on the outer concentric circle. (Not shown). In the case of this arrangement, since the large microneedle 11l that is easy to pierce the human skin is arranged at the center, the center of the base member 15a is fixed to the human skin, and conversely, the outer edge is weak in fixing force. The base member 15a is easily peeled off from the human skin. In addition, this arrangement is effective when a large amount of drug is administered to the central portion and a small amount of drug is administered to the outer edge.

<Example 2 of microneedle arrangement>
As shown in FIGS. 6A and 6B, the microneedle structure 10b is configured such that a plurality of microneedles 11 having different sizes and appearance shapes are arranged on a base member 15b.

  As shown in the cross-sectional shape of FIG. 6B, the external shape of the microneedle 11 is a mixture of different types such as a conical shape, a triangular pyramid shape, a quadrangular pyramid shape, a hexagonal pyramid shape, a two-stage conical shape, Different heights are mixed.

The arrangement of the different types of microneedles 11 on the base member 15b may be determined by the correlation between the position of the affected area of the skin, the type of drug, and the amount. As described above, even when a plurality of microneedles 11 having different sizes and appearance shapes are arranged, each microneedle 11 can be molded with high accuracy.

<Example 3 of microneedle arrangement>
5 and 6A, the microneedles 11 are geometrically concentrically arranged. However, the present invention is not limited to this. For example, the microneedles 11 having the same size and appearance are arranged in parallel. Alternatively, the microneedles 11 may be irregularly arranged (not shown) according to how the microneedles 11 are pierced into the skin or the shape of the affected area of the skin.

  In addition, it is not necessary to fill all the microneedles 11 with a drug. For example, the microneedles 11 intended to fix the base member 15 may be disposed only by being inserted into a human body.

  In the process of step S4 shown in FIG. 1, the process of filling the needle recess 31 of the mold 30 with the drug and molding the microneedle 11 and the microneedle structure 10 has been described. In the case where a plurality of different microneedles 11 are arranged, the medicine can be changed for each microneedle 11. In this case, the manufacturing process includes a process of filling the microneedle 11 with the drug (step S4) and a process of solidifying the drug or polylactic acid filled in step S4 for each type of the microneedle 11 or for each drug (step S5). By repeating the above, the microneedle 11 and the microneedle structure 10 can be created.

  As described above, according to the present invention, a master mold is created with a high-precision mold, and a fluororesin is used as a mold to uniformize the height, appearance shape, tip angle, etc. of each microneedle. Therefore, a highly accurate microneedle and microneedle structure can be created.

  In addition, according to the present invention, a master mold can be created with a high-precision mold, so that a plurality of microneedles having different heights, appearance shapes, tip angles, and the like can be created with high precision.

  In addition, according to the present invention, a plurality of types of microneedles having different heights, appearance shapes, tip end angles, and the like can be provided on the microneedle structure, and the arrangement of the microneedles is inserted into the skin. An easy arrangement pattern can be selected.

  In addition, according to the present invention, since different types of microneedles such as height, appearance shape, and tip angle suitable for the drug filled in the microneedles can be provided on the microneedle structure, it is effective for treatment. A typical microneedle arrangement pattern can be selected.

  Further, according to the present invention, since the medicine to be filled can be changed depending on the type of the microneedle, the microneedle becomes a mark of the medicine, and medical errors can be reduced.

  The present invention can be embodied in many forms without departing from its essential characteristics. Therefore, it is needless to say that the above-described embodiment is exclusively for description and does not limit the present invention.

DESCRIPTION OF SYMBOLS 10 Microneedle structure 11 Microneedle 15 Base member 20 Master type | mold 21 Needle convex part 30 Mold 31 Needle recessed part 110 Microneedle device 111 Substrate 112 Needle-like protrusion 115 Fluid conduit

Claims (8)

A plurality of cone-shaped needle protrusions that pierce skin of different heights are individually formed into a master mold by metal processing,
Injecting a releasable material into the master mold by injection molding to form a mold having needle concave portions having different depths and diameters corresponding to the plurality of needle convex portions,
Filling the needle recess with a drug to form a plurality of cone-shaped microneedles that pierce the skin with different volumes depending on the height and diameter ,
Forming a flexible base member to cover the microneedles,
The microneedles having different volumes according to the shape of the human body are mixed and arranged so that the volume of the microneedles arranged at the center portion of the base member and the outer edge portion outside thereof is mixed, and the microneedles are placed on the skin. And forming a microneedle having a structure in which the base member is brought into contact with the skin . 2. The method of manufacturing a microneedle structure according to claim 1, wherein the microneedles are formed on a base member with a plurality of microneedles having different volumes and different external shapes and tip angles.   3. The microneedle structure according to claim 1, wherein the microneedle is formed by coagulating a drug as a whole or molding it hollow with a resin and filling the hollow part with the drug. Production method. 4. The microneedle structure according to claim 1, wherein the drug has a different volume , and is filled with a different drug for each of a plurality of microneedles having different appearance shapes and tip angles. Manufacturing method.   The microneedle has a height H of 100 μm to 600 μm, a tip angle θ in a range of 20 ° to 60 °, and an external shape of a conical shape, a triangular pyramid shape, a quadrangular pyramid shape, a hexagonal pyramid shape, and a double cone shape The method for producing a microneedle structure according to any one of claims 1 to 3, wherein: A plurality of cone-shaped needle protrusions that pierce the skin with different volumes depending on the height and diameter individually formed by metal processing on the master mold,
Needle concave portions having different depths and diameters corresponding to the plurality of needle convex portions formed by injecting a releasable material into the mold by injection molding with respect to the master mold,
A plurality of cone-shaped microneedles that pierce the skin with different volumes depending on the height and diameter formed by filling the needle recess with a drug;
A base member having flexibility so as to cover the microneedles,
The microneedles arranged at the center part of the base member and the outer edge part outside thereof are made to have different volumes , and the microneedles having different volumes are mixed and arranged to pierce the microneedles into the skin, A microneedle structure characterized in that a base member is formed in a structure for fixing to the skin . The microneedle structure according to claim 6, wherein the microneedles have a volume , a plurality of microneedles having different external shapes and tip angles, and are molded on a base member.   The microneedle structure according to claim 6 or 7, wherein the microneedle is formed by coagulating a drug as a whole or molding it hollow with resin and filling the hollow part with the drug. body.

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