INJECTION NEEDLE

Abstract

The invention relates to an injection needle 1A comprising: projections projecting from a sheet base (2). The projections include a first projection (31) having an opening (31a) at a tip end portion and being hollow, and a second projection (32) without an opening at a tip end portion; and an insertion depth controller (40) provided at an intermediate position lower than a tip end position of the first projection (31) and higher than a surface of the sheet base (2). A height difference between the tip end position of the first projection (31) and a position of the insertion depth controller (40) is preferably 1 μm or more and 5,000 μm or less.

Description

Title of the invention: INJECTION NEEDLE Technical field

[0001] The present invention relates to an injection needle. Prior art

[0002] In recent years, in the fields of medicine, cosmetics, and the like, there has been interest in the percutaneous absorption of drugs using a liquid injection tool comprising fine needle-like projections, also called microneedles. With this liquid injection tool, it is possible to inject a liquid into a human body by inserting the microneedles into a relatively shallow layer of the skin, such as the stratum corneum, thereby significantly reducing the pain experienced by the subject compared with an ordinary syringe. Accordingly, attention has been paid to such a liquid injection tool as a minimally invasive liquid injection means.

[0003] Patent Literature 1 discloses a micro-protrusion instrument comprising a first hollow needle-shaped protrusion formed to protrude from an upper surface, which is a surface of a base sheet having a circular shape in a plan view and a second hollow protrusion formed to protrude near the first protrusion on the upper surface of the base sheet and having a protrusion height less than that of the first protrusion. In Patent Literature 1, when the first protrusion is inserted into the skin from the tip end side, the insertion of the first protrusion is stopped at a time when a tip end of the second protrusion near the first protrusion comes into contact with the surface of the skin, and the first protrusion is prevented from being inserted into a deeper site of the skin.An opening is formed at a tip end portion of the first protrusion, and a hollow portion of the first protrusion communicates with the outside through the opening. In Patent Literature 1, the tip end portion of the first protrusion is inserted into the skin, a liquid medicine stored in the hollow portion of the first protrusion is injected into the skin from the opening of the tip end portion.

[0004] Patent Literature 2 discloses a microneedle sheet in which a plurality of minute-sized needle groups protruding from the surface are formed. In Patent Literature 2, the needle groups include a penetrating needle group each having a through-hole formed from one side of the front surface to one side of the back surface and a dummy needle group having no through-hole.

[0005] List of quotes

[0006] Patent literature

[0007] [Patent Literature 1] US2018 / 185624A1

[0008] [Patent Literature 2] WO2021 / 177317A1 Summary of the invention

[0009] The present invention relates to an injection tool comprising projections projecting from a sheet base.

[0010] The injection needle of the present invention preferably comprises, as projections, a first projection having an opening at a tip end portion and being hollow, and a second projection having no opening at a tip end portion.

[0011] The injection needle of the present invention preferably comprises an insertion depth controller provided at an intermediate position lower than a tip end position of the first projection and higher than a surface of the sheet base. Brief description of the drawings

[0012] [Fig-1] [Fig.l] is a cross-sectional view in a thickness direction of an injection needle according to a preferred embodiment of the present invention.

[0013] [Fig.2] [Fig.2] is a plan view of the injection needle shown in [Fig.l].

[0014] [Fig.3] [Fig.3] is a diagram schematically representing a state of using the injection needle shown in [Fig.l], and a diagram showing a state in which a first projection of the injection needle is inserted into a stratum corneum of a skin and an insertion depth controller is in contact with a surface of the skin without being inserted into the skin.

[0015] [Fig.4] [Fig.4] is an explanatory diagram showing a method of measuring a tip end diameter of the projection in the injection needle.

[0016] [Fig. 5]: [Fig.5A], [Fig.5B], [Fig.5C], [Fig.5D] and [Fig.5E] are plan views schematically showing arrangement diagrams of the projection in the injection needle shown in [Fig.l].

[0017] [Fig.6] [Fig.6] is a cross-sectional view according to another mode of preferred embodiment of the present invention, and is a view corresponding to [Fig.l].

[0018] [Fig.7] [Fig.7] is a diagram schematically representing a state of use of the injection needle shown in [Fig.6], and is a diagram corresponding to [Fig.3].

[0019] [Fig. 8]: [Fig.8A], [Fig.8B] and [Fig.8C] are plan views schematically showing arrangement diagrams of the projection in the injection needle shown in [Fig.6].

[0020] [Fig.9] [Fig.9] is a cross-sectional view according to another preferred embodiment of the present invention, and is a view corresponding to [Fig.l].

[0021] [Fig. 10] [Fig. 10] is a diagram schematically representing a state of use of the injection needle shown in [Fig.9], and is a diagram corresponding to [Fig.3].

[0022] [Fig. 11]: [Fig.llA], [Fig.llB] and [Fig.llC] are plan views schematically showing arrangement diagrams of the projection in the injection needle shown in [Fig.9].

[0023] [Fig. 12]: [Fig.l2A] is a cross-sectional view schematically showing a modification of a first composite protrusion and a second composite protrusion; [Fig.l2B] is a cross-sectional view schematically showing a modification of a second protrusion.

[0024] [Fig. 13]: [Fig.l3A] is a cross-sectional view in a thickness direction of an injection needle according to Comparative Example 1; [Fig.l3B] is a plan view schematically showing an arrangement diagram of a projection in the injection needle of Comparative Example 1.

[0025] [Fig. 14]: [Fig.l4A] is a plan view schematically showing an arrangement diagram of a projection in an injection needle of Example 5; [Fig.l4B] is a plan view schematically showing an arrangement diagram of a projection in an injection needle of Example 6; and [Fig.l4C] is a plan view schematically showing an arrangement diagram of a projection in an injection needle of Example 7.

[0026] Description of embodiments

[0027] In the micro-protrusion instrument disclosed in Patent Literature 1, the protrusions of the micro-protrusion instrument include the first protrusion having a recess and an opening and the second protrusion having the protrusion height less than that of the first protrusion. Only the first protrusion is inserted into the skin. Furthermore, the second protrusion having the protrusion height less than that of the first protrusion acts as a stopper that limits the insertion depth of the first protrusion. For this reason, in such a micro-protrusion instrument of Patent Literature 1, a blood circulation promoting effect caused by pressing the protrusion against the skin or inserting it into the skin is limited, and it is possible to improve it. In particular, only the first protrusion is disclosed as a protrusion capable of stimulating the skin, but there is no disclosure aimed at increasing the density of the protrusions or aimed at uniformly imparting a blood circulation promoting effect over a wide area.

[0028] In Patent Literature 2, there is no disclosure to control the insertion depth of the penetrating needle group and the dummy needle group.

[0029] The present invention relates to an injection needle capable of controlling an insertion depth into a skin, injecting a liquid and effectively promoting blood circulation.

[0030] The present invention will be described below with reference to preferred embodiments.

[0031] An injection needle IA of the present invention has a projection protruding from a sheet base 2.

[0032] The injection needle 1A of the present invention typically has a flat sheet shape as a whole, and has a sheet base 2 and a plurality of projections projecting from a surface of the sheet base 2.

[0033] The injection needle IA of the present invention typically has a protrusion arrangement region in which the protrusions are arranged in a distribution state in a plane direction. A shape of the protrusion arrangement region may be any one of a quadrangular shape such as a square or rectangular shape, a circular shape, an elliptical shape, a pentagonal shape, and a polygonal shape such as a hexagonal shape.

[0034] The projections of the injection needle IA preferably include a first projection 31 having an opening 31a at a tip end portion and having a hollow, a second projection 32 having no opening at a tip end portion, and a third projection 33 having a height less than that of any one of the first projection 31 and the second projection 32. The first projection 31 is a micro-projection having a hollow portion 31b, which is called a microneedle.

[0035] The second protrusion 32 and the third protrusion 33 may be hollow, or may be solid, with no space therein. In the first embodiment, the second protrusion 32 and the third protrusion 33 are solid. Since the second protrusion 32 and the third protrusion 33 are solid, it is possible to reduce the amount of drug remaining in the IA injection needle when the drug is injected from the IA injection needle of the present invention.

[0036] Further, preferably, the third projection 33 has a tip end surface of a flat shape, i.e., a straight line shape extending in a horizontal direction, or is formed by a curved line projected in a projection direction of the third projection.

[0037] The injection needle of the present invention preferably comprises an insertion depth controller 40 at an intermediate position which is a position lower than a tip end position of the first projection 31 and higher than the surface of the sheet base 2. Typically, the tip end surface of the third projection 33 is the insertion depth controller 40. Such an example is shown in [Fig.l].

[0038] The insertion depth controller 40 controls an insertion depth of the first protrusion 31. The insertion depth controller 40 is preferably located at a position lower than the position of the tip end of the second protrusion 32.

[0039] In the injection needle IA of the present invention, a plurality of second protrusions 32 are preferably formed around a first protrusion 31. These second protrusions 32 preferably have the same distance from the first protrusion 31.

[0040] In the injection needle IA of the present invention, a plurality of third protrusions 33 are preferably formed around a first protrusion 31. These third protrusions 33 preferably have the same distance from the first protrusion 31.

[0041] More specifically, preferably, a pair of second protrusions 32, 32 are arranged with the first protrusion 31 interposed therebetween in a first X direction, and a pair of second protrusions 32, 32 are arranged with the first protrusion 31 interposed therebetween in a second Y direction orthogonal to the first X direction. Further, preferably, a pair of third protrusions 33, 33 are arranged with the first protrusion 31 interposed therebetween in the first X direction, and a pair of third protrusions 33, 33 are arranged with the first protrusion 31 interposed therebetween in the second Y direction. The third protrusion 33 is preferably arranged between the first protrusion 31 and the second protrusion 32. Such an example is shown in [Fig.2]. The position of the second projection 32 and the position of the third projection 33 can be reversed.In other words, the second projection 32 may be arranged between the first projection 31 and the third projection 33.

[0042] In the injection needle IA of the present invention, a plurality of unit arrangement patterns are continuous in the first X direction and the second Y direction in which the first protrusion 31, the second protrusion 32, and the third protrusion 33 are arranged in a predetermined positional relationship such that the second protrusion 32 is shared with the adjacent unit arrangement pattern.

[0043] In the injection needle IA of the present invention, typically, the first projection 31 and the second projection 32 have a conical shape, and the third projection 33 has a columnar shape. More typically, the plurality of second projections 32 have the same shape and size, and the plurality of third projections 33 also have the same shape and size.

[0044] The injection needle IA preferably contains a thermoplastic resin. Specifically, a base constituting the injection needle preferably contains a thermoplastic resin. Typically, the injection needle IA is preferably formed such that the base sheet containing the thermoplastic resin is plastically deformed by heating. A method of heating the base sheet may be a method of heating only a portion of the base sheet, or a method of heating the entire base sheet.An example of the method of heating only a portion of the base sheet and plastically deforming the base sheet may include a method of inserting a treatment needle into a position where the protrusions are to be formed on the base sheet while applying ultrasonic vibration, or a method of inserting the heated treatment needle into a position where the protrusions are to be formed on the base sheet. An example of the method of heating the entire base sheet and plastically deforming the base sheet may include a method of inserting a treatment needle into a position where the protrusions are to be formed on the base sheet while heating the entire base sheet with a heating instrument such as a heater.

[0045] In order to make the second protrusion 32 and the third protrusion 33 solid, for example, a hollow portion of the second protrusion or the third hollow protrusion formed by inserting the treatment needle into the base sheet may be filled with a resin for forming the protrusions or another resin.

[0046] In the injection needle IA of the present invention, the first projection 31 preferably comprises an opening 31a. Thus, the injection needle IA of the present invention serves as a liquid injection tool which can be used for percutaneous absorption of liquids such as drugs.

[0047] Typically, the opening 31a is formed at the tip end portion of the first protrusion 31, and the hollow portion 31b of the first protrusion 31 communicates with the outside through the opening 31a. The opening 31a is a through hole that penetrates the sheet base 2, which forms the first protrusion 31, in a thickness direction, and is preferably located at the tip end portion of the first protrusion 31 having the conical shape. The hollow portion 31b of the first protrusion 31 functions as a reservoir portion or a passage for a liquid discharged to the outside from the opening 31a. Here, the tip end portion of the first protrusion 31 means a region closer to the tip end at from the intermediate position of a projection height H1 from the surface of the sheet base 2 to the tip end of the first projection 31.

[0048] When the injection needle IA is used for percutaneous absorption of a drug, the tip end portion of the first projection 31 is inserted into a skin S, and a liquid drug L stored in the hollow portion 31b of the first projection 31 is injected into the skin S from the opening 31a of the tip end portion. As described above, the hollow portion 31b of the first projection 31 typically functions as a reservoir portion of the drug in a case where a drug is not supplied from the outside.

[0049] In the case where a drug is supplied from the outside, for example, when a drug supply device (not shown) such as an applicator is used in combination with the injection needle IA, the hollow portion 31b functions as a passage for the drug. The drug supply device may be formed in such a manner that a sheet-shaped member is arranged on a rear surface side of the injection needle IA and a drug-accommodating space is formed between the rear surface of the injection needle IA and the sheet-shaped member, and may supply the drug to the first projection 31 by pressing the sheet-shaped member (see paragraph

[0011] in JP 2020-096790 A).

[0050] The injection needle IA preferably comprises the second projection 32 in addition to the first projection 31.

[0051] In a case where a height H2 of the second protrusion 32 is greater than a height H3 of the insertion depth controller 40, when the injection needle 1A is pressed against the skin and the first protrusion 31 is inserted into the skin from the tip end side, the second protrusion 32 is also inserted into the skin. When the second protrusion 32 is inserted into the skin, the second protrusion 32 stimulates the skin and exerts a blood circulation promoting action. Therefore, with the injection needle 1A having such a configuration, the liquid can be injected into the skin through the first protrusion 31, and the blood circulation can be promoted through the second protrusion 32.Unlike the case where the protrusions included in the micro-protrusion instrument are only the first protrusions capable of injecting the liquid into the skin as in the micro-protrusion instrument disclosed in Patent Literature 1, the injection needle IA can largely stimulate the skin by using both the first protrusion 31 and the second protrusion 32. For this reason, unlike the case where only the first protrusions are increased for the purpose of largely stimulating the skin in the micro-protrusion instrument disclosed in Patent Literature 1, even when protrusions are not partially inserted into the skin when the injection needle IA is applied to the skin, the protrusions are not always the first ones. protrusions having an opening, and it is therefore possible to reduce the probability of liquid leakage.

[0052] When the injection needle IA is pressed against the skin, the second projection 32 can only be pressed against the skin without being inserted into the skin. Typically, this is a case where the height H2 of the second projection 32 is equal to the distance H3 between the surface of the sheet base 2 and the insertion depth controller 40. Even in this case, the second projection 32 can stimulate the skin and exert a blood circulation promoting action.

[0053] Furthermore, the injection needle IA preferably comprises the insertion depth controller 40 in addition to the first protrusion 31 and the second protrusion 32. As described above, in the injection needle IA, the tip end surface of the third protrusion 33 is preferably the insertion depth controller 40. When the first protrusion 31 and the second protrusion 32 are inserted into the skin from the tip end side, the insertion depth controller 40 contacts the skin surface. Then, the insertion of the first protrusion 31 and the second protrusion 32 is stopped, and the first protrusion 31 and the second protrusion 32 are prevented from being inserted into a deeper site of the skin. In other words, the insertion depth controller 40 functions as a stop that limits the insertion depth of the first projection 31 and the second projection 32.

[0054] An example of such a configuration is shown in [Fig.3].

[0055] The presence or absence of the blood circulation promoting effect may be determined by various known methods and can be determined, for example, by the occurrence of an inflammatory reaction on the skin or by visualizing the distribution of blood flow using laser granularity blood flow measurement (LSFG).

[0056] As described above, the injection needle IA enables percutaneous absorption of the drug to a desired depth of the skin, since the insertion depth of each of the first protrusion 31 and the second protrusion 32 into the skin is controllable, and also enables effective promotion of blood circulation. For this reason, with the injection needle IA, the insertion depth of the first protrusion 31 is adjusted according to the type of drug, and thus the effect of the drug can be maximized. In addition, the insertion depth of the second protrusion 32 is adjusted according to the intended degree of the blood circulation promoting action, and thus the blood circulation promoting action can be effectively generated.

[0057] Furthermore, the first protrusion 31 and the second protrusion 32 are inserted into a stratum corneum SI 1, which is a skin surface layer S or a layer S12 located inside relative to the stratum corneum. However, they are prevented to be inserted into a dermis S2 and a hypodermal tissue U which is a deeper site than the skin S. Thus, pain caused by percutaneous absorption can be significantly reduced compared to the syringe according to the related art. Generally, the skin S comprises an epidermis S1 including the stratum corneum S11 constituting the surface layer of the skin S, the dermis S2 located inward with respect to the epidermis SI, and the hypodermal tissue (not shown) located inward with respect to the dermis S2. The layer S12 located inward with respect to the stratum corneum SU in the epidermis SI typically comprises the stratum granulosum, the stratum spinosum and the stratum basale in the order of proximity to the stratum corneum SI 1, and the dermis S2 is located inward with respect to the stratum basale.

[0058] When percutaneous absorption of a drug is performed using a syringe equipped with an injection needle without an insertion depth controller 40, the person into whom the injection needle is inserted must endure pain caused by the insertion of the injection needle since the injection needle is inserted into the S12 site, which is located inward relative to the stratum corneum beyond the stratum corneum, or the S2 dermis, or even into the hypodermic tissue. However, with the injection needle IA, it is possible to perform percutaneous absorption of the drug and promote blood circulation while reducing the pain experienced by the person into whom the injection needle is inserted.

[0059] From the viewpoint of minimally invasive percutaneous absorption and pain reduction, the insertion depth controller 40 preferably controls the tip ends of the first protrusion 31 and the second protrusion 32 so as not to reach the dermis and the hypodermal tissue U, and even more preferably can control the tip ends thereof so as not to reach the site S12 located inward relative to the stratum corneum. Since the insertion depths of the first protrusion 31 and the second protrusion 32 coincide with the distances in a height direction Z between the respective tip ends of the first protrusion 31 and the second protrusion 32 and the insertion depth controller proximate thereto, the above-described effect can be more reliably achieved by appropriately adjusting the distances in the height direction Z.The term "minimal invasiveness" in the present invention means a condition where, when the injection needle is pressed against the skin, the stratum corneum and the site located inside relative to the stratum corneum are damaged, but the dermis and hypodermal tissue are not damaged.

[0060] In the injection needle IA of the present invention, the roles of the first projection 31 and the second projection 32 are different, the effect of promoting blood circulation being provided by the second projection 32 and the effect of promoting blood circulation and injecting the liquid being provided by the first projection 31. Thus, the injection amount of the liquid can be effectively saved compared with a case where a large number of protrusions capable of injecting the liquid are provided for the purpose of achieving the effect of promoting blood circulation. In particular, when the liquid is supplied from a reservoir portion of a drug to the plurality of protrusions capable of injecting the liquid, the degree of insertion into the skin tends to differ depending on each protrusion. With the injection needle IA of the present invention, the drug can be injected uniformly while avoiding leakage and the hypodermic depth at which the injection is made can be made uniform. Furthermore, the injection area of ​​the liquid can also be set to a minimal but sufficiently effective area to enable injection. The second protrusion 32 serves as a guide / indicator for vertical insertion of the injection needle IA into the skin.The second protrusion 32 also has the effect of facilitating the insertion of the first protrusion 31 by limiting the deformation of the skin. In addition, for example, when the injection needle IA is not perpendicular to the skin, inevitably at the time of use, the injection needle IA is inserted obliquely to the skin. Thus, the protrusion arranged on the outer periphery of the injection needle IA may not be sufficiently inserted into the skin depending on the direction. However, when the second protrusion is arranged on an outer periphery of the injection needle IA, the first protrusion arranged on an inner periphery of the injection needle IA can be sufficiently inserted into the skin and the drug can be injected without leakage into the skin S.In other words, the AI ​​injection needle of the present invention can easily control the injection amount of the liquid and the injection area of ​​the liquid, and can effectively inject the medicine.

[0061] From the viewpoint of significantly reducing the pain caused by percutaneous absorption or reliably injecting the drug from the first protrusion 31 into the skin S, a height difference between the tip end position of the first protrusion 31 and the position of the insertion depth controller 40 is preferably 1 μm or more, and more preferably 5 μm or more. The height difference is a difference H1 - H3 between the protrusion height H1 of the first protrusion 31 and the distance H3 between the surface of the sheet base 2 and the insertion depth controller 40.

[0062] Furthermore, the difference H1 - H3 is preferably 5000 pm or less, and more preferably 4000 pm or less, from the point of view of not damaging the dermis more than necessary.

[0063] Further, the difference H1 - H3 is preferably 1 pm or more and 5000 pm or less, and more preferably 5 pm or more and 4000 pm or less.

[0064] From the point of view of the significant reduction of pain associated with the blood circulation promoting effect due to the second projection 32, prevention of poor insertion of the second protrusion due to elasticity of the skin, and sufficient insertion of the second protrusion into the skin, a protrusion height H2 of the second protrusion 32 is equal to or greater than the distance H3 from the surface of the base sheet 2 to the insertion depth controller 40, i.e., preferably H2 is equal to or greater than H3, and more preferably H2 > H3.

[0065] From the same point of view, a difference H2 - H3 is preferably 0 or more, more preferably 100 pm or more, and even more preferably 400 pm or more.

[0066] Furthermore, a difference H2 - H3 is preferably 5000 pm or less, and more preferably 4000 pm or less, from the viewpoint of not damaging the skin more than necessary.

[0067] Further, the difference H2 - H3 is preferably 0 or more and 5000 pm or less, more preferably 100 pm or more and 5000 pm or less, and even more preferably 400 pm or more and 4000 pm or less.

[0068] From the viewpoint of more reliably exerting the blood circulation promoting effect and ensuring the insertion of the first protrusion 31 to prevent drug leakage caused by insufficient insertion, the first protrusion 31 preferably has a higher height than a height of the second protrusion 32. More specifically, a difference H1 - H2 between the protrusion height H1 of the first protrusion 31 and the protrusion height H2 of the second protrusion 32 is preferably 1 µm or more, and more preferably 5 µm or more.

[0069] Furthermore, the difference H1 - H2 is preferably 5000 pm or less, and more preferably 4000 pm or less, from the viewpoint of facilitating the compatibility between the ease of liquid injection and the effect of promoting blood circulation.

[0070] Further, the difference H1 - H2 is preferably 1 pm or more and 5000 pm or less, and more preferably 5 pm or more and 4000 pm or less.

[0071] The protrusion height H1 of the first protrusion 31 is preferably 10 µm or more, and more preferably 20 µm or more, from the viewpoints of preventing inhibition of insertion due to deformation of the skin when the first protrusion 31 is pressed against the skin, improving a puncture capability, and reliably injecting the drug into the skin S.

[0072] Furthermore, the protrusion height H1 of the first protrusion 31 is preferably 5000 pm or less, and more preferably 4000 pm or less, from the viewpoint of minimal invasion.

[0073] Furthermore, the protrusion height H1 of the first protrusion 31 is preferably 10 pm or more and 5,000 pm or less, and more preferably 20 pm or more and 4,000 pm or less, from the viewpoint of achieving both improved puncture capability and minimal invasiveness.

[0074] The protrusion height H2 of the second protrusion 32 is preferably 10 pm or more, and more preferably 20 pm or more, from the viewpoint of stimulating the skin by pressing against the skin and promoting blood circulation.

[0075] Furthermore, the protrusion height H2 of the second protrusion 32 is preferably 5000 pm or less, and more preferably 4000 pm or less, from the viewpoint of minimal invasion.

[0076] Furthermore, the protrusion height H2 of the second protrusion 32 is preferably 10 pm or more and 5000 pm or less, and more preferably 20 pm or more and 4000 pm or less, from the viewpoint of improving the promotion of blood circulation.

[0077] The distance H3 between the surface of the sheet base 2 and the insertion depth controller 40 is preferably 5 pm or more, and more preferably 10 pm or more.

[0078] Furthermore, the distance H3 is preferably 4000 pm or less, and more preferably 3000 pm or less, from the viewpoint of improving the perforation capability of the first projection 31.

[0079] Further, the distance H3 is preferably 5 pm or more and 4000 pm or less, and more preferably 10 pm or more and 3000 pm or less.

[0080] In reality, the tip end diameter of the first projection 31 is preferably 1 µm or more, and more preferably 5 µm or more.

[0081] Furthermore, the tip end diameter of the first projection 31 is preferably 300 µm or less, and more preferably 100 µm or less, from the viewpoint of preventing perforation inhibition due to skin elasticity.

[0082] Further, the tip end diameter of the first protrusion 31 is preferably 1 µm or more and 300 µm or less, and more preferably 5 µm or more and 100 µm or less.

[0083] The tip end diameter of the second projection 32 is preferably 1 µm or more, and more preferably 5 µm or more.

[0084] Furthermore, the tip end diameter of the second protrusion 32 is preferably 300 µm or less, and more preferably 200 µm or less, from the viewpoint of improving the blood circulation promoting effect.

[0085] Further, the tip end diameter of the second protrusion 32 is preferably 1 µm or more and 300 µm or less, and more preferably 5 µm or more and 200 µm or less.

[0086] The tip end diameter of the third projection 33 is preferably 2 µm or more, and more preferably 10 µm or more, from the viewpoint of acting as a stopper that prevents the first projection 31 from being inserted more than necessary.

[0087] The tip end diameter of the second projection 32 may be equal to or greater than the tip end diameter of the first projection 31, or may be equal to or less than the tip end diameter of the first projection 31.

[0088] Furthermore, the tip end diameter of the third protrusion 33 is preferably 2000 μm or less, and more preferably 100 μm or less, from the viewpoint of improving the density degree of the first protrusion and the second protrusion.

[0089] Further, the tip end diameter of the third projection 33 is preferably 2 μm or more and 2000 μm or less, and more preferably 10 μm or more and 100 μm or less.

[0090] The tip end diameter of the third projection 33 may be equal to or greater than the tip end diameter of the first projection 31, or may be equal to or less than the tip end diameter of the first projection 31.

[0091] The tip end diameters of the first to third projections 31 to 33 are measured by the following method.

[0092] [Method for measuring the tip end diameter of the projection on the injection needle]

[0093] The tip end portion of the protrusion (first protrusion 31, second protrusion 32, or third protrusion 33) to be measured is observed using a scanning electron microscope (SEM) or a microscope, as shown in [Fig. 4]. Then, as shown in [Fig. 4], a virtual straight line ILa extends along a straight line on one lateral side 1a of the two lateral sides 1a and 1b, and a virtual straight line ILb extends along a straight line on the other lateral side 1b. Then, on the tip end side, a first tip end point 1al is obtained as a point where one lateral side 1a is separated from the virtual straight line ILa, and a second tip end point Ibl is obtained as a point where the other lateral side 1b is separated from the virtual straight line ILb.A length L of a straight line connecting the first tip end point lal and the second tip end point Ibl obtained in this way is measured. The measured length of the straight line is defined as the tip end diameter of the projection to be measured.

[0094] The first projection 31 preferably has the opening 31a at the tip end portion as described above. Then, the opening 31a is preferably not formed at the tip end of the first projection 31, but is formed on the side surface of the first projection 31. When the opening 31a is formed in such a position, the opening 31a is not easily crushed when the first projection 31 is inserted into the skin, and the liquid such as a drug can be stably introduced into the skin from the injection needle IA through the opening 31a.

[0095] The first protrusion 31 may be arranged at an arbitrary position in the protrusion arrangement region, but it is preferably located at an inner position relative to the second protrusion 32 in the protrusion arrangement region, i.e., on a central side of the protrusion arrangement region. Thus, when the injection needle 1A is pressed against the skin, a load is easily applied to the first protrusion 31, and the first protrusion 31 is easily inserted into the skin. Furthermore, the first protrusion 31 is preferably surrounded by the second protrusion 32. Thus, the insertion site of the first protrusion 31 is surrounded by a region where blood circulation is promoted and induced by immunity by the weak stimulation of the second protrusion 32, and it is considered that a medicinal effect of the drug injected by the first protrusion 31 can be improved.Furthermore, when the injection needle IA is used, the injection needle 1A may not be perpendicular to the skin unavoidably and may be inserted obliquely into the skin. In this case, since the first protrusion 31 is located on the central side, the first protrusion 31 can be stably inserted into the skin regardless of the direction in which the injection needle IA is inclined relative to the skin, and leakage of the drug can be effectively prevented when the insertion is insufficient. From the viewpoint of making these effects more remarkable, the second protrusion 32 is preferably located on the outermost side of the protrusion arrangement region.

[0096] An arrangement scheme of the first projection 31, the second projection 32 and the third projection 33 is not particularly limited.

[0097] From the viewpoint of precise control of the insertion depth, an array (hereinafter referred to as "first array") is preferable in which either or both of the first protrusion 31 and the second protrusion 32 are arranged between a pair of third protrusions 33 adjacent to each other. An array (hereinafter referred to as "second array") is also preferable in which either or both of the first protrusion 31 and the second protrusion 32, not having an insertion depth controller, are arranged between the composite protrusions (first composite protrusion 51 or second composite protrusion 52) having the insertion depth controller.

[0098] The protrusion located between the third protrusions 33 in the first array or the protrusion located between the composite protrusions in the second array may be any one of only the first protrusion 31, only the second protrusion 32, or both the first protrusion 31 and the second protrusion 32. The number of protrusions located between the third protrusions 33 or the composite protrusions is preferably 1 or more and 4 or less, and more preferably 1 or 2.

[0099] For example, the arrangement diagrams shown in Figures 5(a), 5(b) and 5(e) include a first array arranged in the first X direction, a first array arranged in the second Y direction, and a first array arranged in a direction inclined relative to both of the first X direction and the second Y direction, more specifically, arranged in a direction inclined at an angle of 45 degrees. The arrangement diagrams shown in Figures 5(d) and 5(c) comprise a first array in which a plurality of protrusions, which are the first or second protrusions 31 or 32, are arranged between the third protrusions 33. The arrangement diagrams shown in Figures 8(a) and 11(a) comprise a second array arranged in the first X direction and a second array arranged in the second Y direction.The arrangement diagrams shown in Figures 8(c) and 11(b) include a second array arranged in the first X direction, a second array arranged in the second Y direction, and a second array arranged in a direction inclined with respect to both of the first X direction and the second Y direction, more specifically, arranged in a direction inclined at an angle of 45 degrees.

[0100] The plurality of first gratings or second gratings are preferably present in the protrusion arrangement region, and are preferably present in a state of dispersion in the plane direction of the protrusion arrangement region.

[0101] From the viewpoint of precise control of the insertion depth, it is also preferable to have an array (hereinafter referred to as "third array") in which at least three or more third protrusions 33 are arranged so as to surround the periphery of the first protrusion 31 or the second protrusion 32, or an array (hereinafter referred to as "fourth array") in which at least three or more protrusions, which are the second protrusions 32 or the third protrusions 33, are arranged so as to surround the periphery of the first protrusion 31. It is also preferable to have an array (hereinafter referred to as "fifth array") in which at least three or more composite protrusions (first composite protrusion 51 or second composite protrusion 52) having the insertion depth controller are arranged so as to surround the periphery of the first protrusion 31 or the second projection 32 having no insertion depth controller.

[0102] The protrusion surrounded by the third protrusions 33 in the third array or the protrusion surrounded by the composite protrusions in the fifth array may be any one of only the first protrusion 31, only the second protrusion 32, or both the first protrusion 31 and the second protrusion 32. With respect to the third array or the fifth array, the number of protrusions surrounded by the third protrusion 33 or the composite protrusion is preferably 1 or more and 4 or less, and more preferably 1 or 2. With respect to the fourth array, the number of first protrusions 31 surrounded by the second or third protrusions 32 or 33 is preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less.

[0103] For example, the arrangement diagrams shown in Figures 5(a), 5(b) and 5(e) include a third array in which the third projection 33 is surrounded by a single projection, which is the first or second projection 31 or 32. The arrangement diagrams shown in Figures 5(c) and 5(d) include a third array in which the third projection 33 is surrounded by a plurality of projections, which are the first or second projection 31 or 32.

[0104] The plurality of third gratings, fourth gratings, or fifth gratings are preferably present in the protrusion arrangement region, and are preferably present in a state of dispersion in the plane direction of the protrusion arrangement region.

[0105] The arrangement scheme of the first protrusion 31, the second protrusion 32 and the third protrusion 33 may be, for example, as shown in [Fig. 5](a), wherein a pair of second protrusions 32, 32 are arranged with the first protrusion 31 interposed therebetween in the first X direction and the second Y direction, and the third protrusions 33 may be arranged with the second protrusion 32 interposed therebetween in the first X direction or the second Y direction. Further, as shown in [Fig. 5](b), the second protrusion 32 and the third protrusion 33 may be arranged to surround the periphery of the first protrusion 31, and the second protrusion 32 may be arranged outside the third protrusion 33. Further, as shown in [Fig.5](c), the second protrusion 32 and the third protrusion 33 may be arranged to surround the periphery of the first protrusion 31, and the second protrusion 32 may be arranged inside the third protrusion 33. Further, as shown in [Fig. 5](d), the first protrusion 31 and the third protrusion 33 may be arranged to surround the periphery of the second protrusion 32, and the third protrusion 33 may be arranged outside the first protrusion 31. Further, as shown in [Fig. 5](e), the first protrusion 31 and the third protrusion 33 may be arranged to surround the periphery of the second protrusion 32, and the third protrusion 33 may be arranged inside the first protrusion 31. In Figures 5(a) to 5(e), the first protrusion 31 is shown by upper-right hatching, the second protrusion 32 is shown by lower-right hatching, and the third protrusion 33 is shown by dot hatching..

[0106] In a plan view of the sheet base 2, a distance D between the tip ends of the projections adjacent to each other is preferably 0.01 mm or more, more preferably 0.02 mm or more, even more preferably 0.1 mm or more, and even more preferably more than 0.5 mm, from the viewpoint of reducing the prevention of insertion of the first projection due to the interference caused by the deformation of the skin when the adjacent projections are pressed against the skin.

[0107] Furthermore, the distance D is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less, from the viewpoint that the blood circulation improving effect induced by the adjacent protrusions can be achieved in the applicable area without gap.

[0108] Further, the distance D is preferably 0.01 mm or more and 10 mm or less, more preferably 0.1 mm or more and 5 mm or less, and even more preferably more than 0.5 mm and 3 mm or less.

[0109] Adjacent protrusions are two protrusions whose distance between the apexes is the shortest, and when a protrusion is surrounded by a plurality of other protrusions with the same distance between the protrusions, it is one protrusion and the other protrusion. The distance D is measured only by using the first protrusion 31 and the second protrusion 32 as protrusions adjacent to each other. In other words, even when the third protrusion 33, the tip end surface of which is the insertion depth controller 40, exists, the distance D is measured without using the third protrusion 33.

[0110] A thickness T of the sheet base 2 of the injection needle IA is preferably 5 qm or more, more preferably 10 qm or more, and even more preferably 20 qm or more.

[0111] Furthermore, the thickness T is preferably 2000 qm or less, more preferably 1000 qm or less, and even more preferably 500 qm or less, from the viewpoint of facilitating the pressure of the IA injection needle against the skin.

[0112] Further, the thickness T is preferably 5 qm or more and 2000 qm or less, more preferably 10 qm or more and 1000 qm or less, and even more preferably 20 qm or more and 500 qm or less (see [Fig.l]).

[0113] The thickness T of the sheet base 2 can be measured by the following method.

[0114] <Méthode de mesure de l’épaisseur d’une base en feuille>

[0115] The sheet base 2 of the injection needle 1A is observed using an SEM or a microscope in a state of magnification by a predetermined magnification as shown in [Fig.l]. Then, as shown in [Fig.l], a distance in a thickness direction Z of the sheet base 2 is measured from a surface on the side of the sheet base 2 where the protrusion protrudes to a surface opposite the surface. The distance measured in this way is defined as a thickness T of the base portion.

[0116] The injection needle IA may have only the first projection 31, but preferably has a plurality of first projections.

[0117] Furthermore, the injection needle IA preferably has a region in which the number NI of the first projections 31 per 1 cm2 or the number N2 of the second projections per 1 cm2 is as follows when viewed in a plan view.

[0118] The number NI of the first protrusions 31 or the number N2 of the second protrusions is preferably 1 or more, more preferably 5 or more, and even more preferably 10 or more, from the point of view of enabling efficient injection of the liquid.

[0119] Furthermore, the number NI of the first protrusions 31 or the number N2 of the second protrusions is preferably 400 or less, more preferably 300 or less, and even more preferably 200 or less, from the viewpoint of easily controlling the injection amount of the liquid and the injection area of ​​the liquid.

[0120] Furthermore, the number NI of the first protrusions 31 or the number N2 of the second protrusions is preferably 1 or more and 400 or less, more preferably 5 or more and 300 or less, and even more preferably 10 or more and 200 or less, according to these two points of view.

[0121] The injection needle IA may have only the second projection, or may have a plurality of second projections but preferably has a plurality of first projections 31.

[0122] The injection needle IA preferably has a region in which the total number NI + N2 of the first projections 31 and the second projections 32 per 1 cm2 is as follows when viewed in a plan view.

[0123] The total number NI + N2 is preferably 2 or more, more preferably 5 or more, even more preferably 10 or more, even more preferably 20 or more, and even more preferably 30 or more, from the viewpoints of triggering an inflammatory reaction in the entire area where the IA injection needle is applied and facilitating the blood circulation promoting effect and from the viewpoints of enabling effective injection of the liquid.

[0124] The total number NI + N2 is preferably 500 or less, more preferably 300 or less, even more preferably 200 or less, and even more preferably less than 200, from the viewpoint of easy control of the liquid injection amount and the liquid injection area.

[0125] The total number NI + N2 is preferably 10 or more and 500 or less, more preferably 20 or more and 300 or less, and even more preferably 30 or more and less than 200, from these two points of view.

[0126] A ratio N2 / N1 of the number N2 of the second protrusions per 1 cm2 to the number NI of the first protrusions 31 per 1 cm2 is preferably 0.01 or more, more preferably 0.1 or more, even more preferably 0.5 or more, even more preferably 1 or more, and even more preferably 2.4 or more. It is preferable from the viewpoint of effectively triggering an inflammatory reaction around the first protrusion 31 through which the liquid is injected and achieving the effect of promoting blood circulation. It is also preferable from the viewpoint of view of improving the probability of injection by preventing the first projection 31 from not being inserted into the skin when the injection needle IA is pressed against the skin.

[0127] The N2 / N1 ratio is preferably 100 or less, more preferably 50 or less, and even more preferably 10 or less, from the viewpoint of enabling insertion with low insertion pressure and enabling efficient injection of liquid by reducing the amount of liquid to be injected from a first protrusion.

[0128] The N2 / N1 ratio is preferably 0.01 or more and 100 or less, more preferably 1 or more and 50 or less, and even more preferably 2.4 or more and 10 or less, from both points of view.

[0129] The number of first projections 31 per 1 cm2 when the IA injection needle is viewed in a plan view can be measured by the following method.

[0130] <Méthode de mesure du nombre de premières saillies par 1 cm2 >

[0131] The number of first protrusions 31 per 1 cm2 can be calculated in such a way that the number (pcs) of the first protrusions 31 included in the protrusion arrangement region where a plurality of micro-protrusions 3 are dispersed in a plan direction is divided by a total area (cm2) of the protrusion arrangement region. The total area of ​​the protrusion arrangement region is an area of ​​a region enclosed by a virtual line connecting the apices of the protrusions arranged on an outer edge of the region when the injection needle IA is viewed in a plan view. When the number of protrusions of the injection needle IA is 2 or less, the number of first protrusions 31 included in a square region of 1 cm square can be measured by counting when the injection needle IA is viewed in a plan view.

[0132] By using the injection needle of the present invention, it is possible to achieve the effect of promoting blood circulation in a wide area in which the first protrusion and the second protrusion are arranged, and to reliably inject the drug into the skin.

[0133] The inventors consider that the drug is injected into the skin and the blood circulation is improved around the skin into which the drug is injected, so that the drug can be easily absorbed by the skin, the drug likely to not be absorbed can be prevented from flowing out of the skin, and the effect of the drug can be easily obtained.

[0134] Next, another embodiment of an injection needle of the present invention will be described. In such an embodiment, only the differences from the embodiment described above will be described, the description of the embodiment described above will be applied appropriately unless otherwise specifically described, and like elements will be designated by like numerals. reference. Examples are shown in Figures 6 to 8(c) and Figures 9 to 11(c).

[0135] An injection needle of the present invention preferably comprises a first composite protrusion 51 in which the third protrusion and the insertion depth controller 40 are integrally formed in the sheet base direction of the first protrusion 31. An example of the injection needle (hereinafter also referred to as "injection needle IB") comprising the first composite protrusion 51 will be described. In the injection needle IB, the first protrusion 31 is integrally molded with the insertion depth controller 40 on the outer periphery on the base side. More specifically, an enlarged diameter portion 41 is formed on the base side, and a stepped portion is formed at an upper end portion of the enlarged diameter portion 41 so as to overhang outward in a radial direction of the first protrusion 31.The stepped portion then constitutes the insertion depth controller 40.

[0136] An overhang length L1 of the stepped portion of the first composite projection 51 is preferably 0.002 mm or more, and more preferably 0.01 mm or more, from the viewpoint of acting as a stopper to prevent the first projection 31 from being inserted more than necessary.

[0137] Furthermore, the length L1 is preferably 2 mm or less, and more preferably 0.1 mm or less, from the viewpoint of improving the density degree of the first protrusion 31 and the second protrusion 32 and achieving the effect of promoting blood circulation in a wide area to which the micro-protrusion instrument is applied.

[0138] Further, the length L1 is preferably 0.002 mm or more and 2 mm or less, and more preferably 0.01 mm or more and 0.1 mm or less.

[0139] The length L1 is a linear distance obtained by measuring a distance between an inner end portion and an outer end portion of the stepped portion along a plane orthogonal to the height direction, and is a distance between two contacts of each of the inner end portion and the outer end portion and each of tangent lines PI and P2 forming 45 degrees to a center line CL of the first projection as shown in [Fig.6].

[0140] Still in the injection needle IB, when the first composite protrusion 51 and the second protrusion 32 are inserted into the skin from the tip end side, the insertion depth controller 40 contacts the surface of the skin. Then, the insertion of the first composite protrusion 51 and the second protrusion 32 is stopped, and the first composite protrusion 51 and the second protrusion 32 are prevented from being inserted into a deeper site of the skin. In the first composite protrusion 51, since the insertion depth controller 40 is formed of a single holding around the first projection 31, the first composite projection 51 can be reliably prevented from being inserted into the deeper site of the skin. Such an example is shown in [Fig.7].

[0141] An arrangement scheme of the first composite protrusion 51 and the second protrusion 32 is not particularly limited. For example, as shown in [Fig. 8](a), a pair of second protrusions 32, 32 may be arranged with the first composite protrusion 51 interposed therebetween in the first X direction and the second Y direction. Further, as shown in [Fig. 8](b), the second protrusions 32 may be arranged so as to surround the periphery of the first composite protrusion 51. Further, as shown in [Fig. 8](c), the first composite protrusion 51 may be arranged to surround the periphery of the second protrusion 32. In Figures 8(a) and 8(b), the first composite protrusion 51 is shown by hatching toward the upper right, and the second protrusion 32 is shown by hatching toward the lower right.

[0142] The injection needle of the present invention preferably comprises a second composite protrusion 52 in which the insertion depth controller 40 is integrally formed around the second protrusion 32. An example of the injection needle (hereinafter also referred to as "IC injection needle") comprising the second composite protrusion 52 will be described. In the IC injection needle, the second protrusion 32 is integrally molded with the insertion depth controller 40 on the outer periphery on the base side. More specifically, an enlarged diameter portion 41 is formed on the base side, and a stepped portion is formed at an upper end portion of the enlarged diameter portion 41 so as to overhang outward in a radial direction of the second projection 32. The stepped portion then constitutes the insertion depth controller 40. Such an example is shown in [Fig.9].

[0143] An overhang length L2 of the stepped portion of the second composite projection 52 is preferably 0.002 mm or more, and more preferably 0.01 mm or more, from the viewpoint of acting as a stopper to prevent the second projection 32 from being inserted more than necessary.

[0144] Furthermore, the length L2 is preferably 2 mm or less, and more preferably 0.1 mm or less, from the viewpoint of improving the density degree of the first protrusion 31 and the second protrusion 32 and achieving the effect of promoting blood circulation in a wide area to which the injection needle is applied.

[0145] Further, the length L2 is preferably 0.002 mm or more and 2 mm or less, and more preferably 0.01 mm or more and 0.1 mm or less.

[0146] Length L2 can be measured in the same way as length LL

[0147] Still in the IC injection needle, when the first protrusion 31 and the second composite protrusion 52 are inserted into the skin from the tip end side, the insertion depth controller 40 contacts the surface of the skin. Then, the insertion of the first protrusion 31 and the second composite protrusion 52 is stopped, and the first protrusion 31 and the second composite protrusion 52 are prevented from being inserted into a deeper site of the skin. In the second composite protrusion 52, since the insertion depth controller 40 is integrally formed around the second protrusion 32, the second composite protrusion 52 can be reliably prevented from being inserted into the deeper site of the skin. Such an example is shown in [Fig. 10].

[0148] An arrangement scheme of the first protrusion 31 and the second composite protrusion 52 is not particularly limited. For example, as shown in [Fig. 1 l](a), a pair of second composite protrusions 52, 52 may be arranged with the first protrusion 31 interposed therebetween in the first X direction and the second Y direction. Further, as shown in [Fig. 11 ](b), the second composite protrusions 52 may be arranged so as to surround the periphery of the first protrusion 31. Further, as shown in [Fig. 11 ](c), the first projection 31 may be arranged to surround the periphery of the second composite projection 52. In Figures 11 (a) and 11(b), the first projection 31 is shown by hatching towards the upper right, and the second composite projection 52 is shown by hatching towards the lower right.

[0149] Next, the points common to each of the embodiments described above will be described.

[0150] The injection needle 1A, 1B or 1C of each of the embodiments of the present invention preferably contains a thermoplastic resin from the viewpoint of ensuring the handleability of the material, the strength and workability of the injection needle, and the hardness of the first projection 31 and the second projection 32, and achieving the effect of promoting blood circulation while facilitating the injection of the liquid. The injection needle is further preferably formed of the base sheet containing the thermoplastic resin.

[0151] The base sheet contains a thermoplastic resin as a main constituent material. The main constituent material means that the mass of the thermoplastic resin accounts for 50% or more of the total mass of the base sheet of the micro-protrusion instrument, and the mass of the thermoplastic resin is more preferably 100%.

[0152] Examples of the thermoplastic resin include a polyolefin, a polyester, a polyamide, a polyamide-imide, a polyetheretherketone, a polyetherimide, polyvinyl chloride, acrylic resin, polystyrene resin or a combination thereof.

[0153] Examples of the polyolefin include polypropylene and polyethylene.

[0154] Examples of the polyester include polyethylene terephthalate, polyfatty acid ester, polylactic acid, polycaprolactone and polybutylene succinate.

[0155] An example of the polyamide includes nylon.

[0156] From the viewpoint of biodegradability, a polyfatty acid ester is preferably used. Specific examples of polyfatty acid ester include polylactic acid, polyglycolic acid or combinations thereof.

[0157] The ratio of the mass of the thermoplastic resin included in the injection needle IA, IB or IC to the total mass of the injection needle IA, IB or IC is preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more, from the viewpoint of improving the moldability and dimensional stability of the injection needle.

[0158] Furthermore, the mass ratio of the thermoplastic resin is preferably 100% or less, more preferably 98% or less, and even more preferably 96% or less, from the viewpoint of adding a functional agent to the injection needle to give various effects.

[0159] Further, the mass ratio of the thermoplastic resin is preferably 50% or more and 100% or less, more preferably 70% or more and 98% or less, and even more preferably 90% or more and 96% or less.

[0160] As various functional agents, antibacterial agents, bactericidal agents, moisturizing agents, flow improving agents, antistatic agents and colorants may be used herein.

[0161] Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the embodiments described above and may be modified appropriately.

[0162] For example, in the first embodiment, the second protrusion 32 and the third protrusion 33 are solid, but the second protrusion 32 and the third protrusion 33 may be hollow. In the second embodiment, the second composite protrusion 52 is solid, but the second composite protrusion 52 may be hollow. In the injection needle 1A, 1B, or 1C, the protrusions other than the first protrusion 31 are preferably solid. Thus, the liquid to be discharged from the opening 31a of the first protrusion 31 can be prevented from accumulating inside the other protrusions, and thus the liquid can be injected efficiently.

[0163] In IA to IC injection needles, the projections are arranged in an array shape (a single or a plurality of rows), but the plurality of projections may be a arbitrary arrangement such as an arrangement aligned to form an arbitrary annular shape, for example a circular shape, an elliptical shape, a square shape, a rectangular shape, a hexagonal shape, or a star shape, in addition to the lattice shape.

[0164] In the injection needle IA, the third projection 33 has a columnar shape, but the third projection 33 may have a frustoconical shape with a flat tip end or may have a conical shape with a curved tip end surface. Furthermore, the plan view shape of the third projection 33 is not particularly limited, and may be a circular shape, an elliptical shape, a square shape, a rectangular shape, a hexagonal shape, or a star shape.

[0165] Further, the injection needle of the present invention may include the first protrusion 31, the second protrusion 32, the first composite protrusion 51 and the second composite protrusion 52, may include the first protrusion 31, the second protrusion 32 and the first composite protrusion 51, may include the first protrusion 31, the second protrusion 32, and the second composite protrusion 52, may include the first protrusion 31, the first composite protrusion 51, and the second composite protrusion 52, or may include the first composite protrusion 51 and the second composite protrusion 52.

[0166] Further, the first composite protrusion 51 may be formed such that the insertion depth controller 40 is integrally formed around the plurality of first protrusions 31, as shown in [Fig. 12](A). Further, the second composite protrusion 52 may be formed such that the insertion depth controller 40 is integrally formed around the plurality of second protrusions 32, as shown in [Fig. 12](A).

[0167] Further, the second projection 32 may have a circular cut-out shape in cross-sectional view, as shown in [Fig. 12](B).

[0168] Further, the injection needle of the present invention may have a first protrusion 31 and a second protrusion 32, or may have a plurality of first protrusions 31 and a plurality of second protrusions 32.

[0169] The following additional notes are also disclosed with respect to the embodiments of the present invention described above.

[0170] <1>

[0171] An injection needle comprising:

[0172] protrusions, which protrude from a sheet base, comprising a first protrusion having an opening at a tip end portion and being hollow and a second protrusion having no opening at a tip end portion; and

[0173] an insertion depth controller provided at an intermediate position lower than a tip end position of the first projection and higher than a surface of the sheet base.

[0174] <2>

[0175] The injection needle as defined in clause <1> , wherein the insertion depth controller is located at a position lower than a tip end position of the second projection.

[0176] <3>

[0177] The injection needle as defined in clause <1> Or <2> , wherein the insertion depth controller controls an insertion depth of the first protrusion.

[0178] <4>

[0179] The injection needle as defined in any of the clauses <1> has <3> , wherein a height difference between the tip end position of the first protrusion and a position of the insertion depth controller is 1 pm or more and 5,000 pm or less.

[0180] <5>

[0181] The injection needle as defined in any of the clauses <1> has <4> , wherein a height difference between the tip end position of the first protrusion and a position of the insertion depth controller is 5 pm or more.

[0182] <6>

[0183] The injection needle as defined in any of the clauses <1> has <5> , wherein a height difference between the tip end position of the first protrusion and a position of the insertion depth controller is 4000 pm or less.

[0184] <7>

[0185] The injection needle as defined in any of the clauses <1> has <6> , wherein the first projection has a height greater than a height of the second projection.

[0186] <8>

[0187] The injection needle as defined in any of the clauses <1> has <7> , wherein the injection needle comprises a first composite protrusion in which the insertion depth controller is integrally formed around the first protrusion.

[0188] <9>

[0189] The injection needle as defined in any of the clauses <1> has <8> , wherein the injection needle comprises a second composite projection in which the insertion depth controller is integrally formed around the second projection.

[0190] <10>

[0191] The injection needle as defined in any of the clauses <1> has <9> , wherein the protrusions projecting from the sheet base include a third protrusion arranged around the first protrusion or the second protrusion, and the third protrusion has a tip end surface which is the insertion depth controller.

[0192] <11>

[0193] The injection needle as defined in any of the clauses <1> has <10> , wherein a distance between the tip ends of the projections adjacent to each other is 0.01 mm or more and 10 mm or less in a plan view of the sheet base.

[0194] <12>

[0195] The injection needle as defined in any of the clauses <1> has <11> , wherein a distance between the tip ends of the projections adjacent to each other is 0.1 mm or more, and more preferably more than 0.5 mm in a plan view of the sheet base.

[0196] <13>

[0197] The injection needle as defined in any of the clauses <1> has <12> , wherein a distance between the tip ends of the projections adjacent to each other is 5 mm or less, and preferably less than 3 mm in a plan view of the sheet base.

[0198] <14>

[0199] The injection needle as defined in any of the clauses <1> has <13> , in which the projections other than the first projection are solid.

[0200] <15>

[0201] The injection needle as defined in any of the clauses <1> has <14> , in which the injection needle contains a thermoplastic resin.

[0202] <16>

[0203] The injection needle as defined in any of the clauses <1> has <15> , wherein a ratio of a mass of the thermoplastic resin contained in the injection needle to a total mass of the injection needle is 50% or more and 100% or less.

[0204] <17>

[0205] The injection needle as defined in any of the clauses <1> has <16> , wherein the opening is not formed at a tip end of the first projection, but is formed on a lateral side of the first projection.

[0206] <18>

[0207] The injection needle as defined in any of the clauses <1> has <17> , in which a difference H1 - H2 between a projection height H1 of the first projection and a projection height H2 of the second projection is 1 pm or more and 5,000 pm or less.

[0208] <19>

[0209] The injection needle as defined in any of the clauses <1> has <18> , wherein a difference H1 - H2 between a projection height H1 of the first projection and a projection height H2 of the second projection is 5 pm or more.

[0210] <20>

[0211] The injection needle as defined in any of the clauses <1> has <19> , wherein a difference H1 - H2 between a protrusion height H1 of the first protrusion and a protrusion height H2 of the second protrusion is 4000 pm or less.

[0212] <21>

[0213] The injection needle as defined in any of the clauses <1> has <20> , wherein a tip end diameter of the first projection is 1 pm or more and 300 pm or less.

[0214] <22>

[0215] The injection needle as defined in any of the clauses <1> has <21> , wherein a tip end diameter of the first projection is 5 pm or more.

[0216] <23>

[0217] The injection needle as defined in any of the clauses <1> has <22> , wherein a tip end diameter of the first projection is 50 pm or less.

[0218] <24>

[0219] The injection needle as defined in any of the clauses <1> has <23> , wherein a tip end diameter of the second projection is equal to or greater than the tip end diameter of the first projection.

[0220] <25>

[0221] The injection needle as defined in any of the clauses <1> has <24> , wherein the projection height of the first projection is 10 pm or more and 5,000 pm or less.

[0222] <26>

[0223] The injection needle as defined in any of the clauses <1> has <25> , wherein the projection height of the first projection is 20 pm or more.

[0224] <27>

[0225] The injection needle as defined in any of the clauses <1> has <26> , wherein the projection height of the first projection is 4,000 pm or less.

[0226] <28>

[0227] The injection needle as defined in any of the clauses <1> has <27> , wherein a distance between the surface of the sheet base and the insertion depth controller is 5 qm or more and 4000 qm or less.

[0228] <29>

[0229] The injection needle as defined in any of the clauses <1> has <28> , wherein a distance between the surface of the sheet base and the insertion depth controller is 10 qm or less.

[0230] <30>

[0231] The injection needle as defined in any of the clauses <1> has <29> , wherein a distance between the surface of the sheet base and the insertion depth controller is 3000 qm or less.

[0232] <31>

[0233] The injection needle as defined in any of the clauses <1> has <30> , wherein the injection needle comprises a plurality of first protrusions and a plurality of second protrusions.

[0234] <32>

[0235] The injection needle as defined in any of the clauses <1> has <31> , wherein a pair of second projections are arranged with the first projection interposed therebetween.

[0236] <33>

[0237] The injection needle as defined in any of the clauses <1> has <32> , wherein the injection needle has a region in which a total number of the first protrusions and the second protrusions per 1 cm2 is 10 or more and 500 or less when viewed in a plan view.

[0238] <34>

[0239] The injection needle as defined in any of the clauses <1> has <33> , wherein the injection needle has a region in which a total number of first protrusions and second protrusions per 1 cm2 is 20 or more, and preferably 30 or more when viewed in a plan view.

[0240] <35>

[0241] The injection needle as defined in any of the clauses <1> has <34> , wherein the injection needle has a region in which a total number of the first protrusions and the second protrusions per 1 cm2 is 300 or less, and preferably 200 or less when viewed in a plan view.

[0242] <36>

[0243] The injection needle as defined in any of the clauses <1> has <35> , wherein a ratio N2 / N1 of the number N2 of second projections to the number NI of first projections per 1 cm2 is 0.01 or more and 100 or less.

[0244] <37>

[0245] The injection needle as defined in any of the clauses <1> has <36> , wherein a ratio N2 / N1 of the number N2 of second projections to the number NI of first projections per 1 cm2 is 1 or more, and preferably 2.4 or more.

[0246] <38>

[0247] The injection needle as defined in any of the clauses <1> has <37> , wherein a ratio N2 / N1 of the number N2 of second projections to the number NI of first projections per 1 cm2 is 50 or less, and preferably 10 or less.

[0248] [Examples]

[0249] Examples of the present invention will be described in more detail below, but the present invention is not limited to these examples.

[0250] [Example 1]

[0251] An injection needle having the same configuration as that of the injection needle 1A shown in [Fig. 1] and having the same arrangement as that shown in [Fig. 5](a) was manufactured. The dimension of each protrusion of the injection needle, the dimension of the sheet base, the number of first protrusions per 1 cm2, a distance between the tip ends of adjacent first protrusions or second protrusions are shown in Table 1. The injection needle was formed by subjecting a base sheet composed of 100% polylactic acid, which is a thermoplastic resin, to a protrusion-forming process using a processing needle to which ultrasonic vibrations were applied.

[0252] [Example 2]

[0253] An injection needle having the same configuration as that of the injection needle IA shown in [Fig. 1] and having the same arrangement as that shown in [Fig. 5](d) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0254] [Example 3]

[0255] An injection needle having the same configuration as that of the IC injection needle shown in [Fig. 9] and having the same arrangement as that shown in [Fig. 11 ](a) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0256] [Example 4]

[0257] An injection needle having the same configuration as that of injection needle IB shown in [Fig. 6] and having the same arrangement as that shown in [Fig. 8](a) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0258] [Example 5]

[0259] An injection needle having the same configuration as that of the injection needle IA shown in [Fig. 1] and having the same arrangement as that shown in [Fig. 14](a) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0260] [Example 6]

[0261] An injection needle having the same configuration as that of the injection needle IA shown in [Fig. 1] and having the same arrangement as that shown in [Fig. 14](b) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0262] [Example 7]

[0263] An injection needle having the same configuration as that of the injection needle IA shown in [Fig. 1] and having the same arrangement as that shown in [Fig. 14](c) was manufactured. It was identical to that of Example 1, except that each element was as shown in Table 1.

[0264] [Comparative Example 1]

[0265] An injection needle having a first projection 31 and a third projection 33 was fabricated (see Figures 13(a) and 13(b)). It was identical to that of Example 1, except that each element was as shown in Table 1 and the projections 31 and 33 were arranged as shown in [Fig. 13](b).

[0266] [Assessment of the inflammatory reaction]

[0267] An inflammatory reaction of the injection needles of Examples 1 to 7 and Comparative Example 1 was evaluated by the following method.

[0268] Each of the injection needles of Examples 1 to 7 and Comparative Example 1 was attached to the subject's skin, and pressed with a load of about 5 N for 10 seconds. After being pressed for 10 seconds, a micro-protrusion instrument was peeled off, the part where the micro-protrusion instrument was pressed was observed with a microscope at a magnification of 30 times, and a range of the inflammatory reaction was evaluated according to the following criteria. The evaluation results are shown in Table 1.

[0269] A: The area occupied by the inflammatory reaction is 70% or more.

[0270] B: The area occupied by the inflammatory reaction is 30% or more and less than 70%.

[0271] C: The area occupied by the inflammatory reaction is 10% or more and less than 30%.

[0272] D: The area occupied by the inflammatory reaction is 0% or more and less than 10%.

[0273] The area occupied by the inflammatory reaction was calculated by the following formula.

[0274] Area occupied by the inflammatory reaction (%) = Area where the inflammatory reaction occurred / Area of ​​the projection arrangement region 100

[0275] The area of ​​the projection arrangement region was defined as an area surrounded by the outermost projections 31, 32 and 33 included in the area.

[0276] [Assessment of suitability for drug injection]

[0277] The drug injection suitability of the injection needles of Examples 1 to 7 and Comparative Example 1 was evaluated by the following method.

[0278] Each of the injection needles of Examples 1 to 7 and Comparative Example 1 was attached to a syringe (GASTIGHT#1710, manufactured by Hamilton Company), was inserted into the removed pigskin with momentum in a state of being inclined 10 degrees from the vertical with a load of 2 N or more, and a 100 pL drug solution was injected at an injection speed of 1 pL / s. After the injection, the syringe was removed from the pigskin, and the overflowing or leaking drug that did not penetrate the pigskin was wiped off with a waste cloth. A weight of the removed pig skin before and after injection of the drug solution was measured, a weight difference from the pig skin before injection of the drug solution was used as the injected amount of the drug solution, and the injected amount / dosage 100 was evaluated as the injection rate (%) according to the following criteria.Regarding the insertion depth of the injection needle, it was confirmed that the insertion of the first protrusion was suppressed by the insertion depth controller.

[0279] The results of the evaluation are shown in Table 1.

[0280] A: The injection rate is 75% or more and 100% or less

[0281] B: The injection rate is 50% or more and less than 75%.

[0282] C: The injection rate is 25% or more and less than 50%.

[0283] D: The injection rate is 0% or more and less than 25%.

[0284] [Tables 1] Dimension First projection Tip end diameter (ym) Exempt [ Exempt ' 1 2 w î fô Exempt 3 ___ Example T Example [ Exempt. 4 5 6 Example [ Exempt 7 Comparison ! 1 Height of projection H1 (pm) 2300 2000 2000 2003 | 2000 2000 2000 2000 Number NI {pieces) of projections per 1 cm? 25 | 3 144 144 5 \ tl 4 58 Height of projection H2 (pm) 150 j 150 550 ■^500™” 150 ! 150 \ 150 160 ] Number N2 (pieces) of projections per 1 cm- 33 | 22 133 133 20 \ 99 10 Û Ratio N2 / N1 of the number of second projections to the number NI of first projections per 1 cm? 58 1 25 1.3 \ 0.1 _______27g_________ 0.-9 ________27g________i________25_________[________m________ 0.8 4.0 \ 9.0 __________14________j___________58__________ 2.5 0.0 Punch depth controller Distance H3 (pm) between sheet base surface and punch depth controller S00 \ 900 900 900 900 \ 900 900 900 Difference H1-H3 (pm) between the protrusion height of the first protrusion and the distance between sheet base surface and punch depth controller Difference H2-H3 (pm) is the height of the protrusion of the first protrusion and the distance between the sheet base surface and punch depth controller S iwo \ no 11:00 1100 HOC \ 1100 1100 1100 eoo \ oœ 600 eao ooo \ 600 600 Difference H 1*H2 yjm i between the gripping height of the first projection and the projection height of the second projection ^stance D (mm) between the gripping ends of the first and second projections adjacent to each other 600 il 600 1250 \ 1:50 600 0.75 600 600 \ 600 075 | 2.23 \ 1.50 600 5.00 Sheet base Thickness (pm) 400 \ 400 400 400 400 \ 400 400 400 {skin est Inflammatory reaction assessment B ) B: AAB \ BCB Drug interaction ability B | ABB j BIAB j D .

[0285] As shown in Table 1, in the injection needle of Comparative Example 1, the inflammatory reaction was evaluated as B, but the drug injection suitability was evaluated as D. In other words, it can be seen that the injection needle of Comparative Example 1 achieves the effect of promoting blood circulation, but it is difficult to inject the liquid. In the injection needle of Comparative Example 1, according to the evaluation of the drug injection suitability, because the insertion of the injection needle may have been insufficient, the majority of the drug leaked from the opening (drug solution injection part) where the insertion was insufficient, and thus the injection was difficult.

[0286] Unlike the injection needle of Comparative Example 1, the injection needles of Examples 1 to 7 had an inflammatory reaction evaluated as A or B, and the drug injection suitability evaluated as A, B or C. In other words, it can be seen that the injection needles of Examples 1 to 7 can easily inject the liquid and achieve the effect of promoting blood circulation.

[0287] Industrial applicability

[0288] With the injection needle of the present invention, it is possible to control an insertion depth into a skin, inject a liquid and effectively promote blood circulation.

Claims

Claims

1. An injection needle (IA, IB, IC) comprising: protrusions, which protrude from a sheet base (2), comprising: a first protrusion (31) having an opening (31a) at a tip end portion and being hollow; and a second protrusion (32) having no opening at a tip end portion; and an insertion depth controller (40) provided at an intermediate position lower than a tip end position of the first protrusion (31) and higher than a surface of the sheet base (2), wherein the insertion depth controller (40) is located at a position lower than a tip end position of the second protrusion (32), and wherein the first protrusion (31) has a height greater than a height of the second protrusion (32).

2. An injection needle (IA, IB, IC) comprising: projections, which project from a sheet base (2), comprising: a first projection (31) having an opening (31a) at a tip end portion and being hollow; and a second projection (32) having no opening at a tip end portion; and an insertion depth controller (40) provided at an intermediate position lower than a tip end position of the first protrusion (31) and higher than a surface of the sheet base (2), wherein the protrusions protruding from the sheet base include a third protrusion (33) arranged around the first protrusion (31) or the second protrusion (32), and the third protrusion (33) has a tip end surface which is the insertion depth controller, and wherein the first protrusion (31) has a height greater than a height of the second protrusion (32).

3. An injection needle (IA, IB, IC) comprising: projections, which project from a sheet base (2), comprising: a first projection (31) having an opening (31a) at a tip end portion and being hollow; and a second projection (32) having no opening at a tip end portion; and an insertion depth controller (40) provided at an intermediate position lower than a tip end position of the first protrusion (31) and higher than a surface of the sheet base (2), wherein the second protrusion is a second composite protrusion (52) in which the insertion depth controller (40) is integrally formed around the second protrusion (32).

4. An injection needle (IA, IB, IC) according to any one of claims 1 to 3, wherein a height difference between the tip end position of the first projection (31) and a position of the insertion depth controller (40) is 1 qm or more and 5,000 qm or less.

5. An injection needle (IA, IB, IC) according to claim 3 or claim 4 when dependent on claim 3, wherein the first projection (31) has a height greater than a height of the second projection (32).

6. An injection needle (IA, IB, IC) according to any one of claims 1 to 5, wherein a distance (D) between the tip ends of the projections adjacent to each other is 0.01 mm or more and 10 mm or less in a plan view of the sheet base (2).

7. An injection needle (IA, IB, IC) according to any one of claims 1 to 6, wherein the injection needle (IA, IB, IC) is formed from a base sheet (2) containing a thermoplastic resin.

8. An injection needle (IA, IB, IC) according to any one of claims 1 to 7, wherein the opening (31a) is not formed at a tip end of the first projection (31), but is formed on a lateral side of the first projection (31).

9. An injection needle (IA, IB, IC) according to any one of claims 1 to 8, wherein the injection needle comprises a plurality of first projections (31) and a plurality of second projections (32).

10. An injection needle (IA, IB, IC) according to any one of claims 1 to 9, wherein a pair of second projections (32) are arranged with the first projection (31) interposed therebetween.

11. An injection needle (IA, IB, IC) according to any one of claims 1 to 10, wherein the injection needle (IA, IB, IC) has a region in which a total number of the first protrusions (31) and second projections (32) per 1 cm2 is 10 or more and 500 or less when viewed in plan view.

12. An injection needle (IA, IB, IC) according to any one of claims 1 to 8, wherein a ratio of the number of second protrusions (32) to the number of first protrusions (31) per 1 cm2 is 0.01 or more and 100 or less.

13. An injection needle (IA, IB, IC) according to any one of claims 1 to 12, wherein the second projection (32) is arranged to surround the periphery of the first projection (31), the third projection (33) is arranged to surround the periphery of the second projection (32), and the third projection (33) has a tip end surface which is the insertion depth controller (40).

14. An injection needle (IA, IB, IC) according to any one of claims 1 to 13, wherein a liquid medicine is stored in a hollow portion (31b) of the first projection (31).

15. An injection tool comprising: the injection needle (IA, IB, IC) according to any one of claims 1 to 13, and a drug supply device which can supply a drug to the first projection (31) of the injection needle (IA, IB, IC).

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