Device for fluid injection therapy

Abstract

To provide a device for fluid injection therapy.SOLUTION: The device comprises: an injecting unit including a fluid container configured to store a fluid for the fluid injection therapy, one or more hollow needles, each hollow needle having an inner passage configured to deliver the fluid from the fluid container into a skin, and a filter between the fluid container and the one or more hollow needles, the filter being configured to control the flow of the fluid; and a charging unit configured to be removably attached to the injecting unit and supply the fluid to the injecting unit.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a device for fluid injection therapy, such as carboxytherapy. [Background technology]

[0002] Dark circles on the skin are a major consumer concern and remain an unaddressed problem. Cosmetics are the only at-home solution, but they are not sufficient for many people. On the other hand, more invasive procedures exist but must be performed in a clinic.

[0003] Carboxytherapy is a medical treatment that has been successfully and widely used in various fields of medicine. For example, Patent Document 1 (WO 2014 / 142970) discloses a carboxytherapy device for injecting CO2 gas into the skin. Carboxytherapy consists of injecting CO2 into the dermis and has shown excellent results in preventing facial aging, particularly in reducing dark circles. In fact, dark circles are caused by a variety of factors, including deep facial anatomical structures (e.g., intradermal capillary network), contributions from the skin (e.g., excessive pigmentation), and soft tissue aging (e.g., thin skin or shadows due to skin laxity). These diverse factors make the problem of dark circles extremely complex. CO2 injection provides multiple benefits, such as oxygen supply, improved microcirculation, anti-inflammation, and collagen stimulation, which can address the above-mentioned multifactorial problem. Clinically observed cosmetic effects include the improvement of circular pigmentation under the eyes, i.e., brightening the area around the eyes.

[0004] In medical treatments, typical volumes per injection are between a few microliters and a few milliliters. However, that amount of gas is associated with several side effects, such as pain. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 142970 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a device for fluid injection therapy, such as carboxytherapy, that can reduce side effects such as pain in fluid injection therapy. [Means for solving the problem]

[0007] To achieve the above object, one aspect of the present invention provides a device for fluid injection therapy, the device including an injection unit including a fluid container configured to store fluid for fluid injection therapy, one or more hollow needles each having an internal passageway configured to deliver the fluid from the fluid container into the skin, and a filter between the fluid container and the one or more hollow needles configured to control fluid flow, and a filling unit configured to be removably attached to the injection unit and to supply fluid to the injection unit.

[0008] According to one embodiment of the device, the filter may have at least one hole or slit to control the flow rate of fluid into the interior passage of the one or more hollow needles.

[0009] According to one embodiment of the device, the at least one hole or slit and the internal passage may together form a microfluidic channel.

[0010] According to one aspect of the device, the fluid container may have an expandable and contractible shell to change the interior volume of the fluid container.

[0011] According to one embodiment of the device, the flow rate of the fluid exiting the one or more hollow needles can be between 0.1 mL / min and 60 mL / min.

[0012] According to one embodiment of the device, the filter may have one or more holes with a diameter between 0.01 μm and 10 μm and / or one or more slits with a width between 0.01 μm and 10 μm.

[0013] According to one embodiment of the device, the hollow needle or needles may have an inner diameter of between 10 μm and 150 μm.

[0014] According to one embodiment of the device, the one or more hollow needles may have a length between 20 μm and 1,000 μm.

[0015] According to one embodiment of the device, one or more hollow needles may have a water-soluble or water-dispersible plug at their end.

[0016] According to one aspect of the device, the filling unit may include a fluid reservoir configured to store a fluid having a pressure higher than atmospheric pressure, and a pressure regulator configured to control the pressure of the fluid supplied from the fluid reservoir to the injection unit.

[0017] According to one aspect of the device, the pressure regulator may be configured to reduce the pressure of the fluid from the fluid reservoir and provide the fluid at the reduced pressure to the infusion unit.

[0018] According to one aspect of the device, the fluid infusion therapy may be carboxytherapy and the fluid may be carbon dioxide.

[0019] Non-limiting exemplary embodiments of the present invention will now be described in detail below with reference to the accompanying drawings so that the present invention may be better understood. [Brief explanation of the drawings]

[0020] [Figure 1A] 1 is a plan view of a device 1 for fluid injection therapy in a non-inflated state according to a first embodiment; FIG. [Figure 1B]1 is a plan view of a device 1 for fluid injection therapy in an expanded state according to a first embodiment; FIG. [Figure 2] 1 is a plan view of an injection unit 10 according to a first embodiment. [Figure 3] 1 is a front view of an injection unit 10 according to a first embodiment. [Figure 4] 4 is a cross-sectional view of the injection unit 10 according to the first embodiment taken along line IV-IV in FIG. 3. [Figure 5] FIG. 2 is a perspective view of a filter 18 according to a first embodiment. [Figure 6] 1 is a schematic diagram of a method for injecting CO2 gas into the skin S using an injection unit 10. FIG. [Figure 7] FIG. 10 is a perspective view of a filter 18 according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail. An XYZ coordinate system is defined as shown in the figures, but this is not intended to limit the present invention.

[0022] A carboxytherapy device for injecting CO2 gas into the skin is described below through examples. However, the fluid to be injected is not limited to CO2, but may be a gas such as N2O, NO, O2 or H2, a mixture of gases, a liquid, a mixture of liquids, a medical solution, or other fluids, or a combination thereof.

[0023] [First embodiment] (Device for fluid injection therapy) A device 1 for fluid injection therapy according to a first embodiment will be described with reference to Figures 1A to 6. According to the first embodiment, Figure 1A is a plan view of the device 1 for carboxytherapy in a non-inflated state, and Figure 1B is a plan view of the device 1 for carboxytherapy in an inflated state.

[0024] 1A and 1B, device 1 includes an injection unit 10 and a filling unit 50. Injection unit 10 and filling unit 50 are detachably attached to each other. Alternatively, injection unit 10 and filling unit 50 may be integrally formed. Device 1 is transformed from the uninflated state in FIG. 1A to the inflated state in FIG. 1B by supplying CO gas from filling unit 50 to injection unit 10.

[0025] (Injection Unit 10) Figure 2 is a plan view of the injection unit 10 in an uninflated state according to the first embodiment. Figure 3 is a front view of the injection unit 10 according to the first embodiment. Figure 4 is a cross-sectional view of the injection unit 10 according to the first embodiment taken along line IV-IV in Figure 3.

[0026] 2 and 4, the injection unit 10 stores CO2 gas therein and is applied to the user's skin S as a patch device for injecting the CO2 gas into the skin S. The injection unit 10 includes a gas container 12 (an example of a "fluid container"), a support member 14, a hollow needle 16, a filter 18, and a connector 20.

[0027] The gas container 12 is the main body of the injection unit 10. The internal space of the gas container 12 serves as a gas chamber for CO2 gas. The gas container 12 stores CO2 gas therein, for example, at a pressure higher than atmospheric pressure. The internal pressure, particularly for CO2 gas, is, for example, between 0.1 MPa (1 bar) and 1 MPa (10 bar), preferably between 0.15 MPa (1.5 bar) and 0.4 MPa (4 bar), and more preferably between 0.15 MPa (1.5 bar) and 0.3 MPa (3 bar). The volume filled inside the gas container 12 is, for example, between 0.1 mL and 10 mL depending on the condition of the skin S.

[0028] In this embodiment, the gas container 12 has an inflatable and contractible shell 13, which allows the gas container 12 to expand, for example, as shown in FIG. 1B due to increasing internal pressure in response to the supply of CO2 gas. The inflatable / contractible shell 13 thereby allows the internal volume of the gas container 12 to change, allowing the gas container 12 to adapt to various CO2 gas pressures. For example, the shell 13 of the gas container 12 is made of a flexible and / or elastic material, such as a thermoplastic elastomer, silicone, or polymer layer. Additionally or alternatively, the shell 13 may have a bellows structure or any other expandable structure. Alternatively, the gas container 12 may have a rigid, non-expandable shell 13.

[0029] As shown in Figures 2 and 4, the gas container 12 in its uninflated state generally has an ellipsoidal spherical shape with its major axis along the Y direction and has a distal end 12a and a proximal end 12b in the X direction. The gas container 12 in its uninflated state is thin in the X direction so as to be suitable for remaining on the user's face or skin S during application. As shown in Figures 2-4, an adhesive layer 13a is provided on the distal end 12a of the gas container 12 to help the injection unit 10 remain on the user's face or skin S.

[0030] Support member 14 is provided on distal end 12a of gas canister 12 for supporting hollow needle 16 thereon. For example, support member 14 is attached to gas canister 12 around filter 18, for example, using adhesive 24. Adhesive 24 may be part of adhesive layer 13a. Alternatively, support member 14 may be integrally formed with or formed as part of gas canister 12.

[0031] The support member 14 has a contact surface 22 that will come into contact with the skin S. In this embodiment, the support member 14 is made of a flexible material, such as a plastic elastomer, silicone, or polymer layer, to conform to the shape of the user's skin S during application.

[0032] 2 and 4, hollow needles 16 are provided on the contact surface 22 of the support member 14. During use, the hollow needles 16 penetrate the skin S and deliver CO2 gas through the hollow needles 16 and into the skin S. Each of the hollow needles 16 has a cylindrical shape, which is preferably at least partially tapered.

[0033] The outer diameter of the hollow needle 16 can be determined depending on the application. For example, the outer diameter (e.g., maximum outer diameter) of the hollow needle 16 is between 40 μm and 200 μm. For example, the outer diameter of the hollow needle 16 can be 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, or 100 μm or more, and 190 μm or less, 180 μm or less, 170 μm or less, 160 μm or less, or 150 μm or less. If the outer diameter of the hollow needle 16 is too small, the needle 16 will easily break during insertion into the skin S. On the other hand, if the outer diameter of the hollow needle 16 is too large, the needle 16 will cause pain. In this embodiment, the hollow needle 16 is a hollow microneedle.

[0034] The injection unit 10 can have one or more hollow needles 16. For example, 16 hollow needles 16 are shown in FIG. 3 . The number of hollow needles 16 can be 1, 2, 3, 4, 6, 8, 9, 12, 16, 25, 36, or any other number. The multiple hollow needles 16 can be arranged regularly or irregularly (randomly) on the contact surface 22. Note that the injection unit 10 does not need to have multiple hollow needles 16 because CO gas diffuses quickly and effectively, so a single hollow needle 16 is sufficient to deliver a sufficient amount of CO gas into the skin S during use.

[0035] As shown in FIG. 4, each hollow needle 16 has an interior passageway 26 and a water-soluble or water-dispersible plug 28 within the interior passageway 26 .

[0036] An internal passageway 26 extends through each of the hollow needles 16 and communicates with the gas chamber inside the gas container 12 through holes 30 in the filter 18. The internal passageway 26 allows CO2 gas to pass from the gas container 12 through the internal passageway 26.

[0037] The diameter of the internal passage 26, i.e., the inner diameter of the hollow needle 16, can be determined depending on the application. For example, the diameter of the internal passage 26 is between 10 μm and 150 μm. For example, the diameter of the internal passage 26 can be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more, and 140 μm or less, 130 μm or less, 120 μm or less, 110 μm or less, or 100 μm or less. If the diameter of the internal passage 26 is too small, it will take a long time to complete the injection of CO2 gas. On the other hand, if the diameter of the internal passage 26 is too large, the total diameter of the hollow needle 16 will be too large and will cause pain. The diameter of the internal passage 26 does not need to be constant and may vary, for example, along the longitudinal direction of the internal passage 26.

[0038] The length of the hollow needle 16 can be determined depending on the target depth. For example, the hollow needle 16 may have a length between 20 μm and 1,000 μm. For cosmetic applications, the hollow needle 16 may have a length between 50 μm and 250 μm to deliver gas into a thin layer of the skin S, such as the stratum corneum S1 or the epidermis S2 (see FIG. 6 ). Because the hollow needle 16 is inserted into a shallow layer, such as the stratum corneum S1 or the epidermis S2, rather than into a deeper layer, such as the dermis S3, an injection unit 10 having a hollow needle 16 with a length between 50 μm and 250 μm can reduce pain to the user. If the hollow needle 16 is too long, the hollow needle 16 may cause pain. On the other hand, if the hollow needle 16 is too short, it may be difficult to insert the hollow needle 16 into the skin S.

[0039] The water-soluble or water-dispersible plug 28 blocks the distal end of the internal passage 26 to prevent CO2 gas from leaking out. The water-soluble or water-dispersible plug 28 is made of a water-soluble or water-dispersible material, such as a water-soluble or water-dispersible polymer. For example, the water-soluble or water-dispersible material is at least one selected from the group consisting of hyaluronic acid, neutral monosaccharides, disaccharides, oligosaccharides, polysaccharides, dextrin, dextran, polyethylene glycol, polyvinyl alcohol, poly(methyl vinyl ether / maleic anhydride), polyvinylpyrrolidone, poly(methyl vinyl ether / maleic anhydride) (PMVE / MA), hydrolyzed collagen and their esters, and poly(methyl vinyl ether / maleic anhydride) (PMVE / MAH). Therefore, when the hollow needle 16 is inserted into the skin S, the water-soluble or water-dispersible plug 28 dissolves in water or body fluid, thereby releasing CO2 gas from the hollow needle 16 into the skin S.

[0040] The hollow needle 16 may be made of any material other than the water-soluble or water-dispersible plug 28, including metals such as stainless steel, silicone compounds, biodegradable polymers, thermoplastic resins, and water-soluble polymers. Examples of biodegradable polymers include polyglycolic acid (PGA) and polylactic acid (PLA). Examples of thermoplastic resins include medical-grade silicone, polymer materials, UV-curable resins, polydimethylsiloxane, polycarbonate, and cyclic olefin copolymers. Examples of water-soluble polymers include carboxymethylcellulose (CMC), methylcellulose (MC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), polyvinyl alcohol (PVA), polyacrylic acid-based polymers, polyacrylamide (PAM), polyethylene oxide (PEO), pullulan, alginate, pectin, chitosan, chitosan succinamide, and oligochitosan.

[0041] As shown in FIG. 4, the filter 18 is provided at the distal end 12a of the gas container 12. For example, the distal end 12a of the gas container 12 has an opening for attaching the filter 18. The filter 18 is a thin member, such as a porous membrane, film, or plate, having at least one hole 30 therethrough. The filter 18 can cover an outlet to the internal passage 26 of the gas container 12, allowing CO2 gas to pass through the filter 18. The filter 18 can slow or restrict the flow of CO2 gas from the gas container 12 through the filter 18.

[0042] 5 is a perspective view of the filter 18 according to the first embodiment. As shown in FIG. 5, the filter 18 according to the first embodiment has a plurality of holes 30. The holes 30 allow CO2 gas to pass through the holes 30, but the filter 18 partially blocks CO2 gas from passing from the gas container 12 to the internal passage 26 due to the small cross-sectional area of ​​the holes 30.

[0043] The thickness of the filter 18 can be determined depending on the application. For example, the thickness of the filter 18 is between 50 μm and several millimeters, preferably between 50 μm and 500 μm. The number of filters 18 is not limited to one, and multiple filters may be provided to achieve an optimal flow rate of CO2 gas.

[0044] The diameter of the holes 30 can be determined depending on the target flow rate. For example, the diameter of the holes 30 is between 0.01 μm and 10 μm. For example, the diameter of the holes 30 is 0.02 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, or 1 μm or more, and 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less.

[0045] The material of the filter 18 can be appropriately determined depending on the fluid to be infused. For example, the filter 18 can be a woven fabric filter, a membrane filter, or a porous material filter made of a polymer, metal wire, or the like. The material of the filter 18 is not particularly limited and can include paper, polymer, metal, or ceramic. For example, the filter 18 can be made of nylon, PES (polyethersulfone), or PVDF (polyvinylidene fluoride).

[0046] The holes 30 in the filter 18 and the internal passages 26 of the hollow needle 16 together form a fluid channel. CO2 gas in the gas container 12 passes through the holes 30, is distributed to each of the internal passages 26, and exits the hollow needle 16. When applying CO2, the holes 30 and the internal passages 26 are preferably designed on a microscale, thereby together forming a microfluidic channel 32. This microfluidic channel 32 provides fluid resistance to control the flow rate of CO2 gas exiting the hollow needle 16 without any additional input.

[0047] The flow rate of the exiting CO2 gas can be determined by the design of the microfluidic channel 32 depending on the application. For example, the flow rate of the CO2 gas exiting the hollow needle 16 is between 0.1 mL / min and 60 mL / min. For example, the flow rate of the CO2 gas is 0.2 mL / min or more, 0.5 mL / min or more, 1 mL / min or more, 2 mL / min or more, 5 mL / min or more, or 10 mL / min or more, and 55 mL / min or less, 50 mL / min or less, 45 mL / min or less, 40 mL / min or less, 35 mL / min or less, or 30 mL / min or less. If the flow rate of the CO2 gas is too small, it will take a long time to complete the injection of the CO2 gas. On the other hand, if the flow rate of the CO2 gas is too large, the rapid injection of the CO2 gas may cause swelling of the skin, which may lead to further adverse effects.

[0048] The connector 20 connects the gas container 12 to the one-way valve 66 of the filling unit 50, allowing the filling unit 50 to fill the gas container 12 with CO2 gas. The connector 20 is a rigid cylindrical portion disposed on the proximal end 12b of the gas container 12. Any known connection mechanism is possible for the connector 20.

[0049] The injection unit 10 may be a completely single-use unit and disposable. Alternatively, the support member 14 may be removably attached to the gas container 12 and disposed of separately from the gas container 12. In such cases, the support member 14 may be a single-use component and disposable along with the hollow needle 16. The gas container 12 can be reused repeatedly by disposing of the support member 14 and hollow needle 16, making it cost-effective. Multiple uses of the support member 14 and hollow needle 16 are also possible, as long as they are effectively sterilized.

[0050] (Filling unit 50) 1A, the charging unit 50 stores CO2 gas therein and charges the CO2 gas into the injection unit 10. The charging unit 50 includes a gas storage section 52 and a pressure regulator 54.

[0051] The gas storage unit 52 is a cartridge for storing CO2 gas at a high pressure (for example, several MPa or several tens of MPa or more) that varies depending on the gas usage. A conventional replaceable gas cylinder can be used as the gas storage unit 52.

[0052] The gas storage unit 52 is detachably connected to a pressure regulator 54. The pressure regulator 54 delivers CO gas from the gas storage unit 52 to the gas container 12 and regulates the pressure of the delivered CO gas. The pressure regulator 54 controls the pressure of the CO gas to be delivered to the gas container 12 so that it remains constant, and reduces the pressure of the CO gas from the gas storage unit 52 to the supply pressure for the gas container 12. The supply pressure can be determined depending on the application. For example, the supply pressure is between 0.15 MPa (1.5 bar) and 0.4 MPa (4 bar). The pressure regulator 54 can thereby consistently maintain the pressure of the CO gas and steadily supply CO gas at an appropriate pressure to the gas container 12.

[0053] As shown in FIG. 1A, the pressure regulator 54 includes a pressure indicator 60 , an operating unit 62 , an injection switch 64 , a one-way valve 66 , and a gas reservoir connector 68 .

[0054] The pressure indicator 60 visually indicates the pressure of the CO2 gas being supplied to the gas container 12. The user can control the supply pressure by checking the pressure indication on the pressure indicator 60.

[0055] The operation unit 62 is a unit for allowing a user to adjust the supply pressure. For example, the operation unit 62 may be embodied as a manual dial member, as shown in FIG. 1A.

[0056] The injection switch 64 is a unit for a user to start / stop injection of CO2 gas into the gas container 12. For example, the injection switch 64 may be embodied as a manual button, as shown in Fig. 1A. For example, the injection switch 64 may be configured as a button for starting injection of CO2 gas into the gas container 12 when the user presses the injection switch 64, and for stopping injection when the user releases the injection switch 64.

[0057] 1A , the one-way valve 66 allows CO2 gas to pass through the one-way valve 66 only in one direction, i.e., the +X direction in FIG. 1A . Specifically, the one-way valve 66 allows CO2 gas from the gas storage unit 52 to pass through the one-way valve 66 (+X direction) but prevents CO2 gas from the gas container 12 from passing through the one-way valve 66 (−X direction). In this way, the one-way valve 66 can prevent the reverse flow of CO2 gas in the −X direction.

[0058] A gas reservoir connector 68 connects the gas reservoir 52 to the pressure regulator 54. Any known connection mechanism is possible for the gas reservoir connector 68.

[0059] (How to Use a Device for Fluid Infusion Therapy) A method of using the device 1 according to this embodiment is described below.

[0060] As shown in FIG. 1A, the user first assembles the device 1 by attaching the connector 20 of the injection unit 10 to the one-way valve 66 of the pressure regulator 54. The user then attaches the gas reservoir 52 to the gas reservoir connector 68. The user then adjusts the supply pressure of the CO2 gas using the operation unit 62 and the injection switch 64 and injects the CO2 gas into the gas container 12 by operating the injection switch 64. After filling the gas container 12 with the required amount of CO2 gas (e.g., 0.1 mL to 10 mL), the user stops injecting the gas into the gas container 12 by operating the injection switch 64. FIG. 1B shows the injection unit 10 in an inflated state after injecting the CO2 gas into the gas container 12. The user then detaches the injection unit 10 from the filling unit 50 for portable use.

[0061] FIG. 6 is a schematic diagram of a method for injecting CO2 gas into skin S using the injection unit 10. As shown in FIG. 6, a user places the contact surface 22 of the injection unit 10 near the subject's skin S. The support member 14 and / or the gas container 12 conform to the shape of the skin S. Before applying the injection unit 10, the water-soluble or water-dispersible plug 28 blocks the internal passage 26 to prevent CO2 gas from escaping from the gas container 12. The user then presses the contact surface 22 and hollow needle 16 against the skin S. As a result, the hollow needle 16 penetrates the stratum corneum S1 of the skin S, and the water-soluble or water-dispersible plug 28 dissolves in water or bodily fluids.

[0062] After the water-soluble or water-dispersible plug 28 dissolves, the CO2 gas is slowly released through the internal passage 26 of the hollow needle 16. The pressure of the CO2 gas within the injection unit 10 must be higher than atmospheric pressure. The CO2 gas in the sub-stratum corneum layer diffuses into deeper layers of the skin S, as shown in Figure 6.

[0063] As described above, the microfluidic channel 32 inside the injection unit 10 can control the flow rate of CO2 gas into the epidermis S2 to, for example, between 0.1 mL / min and 60 mL / min. This is a relatively slow release compared to conventional techniques, resulting in less or no pain or discomfort. Furthermore, if the length of the hollow needle 16 is relatively short compared to conventional techniques, the hollow needle 16 can be inserted to a shallower depth in the skin S, for example, to the stratum corneum S1 or the upper part of the epidermis S2, rather than to the dermis S3. This therefore results in little or no pain or discomfort. Note that the insertion depth of the hollow needle 16 depends on the length of the needle, so a hollow needle 16 of sufficient length can be inserted into the dermis S3.

[0064] The total treatment time may be between several minutes and several hours, depending on, for example, the purpose or area of ​​treatment. During treatment, the injection unit 10 can remain on the skin S by means of the adhesive layer 13a that adheres to the skin S. After the injection of CO2 gas into the skin S is complete, the user removes the injection unit 10, separates the support member 14 having the hollow needle 16 from the gas container 12, and discards the support member 14 for sanitary reasons. Note that the user may change the application position of the injection unit 10 on the skin S as needed during treatment.

[0065] (effect) According to device 1, filter 18 between gas container 12 and hollow needle 16 can control the flow rate of gas to achieve slow injection into shallow depths of skin S and slow release of gas. Device 1 can thereby reduce side effects of fluid injection therapy, such as carboxytherapy, such as pain or discomfort. In this way, fluid injection therapy using device 1 can be less invasive than existing treatments, while having significantly better performance and longer duration than topical application.

[0066] Moreover, since the injection unit 10 is detachable from the filling unit 50, the injection unit 10 has good portability and is easy to handle and hold by hand.

[0067] [Second embodiment] The second embodiment will be described below. The second embodiment differs from the first embodiment in that the filter 18 has one or more slits 130 instead of holes 30. The description of the same configuration as the first embodiment will not be repeated below.

[0068] Figure 7 is a perspective view of a filter 18 according to a second embodiment. As shown in Figure 7, the filter 18 according to the second embodiment has one or more slits 130. The slits 130 allow CO2 gas to pass through the slits 130, but the filter 18 partially blocks CO2 gas from passing from the gas container 12 to the internal passage 26 by restricting the flow of the channel.

[0069] The width of the slit 130 can be determined depending on the target flow rate. For example, the width of the slit 130 is between 0.01 μm and 10 μm. For example, the width of the slit 130 is 0.02 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, or 1 μm or more, and 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less.

[0070] It should be noted that the filter 18 may have both one or more holes and one or more slits. [Example]

[0071] To assess the feasibility of delivering CO2 into the stratum corneum or epidermis, in vitro studies were performed on pig skin using optical coherence tomography and histology. Experiments were performed using a user-friendly device consisting of an injection unit with a single hollow microneedle and a filling unit containing a CO2 cartridge connected to a pressure regulator.

[0072] Using a very short hollow microneedle with a length of 70 μm, needle penetration was limited to the stratum corneum and epidermis, but CO2 bubbles were observed in the skin after injection using optical coherence tomography. Thus, the device according to the present application demonstrated the feasibility of injecting CO2 gas into the skin without penetrating the dermis with a needle.

[0073] After CO2 injection, the effects on the surrounding tissue were checked using histology. No major tissue damage was observed and tissue integrity was maintained. [Explanation of symbols]

[0074] 1 device 10 Injection Unit 12 Gas bottles 12a distal end 12b proximal end 13. Shell 13a Adhesive layer 14 Support member 16 hollow needle 18 Filters 20 Connectors 22 Contact surface 24 Adhesive 26 Internal passage 28 Plug 30 holes 32 Microfluidic Channels 50 filling units 52 Gas storage unit 54 Pressure Regulator 60 Pressure Indicator 62 Operation Unit 64 Injection Switch 66 One-way valve 68 Gas reservoir connector 130 slit

Claims

1. 1. A device for fluid infusion therapy, comprising: a fluid container configured to store fluid for said fluid injection therapy; one or more hollow needles, each having an internal passage configured to deliver the fluid from the fluid reservoir into the skin; a filter between the fluid container and the one or more hollow needles configured to control the flow of the fluid; and an injection unit including a support member provided at a distal end of the fluid container to support the one or more hollow needles, the support member forming a contact surface that contacts the skin of a user; a filling unit configured to be removably attached to the injection unit and to supply the fluid to the injection unit.

2. The device of claim 1 , wherein the filter has at least one hole or slit for controlling the flow rate of the fluid into the interior passage of the one or more hollow needles.

3. The device of claim 2 , wherein the at least one hole or slit and the internal passage together form a microfluidic channel.

4. A device for fluid injection therapy, comprising: a fluid container configured to store fluid for said fluid injection therapy; one or more hollow needles, each having an internal passage configured to deliver the fluid from the fluid reservoir into the skin; and an injection unit including a filter between the fluid container and the one or more hollow needles configured to control the flow of the fluid; a filling unit configured to be removably attached to the injection unit and to supply the fluid to the injection unit; A device wherein the fluid enclosure has a shell that is expandable and contractible to change the interior volume of the fluid enclosure.

5. 5. The device of claim 1, wherein the flow rate of the fluid exiting the one or more hollow needles is between 0.1 mL / min and 60 mL / min.

6. 6. The device of claim 1, wherein the filter has one or more holes with a diameter of 0.01 μm to 10 μm and / or one or more slits with a width of 0.01 μm to 10 μm.

7. 7. The device of claim 1, wherein the one or more hollow needles have an inner diameter of 10 μm or more and 150 μm or less.

8. 8. The device of claim 1, wherein the one or more hollow needles have a length of at least 50 μm and not more than 1,000 μm.

9. 9. The device of claim 1, wherein the one or more hollow needles have a water-soluble or water-dispersible plug at their ends.

10. A device for fluid injection therapy, comprising: a fluid container configured to store fluid for said fluid injection therapy; one or more hollow needles, each having an internal passage configured to deliver the fluid from the fluid reservoir into the skin; and an injection unit including a filter between the fluid container and the one or more hollow needles configured to control the flow of the fluid; a filling unit configured to be removably attached to the injection unit and to supply the fluid to the injection unit; The filling unit comprises: a fluid reservoir configured to store the fluid at a pressure greater than atmospheric pressure; a pressure regulator configured to control the pressure of the fluid delivered from the fluid reservoir to the injection unit.

11. The device of claim 10 , wherein the pressure regulator is configured to reduce the pressure of the fluid from the fluid reservoir and supply the fluid at the reduced pressure to the infusion unit.

12. 12. The device of any one of claims 1 to 11, wherein the fluid injection therapy is carboxytherapy and the fluid is carbon dioxide.

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