Drug cartridge for needle-free injector and needle-free injector comprising said drug cartridge

Abstract

The present invention relates to a drug cartridge for a needle-free injector and a needle-free injector comprising said drug cartridge. The needle-free injector, in a state where a jet opening is in contact with the surface of the skin, ejects a target injection liquid from the jet opening into the epidermis and dermis of the skin; and the drug cartridge of the needle-free injector comprises an accommodating portion and a nozzle portion. The accommodating portion has an accommodating space that accommodates the target injection liquid; the nozzle portion is in fluid communication with the accommodating portion and is provided with the jet opening, and said nozzle portion guides the target injection liquid accommodated in the accommodating portion to the jet opening. The diameter of the jet opening is less than or equal to 0.12 mm. Smaller diameters for the jet opening are more advantageous for intradermal injection, and during the entire injection procedure, the target injection liquid in the accommodating space of the accommodating portion is pressurized to between 10 MPa and 26 MPa, so as to realize stable injection of the target injection liquid into the epidermis and dermis of the skin.

Description

Medicine tube for needle-free syringe and needle-free syringe including the medicine tube Technical Field

[0001] The present invention relates to the technical field of medical devices, in particular to a medicine tube for a needle-free syringe and a needle-free syringe comprising the medicine tube. Background Art

[0002] Intradermal injections are injections of medications into the epidermis and dermis of the skin, not into the subcutaneous tissue. Intradermal injections are commonly used for drug testing to prevent allergies (e.g., penicillin skin test), as preparation for local anesthesia in surgery (e.g., procaine skin test), and for vaccinations (e.g., BCG). Intradermal injections can also reduce vaccine dosage and increase vaccine utilization.

[0003] Intradermal injections are usually performed using needle syringes or needle-free syringes. However, needle-based intradermal injections have the problems of difficult operation and injection pain. The diameter of the nozzle of an existing needle-free syringe is between 0.16 mm and 0.2 mm. For example, when using an existing needle-free syringe powered by pneumatics for intradermal injection, the liquid pressure (i.e., stagnation pressure) inside the medicine tube can be adjusted by changing the gas pressure (i.e., injection pressure) provided by the air pressure device. However, when the diameter of the nozzle of the needle-free syringe is between 0.16 mm and 0.2 mm, it is impossible to stably achieve intradermal injection by adjusting the stagnation pressure inside the medicine tube. In addition, other operations that can stably achieve intradermal injections can also be used, for example, changing the injection distance (i.e., the distance between the nozzle of the needle-free syringe and the skin) by using spacers of different thicknesses. However, these other operations are not universally applicable to all needle-free syringes, and therefore have low universality.

[0004] The above description of the background technology is only intended to facilitate an in-depth understanding of the technical solution of the present invention (such as the technical means used, the technical problems solved, and the technical effects produced), and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art. Summary of the Invention

[0005] An object of the present invention is to provide a drug cartridge for a needle-less injector and a needle-less injector including the drug cartridge, which can achieve stable intradermal injection.

[0006] According to one embodiment of the present invention, a medicine barrel for a needle-free syringe is provided, wherein the needle-free syringe ejects a target injection liquid from the ejection port into the epidermis and dermis of the skin in a state where the ejection port is in contact with the surface of the skin, and the medicine barrel comprises: a container portion having a storage space for accommodating the target injection liquid; a nozzle portion, which is fluidically connected to the container portion and is provided with the ejection port, and guides the target injection liquid accommodated in the container portion to the ejection port; wherein the diameter of the ejection port is less than or equal to 0.12 mm.

[0007] Preferably, the diameter of the ejection port is less than or equal to 0.1 mm.

[0008] Preferably, when the ejection port is formed by laser drilling, the diameter of the ejection port is between 0.05 mm and 0.1 mm; when the ejection port is formed by injection molding, the diameter of the ejection port is between 0.08 mm and 0.1 mm.

[0009] Preferably, when the diameter of the ejection port is less than or equal to 0.12 mm, the target injection liquid in the accommodating space is pressurized to between 10 MPa and 26 MPa during the entire injection process.

[0010] Preferably, when the diameter of the ejection port is less than or equal to 0.1 mm, the target injection liquid in the accommodating space is pressurized to between 16 MPa and 26 MPa during the entire injection process.

[0011] Preferably, when the diameter of the ejection port is between 0.05 mm and 0.1 mm or between 0.08 mm and 0.1 mm, the target injection liquid in the accommodating space is pressurized to between 16 MPa and 25 MPa during the entire injection process.

[0012] Preferably, the target injection liquid diffuses laterally within the epidermis and dermis of the skin.

[0013] According to another embodiment of the present invention, a needle-free syringe is provided, comprising: a medicine tube, which is the above-mentioned medicine tube for the needle-free syringe; a driving portion, which imparts injection energy for ejecting the target injection liquid; and a propulsion body, which moves in a predetermined direction inside the accommodating portion by being imparted with the injection energy, thereby pressurizing the target injection liquid contained in the accommodating space.

[0014] The needle-free syringe includes: a core barrel, which has a first accommodating chamber extending along its own length direction as the accommodating part and an injection head connected to the front end of the first accommodating chamber as the nozzle part, the inner wall of the front part of the first accommodating chamber forms a retracted part extending radially inward; a push rod, which serves as the propulsion body and is endowed with the injection energy and can be slidably arranged in the first accommodating chamber; a self-destructive plug, the rear end of the self-destructive plug is connected to the front end of the push rod, and under the push of the push rod, the outer peripheral surface of the self-destructive plug contacts the inner peripheral surface of the retracted part, and the friction between the outer peripheral surface of the self-destructive plug and the inner peripheral surface of the retracted part is greater than the friction between the self-destructive plug and the push rod.

[0015] The needle-free syringe includes: a core barrel, which has a first accommodating chamber extending along its own length direction as the accommodating portion; an injection head, which serves as the nozzle portion, is connected to the front end of the core barrel and is fluidically connected to the first accommodating chamber; a push rod, which serves as the propulsion body and is endowed with the injection energy and can be slidably arranged in the first accommodating chamber; a first injection one-way device, which is arranged in the first accommodating chamber and is used to allow the target injection liquid in the first accommodating chamber to flow toward the injection head; a drug feeding device, which is connected to the core barrel and is fluidically connected to the first accommodating chamber; a second injection one-way device, which is arranged in the drug feeding device and is used to allow the target injection liquid in the drug feeding device to flow to the first accommodating chamber.

[0016] The present invention adopts the above technical solution, which has the following beneficial effects: According to the embodiment of the present invention, by controlling the injection parameters of the medicine tube of the needle-free syringe, the lateral diffusion of the drug solution in the skin can be achieved. Specifically, the diameter of the spray hole of the injection medicine tube is controlled within 0.12 mm, and the stagnation pressure inside the medicine tube (i.e., the liquid strength of the drug) is made within 10 MPa to 26 MPa. The use of these injection parameters is beneficial to the stable injection in the skin. In addition, the spray hole of the injection medicine tube can be formed by laser drilling or by injection molding. It is suitable for the formation of micropores of different sizes, has a reasonable design, and can be promoted on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following will describe exemplary embodiments of the present invention in more detail with reference to the accompanying drawings. For clarity, identical components in different drawings are represented by the same reference numerals. It should be noted that the drawings are for illustrative purposes only and are not necessarily drawn to scale. In these drawings:

[0018] FIG1 is a schematic structural diagram of a needle-free syringe according to an embodiment of the present invention.

[0019] FIG2 shows a schematic structural diagram of a needle-free syringe according to another embodiment of the present invention.

[0020] FIG3 shows a structure in which the push rod 12 of FIG1 is endowed with ejection energy by high-pressure gas.

[0021] 4A and 4B are schematic structural diagrams corresponding to the injection head of the needle-free syringe of FIG. 1 and FIG. 2 , respectively. DETAILED DESCRIPTION

[0022] The following is a detailed description of the implementation scheme of the present invention. This implementation scheme is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following implementation scheme.

[0023] Intradermal injection refers to injecting the target injection liquid only into the intradermal space of an individual (i.e., the epidermis and dermis of the skin). "Individual" can be a human, and can also include vertebrates, but is not limited to farm or production animals (such as pigs, cattle, poultry, horses), pets, primates, mice and rats. Throughout the specification, the process and results of the experiment on rats are described. The sum of the thickness of the epidermis and dermis of rat skin is in the range of 1mm to 1.9mm. With respect to the thickness of the epidermis and dermis of human skin, the cheek area is the thinnest, with the sum of the thickness of the epidermis and dermis being 1mm, and the inner area of ​​the upper arm is the thickest, with the sum of the thickness of the epidermis and dermis being 2mm. Since the sum of the thickness of the epidermis and dermis of rat skin is close to the sum of the thickness of the epidermis and dermis of human skin, the experiment on rats can show the experimental effect when the needle-free syringe injects the specific target injection liquid only into the intradermal space of the subject similar to human skin.

[0024] The diameter of the nozzle of the existing needle-free syringe is between 0.16mm and 0.2mm. It is impossible to stably achieve intradermal injection by adjusting the stagnation pressure inside the medicine tube or changing the injection distance and other operations, and its universality is not high.

[0025] For example, the three existing needle-free syringes are a 0-1 ml miniaturized low-pressure needle-free syringe (hereinafter referred to as a "gun-type GV-1 syringe"), an INJEX 3.0 syringe, and a QS-P syringe.

[0026] Table 1 shows the specifications of three existing needle-free syringes.

[0027] Table 1

[0028] As shown in Table 1, the diameters of the nozzle holes of the three needle-free syringes are all 0.16 mm.

[0029] Intradermal injections were tested using these three needle-free syringes.

[0030] Specifically, the needleless syringe's cartridge is fitted with a vial needle and 0.1 ml of methylene blue solution is drawn. Next, the rat is placed on a tray and its back is shaved to expose the skin where the intradermal injection will be performed. The methylene blue solution acts as an indicator or stain, allowing the operator to observe changes in the shape and color of the rat's skin after the intradermal injection.

[0031] The pneumatically powered GV-1 gun-style syringe allows for adjustment of injection pressure and spacer distance. Injection pressure refers to the gas pressure provided by the pneumatic device. The spacer is a device mounted on the nozzle and fitted to the nozzle, pressing against the skin to adjust the injection distance. The spacer distance (i.e., injection distance) refers to the distance between the nozzle and the skin. Methylene blue solution was injected into rats using the GV-1 gun-style syringe, and the injection status (specifically, whether there was seepage or leakage) was observed. Furthermore, leakage can be quantified using the injection completion rate parameter. The injection completion rate represents the ratio of the injected dose to the injected dose, and the injected dose is determined by weighing the amount of drug solution remaining externally. After the injection is completed, the size of the skin papule is measured, and the specimen is dissected and photographed to observe and record the presence of the drug solution (specifically, whether it is intradermal or subcutaneous). After re-adjusting at least one of the injection pressure, spacer distance, and impact interval, the above steps are repeated. The experimental results shown in Table 2 were obtained.

[0032] Table 2

[0033] According to Table 2, when 0.1 ml of methylene blue solution was injected into the rat skin using a gun-type GV-1 syringe by adjusting the injection pressure or the spacer distance, the injection leaked or penetrated through the skin to the subcutaneous layer in most cases.

[0034] The spring-powered INJEX 3.0 syringe does not require injection pressure adjustment. The INJEX 3.0 syringe is not equipped with a spacer. Using the INJEX 3.0 syringe, 0.1 ml of methylene blue solution was injected into rats, and two sets of data were recorded. Thus, the experimental results shown in Table 3 were obtained.

[0035] Table 3

[0036] According to Table 3, when 0.1 ml of methylene blue solution was injected into the rat skin using the INJEX syringe, a skin bump could be formed. However, in most cases, the injection passed through the skin to the subcutaneous layer and more than half of the solution leaked.

[0037] The QS-P syringe does not require preconditioning. A 0.1 ml methylene blue solution was injected into the rat using the QS-P syringe, and two sets of data were recorded. Thus, the experimental results shown in Table 4 were obtained.

[0038] Table 4

[0039] According to Table 4, when the Kuaishuer QS-P syringe injected 0.1 ml of methylene blue solution into the rat's skin, the injection force (i.e., the mechanical energy storage of the spring) of the Kuaishuer QS-P syringe was too large, and the methylene blue solution was injected through the skin to the subcutaneous layer. The injection completion rate was high, but the skin papule formed was small, which did not meet the requirements for intradermal injection.

[0040] When a needle-free syringe is used for injection, there is a situation where the drug solution can be partially injected into the skin or subcutaneously while leaking partially. For example, the test results in Tables 2 to 4 show that when the methylene blue solution is injected into the skin or subcutaneously, leakage occurs at the same time. This is because the initial injection force can meet the injection requirements. As the amount of injected drug increases and the internal pressure at the injection site increases, the subsequent injection force is insufficient to inject all the drug solution into the target site, resulting in leakage. The effectiveness of intradermal injection can be reflected by the injection level and injection completion rate. For example, the higher the injection level and the higher the injection completion rate, the better the intradermal injection effect. However, when the injection level is subcutaneous, no matter how high the injection completion rate is, it cannot indicate the effectiveness of intradermal injection.

[0041] Stable intradermal injection is extremely important for needle-free injection. It is difficult for existing needle-free syringes to achieve reliable and stable intradermal injection for different people (or animals) and different parts of the same patient. In order to solve this problem, the present invention provides a needle-free syringe that can eject the target injection liquid from the ejection port into the epidermis and dermis of the skin while the ejection port is in contact with the surface of the skin. The needle-free syringe of the present invention may include a housing, a nozzle, a driving portion and a propulsion body. The housing has a storage space for accommodating the target injection liquid. The nozzle is in fluid communication with the housing and is provided with an ejection port, and guides the target injection liquid contained in the housing to the ejection port. The driving portion imparts ejection energy for ejecting the target injection liquid. The propulsion body moves in a predetermined direction inside the housing by being endowed with the ejection energy, thereby pressurizing the target injection liquid contained in the storage space.

[0042] FIG1 is a schematic structural diagram of a needle-free syringe according to one embodiment of the present invention. As shown in FIG1 , the needle-free syringe includes a core barrel 11 and a push rod 12. In addition, the needle-free syringe shown in FIG1 is a disposable needle-free syringe and includes a self-destructive plug 16.

[0043] Specifically, the core barrel 11 can serve as the above-mentioned accommodating portion and nozzle portion. The core barrel 11 has a first accommodating chamber 13 (i.e., the accommodating portion) extending along its own length direction and an injection head 14 (i.e., the nozzle portion) connected to the front end of the first accommodating chamber 13. The inner wall of the front part of the first accommodating chamber 13 forms a retracted portion 15 extending radially inward. The target injection liquid is contained in the first accommodating chamber 13 and the injection head 14. A spray hole, i.e., the above-mentioned ejection port, is provided on the injection head 14. The above-mentioned propulsion body is constructed in the shape of a rod extending along the length direction of the first accommodating chamber 13. The push rod 12 serving as the propulsion body can be slidably arranged in the first accommodating chamber 13. Preferably, a sealing ring 17 is provided between the push rod 12 and the inner surface of the first accommodating chamber 13.

[0044] The rear end of the self-destruct plug 16 is connected to the front end of the push rod 12. Under the push of the push rod 12, the outer peripheral surface of the self-destruct plug 16 contacts the inner peripheral surface of the indentation 15, and the friction between the outer peripheral surface of the self-destruct plug 16 and the inner peripheral surface of the indentation 15 is greater than the friction between the self-destruct plug 16 and the push rod 12.

[0045] Therefore, when the push rod 12 drives the self-destructive plug 16 toward the front end of the first accommodating chamber 13 to inject liquid to the injection target, the self-destructive plug 16 moves to the injection head 14 of the core barrel 11. If the user wants to use the injection device again and pulls the push rod 12, the friction between the outer circumference of the self-destructive plug 16 and the inner circumference of the retracted portion 15 is greater than the friction between the self-destructive plug 16 and the push rod 12. As a result, the self-destructive plug 16 will separate from the push rod 12, and then remain in the injection head 14, making the injection device unusable.

[0046] The needle-free injection device may further include a Luer connector 18. During pre-filling, the Luer connector 18 may be used to install a rubber sleeve that isolates the drug core cartridge 11 from the outside world.

[0047] Figure 2 shows a schematic diagram of a needle-free injector according to another embodiment of the present invention. As shown in Figure 2 , the needle-free injector includes an injection head 24, a core cartridge 21, and a push rod 22. The needle-free injector shown in Figure 2 is a continuous-use needle-free injector and includes a first one-way injection device 23, a second one-way injection device 25, and a drug feed device 27.

[0048] The core barrel 21 has a first accommodating chamber 26 extending along its own length direction as the above-mentioned accommodating portion. The injection head (i.e., the nozzle portion) 24 is connected to the front end of the core barrel 21 and is fluidically connected to the first accommodating chamber 26. Therefore, during multiple injections, the injection head 24 can be disassembled and replaced. A spray hole (i.e., an ejection port) is provided on the injection head 14. A push rod (i.e., a propulsion body) 22 is slidably provided in the core barrel 21. The first injection one-way device 23 is provided in the first accommodating chamber 26, for allowing the target injection liquid in the first accommodating chamber 26 to flow toward the injection head 24. The drug feeding device 27 is connected to the core barrel 11 and is fluidically connected to the first accommodating chamber 26. The second injection one-way device 25 is provided in the drug feeding device 27, for allowing the target injection liquid in the drug feeding device 27 to flow toward the first accommodating chamber 26.

[0049] Therefore, continuous injection can be achieved through the reciprocating motion of the push rod 22. When the push rod 22 moves forward, the target injection liquid can be ejected from the injection head 24. When the push rod 22 is pulled back, negative pressure is generated in the first accommodating chamber 26, and the target injection liquid in the drug feeding device 27 is drawn into the first accommodating chamber 26, thus achieving continuous injection.

[0050] In one embodiment of the present invention, the driving part can use high-pressure gas as the injection energy. Taking Figure 1 as an example, Figure 3 shows a structure in which the push rod 12 of Figure 1 is endowed with injection energy by high-pressure gas.

[0051] As shown in Figure 3 , high-pressure gas (i.e., compressed gas) is connected to the through-hole 39 of the handle portion 38 , allowing the high-pressure gas to enter the air inlet chamber 40 of the handle portion 38 . The high-pressure gas in the air inlet chamber 40 is divided into two paths. The first path bypasses the outer circumference of the bracket 41 and enters the front chamber 31A. The second path passes through the first channel 42, the trigger chamber 43, and the second channel 44 and enters the rear chamber 31B. At this point, both the front chamber 31A and the rear chamber 31B are filled with high-pressure gas, ensuring that the air pressure on both sides of the balancing valve 32 is the same.

[0052] Under the elastic force provided by the elastic member 33, the balancing valve 32 contacts the sleeve 34, continuing to block the second accommodating chamber 35. When the trigger 45 is pulled, the trigger 45 pushes the valve stem 36 backward, causing the valve stem 36 to block the trigger chamber 43. The high-pressure gas in the intake chamber 40 can no longer pass through the first channel 42, the trigger chamber 43, and the second channel 44 to enter the rear chamber 31B. At this point, the rear chamber 31B can no longer receive high-pressure gas. However, the front chamber 31A can still continue to receive high-pressure gas, causing the air pressure in the front chamber 31A to be greater than that in the rear chamber 31B, pushing the balancing valve 32 backward while overcoming the elastic member 33.

[0053] After the balancing valve 32 moves backward, it no longer blocks the second accommodating chamber 35, allowing the second accommodating chamber 35 to communicate with the front chamber 31A. This allows the high-pressure gas in the front chamber 31A to enter the second accommodating chamber 35. The high-pressure gas entering the second accommodating chamber 35 pushes the piston 46 and the striker 37 forward, thereby pushing the push rod 12 forward. The target injection liquid contained in the core barrel 11 is pressurized and ejected from the nozzle of the injection head 14, completing the injection.

[0054] However, the present invention is not limited to the structure of the needle-free syringe. That is, the structure of the needle-free syringe is not limited to the two embodiments described above. Specifically, the housing is not limited to a cylindrical shape. The propulsion body is not limited to a rod shape. The propulsion body can also be a film that expands in a specific direction, a fold that stretches along a given specific direction, and so on. The driving unit is not limited to using high-pressure gas as the injection energy. The driving unit can also use electrical energy from a piezoelectric element, mechanical energy from a spring, etc. as the injection energy, or can generate the injection energy by appropriately combining these forms of energy.

[0055] According to an embodiment of the present invention, the diameter of the ejection port is less than or equal to 0.12 mm, and the target injection liquid in the accommodation space is pressurized to an appropriate range (e.g., between 10 MPa and 26 MPa), that is, the stagnation pressure in the accommodation space is between 10 MPa and 26 MPa, so as to achieve stable injection of the target injection liquid into the epidermis and dermis of the skin. In addition, the target injection liquid can diffuse laterally within the epidermis and dermis of the skin.

[0056] Specifically, Figures 4A and 4B are schematic diagrams of the injection heads of the needle-free syringes shown in Figures 1 and 2, respectively. As shown in Figures 4A and 4B, the diameter D (i.e., the ejection port) of the nozzle openings 14 and 24 is within a range of less than or equal to 0.12 mm. In conjunction with Figures 1 and 3, by connecting high-pressure gas to move the push rods 12 and 22, the target injection liquid in the core barrels 11 and 21 is pressurized to between 10 MPa and 26 MPa. Consequently, the needle-free injection device shown in Figures 1 and 2 can stably inject the target injection liquid into the epidermis and dermis of the skin.

[0057] An intradermal injection test was conducted using a needle-free syringe according to various embodiments of the present invention. Similarly, 0.1 ml of methylene blue solution was extracted. Next, the rat was placed on a tray and the hair on the back was shaved to expose the skin to be injected intradermally. The rat was injected with methylene blue solution using a needle-free syringe according to various embodiments of the present invention, and the injection condition was observed. After the injection was completed, the size of the skin papule was measured, and then the dissection was taken and photographed to observe and record the layers of the drug solution. Subsequently, another needle-free syringe was replaced so that the ejection port of the needle-free syringe was changed within a range of less than or equal to 0.12 mm or the stagnation pressure inside the needle-free syringe was changed within a range of 10 MPa to 26 MPa, and the above steps were repeated. Thus, the test results in Table 5 can be obtained.

[0058] Table 5

[0059] As shown in Table 5, the injection levels are all intradermal, and the injection completion rate is in a very high range (i.e., approximately in the range of 85% to 98%). It can be concluded that a needle-free syringe with an ejection port diameter less than or equal to 0.12 mm and a stagnation pressure between 10 MPa and 26 MPa can achieve reliable and stable intradermal injection.

[0060] The diameter of the nozzle orifice of existing needle-free syringes is greater than or equal to 0.16 mm. According to an embodiment of the present invention, the diameter of the nozzle orifice of a needle-free syringe is set to be less than or equal to 0.12 mm. The smaller the nozzle diameter, the more conducive it is to intradermal injection. However, the diameter cannot be infinitely small. If the nozzle diameter is too small, the injection time will be prolonged and it will be easily blocked by suspended matter in the target injection liquid (such as a vaccine) during injection, which is not conducive to injection stability. On this basis, the stagnation pressure inside the drug tube is further controlled within an appropriate range (i.e., between 10 MPa and 26 MPa), thereby achieving reliable and stable intradermal injection.

[0061] In a preferred embodiment, when the diameter of the ejection port is less than or equal to 0.1 mm, the target injection liquid in the accommodation space is pressurized to between 16 MPa and 26 MPa during the entire injection process. The corresponding test results are shown in Table 6.

[0062] Table 6

[0063] As shown in Table 6, the injection level was intradermal. In addition, compared with the injection completion rate shown in Table 5, the injection completion rate shown in Table 6 was further improved, that is, the injection completion rate was approximately in the range of 92% to 98%.

[0064] According to the above test results, a core diameter less than or equal to 0.12mm is conducive to forming a stable intradermal injection, and the smaller the diameter, the more conducive it is to forming a stable intradermal injection. However, due to process limitations, the diameter cannot be infinitely small. The current suitable range of the diameter produced by the injection production process is 0.08mm to 0.12mm. If it is less than 0.08mm, the production qualification rate is very low. Considering the conditions of injection stability, the diameter produced by the injection molding process has a better solution of 0.08mm to 0.1mm for stable intradermal injection. The diameter produced by the laser drilling production process can be as small as 0.01mm, but considering the structural strength and the problem of easy clogging during the injection process (that is, if the diameter is too small, the injection time will be longer and it will be easily clogged by suspended matter in the vaccine during injection and scrapped), the diameter produced by the laser drilling production process has a better solution of 0.05mm to 0.1mm for stable intradermal injection.

[0065] Therefore, in another preferred embodiment, when the ejection port is formed by laser drilling, the diameter of the ejection port is between 0.05 mm and 0.1 mm, and when the ejection port is formed by injection molding, the diameter of the ejection port is between 0.08 mm and 0.1 mm. When the ejection port diameter is between 0.05 mm and 0.1 mm or between 0.08 mm and 0.1 mm, the target injection liquid in the receiving space is pressurized to between 16 MPa and 25 MPa during the entire injection process. The corresponding test results are shown in Table 7.

[0066] Table 7

[0067] As shown in Table 7, the injection level was intradermal. In addition, compared with the injection completion rate shown in Table 5, the injection completion rate shown in Table 7 was further improved, that is, the injection completion rate was approximately in the range of 92% to 99%.

[0068] According to an embodiment of the present invention, by controlling the injection parameters of the needle-free injector's drug cartridge, lateral diffusion of the drug solution within the skin can be achieved. Specifically, the diameter of the injection cartridge's nozzle is controlled within 0.12 mm. A smaller nozzle diameter is more conducive to intradermal injection. Furthermore, the stagnation pressure (i.e., the drug fluid pressure) within the cartridge is maintained within an appropriate range (e.g., 10 MPa to 26 MPa). Using these injection parameters is beneficial for stable intradermal injection.

[0069] In addition, the nozzle hole of the injection tube can be formed by laser drilling or injection molding. It is suitable for forming micropores of different sizes, has a reasonable design, and can be promoted on a large scale.

[0070] The various embodiments of the invention are not an exhaustive list of all possible combinations, but are intended to describe representative aspects of the invention, and what is described in terms of various embodiments can be applied independently or in combinations of two or more.

[0071] The descriptions presented in the above exemplary embodiments are only intended to illustrate the technical solutions of the present invention and are not intended to be exhaustive or to limit the present invention to the precise forms described. Obviously, it is possible for a person of ordinary skill in the art to make many changes and variations based on the above teachings. The exemplary embodiments are selected and described to explain the specific principles of the present invention and its practical applications, so that other persons of ordinary skill in the art can easily understand, implement and utilize the various exemplary embodiments of the present invention and its various selected forms and modified forms. The scope of protection of the present invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A medicine tube for a needle-free syringe, wherein the needle-free syringe ejects a target injection liquid from the ejection port into the epidermis and dermis of the skin in a state where the ejection port is in contact with the surface of the skin, the medicine tube comprising: a containing portion having a containing space for containing the target injection liquid; a nozzle portion, which is in fluid communication with the receiving portion and is provided with the ejection port, and guides the target injection liquid received in the receiving portion to the ejection port; Wherein, the diameter of the ejection port is less than or equal to 0.12 mm; Wherein, when the ejection port is formed by laser drilling, the diameter of the ejection port is between 0.05 mm and 0.1 mm, and when the ejection port is formed by injection molding, the diameter of the ejection port is between 0.08 mm and 0.1 mm; wherein, during the entire injection process, a stagnation pressure is applied to the target injection liquid in the containing space, wherein the stagnation pressure remains unchanged during the entire injection process, and the stagnation pressure is a pressure between 10 MPa and 26 MPa; Wherein, the stagnation pressure is a pressure between 16MPa and 25MPa.

2. The drug cartridge for a needle-free injector according to claim 1, wherein: The target injection fluid spreads laterally within the epidermis and dermis of the skin.

3. A needle-free syringe, comprising: A medicine tube, which is a medicine tube for a needle-free injector according to claim 2; a driving unit that imparts ejection energy for ejecting the target injection liquid; The propelling body is provided with the ejection energy and moves in a predetermined direction inside the accommodation portion, thereby pressurizing the target injection liquid accommodated in the accommodation space.

4. The needle-free injector according to claim 3, wherein: The needle-free syringe comprises: The core barrel has a first accommodating cavity extending along its length direction as the accommodating portion and an injection head connected to the front end of the first accommodating cavity as the nozzle portion, wherein the inner wall of the front portion of the first accommodating cavity forms a retracted portion extending radially inwards; A push rod, which serves as the propulsion body and is endowed with the ejection energy and is slidably disposed in the first accommodating cavity; A self-destructive plug, the rear end of which is connected to the front end of a push rod. Under the push of the push rod, the outer circumference of the self-destructive plug contacts the inner circumference of the indentation, and the friction between the outer circumference of the self-destructive plug and the inner circumference of the indentation is greater than the friction between the self-destructive plug and the push rod.

5. The needle-free injector according to claim 3, wherein: The needle-free syringe comprises: The drug core tube has a first accommodating cavity extending along its length direction as the accommodating portion; An injection head, which serves as the nozzle portion, is connected to the front end of the medicine core barrel and is in fluid communication with the first accommodating chamber; A push rod, which serves as the propulsion body and is endowed with the ejection energy and is slidably disposed in the first accommodating cavity; A first injection one-way device, which is disposed in the first accommodating chamber and is used to allow the target injection liquid in the first accommodating chamber to flow toward the injection head; A drug feeding device, which is connected to the drug core barrel and is in fluid communication with the first accommodating chamber; The second injection one-way device is arranged in the drug feeding device and is used to allow the target injection liquid in the drug feeding device to flow to the first accommodating chamber.

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