Polymer double-cavity prefilled syringe

Abstract

The invention provides a polymer double-cavity prefilled syringe which comprises a barrel with a bypass, the barrel is provided with a finger handle and an adapter, the adapter is provided with a needle seat, a needle body is fixed to the needle seat, and a protective cap is arranged on the outer side of the needle body. A front plunger, a middle plunger and a rear plunger are arranged in the barrel, and the rear plunger abuts against a plunger rod. The cylinder is formed by integral injection molding of polymer, a group of ribs which are arranged side by side and protrude towards the interior of the cylinder are arranged on the inner wall of the cylinder, the axial length of each rib is larger than that of the middle plunger, the bypass is formed by a gap between every two adjacent ribs, and the outer diameter of the cylinder is larger than that of the adapter; the protective cap is tightly connected with the needle seat, a first anti-falling mechanism is arranged on the joint face of the protective cap and the needle seat, and an inner cavity of the protective cap is communicated with the outside through a bacteria-blocking, hydrophobic and breathable filter membrane. The bypass is formed in the mode that the protruding edges protrude inwards, demolding is convenient, integrated injection molding machining can be conducted through polymers, cost is low, damage is not prone to occurring, and the using effect is good. The outer surface of the cylinder is smooth, the heat conduction performance is good, and the vacuum freeze-drying efficiency is high.

Description

Technical Field

[0003] The invention belongs to the technical field of medical devices, and in particular relates to a polymer double-chamber prefilled syringe. Background Art

[0005] Biological injectable drugs are often made into freeze-dried powders when they are sold and transported, and need to be mixed with a diluent before injection. At present, double-chamber prefilled syringes, such as those shown in Chinese patent CN1750852A, are increasingly widely used in the field of biopharmaceuticals. They are not only syringes for biological drugs, but also packaging and transportation containers for biological drugs. The main structure of the double-chamber prefilled syringe is that its barrel is divided into a front chamber and a rear chamber by a partition plunger. The front chamber is filled with freeze-dried powder, and the rear chamber is filled with diluent. Then a bypass is provided between the front chamber and the rear chamber. When the partition plunger is pushed to the bypass, the front chamber is connected to the rear chamber, and the diluent flows to the front chamber to mix with the freeze-dried powder, thereby completing the mixed drug dispensing. In this way, the user can complete the mixed drug injection by performing simple operations, and patients or their families who have not received professional training can also complete the injection.

[0006] However, in order to ensure that the plunger can slide smoothly in the syringe, the inner wall of the barrel should be kept smooth, so the bypass of the existing double-chamber prefilled syringe is basically formed in the inner wall of the barrel. In order not to increase the thickness of the barrel wall, it is basically formed by the barrel wall itself protruding outward, as shown in Chinese patent CN1750852A. The current bypass will not protrude toward the inner side of the barrel, because this will significantly increase the resistance of the separating piston, which is a technical prejudice generally held by those skilled in the art. However, the current groove structure of the bypass is only suitable for glass processing. If injection molding is used, it will obviously be difficult to demold, which is not convenient for mass production. Therefore, the double-chamber prefilled syringes currently seen on the market are basically made of glass. However, as disclosed in the article "Analysis and Safety Evaluation of Tungsten Content in Medical Sodium Hyaluronate Gel" in "Biomedical Engineering" 2017, 36 (2): 183-186, there will be residual tungsten components in the glass prefilled syringe, which has an adverse effect on the medicinal properties of biological drugs, especially protein biological preparations. In addition, glass syringes are fragile and may cause leakage of pre-filled medicines in the barrel. If the leaked medicine is certain anti-tumor biological products, it will cause irreversible pollution and damage to the environment.

[0007] High-performance polymers COP\COC (cyclic olefin polymers\cyclic olefin copolymers) can be used for primary packaging of fine drugs, especially the above-mentioned sensitive biological products. High-performance polymers have high fracture resistance and glass-like transparency, do not contain tungsten and adhesives; and can ensure the precise size of the product during the injection molding process, which can greatly reduce the dead angle in the syringe, thereby reducing the total waste of expensive drugs. In summary, polymer barrels have advantages over glass barrels in some aspects, but the existing bypass structure is difficult to be injection molded with polymers to meet the needs of mass production. Therefore, the current polymer syringe barrels are generally only used in single-chamber prefilled syringes, and have not been widely used in double-chamber prefilled syringes.

[0008] For example, a double-chamber prefilled syringe capable of injection molding is shown in Chinese patent application CN113855933A, which solves the problem of injection molding by separating the syringe barrel. However, the split structure still has many defects such as difficult processing, high cost, and easy leakage.

[0009] In addition, as shown in Chinese patent CN113855933A, in order to ensure the sterility in the syringe, a protective cap is generally provided at the front end of the syringe. However, during the mixing of the medicines in the barrel, as the plunger pushes, gas will be discharged forward, so the syringe needs to take off the protective cap when mixing the medicines so that the gas can be discharged smoothly. At this time, the sterility in the syringe cannot be guaranteed, which will cause the medicines in the barrel to be contaminated before injection, affecting the medicinal properties. In order to solve the above problem, Chinese patent application CN1750852A adds a front plunger in front of the partition plunger. Through the blocking of the front plunger, the sterility in the barrel can still be guaranteed when mixing the medicines. However, the syringe will have air between the front plunger and the protective cap. When the liquid medicine in the front chamber is vacuum-freezed, due to the pressure difference on both sides of the front plunger, the front plunger will be displaced, thereby affecting the space in the front chamber, changing the moving distance of the front plunger during injection, and affecting the overall injection effect. Therefore, the syringe cannot be operated with the protective cap on during vacuum freeze-drying, and the protective cap needs to be removed first to eliminate the pressure difference on both sides of the front plunger. In addition, the protective cap also needs to be removed when mixing drugs, otherwise the air between the front plunger and the protective cap will create resistance, which is not conducive to pushing the separation plunger to mix drugs. In summary, the current dual-chamber prefilled syringe cannot be operated with the protective cap on during assembly and drug mixing, making the filling freeze-drying and drug mixing process cumbersome and inconvenient.

[0010] In addition, as shown in Chinese patent CN1750852A, an adapter is installed at the front end of the cylinder for installing the needle assembly, but the outer diameter of the conventional adapter is larger than the cylinder. In addition, the bypass structure protruding outside the cylinder makes the entire outer surface of the cylinder not flat. As a result, during vacuum freeze-drying, the outer surface of the cylinder is not easy to wrap to closely contact the heat-conducting device, which greatly reduces the efficiency of vacuum freeze-drying.

[0011] Finally, the protective cap of conventional syringes is generally connected to the front end of the syringe barrel through a Luer lock, but it is generally made of plastic. After high-temperature gas sterilization and low-temperature vacuum freeze-drying, or after aging over a long period of time, it often cannot withstand the exhaust shock during drug mixing and is easy to fall off, and the sterility of the drug mixing cannot be guaranteed. Summary of the invention

[0013] The present invention aims to solve the above-mentioned problems of the prior art and provides a polymer double-chamber prefilled syringe, which forms a bypass in the form of ridges protruding inside the barrel, so that the barrel can be injection-molded in one piece with a polymer, and the outer surface of the barrel is flat for easy wrapping, thereby improving the efficiency of vacuum freeze-drying. At the same time, a bacteriostatic and hydrophobic breathable membrane is added to the protective cap to ensure unobstructed gas discharge during drug mixing, thereby overcoming previous technical prejudices and meeting the processing and use requirements of polymer double-chamber prefilled syringes.

[0014] This polymer double-chamber prefilled syringe comprises a barrel with a bypass, a finger handle is provided at the rear end of the barrel, an adapter is provided at the front end of the barrel, a needle seat is provided on the adapter, a needle body is fixed on the needle seat, and a protective cap is provided on the outer side of the needle body; a front plunger, a middle plunger, and a rear plunger are provided in the barrel, wherein the rear plunger abuts against the plunger rod; the barrel is integrally injection-molded by a polymer, and a group of convex ridges arranged side by side and protruding into the barrel are provided on its inner wall, and the axial length of each convex ridge is greater than the axial length of the middle plunger, and the bypass is formed by the gap between two adjacent convex ridges, and the outer diameter of the barrel is greater than or equal to the outer diameter of the adapter; the protective cap is tightly connected with the needle seat, and the joint surface of the two is provided with a first anti-slip mechanism, and the inner cavity of the protective cap is connected to the outside through a bacteriostatic, hydrophobic and breathable filter membrane. The present invention forms a bypass by protruding ridges to the inner side of the barrel, which is convenient for demoulding, so that the double-chamber prefilled syringe can be integrally injection-molded by a polymer, which is low in cost, not easy to damage, and has a good use effect. In addition, the surface of the cylinder is flat, which is convenient for wrapping and vacuum freeze-drying, has good heat conduction performance and high vacuum freeze-drying efficiency. The structure of the protective cap meets the exhaust requirements of mixed medicines, so that the sterilization, filling and mixing processes can be operated with the cap on, so that the medicines in the cylinder will not be exposed to external bacteria and moisture before injection, which can ensure the efficacy of the medicine and the good use effect. At the same time, it reduces the assembly process and reduces the production cost.

[0015] Preferably, the plunger rod is threadedly connected to the finger handle, and the plunger rod is threadedly connected to the finger handle from the time when the middle plunger passes through the ridge until the rear plunger is squeezed onto the ridge as a whole. When the middle plunger and the rear plunger pass through the ridge, the ridge increases the resistance, making it difficult to control the force of the entire push injection. At this time, the force can be more easily controlled by using threaded pushing. The threaded pushing process is basically the drug mixing process, which ensures that the drugs are fully mixed and makes the entire push injection process more controllable.

[0016] Preferably, a barrel groove for inserting the barrel body is provided on the side of the finger handle, and a screw hole for the plunger rod to pass through is provided in the middle of the finger handle. In this way, the piston rod can be easily assembled to ensure that the drug mixing process is thread-driven.

[0017] Preferably, the plunger rod is formed into a quadrangular prism by four support rods, and the outer edges of each support rod are provided with spaced protrusions, and each protrusion is combined into an external thread connected to the finger handle; a push plate is fixed to the front end of the support rod, and the outer diameter of the push plate is not greater than the outer diameter of the quadrangular prism. The above-mentioned external thread structure can minimize the contact area between the plunger rod and the inner wall of the cylinder, so that it can be smoother when non-threaded drive is required before and after the threaded drive. In addition, the plunger rod and the rear plunger are split, and the rear plunger is pushed by a push plate, which allows the entire plunger rod to be more conveniently assembled in the screw hole of the finger handle. And the prefilled syringe is generally disposable, and there is no need to pull the plunger back for reuse, so the split structure can fully meet the use requirements. The outer diameter of the push plate is not greater than the outer diameter of the quadrangular prism, which can meet the need to push the rear plunger and will not interfere with the threaded drive.

[0018] Preferably, the end of the ridge is provided with a guiding slope, which facilitates the demoulding of the injection molding and makes it easier for the middle plunger and the rear plunger to slide onto the ridge.

[0019] Preferably, the needle seat and the adapter mating surface are provided with a second anti-drop mechanism, so that after high-temperature sterilization and vacuum freeze-drying, the needle seat can still withstand the impact of exhaust during drug mixing, and the use effect is good.

[0020] Preferably, the inner diameter of the front end of the adapter is smaller than the inner diameter of the rear end, and the inner diameter of the rear end is consistent with the inner diameter of the barrel. In this way, the sealing effect of the front plunger before squeezing into the front end of the adapter can be ensured, thereby ensuring that the drug solution will not leak from the front end of the adapter when mixing drugs.

[0021] Preferably, a liquid outlet hole communicating with the needle seat inner cavity is formed in the middle of the front end of the adapter, and a liquid guide groove is formed along the inner wall of the adapter leading to the liquid outlet hole, so that the liquid medicine can be discharged smoothly when the front plunger is squeezed into the front end of the adapter.

[0022] The filling method of the above polymer double-chamber prefilled syringe comprises the following steps:

[0023] Step 1: Assemble the needle body, needle seat, protective cap, adapter and barrel together;

[0024] Step 2: using ethylene oxide gas to sterilize the above-mentioned assembled parts, and the ethylene oxide gas enters the inner cavity of the protective cap from the filter membrane to sterilize the needle body;

[0025] Step 3: Place the above-mentioned assembled parts with the needle facing downward, then insert the front plunger into the cylinder to a suitable position, and pour the liquid medicine above the front plunger in the cylinder, and then insert the middle plunger into the cylinder and place it above the convex ridge;

[0026] Step 4: using vacuum freezing technology to prepare freeze-dried powder;

[0027] Step 5: Then pour the diluent into the upper part of the middle plunger in the cylinder; then put the rear plunger into the cylinder to seal the diluent;

[0028] Step 6: Assemble the finger handle and the plunger rod, and place the front end of the plunger rod against the rear plunger;

[0029] Step 7: Package the components formed in the previous step to form the final product.

[0030] The filling method adopted in the present invention application can be operated while wearing a protective cap, which greatly improves efficiency, reduces the operating costs of pharmaceutical companies' filling machines, vacuum freezers, etc., and can ensure the proportion of medicines dispensed, with good use effect.

[0031] The method for using the above polymer double-chamber prefilled syringe comprises the following steps:

[0032] Step 1: Remove the package, push the plunger rod into the cylinder, push the rear plunger to push the diluent to the front end of the cylinder, and then push the middle plunger to the convex ridge;

[0033] Step 2: Rotate the plunger rod, and under the action of the thread, push the rear plunger to continue to move toward the front end of the cylinder, thereby driving the middle plunger to squeeze onto the ridge. When the middle plunger is entirely located on the ridge, the bypass between the two adjacent ridges is connected, allowing the diluent to flow into the front chamber and mix with the lyophilized powder;

[0034] Step 3: Shake the cylinder to mix the diluent and the lyophilized powder to form a mixed solution. At this time, the front plunger is tightly fitted with the inner wall of the cylinder to ensure that the mixed solution will not leak out of the adapter;

[0035] Step 4: Invert the barrel with the needle tip facing upward, and continue to rotate the plunger rod until the rear plunger pushes all the mixed liquid into the front chamber and contacts the middle plunger, and the rear plunger as a whole is squeezed onto the convex ridge; at this time, the front plunger is squeezed into the front end of the adapter, the liquid guide groove opens, the mixed liquid to be injected can be discharged from the needle body through the liquid guide groove, and the plunger rod is disconnected from the threaded connection with the finger handle;

[0036] Step 5: Remove the protective cap, insert the needle tip into the patient's body, and then push the plunger rod. At this time, the mixed liquid passes through the liquid guide groove, the liquid outlet hole, and the needle body and is injected into the patient, thereby completing the injection.

[0037] The injection method adopted by the present invention ensures the drug mixing time through thread drive, mixes the drug more fully, eliminates the influence of increased resistance caused by the ridges protruding into the barrel, makes the entire drug mixing and injection process more controllable, and makes it possible to use polymer integral injection molding for the barrel of the double-chamber prefilled syringe.

[0038] The polymer double-chamber prefilled syringe provided by the present invention has at least the following advantages:

[0039] 1. The bypass of the present invention is formed by the gap between the ridges. The inward ridge structure facilitates the integral injection molding of the cylinder with a polymer, which is more conducive to the storage and transportation of biological drugs. It solves the problem that the glass cylinder is fragile and causes drugs to pollute the environment, and also solves the problem that the tungsten component in the glass destroys the medicinal properties of biological drugs.

[0040] 2. The cylinder of the present invention has a neat appearance, which is more convenient for packaging and vacuum freeze-drying, thereby greatly improving the efficiency of vacuum freeze-drying.

[0041] 3. The convex ridges of the present invention can position the plunger, thereby making the space size of the front chamber and the rear chamber more accurate, and then making the content of each component of the mixed medicine accurate, thereby ensuring the efficacy of the medicine.

[0042] 4. The present invention utilizes threaded drive to allow the middle plunger and the rear plunger to bypass, thereby solving the problem of increased resistance of the ridge to the plunger and poor control of the force of pushing the plunger, overcoming the technical prejudice in this field, thereby making it possible for the ridge to form a bypass, and ensuring that the syringe barrel can be made of polymer integral injection molding.

[0043] 5. The protective cap of the present invention is provided with a bacteriostatic hydrophobic breathable membrane, so that there is no obstruction in the discharge of gas during drug mixing, and the middle plunger and the rear plunger can be squeezed through the bypass smoothly, further making it possible for the ridge to form a bypass, ensuring that the syringe barrel can be made of polymer integral injection molding.

[0044] 6. The present invention is provided with a plurality of anti-slip mechanisms, and even after the plastic material is aged, it can withstand the impact of exhaust gas during drug mixing, overcome the influence of increased exhaust impact force caused by the convex ridge structure of the present invention, and further make it possible for the convex ridge to form a bypass and thread drive, thereby ensuring that the syringe barrel can be made of polymer integral injection molding.

[0045] 7. The protective cap of the present invention does not need to be removed during the entire sterilization, filling and drug mixing process, and the operation can be performed with the cap on, thereby ensuring the sterility of the cylinder body, which is conducive to the application of biological drugs with high sterility requirements.

[0046] 8. The drug filling process of the present invention is simpler, and the protective cap assembly and sterilization process can be completed when the syringe is produced, which greatly reduces the filling cost of the pharmaceutical factory and is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the explosion decomposition three-dimensional structure of the present invention.

[0049] Figure 2 It is a schematic diagram of the three-dimensional structure of the foldable protective cover of the present invention when it is not opened.

[0050] Figure 3 It is a schematic diagram of the three-dimensional structure of the foldable protective cover of the present invention when it is opened.

[0051] Figure 4 It is a schematic diagram of the cross-sectional structure of the present invention.

[0052] Figure 5 It is a schematic diagram of the axial cross-sectional structure of the cylinder bypass of the present invention.

[0053] Figure 6 It is a schematic diagram of the cross-sectional structure of the cylinder bypass of the present invention.

[0054] Figure 7 It is a schematic diagram of the three-dimensional structure of the protective cap of the present invention.

[0055] Figure 8 It is a schematic diagram of the three-dimensional structure of the needle assembly of the present invention.

[0056] Fig. 9 It is a partial cross-sectional structural schematic diagram of the needle and protective cap of the present invention.

[0057] Fig.10 It is a partial cross-sectional structural schematic diagram of the adapter, protective cap and needle seat of the present invention.

[0058] Fig.11 It is a schematic diagram of the three-dimensional structure of the foldable sheath of the present invention.

[0059] Fig.12 It is a front perspective structural schematic diagram of the adapter of the present invention.

[0060] Fig.13 It is a rear perspective structural schematic diagram of the adapter of the present invention.

[0061] Fig.14 It is a schematic diagram of the cross-sectional structure of the front plunger of the present invention when it is squeezed into the adapter.

[0062] Fig.15 It is a schematic diagram of the cross-sectional structure of the front plunger of the present invention when it is squeezed into the adapter without convex strips.

[0063] Fig.16 It is a schematic diagram of the three-dimensional structure of the finger handle of the present invention.

[0064] Fig.17 It is a schematic diagram of the three-dimensional structure of the plunger rod of the present invention.

[0065] Fig.18 It is a schematic diagram of the partial cross-sectional structure of the cylinder before mixing of the present invention.

[0066] Fig.19 It is a schematic diagram of the partial cross-sectional structure of the cylinder when the plunger in the present invention squeezes onto the convex ridge.

[0067] Fig. 20 It is a schematic diagram of the partial cross-sectional structure of the barrel of the present invention after mixing and ready for injection.

[0068] Fig.21 It is a schematic diagram of the partial cross-sectional structure of the barrel after injection of the present invention.

[0069] Description of reference numerals:

[0070] Cylinder body 1, convex ridge 11, guide inclined surface 111, bypass 12, finger handle 2, cylinder groove 21, screw hole 22, plunger rod 3, support rod 31, protrusion 32, push plate 33, adapter 4, adapter convex ring 41, liquid outlet 42, inner inclined surface 43, liquid guide groove 44, convex strip 45, adapter boss 46, anti-rotation convex strip 47, needle seat 5, needle seat undercut 51, needle seat convex ring 52, needle body 6, folding sheath 7, sheath clamping strip 71, protective cap 8, filter membrane 81, elastic sealing ring 82, protective cap convex ring 83, outer inclined surface 84, anti-rotation convex rib 85, front plunger 91, middle plunger 92, rear plunger 93. DETAILED DESCRIPTION

[0072] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0073] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0074] like Figures 1 to 3As shown, this polymer double-chamber prefilled syringe includes a barrel 1 with a bypass 12, and the barrel 1 is formed by integral injection molding of COP polymer (cycloolefin polymer). COP polymer material is a prior art and will not be described in detail here. A finger handle 2 is provided at the rear end of the barrel 1, and an adapter 4 is provided at the front end of the barrel 1. For the convenience of description, in this application, "the direction from the barrel toward the adapter is the front" and "the direction from the barrel toward the finger handle is the back" are uniformly defined. A plunger rod 3 is provided on the rear side of the finger handle 2. A needle seat 5 is inserted at the front end of the adapter 4, and a needle body 6 is fixed to the needle seat 5. The needle seat 5 and the needle body 6 form a needle assembly as a whole. A protective cap 8 is provided on the outside of the needle body 6, and the protective cap 8 is tightly connected to the needle seat 5 to ensure airtightness. A folding sheath 7 is provided on the adapter 4. The folding sheath 7 is a prior art. After the injection is completed, Figure 3 As shown, it can be expanded by pressing to surround the needle body 6, avoiding injury and ensuring that the device of the present invention cannot be used twice. Its basic structure is consistent with that disclosed in Chinese patent application CN1674951A, and will not be described in detail here.

[0075] like Figure 4 As shown, a front plunger 91, a middle plunger 92, and a rear plunger 93 are provided in the cylinder 1, wherein the rear side of the rear plunger 93 is abutted against a plunger rod 3. Each plunger is made of elastic material and is interference fit on the inner wall of the cylinder 1, which can maintain the seal inside the cylinder 1, and at the same time can be compressed so as to slide inside the cylinder 1. The outer diameter of the cylinder 1 is greater than or equal to the outer diameter of the adapter 4, that is, not less than the outer diameter of the adapter 4, and its main purpose is to make the outer surface of the front chamber where the freeze-dried powder is located flat, so that it can be in close contact with the heat-conducting device and improve the efficiency of vacuum freeze-drying. In this embodiment, the plug-in end of the adapter 4 is plugged into the inner wall of the cylinder 1, and is interference fit with the inner wall of the cylinder 1 to maintain the seal. The plunger rod 3 is threadedly connected to the finger handle 2, and the plunger rod 3 is threadedly connected to the finger handle 2 from the middle plunger 92 through the ridge 11 to before the rear plunger 93 is squeezed onto the ridge 11 as a whole. Before the middle plunger 92 starts to pass through the ridge 11 and after the rear plunger 93 is entirely pressed onto the ridge 11, the plunger 3 and the finger handle 2 can be disconnected from the threaded connection, and can be pushed by hand, which is more convenient to operate.

[0076] like Figure 5 , Figure 6 As shown, the inner wall of the cylinder 1 is provided with a group of ridges 11 arranged side by side and protruding into the cylinder, and the axial length of each ridge 11 is greater than the axial length of the middle plunger 92, so that the bypass 12 is connected after the middle plunger 92 squeezes onto the ridge 11. The bypass 12 is formed by the gap between two adjacent ridges 11, and the end of the ridge 11 is provided with a guide slope 111.

[0077] like Figure 7 to Figure 10As shown, the joint surface of the protective cap 8 and the needle seat 5 is provided with a first anti-slip mechanism, which is composed of a protective cap convex ring 83 and a needle seat undercut 51 that cooperate with each other. It can not only withstand the exhaust impact during drug mixing, but also prevent gas and bacteria from passing through this place. The protective cap 8 is also provided with an elastic sealing ring 82 to further ensure the airtightness of the joint surface. The inner cavity of the protective cap 8 is connected to the outside through a bacteriostatic, hydrophobic and breathable filter membrane 81. The bacteriostatic, hydrophobic and breathable filter membrane 81 is made of polymer material and cannot pass liquids and bacteria, but can pass gas. This type of filter membrane is a prior art and can be easily purchased on the market, so it will not be described in detail here. The inner wall of the protective cap 8 is also provided with an anti-rotation convex rib 85. After the assembly is completed, the anti-rotation convex rib 85 can not only prevent the protective cap 8 from rotating without reason, but also during assembly, the protective cap 8 can be pinched by hand to drive the needle seat 5 to rotate so as to assemble it at the front end of the adapter 4. The second anti-slip mechanism is provided on the mating surface of the needle seat 5 and the adapter 4. The second anti-slip mechanism is composed of the adapter convex ring 41 and the needle seat convex ring 52 that are staggered and matched with each other. It can not only withstand the exhaust impact when mixing drugs, but also prevent gas and bacteria from passing through. The third anti-slip mechanism is provided on the joint surface of the protective cap 8 and the adapter 4. The third anti-slip mechanism is composed of the outer inclined surface 84 of the protective cap and the inner inclined surface 43 of the adapter that match each other, which further ensures that the protective cap 8 can withstand the exhaust impact when mixing drugs, and can also prevent gas and bacteria from passing through.

[0078] like Fig.11 , Fig.12 As shown, the joint surface of the foldable sheath 7 and the adapter 4 is provided with a fourth anti-slip mechanism, which is composed of a sheath clamping strip 71 and an adapter boss 46 that cooperate with each other, and can ensure the strength of the connection between the foldable sheath 7 and the adapter 4, and is not easy to fall off. The joint surface of the foldable sheath 7 and the adapter 4 is also provided with a plurality of anti-rotation convex strips 47, which can prevent the foldable sheath 7 from rotating without reason and affecting the use.

[0079] like Fig.13 , 14 As shown, the inner diameter of the front end of the adapter 4 is smaller than the inner diameter of the rear end, and the inner diameter of the rear end is consistent with the inner diameter of the barrel 1. A liquid outlet 42 communicating with the inner cavity of the needle seat 5 is formed in the middle of the front end of the adapter 4, and a liquid guide groove 44 leading to the liquid outlet 42 along its inner wall is formed in the adapter 4. A group of triangular ridges 45 are provided on the inner wall of the adapter 4, which can further squeeze the front plunger 91, so that a liquid medicine channel is also formed between adjacent ridges 45, so that the liquid medicine flows more smoothly.

[0080] Fig.15 Another embodiment of the adapter 4 is disclosed. In this embodiment, there is no convex strip 45 , and the groove structure of the liquid guide groove 44 can also ensure that the liquid medicine flows out from the front end of the adapter 4 .

[0081] like Fig.16 , 17As shown, the side of the finger handle 2 is provided with a barrel groove 21 for inserting the barrel body 1, and the middle of the finger handle 2 is provided with a screw hole 22 for the plunger rod 3 to pass through. The plunger rod 3 is formed of four integrally formed support rods 31 to form a quadrangular prism. This shape of plunger rod is a prior art and will not be described in detail here. The outer edges of each support rod 31 are provided with spaced protrusions 32, and each protrusion 32 is combined into an external thread connected to the finger handle 2; a push plate 33 is fixed to the front end of the support rod 31; the outer diameter of the push plate 33 is smaller than the outer diameter of the quadrangular prism.

[0082] The filling method of the above polymer double-chamber prefilled syringe comprises the following steps:

[0083] Step 1: Assemble the needle body 6, the needle seat 5, the protective cap 8, the adapter 4, and the barrel 1 together;

[0084] Step 2: Use ethylene oxide gas to sterilize the above-mentioned assembled parts. The ethylene oxide gas enters the inner cavity of the protective cap 81 from the filter membrane 81 to sterilize the needle body 6;

[0085] The above two steps can be completed at the device manufacturer. The pharmaceutical factory can directly fill the sterilized assembled parts, saving the assembly and sterilization process.

[0086] Step 3: Place the above-mentioned assembled parts with the needle facing downward, then put the front plunger 91 into the barrel 1 to a suitable position, and pour the liquid medicine into the barrel 1 above the front plunger 91, and then put the middle plunger 92 into the barrel 1, and place it above the convex ridge 11. This process can be completed in a filling machine. Liquid medicine filling is a prior art and will not be described in detail here. The difference between the present invention and the prior art is that the filling can be performed after the needle assembly and the protective cap are installed.

[0087] Step 4: The above-mentioned liquid medicine is made into freeze-dried powder by vacuum freezing technology. This process can be completed in a vacuum freezer. Vacuum freezing is a prior art and will not be described in detail here. The difference between the present invention and the prior art is that vacuum freezing can be performed when the needle assembly and the protective cap are installed.

[0088] Step 5: Next, pour the diluent into the cylinder 1 above the middle plunger 92; then put the rear plunger 93 into the cylinder 1 to seal the diluent;

[0089] Step 6: Assemble the finger handle 2 and the plunger rod 3, and let the front end of the plunger rod 3 abut against the rear plunger 93;

[0090] Step 7: Package the components formed in the previous step to form the final product.

[0091] The filling method of the present invention can be operated with the needle assembly and the protective cap installed during the entire process, thus changing the previous process of assembling the needle assembly after filling, reducing the operating cost of the pharmaceutical factory and facilitating promotion.

[0092] The method for using the above polymer double-chamber prefilled syringe comprises the following steps:

[0093] Step 1: Remove the package, push the plunger rod 3 into the barrel 1, push the rear plunger 93 to push the diluent toward the front end of the barrel 1, and then push the middle plunger 92 to the ridge 11; Fig.18 shown.

[0094] Step 2: Rotate the plunger rod 3, and under the action of the thread, push the rear plunger 93 to continue to move toward the front end of the cylinder 1, thereby driving the middle plunger 92 to squeeze onto the ridge 11. When the middle plunger 92 is entirely located on the ridge 11, the bypass 12 between two adjacent ridges 11 is connected, allowing the diluent to flow into the front chamber and mix with the lyophilized powder; Fig.19 shown.

[0095] Step 3: Shake the cylinder 1 to fully mix the diluent and the lyophilized powder to form a mixed solution. At this time, the front plunger 91 is tightly fitted with the inner wall of the cylinder 1 to ensure that the mixed solution will not leak out from the adapter 4.

[0096] Step 4: Invert the barrel 1 with the needle tip facing upward, and continue to rotate the plunger rod 3 until the rear plunger 93 pushes all the mixed liquid into the front chamber and abuts against the middle plunger 92, and the rear plunger 93 is squeezed onto the convex ridge 11 as a whole; at this time, the front plunger 91 is squeezed into the front end of the adapter 4, the liquid guide groove 44 is opened, and the mixed liquid to be injected can be discharged from the needle body 6 through the liquid guide groove 44, and the plunger rod 3 is disconnected from the threaded connection with the finger handle 2; Fig. 20 shown.

[0097] Step 5: Remove the protective cap 8, insert the needle tip into the patient's body, and then push the plunger rod 3. At this time, the mixed liquid passes through the liquid guide groove 44, the liquid outlet hole 42, and the needle body 6 and is injected into the patient, thereby completing the injection. The syringe after the injection is completed is shown in 21.

[0098] Step 6: Press the folded sheath 7 to expand it and surround the needle body 6. Figure 3 shown.

[0099] The device and the method of use of the present invention do not need to remove the protective cap 8 during the drug mixing process, and the protective cap 8 can be removed before injection, thereby ensuring that the drugs in the barrel 1 will not be contaminated before injection, the efficacy of the drugs can be fully guaranteed, the use effect is good, and it is conducive to promotion.

Claims

1. A polymer double-chamber prefilled syringe, comprising a barrel (1) with a bypass (12), a finger handle (2) being provided at the rear end of the barrel (1), an adapter (4) being provided at the front end of the barrel (1), a needle seat (5) being provided on the adapter (4), a needle body (6) being fixed to the needle seat (5), and a protective cap (8) being provided on the outer side of the needle body (6); a front plunger (91), a middle plunger (92), and a rear plunger (93) being provided inside the barrel (1), wherein the rear plunger (93) is abutted against a plunger rod (3); characterized in that: The barrel (1) is formed by integral injection molding of a polymer, and its inner wall is provided with a group of convex ridges (11) arranged side by side and protruding into the barrel, the axial length of each convex ridge (11) is greater than the axial length of the middle plunger (92), the bypass (12) is formed by the gap between two adjacent convex ridges (11), and the outer diameter of the barrel (1) is greater than or equal to the outer diameter of the adapter (4); the protective cap (8) is tightly connected to the needle seat (5), and the joint surface of the two is provided with a first anti-slip mechanism (83, 51), and the inner cavity of the protective cap (8) is connected to the outside through a bacteriostatic, hydrophobic and breathable filter membrane (81).

2. A polymer double-chamber prefilled syringe according to claim 1, characterized in that: The plunger rod (3) is threadedly connected to the finger handle (2), and the plunger rod (3) and the finger handle (2) remain threadedly connected from the middle plunger (92) through the ridge (11) to before the rear plunger (93) is entirely pressed onto the ridge (11).

3. A polymer double-chamber prefilled syringe according to claim 2, characterized in that: A barrel groove (21) for inserting the barrel body (1) is formed on the side of the finger handle (2), and a screw hole (22) for the plunger rod (3) to pass through is formed in the middle of the finger handle (2).

4. A polymer double-chamber prefilled syringe according to claim 2, characterized in that: The plunger rod (3) is formed of four support rods (31) in a quadrangular prism shape, and the outer edges of each support rod (31) are provided with protrusions (32) distributed at intervals, and each protrusion (32) is combined into an external thread connected to the finger handle (2); a push plate (33) is fixed to the front end of the support rod (31); and the outer diameter of the push plate (33) is not greater than the outer diameter of the quadrangular prism.

5. The polymer double-chamber prefilled syringe according to claim 1, characterized in that: A guiding inclined surface (111) is provided at the end of the convex ridge (11).

6. The polymer double-chamber prefilled syringe according to claim 1, characterized in that: The matching surfaces of the needle seat (5) and the adapter (4) are provided with a second anti-dropping mechanism (52, 41).

7. The polymer double-chamber prefilled syringe according to claim 1, characterized in that: The inner diameter of the front end of the adapter (4) is smaller than the inner diameter of the rear end, and the inner diameter of the rear end is consistent with the inner diameter of the cylinder (1).

8. The polymer double-chamber prefilled syringe according to claim 1, characterized in that: A liquid outlet hole (42) communicating with the inner cavity of the needle seat (5) is formed in the middle of the front end of the adapter (4), and a liquid guide groove (44) is formed along the inner wall of the adapter (4) leading to the liquid outlet hole (42).

9. A method for filling the polymer double-chamber prefilled syringe according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Assemble the needle body (6), the needle seat (5), the protective cap (8), the adapter (4), and the barrel (1); Step 2: using ethylene oxide gas to sterilize the above-mentioned assembled parts, the ethylene oxide gas enters the inner cavity of the protective cap (81) from the filter membrane (81) to sterilize the needle body (6); Step 3: Place the above-mentioned assembled parts with the needle facing downwards, then insert the front plunger (91) into the barrel (1) to a suitable position, and pour the liquid medicine into the barrel (1) above the front plunger (91), and then insert the middle plunger (92) into the barrel (1) and place it above the ridge (11); Step 4: using vacuum freezing technology to prepare freeze-dried powder; Step 5: Next, the diluent is poured into the cylinder (1) above the middle plunger (92); and then the rear plunger (93) is inserted into the cylinder (1) to seal the diluent; Step 6: Assemble the finger handle (2) and the plunger rod (3), and allow the front end of the plunger rod (3) to abut against the rear plunger (93); Step 7: Package the components formed in the previous step to form the final product.

10. A method for using the polymer double-chamber prefilled syringe according to any one of claims 2 to 4, characterized in that: The steps include: Step 1: Remove the package, push the plunger rod (3) into the barrel (1), push the rear plunger (93) to push the diluent toward the front end of the barrel (1), and then push the middle plunger (92) to the convex ridge (11); Step 2: Rotate the plunger rod (3), and under the action of the thread, push the rear plunger (93) to continue to move toward the front end of the cylinder (1), thereby driving the middle plunger (92) to squeeze onto the ridge (11). When the middle plunger (92) is entirely located on the ridge (11), the bypass (12) between two adjacent ridges (11) is connected, allowing the diluent to flow into the front chamber and mix with the lyophilized powder; Step 3: Shake the cylinder (1) to fully mix the diluent and the lyophilized powder to form a mixed solution. At this time, the front plunger (91) is tightly fitted with the inner wall of the cylinder (1) to ensure that the mixed solution does not leak from the adapter (4); Step 4: Invert the barrel (1) with the needle tip facing upward, and continue to rotate the plunger rod (3) until the rear plunger (93) pushes all the mixed liquid into the front chamber and contacts the middle plunger (92), and the rear plunger (93) as a whole is squeezed onto the convex ridge (11); at this time, the front plunger (91) is squeezed into the front end of the adapter (4), the liquid guide groove (44) is opened, and the mixed liquid to be injected can be discharged from the needle body (6) through the liquid guide groove (44), and the plunger rod (3) is disconnected from the threaded connection with the finger handle (2); Step 5: Remove the protective cap (8), insert the needle tip into the patient's body, and then push the plunger rod (3). At this time, the mixed liquid passes through the liquid guide groove (44), the liquid outlet hole (42), and the needle body (6) and is injected into the patient, thereby completing the injection.

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