Polymer double-cavity pre-filled syringe and filling method and medicine mixing method thereof

Abstract

A polymer double-cavity prefilled syringe comprises a barrel with a bypass, the barrel is provided with a finger handle and an adapter, a needle seat is arranged on the adapter, a needle body is fixed on 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

[0001] The invention belongs to the technical field of medical devices, and in particular relates to a polymer double-chamber prefilled syringe and a filling method and a medicine mixing method thereof. Background Art

[0002] 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.

[0003] 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.

[0004] High-performance polymers COP\COC (cycloolefin polymer\cycloolefin copolymer) can be used for the 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 dimensions of products during the injection molding process, which can greatly reduce the dead corners in the syringe, thereby reducing the total waste of expensive drugs. In summary, the polymer barrel has advantages over the glass barrel 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 applied to single-chamber prefilled syringes and are not widely used in double-chamber prefilled syringes.

[0005] As shown in a kind of injection-moldable double-chamber prefilled syringe in Chinese Patent Application CN113855933A, the problem of injection molding is solved by splitting the syringe barrel. However, the split structure still has many defects such as difficult processing, high cost, and easy leakage.

[0006] In addition, as shown in Chinese Patent CN113855933A, in order to ensure the sterility inside the syringe barrel, a protective cap is generally provided at the front end of the syringe barrel. However, during the mixing of the drugs in the barrel, as the plunger is pushed, gas will be discharged forward. Therefore, when mixing the drugs, the protective cap needs to be removed to allow the gas to be discharged smoothly. At this time, the sterility inside the syringe barrel cannot be guaranteed, which will cause the drugs inside the barrel to be contaminated before injection, affecting the drug properties. Chinese Patent Application CN1750852A solves the above problems by adding a front plunger in front of the partition plunger. Through the blockage of the front plunger, the sterility inside the barrel can still be guaranteed during drug mixing. However, there will be air between the front plunger and the protective cap of this syringe. When vacuum freeze-drying the liquid medicine in the front chamber, due to the pressure difference on both sides of the front plunger, the front plunger will shift, thereby affecting the space in the front chamber and changing the moving distance of the front plunger during injection, resulting in affecting the overall injection effect. Therefore, this 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, when mixing the drugs, the protective cap also needs to be removed, otherwise the air existing between the front plunger and the protective cap will generate resistance, which is not conducive to pushing the partition plunger for drug mixing. In summary, the current double-chamber prefilled syringes cannot be operated with the protective cap on during the assembly and drug mixing processes, making the filling, freeze-drying, and drug mixing processes cumbersome and not convenient enough.

[0007] In addition, as shown in Chinese Patent CN1750852A, an adapter is installed at the front end of the barrel for installing the needle assembly. However, the outer diameter of the conventional adapter is larger than that of the barrel. Coupled with the outwardly protruding bypass structure of the barrel, the outer surface of the entire barrel is not flat. This results in that during vacuum freeze-drying, it is not convenient to wrap the outer surface of the barrel to closely contact the heat conduction device, greatly reducing the efficiency of vacuum freeze-drying.

[0008] Finally, the caps of current conventional syringes are generally connected to the front end of the syringe barrel through a Luer lock. However, they are generally made of plastic. After high-temperature gas sterilization and low-temperature vacuum freeze-drying, or due to aging over a long time, they often cannot withstand the exhaust impact during drug mixing and are prone to falling off, thus failing to ensure sterility during drug mixing. SUMMARY OF THE INVENTION

[0009] The present invention aims to solve the above problems of the prior art and provides a polymer double-chamber prefilled syringe and its filling method and drug mixing method. A bypass is formed in the form of convex ridges protruding inward from the inner side of the barrel, so that the barrel can be integrally injection-molded with polymer. Moreover, the outer surface of the barrel is flat and easy to wrap, improving the efficiency of vacuum freeze-drying. At the same time, a bacteria-proof, hydrophobic and breathable membrane is added to the cap, enabling unobstructed gas discharge during drug mixing, overcoming the previous technical prejudice, and meeting the processing and use requirements of polymer double-chamber prefilled syringes.

[0010] This polymer double-chamber prefilled syringe includes a barrel with a bypass. A finger grip is provided at the rear end of the barrel, and an adapter is provided at the front end of the barrel. A needle hub is provided on the adapter, a needle is fixed to the needle hub, and a cap is provided outside the needle. A front plunger, a middle plunger, and a rear plunger are provided inside the barrel, and a plunger rod abuts against the rear plunger. The barrel is integrally injection-molded with polymer, and a group of convex ridges arranged side by side and protruding into the barrel are provided on its inner wall. The axial length of each convex ridge is greater than the axial length of the middle plunger. The bypass is formed by the gap between two adjacent convex ridges. The outer diameter of the barrel is greater than or equal to the outer diameter of the adapter. The cap is tightly connected to the needle hub, and a first anti-detachment mechanism is provided at the joint surface between the two. The inner cavity of the cap communicates with the outside through a bacteria-proof, hydrophobic and breathable filter membrane. The present invention forms a bypass by protruding convex ridges from the inner side of the barrel, facilitating demolding, enabling the double-chamber prefilled syringe to be integrally injection-molded with polymer, having low cost, being not easily damaged, and having good use effects. In addition, the outer surface of its barrel is flat, facilitating wrapping for vacuum freeze-drying, having good heat conduction performance, and high vacuum freeze-drying efficiency. The structure of the cap meets the requirements of drug mixing and exhaust, enabling the operations of sterilization, filling, and drug mixing to be carried out with the cap on, so that the drugs in the barrel will not contact external bacteria and moisture before injection, ensuring the drug efficacy, having good use effects, while reducing the assembly process and having low production cost.

[0011] Preferably, the plunger rod is threadedly connected to the finger grip, and the plunger rod and the finger grip remain threadedly connected from the middle plunger until before the whole is extruded onto the convex ridge through the convex ridge to the rear plunger. When the middle plunger and the rear plunger pass over the convex ridge, the convex ridge increases the resistance, making it inconvenient to control the overall injection force. At this time, by using threaded pushing, the force can be more easily controlled. The threaded pushing process is basically the drug mixing process, ensuring full drug mixing and making the overall injection process more controllable.

[0012] Preferably, a barrel groove for inserting the barrel is provided on the side surface of the finger grip, and a threaded hole for the plunger rod to pass through is provided in the middle of the finger grip. In this way, it is convenient to assemble the piston rod and ensure that the medicine mixing process is driven by threads.

[0013] Preferably, the plunger rod is composed of four struts to form a quadrangular prism shape. Protrusions are provided at intervals on the outer edges of the struts, and the protrusions are combined into an external thread for connecting with the finger grip; a push plate is fixed at the front end of the strut, and the outer diameter of the push plate is not greater than the outer diameter of the quadrangular prism. The above external thread structure can minimize the contact area between the plunger rod and the inner wall of the barrel, so that when driving before and after the thread drive and when non-thread drive is required, it can be smoother. In addition, the plunger rod and the rear plunger are split. Using the push plate to push the rear plunger can make the entire plunger rod more conveniently assembled in the threaded hole of the finger grip. And pre-filled syringes are generally disposable and there is no need to pull back the plunger 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 not only meet the need to push the rear plunger, but also will not interfere with the thread drive.

[0014] Preferably, a guiding inclined surface is provided at the end of the convex rib. The guiding inclined surface facilitates injection molding demolding and at the same time makes it easier for the middle plunger and the rear plunger to slide onto the convex rib.

[0015] Preferably, a second anti-detachment mechanism is provided on the mating surface of the needle seat and the adapter. In this way, after high-temperature sterilization and vacuum freeze-drying, the needle seat can still withstand the impact of exhaust gas during medicine mixing, and the use effect is good.

[0016] Preferably, the inner diameter of the front end of the adapter is smaller than that 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 before the front plunger is squeezed into the front end of the adapter can be ensured, so as to ensure that the liquid medicine will not leak from the front end of the adapter during medicine mixing.

[0017] Preferably, a liquid outlet hole communicating with the inner cavity of the needle seat is provided in the middle of the front end of the adapter, and a liquid guiding groove leading to the liquid outlet hole is provided along the inner wall of the adapter. In this way, when the front plunger is squeezed into the front end of the adapter, the liquid medicine can be discharged smoothly.

[0018] The filling method of the above-mentioned polymer double-chamber pre-filled syringe includes the following steps: Step 1: Assemble the needle body, needle seat, protective cap, adapter, and barrel together; Step 2: Sterilize the above assembled components with ethylene oxide gas. The ethylene oxide gas enters the inner cavity of the protective cap from the filter membrane to disinfect the needle body; Step 3: Place the above assembled components with the needle tip facing down, then place the front plunger into the barrel to a proper position, pour the liquid medicine above the front plunger into the barrel, and then place the middle plunger into the barrel and above the convex rib; Step 4: Use vacuum freezing technology to make the above liquid medicine into freeze-dried powder; 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; Step 6: Assemble the finger handle and the plunger rod, and place the front end of the plunger rod against the rear plunger; Step 7: Package the components formed in the previous step to form the final product.

[0019] 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.

[0020] The drug mixing method of the above polymer double-chamber prefilled syringe comprises the following steps: 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; 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; 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; 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; 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.

[0021] 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.

[0022] The polymer double-chamber prefilled syringe provided by the present invention has at least the following advantages: 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.

[0023] 2. The outer surface of the syringe barrel of the present invention is neat, which is more convenient for wrapping and vacuum freeze-drying, greatly improving the efficiency of vacuum freeze-drying.

[0024] 3. The convex rib of the present invention can position the plunger, so that the space sizes of the front chamber and the rear chamber are more accurate, and then the content of each component of the mixed medicine is accurate, ensuring the drug efficacy.

[0025] 4. The present invention uses screw drive to make the middle plunger and the rear plunger pass through the bypass, solving the problem that the resistance of the convex rib to the plunger increases and the pushing force of the plunger is difficult to control, overcoming the technical prejudice in this field, making it possible for the convex rib to form a bypass, and ensuring that the syringe barrel can be integrally injection-molded with a polymer.

[0026] 5. The protective cap of the present invention is provided with a bacteria-proof, hydrophobic and breathable membrane, so that there is no obstruction in discharging gas during medicine mixing, enabling the middle plunger and the rear plunger to smoothly squeeze through the bypass, further making it possible for the convex rib to form a bypass, and ensuring that the syringe barrel can be integrally injection-molded with a polymer.

[0027] 6. The present invention is provided with multiple anti-detachment mechanisms. Even after the plastic material ages, it can withstand the impact of the discharged gas during medicine mixing, overcoming the influence of the increased exhaust impact force caused by the convex rib structure of the present invention, further making it possible for the convex rib to form a bypass and screw drive, and ensuring that the syringe barrel can be integrally injection-molded with a polymer.

[0028] 7. The protective cap of the present invention does not need to be removed during the entire sterilization, filling and medicine mixing processes, and can be operated with the cap on, thus ensuring the sterility inside the barrel, which is beneficial for application to biological drugs with high requirements for sterility.

[0029] 8. The medicine filling process of the present invention is more concise, and the assembly and sterilization processes of the protective cap can be completed entirely during the production of the syringe, greatly reducing the filling cost of the pharmaceutical factory and being beneficial for promotion.

[0030] 9. The first four steps before injection can be assisted by others in advance and prepared for use. The injector can directly inject after taking it, reducing the waiting time of the patient and reducing the fear of the patient. The protective cap structure extends the time from the completion of medicine mixing to injection, and does not affect the drug property of the medicine in the barrel even under long-term waiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is an exploded three-dimensional structural schematic diagram of the present invention.

[0032] Figure 2 It is a three-dimensional structural schematic diagram of the present invention when the folding sheath is not opened.

[0033] Figure 3Schematic three-dimensional structure diagram when the folding sheath of the present invention is opened.

[0034] Figure 4 Schematic cross-sectional structure diagram of the present invention.

[0035] Figure 5 Schematic axial cross-sectional structure diagram at the bypass of the cylinder body of the present invention.

[0036] Figure 6 Schematic cross-sectional structure diagram of the cross-section at the bypass of the cylinder body of the present invention.

[0037] Figure 7 Schematic three-dimensional structure diagram of the protective cap of the present invention.

[0038] Figure 8 Schematic three-dimensional structure diagram of the needle assembly of the present invention.

[0039] Figure 9 Schematic partial cross-sectional structure diagram of the cooperation between the needle and the protective cap of the present invention.

[0040] Figure 10 Schematic partial cross-sectional structure diagram of the cooperation between the adapter, the protective cap and the needle seat of the present invention.

[0041] Figure 11 Schematic three-dimensional structure diagram of the folding sheath of the present invention.

[0042] Figure 12 Schematic front three-dimensional structure diagram of the adapter of the present invention.

[0043] Figure 13 Schematic rear three-dimensional structure diagram of the adapter of the present invention.

[0044] Figure 14 Schematic cross-sectional structure diagram of the cross-section when the front plunger is inserted into the adapter of the present invention.

[0045] Figure 15 Schematic cross-sectional structure diagram of the cross-section when the front plunger is inserted into the adapter without ribs of the present invention.

[0046] Figure 16 Schematic three-dimensional structure diagram of the finger grip of the present invention.

[0047] Figure 17 Schematic three-dimensional structure diagram of the plunger rod of the present invention.

[0048] Figure 18 Schematic partial cross-sectional structure diagram of the cylinder body before mixing of the present invention.

[0049] Figure 19 Schematic partial cross-sectional structure diagram of the cylinder body when the plunger is pressed onto the convex rib in the present invention.

[0050] Figure 20Schematic diagram of a partial cross-section of the cylinder when ready for injection after mixing according to the present invention.

[0051] Figure 21 Schematic diagram of a partial cross-section of the cylinder after injection according to the present invention.

[0052] Explanation of reference numerals: Cylinder 1, convex rib 11, guiding inclined surface 111, bypass 12, finger handle 2, cylinder groove 21, screw hole 22, plunger rod 3, support rod 31, convex block 32, push plate 33, adapter 4, adapter convex ring 41, liquid outlet hole 42, inner inclined surface 43, liquid guiding groove 44, convex strip 45, adapter boss 46, anti-rotation convex strip 47, needle seat 5, needle seat reverse buckle 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 rib 85, front plunger 91, middle plunger 92, rear plunger 93. Detailed implementation manners

[0053] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0054] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have any technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear description and are not used to limit the scope within which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0055] Such as Figures 1 - 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.

[0056] 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.

[0057] 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.

[0058] like Figures 7 - 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.

[0059] like Figure 11 , Figure 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.

[0060] like Figure 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.

[0061] Figure 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 .

[0062] like Figure 16 , 17As shown in the figure, a cylinder groove 21 for inserting the cylinder body 1 is formed on the side of the finger handle 2, and a threaded hole 22 for the plunger rod 3 to pass through is provided in the middle of the finger handle 2. The plunger rod 3 is formed by four integrally formed struts 31 into a quadrangular prism shape. This shape of the plunger rod is a prior art and will not be elaborated here. The outer edges of the struts 31 are provided with convex blocks 32 distributed at intervals, and the convex blocks 32 are combined into an external thread connected to the finger handle 2; a push plate 33 is fixed at the front end of the strut 31; the outer diameter of the push plate 33 is smaller than the outer diameter of the quadrangular prism.

[0063] The filling method of the above polymer double-chamber pre-filled syringe includes the following steps: Step 1: Assemble the needle body 6, the needle seat 5, the protective cap 8, the adapter 4, and the cylinder body 1 together; Step 2: Sterilize the above assembled components with ethylene oxide gas. The ethylene oxide gas enters the inner cavity of the protective cap 81 from the filter membrane 81 to disinfect the needle body 6; The above two steps can be completed by the instrument manufacturer. The pharmaceutical factory can directly fill the assembled components after disinfection, saving the processes of assembly and disinfection.

[0064] Step 3: Place the above assembled components with the needle tip facing down. Then, place the front plunger 91 into the cylinder body 1 to a suitable position, pour the liquid medicine above the front plunger 91 into the cylinder body 1, and then place the middle plunger 92 into the cylinder body 1 and above the convex rib 11. This process can be completed in a filling machine. The liquid medicine filling is a prior art and will not be elaborated here. The difference between the present invention and the prior art is that the filling can be carried out after the needle assembly and the protective cap are installed.

[0065] Step 4: Use vacuum freezing technology to make the above liquid medicine into freeze-dried powder. This process can be completed in a vacuum freezer. Vacuum freezing is a prior art and will not be elaborated here. The difference between the present invention and the prior art is that the vacuum freezing can be carried out with the needle assembly and the protective cap installed.

[0066] Step 5: Then pour the diluent above the middle plunger 92 into the cylinder body 1; then place the rear plunger 93 into the cylinder body 1 to seal the diluent; Step 6: Assemble the finger handle 2 and the plunger rod 3, and make the front end of the plunger rod 3 abut against the rear plunger 93; Step 7: Package the components formed in the previous step to form the final product.

[0067] The filling method of the present invention can be operated throughout the process with the needle assembly and the protective cap installed, changing the previous process of assembling the needle assembly after filling, reducing the operation cost of the pharmaceutical factory, and being conducive to promotion.

[0068] The mixing method of the above polymer double-chamber pre-filled syringe includes the following steps: 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; Figure 18 shown.

[0069] 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; Figure 19 shown.

[0070] 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. 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; Figure 20 shown.

[0071] 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.

[0072] Step 6: Press the folded sheath 7 to expand it and surround the needle body 6. Figure 3 shown.

[0073] 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 pre-filled syringe, comprising a barrel (1) with a bypass (12), a finger grip (2) is provided at the rear end of the barrel (1), an adapter (4) is provided at the front end of the barrel (1), a needle hub (5) is provided on the adapter (4), the needle hub (5) is fixed with a needle body (6), and a protective cap (8) is provided outside the needle body (6); a front plunger (91), a middle plunger (92), and a rear plunger (93) are provided in the barrel (1), wherein the rear plunger (93) abuts against a plunger rod (3); characterized in that, The cylinder body (1) is integrally injection-molded from a polymer. A set of convex ridges (11) arranged side by side and protruding into the cylinder are provided on its inner wall. 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). 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 before the whole is extruded onto the convex ridges (11) starting from the middle plunger (92) through the convex ridges (11) to the rear plunger (93). The protective cap (8) is tightly connected to the needle base (5), and a first anti-disengagement mechanism (83, 51) is provided on the joint surface between the two. The inner cavity of the protective cap (8) communicates with the outside through a bacteria-blocking, hydrophobic and breathable filter membrane (81).

2. The polymer double-chamber prefilled syringe according to claim 1, characterized in that, The outer diameter of the cylinder body (1) is greater than or equal to the outer diameter of the adapter (4).

3. The polymer double-chamber prefilled syringe according to claim 2, wherein A cylinder groove (21) for inserting the cylinder body (1) is formed on the side surface of the finger handle (2), and a threaded hole (22) for the plunger rod (3) to pass through is provided 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 into a quadrangular prism shape by four support rods (31). Protrusions (32) are provided at intervals on the outer edges of the support rods (31). The protrusions (32) are combined into an external thread for connecting with the finger handle (2). A push plate (33) is fixed at the front end of the support rod (31). The outer diameter of the push plate (33) is not greater than the outer diameter of the quadrangular prism.

5. A polymer double-chamber prefilled syringe according to claim 1, wherein, 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, wherein A second anti-disengagement mechanism (52, 41) is provided on the mating surface between the needle base (5) and the adapter (4).

7. A polymer double-chamber prefilled syringe according to claim 1, wherein 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 its rear end is consistent with the inner diameter of the cylinder body (1).

8. A 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 base (5) is formed in the middle of the front end of the adapter (4), and a liquid guiding groove (44) leading to the liquid outlet hole (42) along the inner wall of the adapter (4) is provided on the adapter (4).

9. A filling method for the polymer double-chamber prefilled syringe according to any one of claims 1 to 8, characterized in that, It includes the following steps: Step 1: Assemble the needle body (6), the needle base (5), the protective cap (8), the adapter (4), and the cylinder body (1) together; Step 2: Sterilize the above assembled components with ethylene oxide gas. The ethylene oxide gas enters the inner cavity of the protective cap (8) from the filter membrane (81) to sterilize the needle body (6); Step 3: Place the above assembled components with the needle tip facing downwards. Then, place the front plunger (91) into the cylinder body (1) to a proper position, and pour the liquid medicine above the front plunger (91) into the cylinder body (1); Step 4: Use vacuum freezing technology to make the above liquid medicine into freeze-dried powder; Step 5: Place the middle plunger (92) into the cylinder body (1) and above the convex ridge (11). Then, pour the diluent above the middle plunger (92) into the cylinder body (1). Then, place the rear plunger (93) into the cylinder body (1) to seal the diluent; Step 6: Assemble the finger handle (2) and the plunger rod (3), and make the front end of the plunger rod (3) abut against the rear plunger (93); Step 7: Package the assembly formed in the previous step to form the final product.

10. A method for mixing drugs in the polymer double-chamber prefilled syringe according to any one of claims 1 to 4, characterized in that, It includes the following steps: 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).

Images