Compressed gas automatic syringe

Abstract

The drug delivery device includes a housing; a container disposed within the housing and configured to contain a drug; a plunger slidably disposed within the container; a plunger rod configured to push the plunger through the container to administer the drug when the container contains the drug; and a gas canister configured to move with the plunger rod and to contain compressed gas, and configured to release the compressed gas to drive the plunger rod to administer the drug from the distal end of the container.

Description

TECHNICAL FIELD

[0001] (Cross-Reference to Related Applications) This application claims the benefit of U.S. Provisional Application No. 63 / 586,999, filed on September 29, 2023, the entire contents of which are hereby incorporated by reference in their entirety into the present specification.

[0002] The present disclosure relates to medical injection.

BACKGROUND ART

[0003] Injection typically refers to the act of administering a liquid (e.g., a drug) into the body tissue of a patient. Injecting a medicament into a patient allows the medicament to be absorbed relatively quickly.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEMS

[0004] The present system and method can provide relatively large volume injections of relatively high viscosity medicaments. For example, in some embodiments, the auto-injector described herein provides a relatively easy-to-use device for injecting a 5 milliliter (mL) volume of medicament having a viscosity of 3000 centipoise (cP) without requiring relatively large effort from a user. In general, the gas canister included in the auto-injector provides sufficient injection force to inject the medicament at a desired rate to meet a desired delivery time. Using a gas canister to provide a large injection force reduces the force applied by the user to fully deliver the injection. In some embodiments, the gas canister is contained within the plunger rod to reduce the volume of the auto-injector. In general, an auto-injector with reduced volume is easier for a user to manage and handle than a more bulky auto-injector. In some embodiments, the auto-injector includes an interlock that prevents firing of the auto-injector until a desired time or operation, for example, until a needle is attached to the distal end of the syringe of the auto-injector.

[0005] In one embodiment, a drug delivery device provided herein includes a housing; a container disposed within the housing and configured to contain a drug; a plunger slidably disposed within the container; a plunger rod configured to push the plunger so that it passes through the container in order to administer a drug when the container contains the drug; and a gas canister configured to move with the plunger rod and to contain compressed gas, the gas canister configured to release the compressed gas in order to drive the plunger rod to administer a drug from the distal end of the container.

[0006] Some embodiments provided herein incorporate one or more of the following features:

[0007] In some embodiments, the container holds 1 to 10 mL of the drug.

[0008] In some embodiments, the container holds 2 to 8 mL of the drug.

[0009] In some embodiments, the container holds 4 to 6 mL of the drug.

[0010] In some embodiments, the container holds 5 mL of the drug.

[0011] In some embodiments, the container holds 3 to 10 mL of the drug.

[0012] In some embodiments, the drug has a viscosity in the range of 1 to 3000 cP.

[0013] In some embodiments, the agent has a viscosity in the range of 1 to 2250 cP.

[0014] In some embodiments, the drug has a viscosity in the range of 1750 to 2750 cP.

[0015] In some embodiments, the drug has a viscosity in the range of 2000 to 2200 cP.

[0016] In some embodiments, the drug has a viscosity of at least 2200 cP.

[0017] In some embodiments, the drug delivery device includes a button configured to activate an element configured to puncture a gas canister, which is configured to release compressed gas once punctured.

[0018] In some embodiments, the drug delivery device includes an interlock, which is configured to prevent an element from puncturing a gas canister while the interlock is in the locked position.

[0019] In some embodiments, the housing includes a notch configured to receive the interlock when the interlock is in the unlocked position.

[0020] In some embodiments, when the interlock is in the unlocked position, the notch allows the interlock to flex radially.

[0021] In some embodiments, when the interlock is in the locked position, the housing prevents the interlock from flexing radially.

[0022] In some embodiments, the drug delivery device includes a needle configured to be attached to the distal end of a container.

[0023] In some embodiments, the interlock is configured to move to the unlocked position when the needle is attached to the drug delivery device.

[0024] In some embodiments, the needle is 20-21 gauge.

[0025] In some embodiments, the needle is less than 25 gauge.

[0026] In some embodiments, the needle is 18 to 25 gauge.

[0027] In some embodiments, the needle has a length of at least 1.5 inches.

[0028] In some embodiments, the needle has a length of 1.5 to 2 inches.

[0029] In some embodiments, the needle has a length of 0.75 to 2.25 inches.

[0030] In some embodiments, the medicament delivery device includes a needle guard configured to selectively cover the needle.

[0031] In some embodiments, the housing includes at least one vent hole.

[0032] In some embodiments, the gas canister is attached to the plunger rod.

[0033] In some embodiments, the gas canister is disposed within the plunger rod.

[0034] In another embodiment, provided herein is a method of delivering a medicament contained within a container, comprising piercing a gas canister to release compressed gas to drive a plunger rod to administer the medicament, wherein the gas canister is configured to move together with the plunger rod.

[0035] Some of the embodiments provided herein include one or more of the following features.

[0036] In some embodiments, piercing the gas canister comprises pressing a button to actuate an element configured to pierce the gas canister.

[0037] In some embodiments, the method includes attaching a needle to the distal end of the container.

[0038] In some embodiments, attaching the needle to the container moves the interlock from a locked position to an unlocked position, the interlock preventing the button from moving in the locked position and allowing the button to move in the unlocked position.

[0039] In some embodiments, attaching the needle to the container involves screwing the needle hub onto the threads of the container holder.

[0040] In some embodiments, the method includes venting compressed gas from the housing through one or more vents.

[0041] In some embodiments, the gas canister is attached to a plunger rod.

[0042] In some embodiments, the gas canister is located within the plunger rod.

[0043] In one embodiment, a kit is provided herein that includes a drug delivery device according to any one of the embodiments described above. The kit also includes a needle.

[0044] In some embodiments, the needle is configured to be attached to a drug delivery device.

[0045] In some embodiments, the kit includes multiple needles.

[0046] In some embodiments, the needles have different sizes.

[0047] In some embodiments, the needles have different shapes.

[0048] In some embodiments, these needles are configured to be attached to a drug delivery device.

[0049] Details of one or more embodiments of the subject matter described herein are given in the accompanying drawings and the following description. Other features, purposes, and advantages of the subject matter will become apparent from the description and drawings, as well as the claims. [Brief explanation of the drawing]

[0050] [Figure 1] An example of an automatic syringe is shown. [Figure 2] An example of the internal components of an automatic syringe is shown. [Figure 3] This shows the gas canister located inside the plunger. [Figure 4A] This shows an interlock to prevent accidental discharge of an automatic syringe. [Figure 4B] This shows an interlock to prevent accidental discharge of an automatic syringe. [Figure 4C] This shows an interlock to prevent accidental discharge of an automatic syringe. [Figure 5] This shows the needle attached to the automatic syringe. [Figure 6A] This shows the unlocked interlock that enables the automatic syringe to fire. [Figure 6B] This shows the unlocked interlock that enables the automatic syringe to fire. [Figure 7A] This shows the movement of the interlock to enable the automatic syringe to dispense. [Figure 7B] This shows the movement of the interlock to enable the automatic syringe to dispense. [Figure 7C] This shows the movement of the interlock to enable the automatic syringe to dispense. [Figure 8A] This shows the firing of an automatic syringe. [Figure 8B] This shows the firing of an automatic syringe. [Figure 9] This shows a needle safety cap for covering the needle. [Figure 10] This is a table showing the relationship between delivery time and force for high-viscosity drugs.

[0051] Similar reference numbers and names in various drawings refer to the same elements. [Modes for carrying out the invention]

[0052] In some embodiments, the systems and methods provided herein provide relatively large-volume injections of relatively high-viscosity drugs, resulting in a relatively large injection force while reducing the force applied by the user to adequately deliver the injection. In some embodiments, the systems and methods also prevent the auto-injector from firing until a desired time or operation, for example, until the needle is attached to the auto-injector.

[0053] Figure 1 shows an exemplary auto-syringe 100, which includes a housing 102, a button 104 on the proximal end 106 of the housing 102, and a needle hub 108 attached to the distal end 110 of the housing 102. The needle hub 108 includes a needle safety device 112 that can selectively cover the needle 114 of the needle hub 108. For example, a user can bend the needle safety device 112 around a hinge 116 to move the needle safety device 112 to cover the needle 114. The needle 114 is covered by a needle cap 118, which is removed by the user before use of the auto-syringe 100. In some embodiments, the button 104 is located elsewhere on the auto-syringe. For example, the button 104 may be a side button located somewhere between the proximal end 106 and the distal end 110 of the housing 102. In some embodiments, the button is a lever that rotates relative to the housing 102 to activate the device. In some embodiments, the housing 102 includes a flange configured to accommodate the user's fingers.

[0054] The housing 102 includes a label 122 that provides information about the auto-injector 100. For example, in some embodiments, the label 122 includes drug information such as the type of drug, the size of the dose, the time of delivery of the dose, the expiration date of the drug, the batch or lot number, information identifying the auto-injector 100 as a single-use auto-injector, and company information. Optionally, the housing 102 does not include a label 122.

[0055] The housing 102 also includes a window 120 through which the user can see inside the auto-injector 100, for example, the drug contained in the container of the auto-injector 100 (see below). In some embodiments, the window 120 helps the user determine whether the auto-injector 100 has been used. Before using the auto-injector 100, the user can look through the window 120 to determine whether there is drug inside the auto-injector 100, for example, to determine that the auto-injector has not been used. In some embodiments, during use of the auto-injector 100, the user can look through the window 120 to determine whether the volume of drug inside the auto-injector 100 has decreased. In some embodiments, after using the auto-injector 100, the user can look through the window 120 to determine whether there is no drug inside the auto-injector 100, for example, to determine that the auto-injector 100 has been used. In some embodiments, the user can look at the plunger rod through the window 120 to determine that the auto-injector 100 has been used. In some embodiments, the user determines that the automatic syringe has been used because button 104 remains in the used position.

[0056] In some embodiments, the auto-injector 100 is used for intramuscular injections, which are injected into the patient's muscle. Intramuscular injections may require longer and / or thicker needles than subcutaneous injections, which are directed into the adipose tissue between the patient's skin and muscle. As an example, in some embodiments, the needle 114 is 20 gauge and 1.5 inches long. As another example, in some embodiments, the needle 114 is 27 gauge and 0.5 inches long. Injecting a drug through a longer needle may require a relatively greater injection force compared to injecting a drug through a shorter needle, for example, when the drug is a high-volume, high-viscosity drug. Similarly, injecting a drug through a thinner needle may require a relatively greater injection force compared to injecting a drug through a thicker needle. Intramuscular injection of high-volume, high-viscosity drugs can be relatively difficult, for example, because it requires a relatively large injection force and delivery time. In some embodiments, the auto-injector 100 (and other auto-injectors described herein) provides sufficient injection force to inject relatively high-volume, relatively high-viscosity drugs through a needle configured for intramuscular injections within the delivery time described below. Needles can have various gauges for intramuscular injection (e.g., 20–21 gauge, less than 25 gauge, 18–25 gauge, etc.). Needles can also have various lengths for intramuscular injection (e.g., at least 1.5 inches, 1.5–2 inches, 1–2 inches, 0.75–2.25 inches, etc.). In some embodiments, the kit includes an auto-injector 100 and multiple needles. The multiple needles may be of different sizes, different gauges, different shapes, etc., and the user can select the needle suitable for a particular injection. The user can attach the selected needle to the auto-injector 100 and use the auto-injector 100 as described herein.

[0057] Figure 2 shows an exemplary auto-injector 200, which can provide a relatively large injection force for injecting relatively large volumes of relatively high-viscosity drugs through a needle 234 configured for intramuscular injection (similar to, for example, the auto-injector 100 in Figure 1). The auto-injector 200 includes a housing 202, a container 204 held within the housing 202, a plunger 206 slidably positioned within the container 204, a piston 208, and a gas canister 210. The container 204 is held within a container holder 212 connected to the housing 202. The container 204 can contain a drug (not shown), and the auto-injector 200 can be operated by a user to administer the drug from the container 204. For example, a user can puncture the gas canister 210 and release compressed gas from within the gas canister 210 by pressing a button 214 on the proximal end 226 of the housing 202. The compressed gas may include, for example, argon, carbon dioxide, krypton, xenon, etc. Button 214 is biased proximal by button spring 218. Button 214 acts on a launch pin 216 that punctures the end of the gas canister 210, as will be described later. The compressed gas expands, driving piston 208 against plunger 206 and through container 204. As plunger 206 moves distally through container 204, the drug is administered through needle 234. When the drug is a relatively high viscosity drug (e.g., 3000 cP), plunger 206 can generate a relatively large force (e.g., 380 Newtons (N), which may be a time-averaged force) to administer the drug from needle 234 within a desired delivery time (e.g., less than 50 seconds). Rapidly expanding gas (e.g., released from gas canister 210) can generate the force required for, for example, intramuscular injection. For example, in some embodiments, a rapidly expanding gas, such as that described with respect to the automatic syringe 200, can produce a greater force than would be produced by an automatic syringe using a drive spring.

[0058] For example, in some embodiments, the container 204 has an internal volume for holding 5 mL of drug. In some embodiments, the container 204 accommodates drugs of various volumes (e.g., 1-10 mL of drug, 2-8 mL of drug, 4-6 mL of drug, 3-10 mL of drug, etc.).

[0059] In the automatic syringe 200, the gas canister 210 is located within the piston 208. For example, the piston 208 includes a plunger rod portion 220 and a canister holder portion 222. The plunger rod portion 220 is configured to interact with the plunger 206 to drive the plunger 206 through the container 204. This interaction may involve inserting the distal end of the plunger rod portion 220 into a defined gap within the plunger 206. The canister holder portion 222 provides a recess for receiving the gas canister 210 within the canister holder portion 222. A seal 224 seals the connection between the plunger rod portion 220 and the canister holder portion 222, and also seals the other end of the canister holder portion 222. When the gas canister 210 releases compressed gas, the seal 224 prevents the released gas from escaping from other parts of the piston 208. The release gas is directed proximal so that the force of the expanding gas drives the piston 208 distally to administer the drug. The pressure vessel 228 is connected to the container holder 212 and holds the piston 208 aligned with the container 204. The release gas expands within the pressure vessel 228, driving the piston 208 and plunger 206 into the container 204.

[0060] By placing the gas canister 210 inside the piston 208, the volume of the auto-syringe 200 is reduced. For example, if the gas canister were not placed inside the piston, the housing would need to extend beyond the piston 208 by at least the length of the gas canister 210 to provide sufficient space for the gas canister 210. In contrast, since the length of the gas canister 210 is incorporated into the piston 208, the housing 202 does not need to extend beyond the piston 208 by the additional length of the gas canister 210. In some embodiments, the gas canister is placed partially (for example, at least partially) inside the piston. Reducing the volume of the auto-syringe 200 is advantageous because a reduced-volume auto-syringe is easier for the user to manage and handle than a larger, bulkier auto-syringe.

[0061] The automatic syringe 200 also includes a needle hub 230 that is detachably connected to the distal end of the container 204. The needle hub 230 includes a needle safety device 232 that can selectively cover the needle 234 of the needle hub 230 (similar to, for example, the needle hub 108 in Figure 1). The needle 234 is covered by a needle cap 236, which is removed by the user before use of the automatic syringe 200. The needle hub 230 also includes a needle hub seal 238 that seals the connection between the needle hub 230 and the container 204. The needle hub seal 238 can prevent leakage between the container 204 and the needle hub 230.

[0062] In some embodiments, the auto-injector cap 240 is connected to the distal end of the housing 202 before the needle hub 230 is attached to the distal end of the container 204. For example, to use the auto-injector 200, the user can remove the auto-injector cap 240 from the distal end of the auto-injector 200 and then connect the needle hub 230 to the distal end of the container 204. The user can then administer the drug by pressing the button 214 as described above. In some embodiments, the auto-injector cap 240 includes a Luer tip cap 242 that seals the distal end of the container 204. The Luer tip cap 242 reduces (e.g., prevents) leakage from the distal end of the container 204 before use of the auto-injector 200. In some embodiments, the Luer tip cap 242 is configured to be releasably attached to a corresponding Luer tip located on the distal end of the container 204.

[0063] The automatic syringe 200 may also include an interlock 244 to prevent the button 214 from being pressed before the needle hub 230 is attached to the container 204. The interaction between the interlock 244 and the button 214 is described in more detail below. Before use of the device, the interlock 244 is biased distally by an interlock spring 246 and is in the locked position. For example, the interlock spring 246 may be provided between the housing 202 and the interlock 244 to bias the interlock 244 distally. The interlock 244 prevents the button 214 from being pressed while the interlock 244 is in the locked position, as will be described further below. Because the interlock 244 prevents the button 214 from being pressed, the discharge pin 216 cannot puncture the gas canister 210 to administer the drug. When the needle hub 230 is attached to the container 204, the needle hub 230 moves the interlock 244 against the biasing force of the interlock spring 246 to the unlocked position. The interlock 244 allows the button 214 to be pressed while the interlock 244 is in the unlocked position, as will be described later. Since the interlock 244 allows the button 214 to be pressed (after the needle hub 230 has been attached to the container), the launch pin 216 can puncture the gas canister 210 in order to administer the drug through the needle hub 230.

[0064] Figure 3 shows an example of a pressure vessel 300. The pressure vessel 300 may be similar to the pressure vessel 228 in Figure 2. The pressure vessel 300 is connected to a vessel holder 302 and holds a piston 304 aligned with the vessel 306. The piston 304 includes a gas canister 308 located within the piston 304. For example, the piston 304 includes a plunger rod portion 310 and a canister portion 312. The plunger rod portion 310 is configured to interact with the plunger 314 to drive the plunger 314 through the vessel 306. The canister portion 312 provides a recess for receiving the gas canister 308 within the canister portion 312.

[0065] In some embodiments, the pressure vessel 300 includes one or more piston seals 316 that seal the connection between the plunger rod portion 310 and the canister portion 312. The piston seals 316 can be made of, for example, nitrile butadiene rubber (e.g., having a hardness of 70 Shore A). The piston seals 316 prevent gas released from the gas canister 308 from escaping through the connection between the plunger rod portion 310 and the canister portion 312. In some embodiments, one or more piston seals 316 are static seals. For example, static seals can create a seal between parts that do not move relative to each other. In some embodiments, there is no seal between the plunger rod portion 310 and the canister portion 312. For example, the plunger rod portion 310 and the canister portion 312 can be formed from a single part such that there is no connection between the plunger rod portion 310 and the canister portion 312 through which gas can escape. If the plunger rod portion 310 and the canister portion 312 are two connected parts, one or more piston seals 316 can prevent gas from leaking out through the connection between the plunger rod portion 310 and the canister portion 312.

[0066] In some embodiments, the pressure vessel 300 also includes one or more lip seals 318 that seal the area between the piston 304 and the pressure vessel 300. The lip seals 318 can be formed of, for example, nitrile butadiene rubber (e.g., having a Shore A hardness of 75 or 85). The lip seals 318 prevent gas from leaking out from around the piston 304 into the vessel 306. By keeping the expanding gas proximal to the piston 304, the piston 304 is driven distally. If gas is allowed to leak around the piston 304, the piston 304 may not be driven distally enough to administer the drug. The lip seals 318 can keep the expanding gas proximal to the piston 304 by sealing the area between the piston 304 and the pressure vessel 300. In some embodiments, one or more lip seals 318 are dynamic seals. For example, dynamic seals can create a seal between parts that move relative to each other.

[0067] In some embodiments, the pressure vessel 300 also includes one or more launch pin seals 320 that seal the area between the pressure vessel 300 and the launch pin 322 that perforates the gas canister 308. The launch pin seals 320 can be formed of, for example, an elastomer (e.g., a fluoroelastomer such as Viton® having a hardness of 70 Shore A). The launch pin seals 320 can be formed of rubber. The launch pin seals 320 prevent gas from leaking out through the rear of the pressure vessel 300. By keeping the expanding gas inside the pressure vessel 300, a defined volume is provided for the gas to expand within it. By providing a defined volume for the gas to expand within it, the force exerted by the expanding gas on the piston 304 is controlled. For example, if the expanding gas is not limited to a defined volume, the gas may not exert the desired injection force on the piston 304. The launch pin seal 320 can keep the expanding gas within a defined volume of the pressure vessel 300 by sealing the area between the pressure vessel 300 and the launch pin 322. In some embodiments, one or more launch pin seals 320 are dynamic seals.

[0068] Figures 4A to 4C show the automatic syringe 200 with the interlock 244 in the locked position, and the cap 240 that is removed by the user before use of the automatic syringe 200. By removing the cap 240 from the automatic syringe 200, it becomes possible to connect a needle hub (not shown) to the automatic syringe 200, as described above.

[0069] The interlock 244 is biased distally and locked by an interlock spring 246. For example, the interlock spring 246 can be provided between the housing 202 and the interlock 244 to bias the interlock 244 distally. The interlock 244 prevents the button 214 from being pressed while the interlock 244 is in the locked position. For example, the interlock 244 includes an interlock snap 248, which interacts with a button snap 250 to prevent the button 214 from being pressed. For example, when a user attempts to press the button 214, as indicated by arrow F in Figure 4B, the interlock snap 248 interacts with the button snap 250 to prevent the button 214 from moving far enough for the firing pin 216 to penetrate the gas canister 210. For example, Figure 4C shows a magnified view of the firing pin 216 in a state where it cannot penetrate the gas canister 210.

[0070] In some embodiments, the button 214 can move only a relatively short distance (e.g., 2 mm) while the interlock 244 is in the locked position. This relatively short distance is still not sufficient for the firing pin 216 to penetrate the gas canister 210. The button spring 218 can bias the button 214 proximal away from the interlock 244.

[0071] In some embodiments, the pressure vessel 228 includes a projection 252 which, while the interlock 244 is in the locked position, biases the button snap 250 inward to move away from the interlock snap 248 and prevents it from passing through the interlock snap 248. In some embodiments, the button snap 250 is not flexible and cannot be biased inward, and the projection 252 is optional.

[0072] Figure 5 shows the needle hub 230 attached to the automatic syringe 200. For example, a user can attach the needle hub 230 to the automatic syringe 200. By attaching the needle hub 230 to the automatic syringe 200, the interlock can be moved from the locked position to the unlocked position, as described above. In the illustrated example, the needle hub 230 is rotated and attached to the automatic syringe 200, for example, by a screw connection. In some embodiments, the needle hub 230 is attached to the automatic syringe by other connections, such as a bayonet connection or a snap connection. The needle hub 230 can be connected to the container 204 of the automatic syringe 200, as described above. The rotation of the needle hub 230 is indicated by the clockwise arrow 254. In some embodiments, the needle hub 230 is rotated 90° to attach the needle hub 230 to the automatic syringe 200. The needle hub 230 can be designed to rotate by various amounts (e.g., 180°, 270°, 360°, etc.) in order to attach the needle hub 230 to the automatic syringe 200.

[0073] Figures 6A and 6B show the auto-injector 200 with the interlock 244 moved to the unlocked position by attaching the needle hub 230. As described above, by attaching the needle hub to the auto-injector, the interlock can be moved proximal to the unlocked position. The proximal movement of the interlock 244 is indicated by arrow 258. When the interlock 244 is in the unlocked position, the button 214 can be pressed, as a result the discharge pin 216 punctures the gas canister 210 to administer the drug. As shown in Figure 6B, the user can press the button 214, as a result the button snap 250 of the button 214 passes through the interlock snap 248 of the interlock. The pressing of the button is indicated by arrow 260. When the button 214 is pressed, the button spring 218 is pressed, and the button snap 250 passes through the interlock snap 248. The interlock snap 248 flexes radially outward through the notch 256 in the housing 202, allowing the button snap 250 to pass through the interlock snap 248. The radial flexion of the interlock snap 248 is indicated by arrow 262. When the interlock 244 is moved proximal to the unlocked position, the interlock snap 248 aligns with the notch 256 in the housing 202, allowing the interlock snap 248 to flex outward. As the interlock snap 248 flexes radially outward through the notch 256, the button snap 250 has space to pass through the interlock snap 248, and as a result, the firing pin 216 can puncture the gas canister 210. For example, Figure 6B shows the firing pin 216 puncturing the gas canister 210. As described above, the expanding gas can provide a large injection force for injecting large volumes of high-viscosity drugs through a needle configured for intramuscular injection.

[0074] Figures 7A to 7C show the interlock snap 248, button snap 250, and notch 256 within the housing 202 when the interlock 244 is in the locked position and when the interlock 244 is in the unlocked position. Figure 7A shows the interlock snap 248, button snap 250, and notch 256 when the interlock 244 is in the locked position, for example, before the needle hub 230 is attached to the automatic syringe 200. The interlock snap 248 is not aligned with the notch 256 in the housing 202 while the interlock 244 is in the locked position. Therefore, the housing 202 prevents the interlock snap 248 from bending radially outward. Since the interlock snap 248 cannot bend radially outward, the interlock snap 248 prevents the button snap 250 from moving distally.

[0075] Figure 7B shows the interlock snap 248, button snap 250, and notch 256 when the interlock 244 is in the unlocked position. For example, when the needle hub 230 is attached to the autosynergy 200, the interlock 244 moves proximal from the locked position to the unlocked position. The proximal movement of the interlock 244 to the unlocked position aligns the interlock snap 248 with the notch 256 in the housing 202. When the interlock snap 248 is aligned with the notch 256, the interlock snap 248 can bend radially outward. The angled engagement between the button snap 250 and the interlock snap 248 causes the interlock snap 248 to bend radially outward. The outward bending of the interlock snap 248 is indicated by arrow 262. Since the interlock snap 248 aligns with the notch 256, the housing 202 does not prevent the interlock snap 248 from flexing radially outward. Because the interlock snap 248 can flex radially outward, the interlock snap 248 does not prevent the button snap 250 from moving distally.

[0076] Figure 7C shows the interlock snap 248, button snap 250, and notch 256 as the button snap 250 passes through the interlock snap 248. Since the needle hub 230 is connected to the auto-injector 200, the interlock snap 248 is aligned with the notch 256. The button snap 250 has passed through the interlock snap 248, and the movement of the button snap 250 is indicated by arrow 264. The interlock snap 248 is now proximal to the button snap 250 due to the movement of the button snap 250. The interlock snap 248 prevents the button snap 250 from moving proximal after injection has started. By preventing the button snap 250 from moving proximal, it prevents the button 214 from moving proximal after injection has started. The engagement between the interlock snap 248 and the button snap 250 is not an oblique engagement, and therefore the button snap 250 does not bend the interlock snap 248 radially outward. As the button snap passes through the interlock snap 248, the launch pin 216 punctures the gas canister 210, as described above. The expanding gas can provide a large injection force for injecting a large volume of high-viscosity medication through a needle configured for intramuscular injection, as described above.

[0077] Figures 8A and 8B show the auto-injector 200 that administers the drug after the button snap 250 passes the interlock snap 248. The launch pin 216 punctures the gas canister 210 as described above and shown in Figure 8A. Puncturing the gas canister 210 expands the compressed gas into the pressure vessel 228, driving the piston 208 distally and administering the drug as described above. The rapid expansion of the compressed gas provides sufficient injection force to inject a large volume of high-viscosity liquid within the desired injection time. Figure 8B shows the movement of the piston 208 into the vessel 204 for drug administration. The movement of the piston 208 is represented by arrow 268.

[0078] In some embodiments, the automatic syringe 200 includes a drug initiation click mechanism 266 that generates an audible sound when the discharge pin 216 punctures the gas canister 210. For example, the click mechanism 266 may emit an audible sound when the piston 208 compresses the click mechanism 266. Emitting an audible sound can serve, for example, to warn the user that the gas canister 210 has been punctured. In some embodiments, the click mechanism 266 may emit an audible sound when the dose has been fully administered. In some embodiments, the click mechanism 266 may continuously click during dose administration.

[0079] In some embodiments, the auto-injector 200 includes several vents 270 that allow compressed gas to exit the auto-injector 200 after the dose has been fully administered. For example, the pressure vessel 228, interlock 244, and housing 202 may include vents 270. The position of the vents 270 allows compressed air to push the piston 208 through the vessel 204, and the vents 270 do not allow gas to leak during administration. For example, the vents 270 are not accessible to the expanding gas until the piston moves to the end-of-dose distal position. Until the piston 208 reaches the end-of-dose distal position, the gas cannot reach the vents 270.

[0080] Figure 9 shows the needle hub 230 after the dose has been administered, as described above. In some embodiments, the user may move the needle safety device 232 by bending it around the hinge to cover the needle 234. The movement of the needle safety device 232 to cover the needle 234 is represented by arrow 272. Covering the needle 234 with the needle safety device 232 can prevent accidental needle stick injuries after the dose has been administered.

[0081] Figure 10 shows a table of exemplary forces and delivery times for delivering high-volume, high-viscosity drugs using the automatic syringe 200 described above. High-viscosity drugs can have a viscosity of, for example, 2250 cP. In some embodiments, drugs can have a range of viscosities (e.g., 1-3000 cP, 1-2250 cP, 1750-2750 cP, 2000-2500 cP, at least 2200 cP, etc.). The viscosity of the drug can also vary with temperature. For example, a drug can have a higher viscosity at 18°C ​​than at 28°C. In one example, a drug can have a viscosity of 2220 cP at 18°C, 1330 cP at 23°C, and 800 cP at 28°C. The force provided by the compressed gas can be designed to satisfy the desired delivery time for varying viscosities of the drug. The values ​​in Figure 10 are illustrative values ​​for a drug with a viscosity of 2220 cP at 18°C, 1330 cP at 23°C, and 800 cP at 28°C. The values ​​were calculated for a needle length of 2 inches, a needle gauge of 20 gauge, a drug volume of 5 mL, and a container radius of 5.93 mm. Relatively low injection force (e.g., average force of 140 N) results in a maximum delivery time of 142 seconds (e.g., when the drug has a viscosity of 2220 cP at 18°C) and a minimum delivery time of 50 seconds (e.g., when the drug has a viscosity of 800 cP at 28°C). Relatively moderate injection force (e.g., average force of 230 N) results in a maximum delivery time of 83 seconds (e.g., when the drug has a viscosity of 2220 cP at 18°C) and a minimum delivery time of 30 seconds (e.g., when the drug has a viscosity of 800 cP at 28°C). A relatively high injection force (e.g., an average force of 380 N) results in a maximum delivery time of 50 seconds (e.g., when the drug has a viscosity of 2220 cP at 18°C) and a minimum delivery time of 18 seconds (e.g., when the drug has a viscosity of 800 cP at 28°C). Therefore, if the desired maximum delivery time is 50 seconds, the gas canister needs to exert an average injection force of 380 N to meet the desired delivery time.

[0082] Several embodiments are described. However, it should be understood that various modifications can be made without departing from the spirit and scope of this disclosure. Therefore, other embodiments are also within the scope of the following claims.

Claims

1. A drug delivery device, Housing and A container arranged within the housing and configured to contain a drug, A plunger slidably disposed within the container, A plunger rod is configured to push the plunger so that it passes through the container, in order to administer the drug when the container contains the drug. A gas canister configured to move together with the plunger rod and to contain compressed gas, and configured to release the compressed gas in order to drive the plunger rod to administer the drug from the distal end of the container, A drug delivery device equipped with the following features.

2. The drug delivery device according to claim 1, wherein the container contains 1 to 10 mL of drug.

3. The drug delivery device according to claim 1 or 2, wherein the container contains 2 to 8 mL of drug.

4. The drug delivery device according to any one of claims 1 to 3, wherein the container contains 4 to 6 mL of drug.

5. The drug delivery device according to any one of claims 1 to 4, wherein the container contains 5 mL of drug.

6. The drug delivery device according to claim 1 or 2, wherein the container contains 3 to 10 mL of drug.

7. The drug delivery device according to any one of claims 1 to 6, wherein the drug has a viscosity in the range of 1 to 3000 cP.

8. The drug delivery device according to any one of claims 1 to 7, wherein the drug has a viscosity in the range of 1 to 2250 cP.

9. The drug delivery device according to any one of claims 1 to 8, wherein the drug has a viscosity in the range of 1750 to 2750 cP.

10. The drug delivery device according to any one of claims 1 to 9, wherein the drug has a viscosity in the range of 2000 to 2200 cP.

11. The drug delivery device according to any one of claims 1 to 10, wherein the drug has a viscosity of at least 2200 cP.

12. The system further comprises a button configured to activate an element configured to puncture the gas canister, The drug delivery device according to any one of claims 1 to 11, wherein the gas canister is configured to release the compressed gas when punctured.

13. A drug delivery device according to any one of claims 1 to 12, further comprising an interlock configured to prevent the element from puncturing the gas canister while the interlock is in the locked position.

14. The drug delivery device according to claim 13, wherein the housing comprises a notch configured to receive the interlock when the interlock is in the unlocked position.

15. The drug delivery device according to claim 14, wherein the notch allows the interlock to flex radially when the interlock is in the unlocked position.

16. A drug delivery device according to any one of claims 13 to 15, wherein the housing prevents the interlock from bending radially when the interlock is in the locked position.

17. The drug delivery device according to any one of claims 1 to 16, further comprising a needle configured to be attached to the distal end of the container.

18. The drug delivery device according to claim 17, wherein the interlock is configured to move to the unlocked position when the needle is attached to the drug delivery device.

19. The drug delivery device according to claim 17 or 18, wherein the needle is 20 to 21 gauge.

20. The drug delivery device according to claim 17 or 18, wherein the needle is less than 25 gauge.

21. The drug delivery device according to claim 17 or 18, wherein the needle is 18 to 25 gauge.

22. The drug delivery device according to any one of claims 17 to 21, wherein the needle has a length of at least 1.5 inches.

23. The drug delivery device according to any one of claims 17 to 21, wherein the needle has a length of 1.5 to 2 inches.

24. The drug delivery device according to any one of claims 17 to 21, wherein the needle has a length of 0.75 to 2.25 inches.

25. The drug delivery device according to any one of claims 17 to 24, further comprising a needle guard configured to selectively cover the needle.

26. The drug delivery device according to any one of claims 1 to 25, wherein the housing comprises at least one ventilation hole.

27. The drug delivery device according to any one of claims 1 to 26, wherein the gas canister is attached to the plunger rod.

28. The drug delivery device according to any one of claims 1 to 27, wherein the gas canister is located within the plunger rod.

29. A method for delivering a drug contained in a container, A method comprising driving a plunger rod to puncture a gas canister to release compressed gas for administering the drug, wherein the gas canister is configured to move together with the plunger rod.

30. The method according to claim 29, wherein perforating the gas canister includes pressing a button to activate an element configured to perforate the gas canister.

31. The method according to claim 29 or 30, further comprising attaching a needle to the distal end of the container.

32. Attaching the aforementioned needle to the container moves the interlock from the locked position to the unlocked position, The method according to claim 31, wherein the interlock prevents the movement of the button in the locked position and allows the movement of the button in the unlocked position.

33. The method according to claim 31 or 32, wherein attaching the needle to the container includes screwing the needle hub onto the threads of the container holder.

34. The method according to any one of claims 29 to 33, further comprising passing the compressed gas out of the housing through one or more vents.

35. The method according to any one of claims 29 to 34, wherein the gas canister is attached to the plunger rod.

36. The method according to any one of claims 29 to 35, wherein the gas canister is located within the plunger rod.

37. A drug delivery device according to any one of claims 1 to 28, A needle, A kit that includes the following:

38. The kit according to claim 37, wherein the needle is configured to be attached to the drug delivery device.

39. The kit according to claim 37, wherein the kit comprises a plurality of needles.

40. The kit according to claim 39, wherein the needles have different sizes.

41. The kit according to claim 39 or 40, wherein the needles have different shapes.

42. The kit according to any one of claims 37 to 41, wherein the needle is configured to be attached to the drug delivery device.

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