Syringe unit for reusable injection devices

Abstract

The invention relates to a disposable syringe unit (2) for an injection device (1), which is adapted to be releasably attached to a reusable drive unit (3) of the injection device. The syringe unit (2) comprises: a pre-filled syringe comprising a reservoir and an injection needle (18); and a syringe holder (30) for holding the pre-filled syringe (15). The syringe unit further comprises: a cover member (20) guided by the guide means (31) thereby being movable along the longitudinal axis relative to the syringe holder (30) between a cover position in which the injection needle (18) is covered and a retracted position in which the injection needle (18) protrudes from the cover member (20); and a cap (10) releasably attached to the distal end of the cover member (20) or the syringe holder (30). In addition to the pre-filled syringe, the syringe unit (30) comprises no more than three separate components in total.

Description

Technical Field

[0001] The present invention relates to a drug delivery device or a medicament delivery device for injecting, delivering, administering, infusing or dispensing substances and / or liquids such as insulin, hormone preparations or vaccines. It starts with an injection device comprising a reusable drive unit and a disposable syringe unit configured for releasably attaching to the drive unit. Background Art

[0002] There are a variety of diseases that require routine treatment through subcutaneous administration of medicaments, and many drug delivery devices have been developed to support patients in the accurate and controllable delivery of a certain amount of drugs during self-administration. Delivery devices include injection devices that are removed from the injection site after each medication event or drug delivery process and infusion devices with cannulas or needles that remain in the patient's skin for a long time.

[0003] For example, diabetes can be treated by self-administration of insulin or its derivatives with the aid of a variable-dose insulin injection pen. The injection pen device generally has an elongated device body defining a longitudinal main device axis. An automatic injection device has a motor or drive spring for biasing a plunger rod and displacing a piston in a container barrel, wherein the drive spring may have to be manually loaded or tightened before injecting a dose. Manually energized delivery drives require a user to manually provide energy to move the piston, for example by applying a distal force component to the injection device.

[0004] The dose of medicament to be injected can typically be selected manually by turning a dose knob and observing the actual dialed dose from a dose window or display of the insulin pen. The dose is dispensed by inserting a needle into a suitable portion of human skin and by manually moving a piston or pressing a release button of the automatic injection device. The automatic injection device may include an electronic dose dial mechanism for automatically setting the dose.

[0005] It is also known to use an auto-injector with a syringe. An auto-injector generally comprises a body for housing the syringe and a drive mechanism for moving the plunger of the syringe upon actuation of the auto-injector. The drive mechanism typically comprises a drive source such as a motor or a strong spring for moving a transfer element (e.g. a rod) acting on the plunger of the syringe.

[0006] For safety and hygiene reasons, it is desirable that the needle does not protrude from the housing of the autoinjector except for the time when the needle is being used to inject a medicament. Therefore, the autoinjector moves the needle out of the housing for injection and back into the housing after the injection, or the housing provides a needle guard that can be moved to unhood the needle for injection and that can be moved back into the needle covering position after the injection.

[0007] Most auto-injectors are constructed as single-use devices, which combine both the syringe and the drive mechanism in the same housing. For hygienic reasons, such devices are usually disposable.

[0008] Disposable auto-injectors including electric actuators or electronic controllers require an energy source, usually in the form of batteries. However, in this case, the auto-injector should not be disposed of in conventional waste, but must undergo special disposal or recycling, which is an additional burden for the patient. In addition, disposing of batteries, motors and / or electronics after a single use is a waste of resources and increases the cost of the auto-injector.

[0009] In order to meet the need of handling and disposing of auto-injector parts in different ways, semi-reusable auto-injectors have been developed. Such auto-injectors typically include a reusable drive unit and a disposable syringe unit that can be releasably coupled to the drive unit. The drive unit usually includes a drive mechanism and electronics, while the syringe unit includes a syringe with a needle and a needle covering sleeve. Therefore, the user can discard the syringe unit when the syringe unit is empty or after use, and can load a new syringe unit for the drive unit for an upcoming injection.

[0010] WO 2010 / 076569 discloses a reusable autoinjector in which an injector unit is coupled to a drive unit by a bayonet connection. Once the cam of the drive unit is inserted into a slot in the injector unit housing, the cover sleeve is unlocked and can be moved to unhood the needle for injection. The injector unit comprises a unit housing, a shield, a syringe holder and two springs biasing the shield to a covering position.

[0011] WO 2021 / 069106 discloses an automatic injector comprising a disposable injector unit and a reusable drive unit. In addition to a syringe barrel with a rigid needle shield, the injector unit comprises a syringe holder, a syringe holder support tube, a syringe holder arm, a box housing, a sensor sleeve, an outer shield tube, and a box cap mounted on the distal end of the injector unit.

[0012] WO 2012 / 145685 further discloses a reusable autoinjector having a disposable or single-use cartridge and a reusable drive unit. The cartridge comprises an outer housing, an inner sleeve, a shield remover, a removable cover and a locking cap that locks the syringe to the inner sleeve. Summary of the invention

[0013] It is an object of the present invention to provide a semi-reusable injection device with simplified manufacturing, handling and reduced waste.

[0014] This object is achieved by a disposable syringe unit or an injection device according to the independent claim. Preferred embodiments are evident from the dependent claims.

[0015] The present invention relates to a disposable or single-use syringe unit (or reservoir unit) for an injection device, which is configured for releasable attachment to a reusable drive unit of the injection device. According to the present invention, the syringe unit consists of: a prefilled syringe comprising a reservoir and an injection needle (18) which is permanently connected to the reservoir and which is optionally covered by a needle shield in a transport state; - a syringe holder (30) for holding a prefilled syringe (15), the syringe holder (30) comprising a guide means (31) and defining a longitudinal axis; a covering member (20) guided by a guide device (31) so as to be movable relative to the syringe holder (30) along the longitudinal axis between a covering position in which the injection needle (18) is covered and a retracted position in which the injection needle (18) is exposed and protrudes from the covering member (20); - a cap (10) which is releasably attached to the distal end of the covering member (20) or the syringe holder (30); apart from the prefilled syringe (including the syringe elements), the syringe unit (30) comprises in total no more than three separate components.

[0016] The syringe elements may be an injection needle separately connected to a glass syringe barrel, a piston movably arranged inside the syringe barrel, and a needle shield directly mounted to the metal injection needle in an unused or transport state.

[0017] This means that according to the invention the syringe unit comprises or consists of a total of a maximum of three separate parts (the prefilled syringe with syringe element is not counted) made of plastic or metal or both plastic and metal, which are preferably produced separately.

[0018] Since the syringe unit includes no more than three parts in addition to the pre-filled syringe, the manufacture, assembly, handling and storage of the syringe unit are simplified compared to syringe units having more parts. Therefore, the reduced number of parts can help reduce the overall production cost and reduce the complexity of the syringe unit.

[0019] Besides this, the number of discarded parts and thus the waste of the reusable injection device concept can be reduced, which is advantageous from an environmental point of view.

[0020] The disposable syringe unit is part of a semi-disposable or semi-reusable injection device. Thus, the syringe unit is not operable without a reusable drive unit of the injection device. In order to prepare the injection device for injection, the user has to attach or connect the syringe unit to the drive unit. The drive unit may comprise a drive device adapted to dispense liquid medicine from a syringe held inside the syringe unit once the syringe unit is attached to the drive unit.

[0021] The injection device may be a manual or automatic injection device. Automatic devices or auto-injectors typically include an automatic drive device, such as an elastic element (e.g. a pre-tensioned spring) or an electric motor, to drive a dispensing member to dispense liquid medicine from a syringe. Manual injection devices include a manual drive, such as a dispensing button that must be pressed by a user to move the dispensing member in a dispensing direction.

[0022] The covering member or needle cover is movable along the longitudinal axis and guided by the syringe holder. The covering member may be implemented as a shield or a sleeve or a sleeve-shaped element, which is adapted to cover or enclose the needle of the prefilled syringe mounted inside the syringe holder. The movement of the needle cover allows switching between a safety state, in which the needle is covered and does not protrude from the device housing, and an injection state, in which the needle is uncovered and exposed or protrudes from the housing.

[0023] In a preferred embodiment, the covering member is the outermost component of the disposable syringe unit. This means that the syringe unit does not comprise any outer casing or housing but only a removable covering member. This provides a simple design.

[0024] The syringe holder, the covering member and the cap are preferably plastic parts. The term "separate" means that the parts can be handled independently of each other before assembly and are preferably produced separately and independently from the other parts. This does not exclude that the parts can be connected when assembling the syringe unit. The parts can be connected to each other, for example, by snap fit or threading.

[0025] As stated above, prefilled syringes with their possible needle shield (often called rigid needle shield, RNS) are not counted, since the syringe is usually inserted and fixed to the preassembled syringe unit at a later stage. Likewise, possible labels, stickers or labels attached to the external surface of one of the syringe unit components are not counted as separate components.

[0026] In the present context, the terms "substance", "drug", "medicament" or "drug" will be understood to include any flowable medical formulation suitable for controlled administration by a device such as, for example, a cannula or a hollow needle, and include liquids, solutions, gels or fine suspensions containing one or more medically active ingredients. A medicament may be a composition comprising a single active ingredient, or a premixed or co-formulated composition in which more than one active ingredient is present in a single container. Drugs include drugs such as peptides (e.g., insulin, insulin-containing drugs, GLP-1-containing drugs or derivative or similar preparations), proteins and hormones, active ingredients derived from or harvested from biological sources, hormone- or gene-based active ingredients, nutritional formulations, enzymes and other substances in both solid (suspended) or liquid form, as well as polysaccharides, vaccines, DNA, RNA, oligonucleotides, antibodies or parts of antibodies, and appropriate basic substances, auxiliary substances and carrier substances.

[0027] The term "distal" means the direction or end of the drug delivery device carrying the injection needle or injection cannula, whereas the term "proximal" means the opposite direction or end pointing away from the needle or cannula.

[0028] The term "injection system" or "syringe" refers to a device that is removed from the injection site after each dosing event or drug delivery procedure, while the term "infusion system" refers to a device with a cannula or needle that remains in the patient's skin for an extended period of time, such as several hours.

[0029] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. For example, "an arm" does not exclude the fact that there may be two arms that functionally or structurally achieve the purpose of the "arm". The fact that certain elements or steps are recited in different claims should not exclude the existence of further meaningful combinations of these elements or steps.

[0030] Preferably, the syringe holder, the covering sleeve and the cap are individually injection molded thermoplastic parts. This means that the syringe holder, the covering sleeve and the cap are not made of elastomeric materials. In contrast, the piston or the stopper arranged inside the glass barrel of the syringe can be made of elastomeric materials (such as rubber). Such a piston or stopper is a syringe element.

[0031] Injection molded components allow cost effective production of syringe unit components, especially in high volume production.

[0032] The syringe is preferably arranged immovably in the syringe holder after assembly. This means that the syringe does not move relative to the syringe holder during injection, which means that the user must insert or penetrate the injection needle into the injection site by manual insertion force.

[0033] The syringe generally comprises a cylindrical barrel made of glass and an injection needle made of steel that is inseparably connected to the barrel. In addition, the syringe may comprise a rigid needle shield that is directly mounted to the injection needle when the syringe is produced and that prevents access to the needle before removing the rigid needle shield.

[0034] Therefore, a syringe with a barrel, an injection needle and a rigid needle shield is produced as a unit which can be mounted inside a syringe holder.

[0035] In a preferred embodiment, apart from the syringe with its syringe elements (piston, needle, rigid needle shield mounted directly on the needle in the transport state), the syringe unit comprises only plastic parts, and more preferably, the syringe unit comprises only injection-moulded thermoplastic parts (apart from the syringe and its syringe elements). This means that the syringe unit does not have any metal parts such as springs, clamps etc. This facilitates production and contributes to a cost-effective design.

[0036] Optionally, the syringe holder comprises at least one radially protruding flexible arm having a free end portion, and wherein the covering member comprises at least one stop surface, and wherein the free end portion is adapted to engage the stop surface to hold the covering member in the covering position and thus prevent the covering member from moving out of the covering position towards the retracted position. This means that the arm allows the covering member to be reliably held in the covering position in which it covers the injection needle. Furthermore, by movement of the arm or the free end portion, the covering member can be unlocked and thus allows quick unlocking of the covering member so that it can be retracted to expose the injection needle.

[0037] The stop surface may, for example, be arranged on a ridge or a projection and is preferably arranged on or inside the covering member housing.

[0038] In a preferred embodiment, at least one arm is integrally formed in the syringe holder. This means that the arm is integral with the syringe holder. This allows efficient production and handling, since the syringe holder and the arm can be produced from one single injection-moulded plastic part.

[0039] Advantageously, the end portion of at least one arm engages at least one stop surface in the non-deflected position of the arm and the end portion disengages from the ridge in the deflected state of the arm, thereby allowing the cover member to move out of the cover position towards a retracted position in which the injection needle is exposed. The deflectable arm allows for quick and reliable locking or unlocking of the cover member.

[0040] In a preferred embodiment, the cover member includes a machine readable code attached to the surface of the cover member. The code includes identification information specific to the syringe unit. An external code reader can read information from the code, and based on the read identification information, the syringe unit and preferably the drug inside the syringe can be identified. The identification information may include data about the syringe, the drug, the volume, and the expiration date or injection instructions of the drug contained inside the syringe.

[0041] The external code reader may be an external device, or it may be in the drive unit and adapted to read the code once the injector unit is attached to the drive unit.

[0042] The machine-readable code may be implemented in the form of an optical code or a code readable based on an electromagnetic field. Examples of optical codes are object identifier codes (OID), QR codes, bar codes, color codes, and optical patterns. Examples of electromagnetic field-based codes are radio frequency identification (RFID) tags or near field communication (NFC) tags.

[0043] The code may be attached to the outer surface of the covering member, for example by means of a label or sticker comprising the code. Alternatively, the code may be on the inner surface of the covering member or integrally formed in the wall of the covering member as an electromagnetic tag or chip.

[0044] In a preferred embodiment, the covering member is a sleeve. The syringe holder is then arranged concentrically inside the sleeve. Thus, if the covering member is not blocked or held in the covering position, the covering sleeve can be moved along the longitudinal axis outside and relative to the syringe holder. The sleeve form allows a compact design.

[0045] Preferably, the covering sleeve comprises a first radial opening or openings. Thus, the arm of the syringe holder is accessible from the outside through the first opening. Thus, the arm can be actuated through the opening to move or release the arm, which in turn allows respectively unlocking the covering member from the covering position or locking the covering member in the covering position.

[0046] Furthermore, the syringe holder preferably comprises a radially extending protrusion or rim for holding the syringe unit by the reusable unit when the syringe unit is attached or connected to the drive unit.The sleeve preferably comprises a second radial opening, wherein the protrusion or rim is accessible from the outside through the second opening.

[0047] Thus, the syringe unit may be retained by a clamp or retaining arm extending through the second opening in the cover member sleeve.

[0048] The guiding means of the syringe holder comprises a longitudinal groove or a longitudinal spline on the outer surface, and the cover sleeve comprises the other of the longitudinal groove or the longitudinal spline on the inner surface. Therefore, the cover sleeve is reliably guided by the spline and the groove and can be moved along the longitudinal axis.

[0049] The splines may be implemented as protrusions or ridges or dovetails.The guiding means may alternatively be implemented as a guide rail and a clamp adapted to engage the guide rail.

[0050] The present invention also relates to an injection device comprising a disposable syringe unit as described above and a reusable drive unit. The reusable drive unit may comprise a plunger rod and a drive for moving the plunger rod in a dispensing direction to dispense the drug from the syringe. The syringe unit can be releasably attached to the drive unit.

[0051] As mentioned above, the injection device may be a manual injection device requiring user force to drive a plunger rod to dispense the drug, or alternatively the injection device may be an automatic injection device comprising an automatic drive, for example in the form of a biased spring member or an electric motor.

[0052] The drive unit may further comprise flexible retaining arms which engage radially extending protrusions or rims of the syringe holder if the syringe unit is attached to the drive unit.The flexible retaining arms allow the syringe unit to be releasably attached to the drive unit.

[0053] In a preferred embodiment, the cover member can be locked to the syringe holder in the covering position and the cover member can be unlocked by relative movement between the syringe unit and the drive unit.The syringe unit can be moved manually by a user or automatically by an automatic drive of the drive unit.

[0054] Preferably, the injection device is a semi-reusable (or semi-disposable) autoinjector.The automatic drive may comprise an electric motor adapted to drive a plunger rod to dispense the drug from the syringe. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments illustrated in the accompanying drawings, in which:

[0056] Figure 1 Depicting a perspective view of a semi-reusable autoinjector according to the present invention;

[0057] Figure 2 Depicted from Figure 1 An exploded view of the injector unit of the auto-injector;

[0058] Figure 3 depicts a cross-sectional view of a drive unit of an autoinjector;

[0059] Figure 4 depicts the drive unit with the syringe unit inserted, and

[0060] Figure 5 Depicts a cross-sectional view of an autoinjector with the injector unit locked to the drive unit.

[0061] The reference numerals used in the drawings and their main meanings are listed in summary form in the list of drawings. In principle, identical components have the same reference numerals in the drawings. DETAILED DESCRIPTION

[0062] In this specification, the term "distal" refers to the side where the injection needle is located. Figures 1 to 5 The term "proximal" refers to the opposite side or rear end of the device and is on the right-hand side in the figures.

[0063] Figure 1 A perspective view of a drug delivery device of a first embodiment of the present invention is shown in the form of a semi-reusable auto-injector 1. The auto-injector 1 comprises a disposable syringe unit 2 and a reusable drive unit 3. Figure 1 As shown in FIG. 1 , the drive unit 3 has an elongated housing defining a longitudinal axis and comprises a button 4 at a proximal end thereof.

[0064] The structural features of the injector unit and the drive unit will be described in detail below. Subsequently, the functioning of the semi-reusable autoinjector 1 will be explained.

[0065] Figure 2 Depicts an exploded view of the injector unit 2. Figure 2 As shown in the figure, the syringe unit 2 comprises a syringe holder 30, a cover sleeve 20 coaxially arranged around the syringe holder 30 and movable relative to the syringe holder along the longitudinal axis, a label 25 wrapped around the cover sleeve 20, a cap 10 and a prefilled syringe 15, which comprises a liquid drug and a rigid needle shield 17 on the injection needle. The syringe holder 30, the cover sleeve 20 and the cap 10 are separately injection molded plastic parts.

[0066] A prefilled syringe 15 having a barrel made of glass is rotatably and axially fixed inside a sleeve-shaped syringe holder 30. For this purpose, the syringe holder 30 comprises a clamping element (not shown) which presses on the outer surface of the syringe barrel, and the distal shoulder of the syringe abuts against a bearing surface 34 inside the syringe holder 30 (see Figure 4 ).like Figure 2As shown in , the syringe holder 30 also characteristically has a longitudinal guide rail 31 for covering the sleeve 20 on its exterior, so that the covering sleeve 20 can be displaced relative to the syringe holder 30 only in the longitudinal direction. In addition, the syringe holder 30 includes two radially deflectable locking elements in the form of locking arms 32 arranged on opposite sides of the syringe holder 30. In the initial state, the locking arms 32 are in a non-deflected state and a locked position, and prevent the movement of the covering sleeve 20 relative to the syringe holder 30 in the proximal direction. Therefore, the covering sleeve 20 shields or covers the injection needle of the syringe 15 in the covering position. For this purpose, the free end of the locking arm 32 abuts against a stop surface (not shown) inside the covering sleeve 20. As will be described below, once the locking arm 32 deflects radially inwardly, the covering sleeve 20 can be pushed proximally. The syringe holder 30 also includes two relatively arranged and radially protruding ridges 33 at the proximal end of the syringe holder 30, which are used to engage with the clamping arm 61 ( Figure 4 ) join.

[0067] The cover sleeve 20 has a non-circular cross section in a plane perpendicular to the longitudinal axis. This means that the two sides of the cover sleeve are flat. The cover sleeve comprises a first lateral opening 21 for accessing the locking arm 32 and a proximal second opening 22 for accessing the ridge 33 from the outside. The label 25 wrapped around the cover sleeve 20 comprises a machine-readable label (not shown) in the form of an RFID or QR code 26 identifying the injector unit 2.

[0068] At the distal end of the covering sleeve 20, the cap 10 is releasably attached by a snap-fit ​​connection. The cap 10 comprises two deflectable elements or tongues 11 on two sides and a protrusion on each side that engages in a corresponding recess 23 in the covering sleeve 20 for a snap-fit ​​connection. Alternatively, the cap 10 may have an elliptical shape in a plane perpendicular to the longitudinal axis, wherein inside the elliptical shape, the protrusion engages the recess in the covering sleeve. The ellipse may be deformed into a circular shape to release the protrusion from the recess 23. The release of the snap fit will be described below with respect to the uncapping of the syringe unit 2. The cap 10 comprises in its interior a sleeve-shaped retainer 12 that can be connected to a rigid needle shield (RNS) 17 of a syringe 15, so that if the cap is released from the needle cover, the RNS 17 is removed together with the cap 10.

[0069] The syringe 15 inside the syringe holder 30 has a barrel made of glass, and a movable piston 16 ( Figure 4 ). Injection needle 18 ( Figure 4) is non-releasably connected to the distal end of the syringe barrel. In the unused state, the injection needle 18 is covered by the RNS 17. Once the syringe 15 is mounted to the syringe holder 30, the RNS 17 is in turn fixedly connected to the cap 10 axially and radially through the holder 12.

[0070] Figure 3 A cross-sectional view depicting a first embodiment of a drive unit 3. The cut of the cross-sectional view extends along the longitudinal axis of the device. The drive unit 3 comprises a housing 80 comprising an outer housing cover and a mechanical sleeve 83 inside the cover, the mechanical sleeve 83 comprising a radial wall 84 which divides the drive unit 3 into a distal part and a proximal part. The mechanical sleeve 83 is immovably connected to the housing 80. A distal housing insert 81 is inside the housing 80 and distal to the dividing wall 84, while a proximal housing insert 85 is located proximal to the wall 84. The distal housing insert 81 and the proximal housing insert 85 are immovably connected to the housing 80. Furthermore, the drive unit 3 comprises an opening in its distal side, which is suitable for accommodating the proximal part of the injector unit 2.

[0071] The gripper sleeve 60 is arranged inside the distal housing part and is guided by the distal housing insert 81 and is movable relative to the housing 80 along the longitudinal axis. The trigger sleeve 50 is arranged coaxially with the gripper sleeve 60. The cover sleeve connector 45 is likewise located inside the trigger sleeve 50 and is biased in the distal direction by the cover sleeve spring 46. The spring abuts the cover sleeve connector 45 on its distal end and abuts the radial wall 84 of the mechanical sleeve 83 on its proximal end. The sleeve-shaped syringe connector 47 is coaxially arranged inside the cover sleeve connector 45 and is biased distally by the syringe connector spring 48 coaxially located inside the cover sleeve spring 46 and is supported proximally by the wall 84. The spring 46 ensures that the syringe connector 45 pushes the syringe 15 of the inserted syringe unit 2 in the distal direction.

[0072] The proximal housing portion houses a proximal housing insert 85, which supports and guides a sleeve-shaped trigger sleeve connector 51 that is movable along the longitudinal axis, a drive assembly having an electric motor 91, a pinion 92 and a gear 93 connecting the motor 91 to the threaded rod 41, a battery 94, the threaded rod 41, and a plunger rod 40 threadedly connected to the threaded rod 41. The proximal housing portion also houses an electronic module (not shown) having a controller that is configured to control the electronic motor 91 and provide information to the user via a display or LED (not shown) or a communication module (not shown). The trigger sleeve connector 51 is fixedly and non-movably connected to the trigger sleeve 50 and is pressed distally onto the proximal end of the plunger rod 40 by the trigger sleeve spring 53. The plunger rod 40 is non-rotatably guided by the mechanical sleeve 83 and includes on its distal end a spring adapted to engage the piston 16 during dispensing (see Figure 4 ) flange 49.

[0073] Inside the proximal housing part there is also an axially arranged detection pin (not shown) which can be axially moved by the cover sleeve connector 45. The detection pin is connected to and interacts with the TMR position sensor. Thus, the presence of the injector unit 2 inside the drive unit housing 80 can be detected via the detection pin and the position sensor which provides a corresponding signal to the controller of the electronic module.

[0074] The gripper sleeve 60 comprises two axially extending and deflectable clamping arms 61 having at their free distal ends a clamp 62 adapted to receive the ridge 33 of the syringe holder. When the syringe unit is inserted into the opening in the drive unit 3, the clamping arms 61 can be deflected radially outwards, allowing the clamps 62 to snap onto the ridge 33 of the syringe holder 30. The gripper sleeve 60 comprises on its exterior splines (not shown) extending in corresponding longitudinal grooves (not shown) in the distal housing insert 81, which guide the gripper sleeve 60 during axial movement relative to the housing 80. Furthermore, each clamping arm 61 provides support for an axially aligned gripper sleeve spring 64, which biases the clamping arm 61 in a holding position.

[0075] The trigger sleeve 50 is axially guided by and displaceable relative to the holder sleeve 60 and the distal housing insert 81. For this purpose, the trigger sleeve 50 comprises longitudinal guide rails (not shown) which engage longitudinal grooves (not shown) in both the distal housing insert 81 and the holder sleeve 60. Figure 3As can be seen in the figure, the trigger sleeve 50 includes a trigger arm 54 arranged oppositely, which includes a guide surface or an inclined contact surface 55 on its proximal free end 56. The trigger arm 54 can be deflected radially inward when the contact surface 55 contacts the mating guide surface or mating inclined contact surface 82 of the distal housing insert 81. As mentioned above, the trigger sleeve 50 is also non-movably connected to the trigger sleeve connector 51 in the proximal housing part. When the trigger sleeve connector 51 is biased by the trigger sleeve spring 53, the trigger sleeve 50 is also biased in the distal direction. The trigger sleeve connector 51 is in turn connected to the plunger rod via a rib 52, which engages the proximal shoulder of the plunger rod 40, so that axial movement of the plunger rod 40 in the proximal direction also causes the trigger sleeve 50 to move proximally.

[0076] exist Figure 3 In the state shown in , the drive unit 3 is ready to be loaded with the syringe unit 2. The controller displays the current state to the user via the display by showing a message like "Syringe unit inserted" or via a green or red LED.

[0077] To prepare the autoinjector 1 for injection, the user attaches the injector unit 2 to the drive unit 3. The electronics in the drive unit 3 are switched from an inactive state or sleep mode to an active mode. Alternatively, the user may press a button 4 to activate the electronics.

[0078] Figure 4 Depicts a cross-sectional view of a drive unit 3 with an inserted injector unit 2. The injector unit 2 has been inserted with its proximal end portion into the distal opening of the drive unit housing 80. Figure 4 In the state shown in FIG, the proximal ridge 33 of the syringe holder 30 snaps into the recess of the clamp 62 of the clamp sleeve clamp arm 61. Thus, the syringe unit 2 is held in the drive unit 3 by the clamp arm 61. However, in Figure 4 In the state shown in , the syringe unit 2 can still be pulled out of the drive unit housing by overcoming the holding force. Therefore, if the user pulls the syringe unit 2 in the distal direction, the syringe holder 30 with the syringe 15 first moves in the distal direction relative to the cover sleeve 20 until it stops, and then the cover sleeve 20 also moves distally. This makes the inclined release surface 27 of the cover sleeve 20 contact the inclined mating surface 65 of the clamp arm 61. If the cover sleeve 20 is further pulled in the distal direction, the clamp arm 61 deflects radially outward via the release surface 27 and the mating surface 65. Therefore, the ridge 33 of the syringe holder 30 is released from the clamp arm 61, and the syringe unit 2 can be removed from the drive unit 3. Outside the drive unit 3, the clamp arm 61 can deflect radially outward and release the ridge 33.

[0079] This means that Figure 4 In the state shown in , the injector unit 2 is held inside the drive unit 3 , but is not yet locked inside the drive unit 3 .

[0080] Figure 5 An automatic injector 1 in a locked state without a cap is depicted. When the injector unit 2 is inserted as described above, the injector unit 2 moves the detection pin, and thus the position sensor detects the movement and automatically sends a signal to the controller in the electronic module, which detects the presence of the injector unit 2 inside the drive unit housing. A code reader (not shown) in the form of an NFC reader or a QR code reader inside the drive unit 3 reads the RFID or QR code 26 of the injector unit 2. Subsequently, the controller of the drive unit sends the read drug information from the read code 26 to an external device to verify the drug or medicine with predetermined information. Alternatively, the controller compares the read drug information from the code 26 with predetermined information stored in a memory inside the drive unit 2.

[0081] In the case of successful drug authentication, the controller receives an enable signal (from an external device or from an internal comparison). The controller then controls the electric motor 91 to rotate the threaded rod 41 to move the trigger sleeve 50 a short distance of several millimeters in the proximal direction. Such movement of the trigger sleeve 50 is achieved by a kinematic chain as described below.

[0082] The motor 91 rotates the pinion 92, and the gear 93 transmits the rotation to the threaded rod 41, which in turn moves the non-rotating plunger rod 40 in the proximal direction. When the trigger sleeve connector 51 is connected to the proximal shoulder of the plunger rod 40 via its rib 52, the proximal shoulder of the plunger rod 40 causes the trigger sleeve connector 51 to move, and thus the trigger sleeve 50 is also displaced in the proximal direction.

[0083] The proximal movement of the trigger sleeve 50 brings the inclined contact surface 55 of the trigger arm 54 into contact with the mating inclined contact surface 82 of the distal housing insert 81. When the trigger sleeve 50 moves further in the proximal direction, the trigger arm 54 is forced to deflect radially inwardly as the two inclined surfaces 55, 82 slide along each other. The free end 56 of the deflected trigger arm 54 contacts the locking arm 32 of the syringe holder 30 again. Subsequently, the trigger arm 54 deflects the locking arm 32 radially inwardly and thus moves the locking arm 32 out of the locking position. As a result, the locking arm 32 no longer engages the stop surface of the cover sleeve 20 and thus allows the cover sleeve 20 to move out of the covering position and move in the proximal direction inside the housing 80 relative to the syringe holder 30 and relative to the drive unit housing 80.

[0084] At the same time, the trigger sleeve arm 54 deflected radially inwardly abuts against a distal stop surface (not shown) of the syringe holder 30 and thereby locks the syringe holder 30 relative to the trigger sleeve 50, so that the movement of the trigger sleeve 50 is transmitted to the syringe unit 2. Figure 5 ), the injector unit 2 can no longer be pulled out of the drive unit 3.

[0085] The controller displays the locked state to the user via the display. Since the cap is still mounted on the distal end of the covering sleeve 20 in this state, the next step is to remove the cap, which can be initiated by pressing the button 4. The controller then drives the motor 91 to move the trigger sleeve 50 an additional short distance of 1 to 5 mm in the proximal direction and immediately moves the same distance backward in the distal direction. Since the trigger arm 54 fixes the syringe unit 2 relative to the trigger sleeve 50, the syringe unit 2 (and the clamp sleeve 60) also moves back and forth. The proximal movement of the syringe unit 2 with the cap 10 relative to the drive unit housing 80 compresses the trigger sleeve spring 53. Figure 5 In FIG. 8 , it can be seen that the trigger sleeve connector 51 is moved a distance in the proximal direction (see the distance between the ridge 52 and the proximal end of the mechanical sleeve 83). The proximal movement of the syringe unit 2 relative to the housing 80 further causes the deflectable visor 11 of the cap 10 ( Figure 2 ) abuts against the triangular protrusion 86 on the distal end of the drive unit housing 80 ( Figure 3 ). As a result, if the injector unit 2 is moved further into the drive unit housing 80, the projection 86 deflects the cap visor 11 and thereby releases the snap-fit ​​connection of the cap 10 with the covering sleeve 20. Thus, the cap 10 is removed. This results in Figure 5 Then, the controller moves the motor 91 in the opposite direction to move the plunger rod 40 backward by a short distance of 1 to 5 mm without unlocking the syringe unit 2. The syringe unit 2, the trigger sleeve 50, and the holder sleeve 60 move backward due to the spring force of the trigger sleeve spring 53.

[0086] The autoinjector 1 is now uncapped and ready for injection. The controller displays a corresponding notification on the display.

[0087] As a next step, the user places the distal end of the cover sleeve 20 onto the injection site and pushes the auto injector 1 toward the injection site. This causes the cover sleeve 20 to move proximally from the distal cover position into the drive unit housing 80 (pushing on the skin) and compresses the cover sleeve spring 46, which biases the cover sleeve 20 in the distal direction via the cover sleeve connector 45. When pushing on the skin, the cover sleeve connector 45 moves proximally, and therefore the detection pin moves further proximally. This further movement is detected by another TMR position sensor, which triggers the controller in the electronic module to start injection. This means that the controller drives the electric motor 91 in the dispensing direction, and therefore rotates the threaded rod 41, and thus moves the plunger rod 40 in the distal direction. When the trigger sleeve spring 53 biases the trigger sleeve connector 45 on the proximal shoulder of the plunger rod 40 (alternatively, the trigger sleeve connector 45 is immovably connected to the plunger rod 40), the trigger sleeve 50 also moves in the distal dispensing direction. The distal flange 49 of the plunger rod 40 moves the piston 16 inside the syringe 15 in the distal direction and thereby dispenses the liquid drug out of the syringe 15 through the injection needle.

[0088] The distal movement of the plunger rod 40 causes the trigger sleeve to move in the distal direction to its initial position via the trigger sleeve connector 51. This means that the trigger arms 54 can move radially outward back to their non-deflected positions. However, when the cover sleeve 20 is in the retracted proximal position, the locking arms 32 are prevented from moving back to the locked position.

[0089] The controller displays a hold time indicating the period of time that the user must hold the auto-injector 1 to the injection side after the injection to ensure that the drug is fully administered and absorbed. The controller may display a countdown counter that informs the user of the remaining hold time. Once the hold time has elapsed, a notification is shown to the user that the auto-injector may be removed from the injection site. Alternatively, the end of the hold time may be indicated by an LED only.

[0090] When the user removes the autoinjector 1 from the injection site, the compressed cover sleeve spring 46 may be released and it may therefore move the cover sleeve 20 distally back to the needle covering position.

[0091] During dispensing, the trigger sleeve 50 moves to its initial distal and unlocked position, in which the trigger arms 54 are no longer deflected and therefore do not contact the locking arms 32 of the syringe holder 30. This means that the locking arms 32 are no longer fully pressed radially inwards and, when the cover sleeve 20 moves to its covering position, the locking arms 32 can switch back to their locking position, in which the free ends of the arms 32 abut against contact surfaces inside the cover sleeve 20, thereby locking the cover sleeve 20 in its covering position, as in Figure 4 In the state shown in .

[0092] Furthermore, since the trigger arm 54 is no longer deflected and therefore does not contact the distal stop surface of the syringe holder 30, the entire syringe unit 2 can be pulled out of the drive unit housing 80 by the user. The user can now discard the syringe unit 2 and the drive unit 3 is ready to be loaded with a new syringe unit.

[0093] Although the present invention has been described in detail in the drawings and the foregoing description, such description is considered to be illustrative or exemplary rather than restrictive. By studying the drawings, the disclosure and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claimed invention.

[0094] List of Figures 1 Auto-injectors 50 Trigger sleeve 2 Injector unit 51 Trigger socket connector 3 Drive unit 52 Raised Ridge 4 Button 53 Trigger sleeve spring 10 cap 54 Trigger arm 11 Deflectable tongue 55 Arm tilted contact surface 12 Fixture 56 Free end 15 Prefilled Syringes 60 Clamp sleeve 16 piston 61 Clamping arm 17 Rigid needle shield 62 Fixture 18 Injection needle 64 Gripper sleeve spring 20 Cover sleeve 65 Pairing release surface 21 First opening 80 case 22 Second opening 81 Distal housing insert 23 Depression 82 Contact surface 25 Signage 83 Mechanical sleeve 26 RFID Tags 84 wall 27 Release Surface 85 Proximal Housing Insert 30 Syringe Holder 86 Protrusion 31 Longitudinal guide rail 91 Electric Motor 32 Locking arm 92 Small gear 33 Raised Ridge 93 gear 34 Support surface 94 Battery 40 Plunger rod 41 Threaded rod 45 Cover sleeve connector 46 Cover sleeve spring 47 Syringe Connectors 48 Syringe Connector Spring 49 Flange

Claims

1. A disposable syringe unit (2) for an injection device (1), adapted to be releasably attached to a reusable drive unit (3) of the injection device (1), the syringe unit (2) comprising: a prefilled syringe comprising a reservoir and an injection needle (18) which is permanently connected to the reservoir and which is optionally covered by a needle shield in a transport state; - a syringe holder (30) for holding the prefilled syringe (15), the syringe holder (30) comprising guiding means (31) and defining a longitudinal axis; a covering member (20) which is guided by the guiding means (31) and is thereby movable relative to the syringe holder (30) along the longitudinal axis between a covering position in which the injection needle (18) is covered and a retracted position in which the injection needle (18) protrudes from the covering member (20); - a cap (10) releasably attached to a distal end of the covering member (20) or the syringe holder (30); Features Apart from the pre-filled syringe, the syringe unit (30) comprises a total of no more than three separate components.

2. A disposable syringe unit (2) according to claim 1, wherein: The syringe holder (30), the covering sleeve (20) and the cap (10) are injection-moulded thermoplastic parts.

3. A disposable syringe unit (2) according to claim 1 or 2, wherein: The syringe is immovably arranged in the syringe holder (30) after assembly.

4. A disposable syringe unit (2) according to any one of claims 1 to 3, wherein: The syringe (15) includes a cylindrical barrel made of glass and an injection needle (18) made of steel inseparably connected to the barrel.

5. A disposable syringe unit (2) according to any one of claims 1 to 4, wherein: The syringe unit (2) without the pre-filled syringe has no metal parts.

6. A disposable syringe unit (2) according to any one of claims 1 to 5, wherein: The syringe holder (30) comprises a radially protruding flexible arm (32) having a free end portion, and wherein the covering member (20) comprises a stop surface, and wherein the free end portion is adapted to engage the stop surface to retain the covering member (20) in the covering position.

7. A disposable syringe unit (2) according to claim 6, wherein: The flexible arm (32) is integrally formed in the syringe holder (30).

8. A disposable syringe unit (2) according to claim 6 or 7, wherein: The end portion engages the stop surface in a non-deflected position of the arm (32), and the end portion disengages from the stop surface in a deflected state of the arm (32), thereby allowing the covering member (20) to move out of the covering position.

9. A disposable syringe unit (2) according to any one of claims 1 to 8, wherein: The cover member (20) includes a machine-readable code (26) attached to a surface of the cover member (20), the code including injector unit-specific identification information.

10. A disposable syringe unit (2) according to any one of claims 1 to 9, wherein: The covering member (20) is a sleeve, and wherein the syringe holder (30) is arranged concentrically inside the sleeve.

11. A disposable syringe unit (2) according to claim 10, wherein: The sleeve comprises a first radial opening (21), wherein the arm (32) of the syringe holder (30) is accessible from the outside through the first opening (21).

12. A disposable syringe unit (2) according to claim 11, wherein The syringe holder (30) comprises a radially extending protrusion (33) for holding the syringe unit (2) by the reusable unit (3), and wherein the sleeve comprises a second radial opening (22), wherein the protrusion (33) is accessible from the outside through the second opening (22).

13. A disposable syringe unit (2) according to any one of claims 10 to 12, wherein: The guiding means (31) of the syringe holder (30) comprises a longitudinal groove or a longitudinal spline on an outer surface, and wherein the sleeve comprises the other of the longitudinal groove or the longitudinal spline on an inner surface.

14. Injection device (1) comprising a disposable syringe unit (2) according to any one of claims 1 to 13 and a reusable drive unit (3), the reusable drive unit (3) comprising a plunger rod (40) and a drive (91) for moving the plunger rod (40) in a dispensing direction for dispensing a drug from the syringe (15), wherein: The injector unit (2) is releasably attachable to the drive unit (3).

15. Injection device (1) according to claim 14, wherein The injection device (1) is a semi-reusable autoinjector and wherein the drive comprises an electric motor (91).

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