Injection device and system for transferring injection solutions

Abstract

Injection device (10), consisting of: - an injection solution container (30); - a piston (70), at least a part of which is slidably received by the injection solution container (30), wherein the piston (70) is displaceable relative to the injection solution container (30) in a distal direction in order to eject an injection solution contained in the injection solution container (30) from the injection solution container (30); - a first housing member (86) rotatable relative to the piston (70), a first metering surface (146) and a second metering surface (148) being formed on the first housing member (86), the second metering surface (148) being defined by a bottom surface of a recess (152) formed in the first metering surface (146); - a first piston stop mechanism (140) adapted to stop a displacement of the piston (70) relative to the injection solution container (30) in the distal direction in a first dosing position (P1), wherein the first piston stop mechanism (140) comprises a dosing element (144) attached to the piston (70) and adapted to bear against the first dosing surface (146); - a second piston stop mechanism (142) adapted to stop a displacement of the piston (70) relative to the injection solution container (30) from the first dosing position (P1) in the distal direction at a second dosing position (P2), wherein the second piston stop mechanism (142) comprises the dosing element (144) attached to the piston (70) and adapted to bear against the bottom surface of the recess (152) formed in the first dosing surface (146), wherein the first and second dosing positions (P1, P2) of the piston (70) are selected such that the piston (70), when displaced relative to the injection solution container (30) between the first dosing position (P1) and the second dosing position (P2), is adapted to dispense a desired dose of the injection solution contained in the injection solution container (30) from the injection solution container (30) emits; and - a locking arrangement (180) adapted to lock the first dosing surface (146) in its position relative to the dosing element (144) after the first dosing surface (146) has been moved relative to the dosing element (144) to release it from the dosing element (144).

Description

[0001] The invention relates to an injection device, in particular a microdose injection device, such as an ophthalmic injection device for intraocular use. Furthermore, the invention relates to a system for transferring an injection solution from a syringe into such an injection device.

[0002] Typically, an injection solution intended for medical treatment is stored in a syringe. The syringe contains a container for holding the injection solution and a plunger that can be moved relative to the container to expel the injection solution from the container. If the patient's medical treatment plan calls for the administration of a dose of the injection solution corresponding to the syringe's fill volume, or if the dosage of the injection solution is of secondary importance for the desired therapeutic effect, the injection solution can be administered to the patient directly from the syringe.However, if the medical treatment plan for a patient requires the administration of a dose of the injection solution that differs from the filling volume of the syringe and / or if precise dosing of the injection solution is required, the injection solution can be transferred from the syringe to an injection device before administration, which is used to finally inject the desired dose of the injection solution into the patient.

[0003] US 2002 / 052578 A1 describes an injection device for injecting a specific dose of medication from a cartridge. The injection device comprises a housing, a threaded piston rod that is linearly displaceable within the housing, and a displaceable nut that moves relative to the housing and engages the thread of the piston rod, allowing the nut to be screwed along the thread of the piston rod. The displacement of the nut along the piston rod determines the amount of medication to be injected by the injection device.

[0004] The invention is based on the object of providing an injection device that enables the precise and reliable administration of a microdose of an injection solution to a patient. Furthermore, the invention is based on the object of providing an injection solution transfer system for transferring an injection solution from a syringe to such an injection device. This object is achieved by an injection device according to claim 1 and an injection solution transfer system according to claim 15.

[0005] An injection device comprises an injection solution container. The injection solution container and the protective outer cylinder can be made of any suitable material or a combination of materials, including plastic or glass. Suitable plastics include, for example, cycloolefin polymers or cycloolefin copolymers. An example of a glass material can be borosilicate glass. Preferably, the glass material is tungsten-free. In one embodiment, the injection solution container can be uncoated. Uncoated means that the injection solution container contains no material other than the material from which the injection solution container is made. Alternatively, the injection solution container can have an internal coating. An internal coating is a coating on the inside of the injection solution container that comes into contact with the injection solution.Examples of such an internal coating include a silicone coating or a fluorocarbon film made of a modified ethylene-tetrafluoroethylene copolymer. The injection solution container may be silicone-free, substantially silicone-free, or contain a small amount of silicone as a lubricant. Preferably, the injection solution container is made of a sterile plastic material. Preferably, the injection solution container is made of a sterile plastic. Preferably, the injection solution container has no internal coating. In one embodiment, the injection solution container may comply with USP789.

[0006] The injection solution container can be designed in the form of an inner injection solution container contained within a protective outer cylinder. An injection solution container designed as an inner injection solution container can be formed integrally with the protective outer cylinder. The protective outer cylinder can be provided with a flange element in the region of its proximal end, which can serve to connect the protective outer cylinder and the inner injection solution container to a housing of the injection device. The housing of the injection device can, for example, have a correspondingly shaped and dimensioned receiving section for receiving the flange element and thus for fastening the protective outer cylinder and the inner injection solution container to the housing.

[0007] A distal end of the injection solution container of the injection device can be provided with a male part of a Luer cone, which can interact with a female part of a Luer cone. The female part of a Luer cone can, for example, be provided on a connection port of an adapter element of a filling adapter, which can be used to connect the injection device to a syringe containing an injection solution to be transferred from the syringe into the injection solution container of the injection device. With the aid of the Luer cone, a fluid-tight connection can be easily established between the distal end of the injection solution container of the injection device and the adapter element of the filling adapter.The outer cylinder of the injection device can be provided with a Luer connection in the region of its distal end, which can interact with a complementary Luer connection provided on the second connection port of the adapter element of the filling adapter, in particular in the region of its outer circumference. This also allows a reliable connection to be established between the outer cylinder of the injection device and the adapter element of the filling adapter.

[0008] The injection device further comprises a piston. The piston may be made of polycarbonate. At least a portion of the piston is slidably received within the injection solution container. The piston is displaceable relative to the injection solution container in a distal direction along a longitudinal axis of the piston to expel an injection solution contained in the injection solution container from the injection solution container. At its proximal end, which may protrude proximally from the injection solution container, the piston may carry an actuating button that can be depressed by a user to displace the piston relative to the injection solution container in a distal direction along the longitudinal axis of the piston. At its distal end, the piston may be provided with a tip element that can be attached to a piston rod.A coupling between the piston rod and the tip element can be achieved, for example, by the interaction of a tip barb provided at the distal end of the piston rod with a barb receptacle of the tip element. Furthermore, the tip element can be provided with a sealing element, which can be provided, for example, in the region of an outer peripheral surface of the tip element and which cooperates in a sealing manner with an inner peripheral surface of the injection solution container.

[0009] The injection device further comprises a first piston stop mechanism configured to stop displacement of the piston relative to the injection solution container in the distal direction at a first dosing position. The injection device further comprises a second piston stop mechanism configured to stop displacement of the piston relative to the injection solution container from the first dosing position in the distal direction at a second dosing position. The first and second dosing positions of the piston are selected such that, when the piston is moved relative to the injection solution container between the first and second dosing positions, it can eject a desired dose of the injection solution contained in the injection solution container from the injection solution container.

[0010] After filling the injection solution container with the injection solution to be administered to a patient, a user of the injection device can expel excess injection solution from the injection solution container by displacing the piston distally relative to the injection solution container until the piston reaches the first dosing position. Once the first dosing position is reached, the first piston stop mechanism stops further displacement of the piston in the distal direction.

[0011] This prevents the user from expelling too much injection solution from the injection solution container. The remaining injection solution contained in the injection solution container can then be administered to a patient by further advancing the plunger distally until the plunger reaches the second dosing position. Upon reaching the second dosing position, the second plunger stop mechanism stops further distal displacement of the plunger, thus preventing excessive injection solution from being administered to the patient.

[0012] The injection device enables the precise and reliable administration of a microdose of an injection solution to a patient. Furthermore, the injection device can be easily and conveniently handled by a user. The injection device is therefore particularly suitable for the treatment of pediatric patients. The injection device can, in particular, be designed in the form of an ophthalmic injection device for intraocular application.

[0013] In one embodiment, the injection device is filled with a dosage volume (i.e., the volume of injection solution to be administered to the patient) of about 1 µl to about 50 µl, preferably about 10 µl to about 20 µl, of an injection solution. In a preferred embodiment, the injection device is filled with a dosage volume of 5 µl, 10 µl, 20 µl, or 30 µl of an injection solution.

[0014] The injection device can be filled with any injection solution, e.g., an injectable drug. In one embodiment, the injection device is filled with an injectable drug containing an active ingredient suitable for the treatment of an eye disease. Examples of such eye diseases include retinopathy of prematurity, geographic atrophy, glaucoma, choroidal neovascularization, age-related macular degeneration (both wet and dry forms), macular edema secondary to retinal vein occlusion (RVO), including both branched RVO (bRVO) and central RVO (cRVO), choroidal neovascularization secondary to pathological myopia (PM), diabetic macular edema (DME), diabetic retinopathy, retinitis pigmentosa, Leber congenital amaurosis, Bietti crystal dystrophy, and proliferative retinopathy. In one embodiment, the drug comprises a biologically active ingredient.The biological agent may be an antibody (or a fragment thereof), a non-antibody protein, nucleic acids for gene therapy, or cellular material for cell therapy. In one embodiment, the pharmaceutical composition comprises a VEGF antagonist. Suitable VEGF antagonists include ranibizumab (Lucentis™), bevacizumab (Avastin™), brolucizumab (also known as RTH258), aflibercept (Eylea™, also known as VEGF-Trap Eye), conbercept (KH902 from Chengdu Kanghong Biotechnologies Co. Ltd, described as FP3 in WO2005 / 121176, the contents of which are hereby incorporated by reference), and the related glycoform KH906 or pazopanib (from GlaxoSmithKline).

[0015] In a preferred embodiment, the injection device is filled with 0.1 mg or 0.2 mg of ranibizumab in 20 µl of injection solution. In a particularly preferred embodiment, the injection device is filled with 20 µl of ranibizumab (0.2 mg) and is used for the treatment of retinopathy of prematurity.

[0016] In a preferred embodiment of the injection device, the first piston stop mechanism comprises a dosing element that is attached to the piston and can abut against a first dosing surface provided on a housing element. Alternatively or additionally, the second piston stop mechanism can comprise a dosing element that is attached to the piston and can abut against a second dosing surface provided on a housing element.

[0017] Preferably, the metering element of the first and / or second piston stop mechanism is formed integrally with the piston. For example, the metering element can be designed in the form of a rib that can protrude from a surface of an actuating button of the piston toward the inner solution container. In principle, it is conceivable for the injection device to comprise a first metering element associated with the first piston stop mechanism and a second metering element associated with the second piston stop mechanism. However, the injection device preferably comprises only one metering element, which is attached to the piston and associated with both the first and second piston stop mechanisms.A single dosing element may be configured such that, upon movement of the piston in the distal direction, it first abuts the first dosing surface when the piston reaches the first dosing position, and then, upon further movement of the piston from the first dosing position in the distal direction, it abuts the second dosing surface when the piston reaches the second dosing position.

[0018] The first and second dosing surfaces can be provided on different housing elements of the injection device. However, in a preferred embodiment of the injection device, the first and second dosing surfaces are both formed on a first housing element, i.e., on the same housing element of the injection device. The first and second dosing surfaces preferably run substantially parallel to one another, wherein the second dosing surface can be arranged offset in the distal direction parallel to the first dosing surface. A distance between the first and second dosing surfaces in the distal direction can correspond to a desired travel path of the piston in the distal direction between the first and second dosing positions.

[0019] By appropriately arranging the first and second dosing surfaces, the desired piston displacement between the first and second dosing positions and thus the desired injection solution dose ejected from the injection solution container when the piston is moved from the first to the second dosing position can be adjusted. The first and second dosing surfaces can extend substantially parallel to a contact surface of the dosing element. For example, the first and second dosing surfaces as well as the contact surface of the dosing element can extend substantially perpendicular to the longitudinal axis of the piston.

[0020] The first piston stop mechanism can be designed to provide a resistance force suitable for stopping the displacement of the piston in the first dosing position, but which can be overcome, e.g., by increasing the actuating force acting on the piston. However, in a particularly preferred embodiment of the injection device, the first piston stop mechanism is configured to provide a hard stop for the piston, i.e., it is configured to prevent the piston from being displaced distally relative to the injection solution container from the first dosing position without damaging the first piston stop mechanism.In particular, in the event that the first piston stop mechanism is designed as a hard stop for the piston, the injection device preferably further comprises a piston release mechanism which is designed to deactivate the first piston stop mechanism in order to release the piston and thus to enable a displacement of the piston relative to the injection solution container from the first dosing position in the distal direction, ie in the direction of the second dosing position.

[0021] The second piston stop mechanism can also be designed to provide a resistance force suitable for stopping the displacement of the piston in the second dosing position, but which can be overcome, for example, by increasing the actuating force acting on the piston. In a particularly preferred embodiment, however, the second piston stop mechanism is designed to provide a hard stop for the piston, i.e., it is designed to prevent the piston from being displaced distally relative to the injection solution container from the second dosing position without damaging the second piston stop mechanism. The dose of injection solution to be administered to a patient can thus be set particularly precisely.

[0022] Preferably, the piston release mechanism is designed to enable movement of the dosing element and / or the first dosing surface to release the dosing element from the first dosing surface. The movement of the dosing element and / or the first dosing surface can be manually triggered by a user of the injection device. In a particularly preferred embodiment of the injection device, it is sufficient for a user to move only the first dosing surface to release the dosing element from the first dosing surface. Consequently, it is not necessary for the user to trigger movement of the piston to activate the piston release mechanism. For example, only the housing element with the first dosing surface can be moved to activate the piston release mechanism, while the piston can remain in its position, which simplifies the use of the injection device.

[0023] The piston release mechanism can be designed to enable a rotational movement of the dosing element and / or the first dosing surface in order to release the dosing element from the first dosing surface. The piston release mechanism can be activated, for example, by a manually triggered rotation of the piston and / or the first dosing surface. In particular, the piston release mechanism can be designed to enable a rotational movement of the housing part carrying the first dosing surface in order to activate the piston release mechanism. The actuation of a rotational movement of the piston and / or the first dosing surface, and in particular only of the first dosing surface, can be easily distinguished by a user from the pressure actuation of the piston in order to move the piston in the distal direction. This further simplifies the use of the injection device.In a preferred embodiment of the injection device, the first and second dosing surfaces are arranged offset from one another in a circumferential direction of the piston, for example, on different or identical housing elements. The piston release mechanism can then be designed such that it displaces the first and second dosing surfaces in the circumferential direction of the piston in order to release the dosing element from the first dosing surface and simultaneously align the second dosing surface with the dosing element, such that the dosing element bears against the second dosing surface when the piston reaches the second dosing position during its displacement relative to the injection solution container from the first dosing position in the distal direction. Such a configuration of the piston release mechanism enables particularly simple and safe handling of the injection device.

[0024] Preferably, the first and second metering surfaces are formed on the first housing element, which is rotatable relative to the piston. If the first and second metering surfaces are arranged offset from one another on the first housing element in the circumferential direction of the piston, the metering element can be easily released from the first metering surface and the second metering surface simultaneously arranged in a position in which the second metering surface is ready for engagement with the metering element when the piston reaches the second metering position upon displacement from the first metering position in the distal direction.

[0025] The second dosing surface can be defined by a bottom surface of a recess formed in the first dosing surface. Preferably, the recess is designed, i.e. shaped and dimensioned, such that the dosing element can be received in the recess. When the piston is arranged in its first dosing position and the dosing element bears against the first dosing surface, the recess formed in the first dosing surface can be brought into alignment with the dosing element by a rotary movement of the first housing part. As a result, the dosing element is released from the first dosing surface and the piston can be displaced further in the distal direction until the dosing element is received in the recess and the contact surface formed on the dosing element bears against the second dosing surface, which is defined by the bottom surface of the recess.The depth of the recess defining the distance between the first and second dosing surfaces in the distal direction may correspond to the desired stroke of the piston in the distal direction between the first and second dosing positions.

[0026] The first housing element, which supports the first and second metering surfaces, can be provided with a gripping structure, particularly in the region of an outer surface. The gripping structure can be designed, for example, in the form of a gripping rib array, with the individual gripping ribs extending substantially in the direction of the longitudinal axis of the piston, depending on the shape of the outer surface of the first housing element. The gripping structure simplifies the handling of the piston release mechanism.

[0027] The piston release mechanism preferably comprises a marking system suitable for indicating activation of the piston release mechanism. The marking system can, for example, comprise a first marking element provided on the first housing element carrying the first and second dosing surfaces, for example in the region of an outer surface thereof. The marking system can further comprise a second marking element provided on a second housing element of the injection device, in particular in the region of an outer surface thereof. The first and second marking elements can be arranged on the first and second housing elements such that, when the piston release mechanism is not activated, they are offset from one another, for example in the circumferential direction of the piston, but are positioned in alignment with one another when the piston release mechanism is activated.The marking system provides the user with guidance on how to activate the piston release mechanism, thus simplifying the handling of the injection device.

[0028] The injection device preferably further comprises an activation mechanism configured to prevent activation of the piston release mechanism when the piston is not in the first dosing position and configured to enable activation of the piston release mechanism when the piston is in the first dosing position. The activation mechanism may be configured to prevent movement of the dosing element and / or the first dosing surface relative to each other when the piston is not in the first dosing position. In particular, the activation mechanism may be configured to prevent rotation of the first housing element carrying the first and second dosing surfaces relative to the piston carrying the dosing element when the piston is not in the first dosing position.

[0029] In a preferred embodiment of the injection device, the activation mechanism comprises a guide channel provided on a peripheral surface of the piston, which extends along the longitudinal axis of the piston and which accommodates a guide element provided on a housing element such that the guide channel is displaced relative to the guide element upon displacement of the piston relative to the injection solution container. Interaction between the guide element and opposing side surfaces of the guide channel can prevent rotation of the piston and the housing element relative to each other.If the activation mechanism comprises a guide channel extending along the longitudinal axis of the piston and a corresponding guide element, the activation mechanism fulfills the dual function of ensuring a guided displacement of the piston in the direction of its longitudinal axis and simultaneously preventing inadvertent deactivation of the first piston stop mechanism when the piston is not arranged in the first dosing position. The guide element can be provided on the first housing part, which supports the first dosing surface and preferably also the second dosing surface.

[0030] The activation mechanism may further comprise an activation channel branching off from the guide channel. The activation channel may, for example, extend in a circumferential direction of the piston substantially perpendicular to the guide channel. The activation channel is preferably configured to receive the guide element when the piston is arranged in the first dosing position and the first housing element, which carries the guide element and preferably also the first and second dosing surfaces, is rotated relative to the piston. With such a configuration of the activation mechanism, the first dosing position of the piston is defined by the position of the activation channel along the longitudinal axis of the piston.

[0031] The first and second metering surfaces can be formed on the first housing element, which is rotatable relative to the piston. If the first and second metering surfaces are arranged offset from one another on the first housing element in the circumferential direction of the piston, the detachment of the metering element from the first metering surface and the simultaneous arrangement of the second metering surface in a position in which the second metering surface is ready for engagement with the metering element when the piston, after being displaced distally from the first metering position, has reached the second metering position can be achieved simply by rotating the first housing element by a suitable amount.

[0032] The second dosing surface can be defined by a bottom surface of a recess formed in the first dosing surface. Preferably, the recess is designed, i.e. shaped and dimensioned, such that the dosing element can be received in the recess. When the piston is arranged in its first dosing position and the dosing element bears against the first dosing surface, the recess formed in the first dosing surface can be brought into alignment with the dosing element by a rotary movement of the first housing part. As a result, the dosing element is released from the first dosing surface and the piston can be displaced further in the distal direction until the dosing element is received in the recess and the contact surface formed on the dosing element bears against the second dosing surface, which is defined by the bottom surface of the recess.

[0033] The piston release mechanism may further comprise a locking arrangement adapted to lock the first dosing surface in its position relative to the dosing element after the first dosing surface has been moved relative to the dosing element to release it from the dosing element. The locking arrangement thus allows the piston release mechanism to be used only once to deactivate the first piston stop mechanism. Reuse of the injection device is thereby reliably prevented.

[0034] The locking arrangement may comprise a resilient locking clip configured to resiliently push out of a rest position through cooperation with a locking element when the first metering surface is moved relative to the metering element, thereby decoupled from the metering element. The resilient locking clip may, for example, be provided on the second housing element, while the locking element may be provided on the first housing element, which supports the first metering surface and optionally also the second metering surface. The resilient locking clip may then be resiliently deformed when the first housing element is rotated relative to the second housing element.The locking clip is preferably further configured to deform back into its rest position after the first metering surface has ceased to move and to cooperate with the locking element to lock the first metering surface in its position relative to the metering element. In particular, the locking clip can cooperate with the locking element to prevent counter-rotation of the first housing element relative to the second housing element and the piston after the first housing element has been rotated once to release the first metering surface from the metering element and align the second metering surface with the metering element.

[0035] The injection device may further comprise a limiting mechanism adapted to limit movement of the dosing element and / or both the first dosing surface and the second dosing surface for releasing the dosing element from the first dosing surface and aligning the dosing element with the second dosing surface. The limiting mechanism prevents a user of the injection device from excessively moving the dosing element and the first and second dosing surfaces relative to one another. Furthermore, the limiting mechanism provides the user with haptic feedback that the dosing element has been properly released from the first dosing surface and aligned with the second dosing surface, i.e., that the first piston stop mechanism has been deactivated.

[0036] The limiting mechanism may, in particular, comprise a first limiting element provided on the first housing element that supports the first and second dosing surfaces. Furthermore, the limiting mechanism may comprise a second limiting element provided on a second housing element, wherein the second housing element is configured to remain stationary when the first housing element is moved, in particular rotated, to deactivate the first piston stop mechanism. The first limiting element may be configured to bear against the second limiting element when the dosing element is released from the first dosing surface and aligned with the second dosing surface.

[0037] In the event that the injection device comprises an activation mechanism as described above with an activation channel and a guide element formed on the first housing element, which also carries the first and second dosing surfaces, the movement of the first dosing surface relative to the dosing element fastened to the piston can also be limited by an interaction between the guide element and an end surface of the activation channel, which can act as a stop surface for the guide element when the first housing element, after being rotated relative to the piston, has reached a position in which the dosing element is released from the first dosing surface and aligned with the second dosing surface.

[0038] The injection device can further comprise a first locking mechanism that exerts a holding force that holds the piston in its current position relative to the injection solution container. The first locking mechanism thus prevents an unwanted displacement of the piston relative to the injection solution container, i.e., due to the presence of the first locking mechanism, an active manual actuation, e.g., by applying a pressure force, is necessary to displace the piston relative to the injection solution container. The first locking mechanism can comprise a resettable locking element, which can be provided, for example, on the second housing element. The resettable locking element can be designed such that it exerts a resettable holding force on the piston, i.e.,The resettable locking element can be resettable from a rest position into a preloaded position through interaction with the piston and, due to its resettability, exert a resettable reaction force on the piston, which holds the piston in its current position. The resettable locking element can, in particular, interact with a locking rib provided on the outer circumferential surface of the piston and extending substantially parallel to the longitudinal axis of the piston.

[0039] Alternatively or additionally, the injection device can also have a second locking mechanism capable of exerting a holding force that holds the first housing element in its current position, i.e., that holds the first housing element in its position relative to the second housing element. The second locking mechanism thus prevents unwanted displacement of the first housing element relative to the second housing element and thus unwanted deactivation of the first piston stop mechanism. The second locking mechanism can comprise a friction element that is provided on the first limiting element of the limiting mechanism and can cooperate with a holding element of the second housing element.

[0040] The injection device may further comprise a piston positioning mechanism adapted to prevent displacement of the piston relative to the injection solution container from a proximal end position in the proximal direction. The piston positioning mechanism may, for example, comprise a distal end surface of the guide channel provided in the peripheral surface of the piston. Interaction between the distal end surface of the guide channel and the guide element received therein may then define the proximal end position of the piston.

[0041] The injection device can be filled with a preparation via a prefilled syringe (14), a vial or another reservoir.

[0042] In one embodiment, the injection device (whether prefilled or not) is sterilized and supplied in a sealed package. In one embodiment, the injection device is prefilled with a suitable injection solution and finally sterilized. Such a final sterilization step may comprise known techniques such as ethylene oxide sterilization or hydrogen peroxide sterilization. A preferred embodiment of the invention will now be described in more detail with reference to the accompanying schematic drawings, in which: Fig. 1 shows an exploded view of an injection solution transfer system comprising a filling adapter and an injection device; Fig. Figure 2 shows a three-dimensional view of the filling adapter and the injection device in the connected state; Fig. Figure 3 shows a longitudinal section through the filling adapter connected to the injection device; Figs. 4 and 5 show detailed three-dimensional views of a hollow sleeve of the filling adapter; Figs. 6 and 7 show detailed three-dimensional views of an adapter element of the filling adapter; Fig. 8 shows the arrangement of the adapter element in the hollow sleeve of the filling adapter; Fig. 9 shows a three-dimensional longitudinal sectional view of the adapter element and a cannula of the filling adapter; Fig. 10 shows a longitudinal section through the adapter element and the cannula of the filling adapter; Fig. 11 shows a detailed view of an injection solution container of the injection device; Fig. Figure 12 shows a detailed view of the piston of the injection device; Fig. Figure 13 shows a detailed view of a tip element of the piston; Fig. 14 shows the arrangement of the cannula of the filling adapter relative to the piston of the injection device when the filling adapter is connected to the injection device; Fig. 15 shows the interaction between the guide rib of the hollow sleeve and the injection solution container of the injection device; Figs. 16 to 18 show detailed three-dimensional views of a first housing part of the injection device; Figs. 19a and 19b show the interaction between the piston and the first housing part; Figs. 20 and 21 show detailed three-dimensional views of the second housing part of the injection device; Fig. 22 shows the assembly of the second housing part; Fig. 23 shows the attachment of the injection solution container to the second housing part; Figs. 24 and 25 show the interaction between the first and second housing parts; Fig. 26 shows the interaction between the piston and the second housing part; Figs. 27 and 28 show detailed three-dimensional views of a lever element of a piston locking mechanism that prevents the piston of the injection device from being moved from a filling position in a distal direction when the injection device is connected to the filling adapter; Fig. 29 shows the lever element of the piston locking mechanism in an active position; Fig. 30 shows the lever element of the piston locking mechanism in an inactive position; Fig. Figure 31 shows the injection solution transfer system with the filling adapter connected to the injection device, with part of the second housing element removed and the lever element of the piston locking mechanism in its active position; Fig. 32 shows the assembly of the lever element of the piston locking mechanism in the second housing part; Figs. 33a to 33d show the use of the injection solution transfer system when filling the injection device with an injection solution from a syringe; and Figs. 34a to 34d show the use of the injection device in administering an injection solution to a patient.

[0043] The Fig. 1 and Fig. 2 show an injection solution transfer system 100 comprising an injection device 10 and a filling adapter 12. The filling adapter 12 serves to connect a syringe 14 containing an injection solution to the injection device 10 in order to fill the injection device 10 with the injection solution from the syringe 14, as shown in FIGS. Fig. 33a to 33d and described further below. The syringe 14 is designed as a prefilled syringe 14 containing an injection solution for intraocular administration.

[0044] The filling adapter 12 consists of a hollow sleeve 16, which is inserted into the Fig. 4 and Fig. 5. The hollow sleeve 16 is made of a colored plastic material, for example, polycarbonate / acrylonitrile butadiene styrene (PC-ABS), and is provided with an internal lumen dimensioned to allow the insertion of at least a distal portion of the syringe 14 at one end and at least a distal portion of the injection device 10 at an opposite end. In the embodiment of a filling adapter 12 shown in the drawings, the hollow sleeve 16 has a substantially circular hollow cylindrical shape, and the lumen extending therethrough has a substantially circular cross-sectional shape. The filling adapter 12 further comprises an adapter element 18 housed in the hollow sleeve 16 and comprising a first connection port 20 and a second connection port 22. The adapter element 18 can be made of polycarbonate, for example, and is shown in the Fig. 6 to 10. As particularly shown in Fig. As shown in Figure 8, the adapter element 18 is provided with two retaining shoulders 23 that protrude in opposite directions from an outer peripheral surface of the adapter element 18. Each retaining shoulder 23 cooperates with a pair of complementary crimp ribs 24 that protrude from an inner peripheral surface of the hollow sleeve 16 to fix the adapter element 18 in its position within the hollow sleeve 16. The retaining shoulders 23 and the complementary crimp ribs 24 form an interference fit to reliably fix the adapter element 18 in its position within the hollow sleeve 16.

[0045] The first connection port 20 of the adapter element 18 is adapted to be connected to the syringe 14, ie a distal end of the syringe 14, when the filling adapter 12 is connected to the syringe 14, as shown in the Fig. 33a to 33c. As can be seen in particular from Fig. As can be seen in Figure 10, the first connection port 20 of the adapter element 18 forms a female Luer cone 25, which can cooperate with a male Luer cone provided at the distal end of the syringe 14 to establish a fluid-tight connection between the syringe 14 and the adapter element 18. The second connection port 22 of the adapter element 18 is provided for connection to the injection device 10.

[0046] The adapter element 18 is provided with a through-opening 26 which extends in a direction substantially parallel to a longitudinal axis L1 of the filling adapter 12, see in particular Fig. 10. A cannula 27 protrudes from the second connection port 22 of the adapter element 18 and is in fluid communication with the through-opening 26 extending through the adapter element 18, see in particular the Fig. 9 and Fig. 10. The cannula 27 is made of stainless steel. However, the hollow sleeve 16 of the filling adapter 12 extends beyond a distal tip of the cannula 27. This protects the user from the cannula 27 when handling the filling adapter 12.

[0047] The adapter element 18 serves to establish a fluid connection between the syringe 14 and the injection device 10, ie when the syringe 14 is connected to the first connection port 20 of the adapter element 18 and the injection device 10 is connected to the second connection port 22 of the adapter element 18, as in Fig. 33a, the injection solution contained in the syringe 14 can be transferred into the injection device 10 by pressing a piston 28 of the syringe 14, as shown in the Fig. 33b and Fig. 33c, is manually pressed to press the injection solution from the distal end of the syringe 14 into the through-opening 26 provided in the adapter element 18 and further via the cannula 27 into an injection solution container 30 of the injection device 10.

[0048] As can be seen in particular from the Fig. 4 and Fig. 5, the hollow sleeve 16 of the filling adapter 12 has, in the region of a first end facing the syringe 14 when the syringe 14 is engaged with the first connection port 20 of the adapter element 18, at least one resettable clip 32 which is suitable for engaging with a collar 34 of the syringe 14 when the syringe 14 is engaged with the first connection port 20 of the adapter element 18, see Fig. 33a and Fig. 33b. In the embodiment of a hollow sleeve 16 shown in the drawings, the hollow sleeve 16 is provided with two resettable clips 32. Each resettable clip 32 comprises an arm 36 that extends in a recess 38 provided in the hollow sleeve 16, substantially parallel to the longitudinal axis L1 of the filling adapter 12, toward the first end of the hollow sleeve 16. A locking lug 40 protrudes from an inner surface of the arm 36 in the region of a free end of the arm 36.

[0049] When the syringe 14 is engaged with the first connection port 20, the resettable clip 32 is bent outward due to the interaction with the collar 34 of the syringe 14. However, once the syringe 14 has reached its final position with respect to the adapter element 18, ie when the distal tip of the syringe 14 is connected to the first connection port 20 of the adapter element 18 and the syringe 14 has Fig. 33b relative to the hollow sleeve 16, the resettable clip 32 returns to its original position substantially parallel to the longitudinal axis L1 of the filling adapter 12, so that the locking lug 40 engages with an end face of the collar 34 of the syringe 14. As a result, the syringe 14 is firmly connected to the hollow sleeve 16.

[0050] The hollow sleeve 16 is provided in the region of its first end on its outer circumferential surface with two first gripping structures 42, each designed in the form of a nub field. The first gripping structure simplifies the handling of the filling adapter 12 when connecting the syringe 14 to the filling adapter 12. Furthermore, the hollow sleeve 16 has an outer diameter in the region of its first end and in the region of a second end facing the injection device 10 when the injection device 10 is engaged with the second connection port 22 of the adapter element 18 that is larger than an outer diameter of the hollow sleeve 16 in an intermediate section arranged between the first and second ends. Such a configuration of the hollow sleeve 16 further simplifies gripping and thus handling of the filling adapter 12.

[0051] As in Fig. 11, the injection solution container 30 of the injection device 10 is designed in the form of an inner injection solution container 30 contained in a protective outer cylinder 44. The inner injection solution container 30 and the protective outer cylinder 44 are formed integrally with one another and are made of a sterile plastic material. In the region of its proximal end, the protective outer cylinder 44 is provided with a flange element 46. A distal end of the injection solution container 30 is provided with a male Luer cone 48, which cooperates with a female Luer cone 50 provided on the second connection port 22 of the adapter element 18 of the filling adapter 12 when the filling adapter 12 is connected to the injection device 10, as shown in FIGS. Fig. 2 and Fig. 3. By means of the Luer cones 48, 50, a fluid-tight connection can be established between the distal end of the injection solution container 30 and the adapter element 18 of the filling adapter 12.

[0052] As from Fig. 11, the outer cylinder 44 of the injection device 10 is provided with a Luer connection 52 in the region of its distal end. The Luer connection 52 cooperates with a complementary Luer connection 54 provided on an outer circumference of the second connection port 22 of the adapter element 18, see Fig. 6 and 8 to 10, when the filling adapter 12 is connected to the injection device 10, as shown in the Fig. 2 and Fig. 3. This also allows a reliable connection to be established between the outer cylinder 44 of the injection device 10 and the adapter element 18 of the filling adapter 12.

[0053] In order to simplify the handling of the filling adapter 12 when engaging the injection device 10 with the second connection port 22 of the adapter element 18, the hollow sleeve 16 is provided with a second gripping structure 56 on its outer circumferential surface in the region of a second end, which faces the injection device 10 when engaging the injection device 10 with the second connection port 22 of the adapter element 18. The second gripping structure 56 is designed in the form of two gripping rib fields, wherein the individual gripping ribs extend substantially parallel to the longitudinal axis L1 of the filling adapter 12. Furthermore, the hollow sleeve 16, as shown in Fig. 15, is provided with longitudinally extending guide ribs 58 which protrude from the inner circumferential surface of the hollow sleeve 16 and extend substantially parallel to the longitudinal axis L1 of the filling adapter 12. The guide ribs 58 serve to guide the injection device 10 into engagement with the second connection port 22. The guiding function of the guide ribs 58 prevents the cannula 27 from coming into contact with the injection solution container 30 of the injection device 10 when the filling adapter 12 is connected to the injection device 10. The hollow sleeve 16 and the longitudinally extending guide ribs 58 are designed, i.e. shaped and dimensioned, such that a close sliding fit is created between the guide ribs 58 and an outer surface of the outer tube 54 of the injection device 10.

[0054] Coming back to the Fig. 9 and Fig. 10, the through-opening 26 extending through the adapter element 18 has an inlet section 26a arranged adjacent to the first connection port 20. When the filling adapter 12 is used, injection solution ejected from the syringe 14 thus enters the through-opening 26 via its inlet section 26a, which has a flow cross-section that decreases in the flow direction of the injection solution ejected from the syringe 14. Furthermore, the through-opening 26 comprises an intermediate section 26b arranged downstream of the inlet section 26a in the flow direction of the injection solution ejected from the syringe 14 when the filling adapter 12 is used. The intermediate section 26b of the through-opening 26 has a substantially constant flow cross-section that substantially corresponds to the smallest flow cross-section of the inlet section 26a adjacent to the intermediate section 26b.Finally, the through-opening 26 has a receiving section 26c, which is arranged downstream of the intermediate section 26b in the flow direction of the injection solution ejected from the syringe 14 when using the filling adapter 12, i.e., adjacent to the second connection port 22. The receiving section 26c has a flow cross-section that is larger than the flow cross-section of the intermediate section 26b.

[0055] As can be seen from the Fig. 9 and Fig. 10, the cannula 27 extends into at least a portion of the intermediate section 26b of the through-opening 26, such that the intermediate section 26b of the through-opening 26, or a portion thereof, defines a cannula receiving bore of the adapter element 18, in which a proximal end of the cannula 27 is secured. The cannula 27 is received in the cannula receiving bore with a tight sliding fit. In addition, the cannula 27 is provided with beveled ends. This design of the cannula 27 and the cannula receiving bore minimizes the formation of wear particles when the cannula 27 is placed in the cannula receiving bore. The final connection between the adapter element 18 and the cannula 27 is achieved by means of a UV-curing adhesive.The cannula 27 extends from the intermediate portion 26b of the through-opening 26 through the receiving portion 26c of the through-opening 26 and the second connection port 22, so that it protrudes from the second connection port 22. The receiving portion 26c of the through-opening 26, the second connection port 22, and the hollow sleeve 16 of the filling adapter 12 form a concentric arrangement around the cannula 27, see in particular. Fig. 3.

[0056] As particularly in Fig. 8, the adapter element 18 is provided with two retaining shoulders 60 which protrude in opposite directions from an outer circumferential surface of the adapter element 18 in the region of the inlet section 26a and the intermediate section 26b of the through opening 26 extending through the adapter element 18.

[0057] When the filling adapter 12 is connected to the injection device 10, the cannula 27 projects into the injection solution container 30 of the injection device 10, ie a distal tip of the cannula 27 is arranged at a distance from the distal end of the injection solution container 30 inside the injection solution container 30, see in particular Fig. 3. This has the consequence that when transferring injection solution from the syringe 14 into the injection device 10, the injection solution emerging from the syringe 14 via the cannula 27 is not supplied to the injection solution container 30 of the injection device 10 in the region of the distal end of the injection solution container 30, but at a position arranged at a distance from the distal end of the injection solution container 30 inside the injection solution container 30.

[0058] By simply holding the filling adapter 12 and the injection device 10 in an upright position, wherein the longitudinal axis L1 of the filling adapter 12 and a longitudinal axis L2 of the injection device 10 are aligned substantially vertically and the distal end of the injection device 10 points downwards, as shown in the Fig. 33a to 33c, a gravity-driven flow of the injection solution can be induced from the distal tip of the cannula 27 downwards toward the distal end of the injection solution container 30 and further toward the adapter element 18. A portion of the injection solution that is expelled from the distal tip of the cannula 27 and flows back toward the adapter element 18 under gravity is received in the receiving portion 26c of the opening 26 provided in the adapter element 18. Gas bubbles that are trapped in the injection solution and are therefore transferred from the syringe 14 into the injection solution container 30 together with the liquid phase of the injection solution are entrained by this gravity-driven flow and, due to the higher specific density of the liquid phase of the injection solution, are pushed toward the distal end of the injection solution container 30 and further toward the adapter element 18.

[0059] Finally, the adapter element 18 is provided with a venting device 64 suitable for venting gas introduced from the syringe 14 into the injection device 10, i.e., into the injection solution container 30 of the injection device 10, into the environment via the through-opening 26 and the cannula 27. Thus, the venting device allows trapped gas bubbles, in particular air bubbles, which are conveyed by the gravity-driven flow of the injection solution from the distal tip of the cannula 27 back to the adapter element 18 as described above, to be expelled into the environment. The filling adapter 12 thus enables gas-free filling of the injection device 10 with the injection solution. Manually expelling trapped gas from the syringe 14 before connecting the syringe 14 to the filling adapter 12 can thus be omitted.Furthermore, an accurate and reliable preparation of a desired dose of the injection solution within the injection device 10 is enabled.

[0060] The venting device 64 comprises two radial bores 66, which connect the through-opening 26 extending through the adapter element 18 to the environment. In particular, the radial bores 66 connect the receiving section 26c of the through-opening 26 to an outer circumferential surface of the adapter element 18 and thus to the environment. In the embodiment of a filling adapter 12 shown in the drawings, the radial bores 66 of the venting device 64 extend coaxially from an outer circumferential surface of the adapter element 18 to the receiving section 26c of the through-opening 26 in order to connect the receiving section 26c of the through-opening 26 to the environment. To ensure that gas bubbles enclosed in the injection solution can be released to the environment as desired without a substantial part of the liquid phase of the injection solution being released to the environment, the flow cross-section, i.e.the diameter of the radial bores 66, is selected depending on the physical properties, in particular the specific density, the viscosity and the surface tension of the injection solution to be transferred from the syringe 14 into the injection device 10.

[0061] To ensure proper functioning of the venting device 64, the retaining shoulders 23 protrude from the outer peripheral surface of the adapter element 18 in the region of the inlet section 26a and the intermediate section 26b of the through-opening 26 extending through the adapter element 18. Such a configuration ensures that, in the region of the receiving section 26c of the through-opening 26, an air gap 68 is present between the outer peripheral surface of the adapter element 18 and the inner peripheral surface of the hollow sleeve 16, which allows unhindered gas escape from the receiving section 26c via the radial bores 66 of the venting device 64.

[0062] The injection device 10 of the injection solution transfer system 100 further comprises a piston 70 which is Fig. 12 is shown in more detail. In the embodiment of an injection device 10 shown in the drawings, the piston 70 is made of polycarbonate. At least a portion of the piston 70 is slidably received by the injection solution container 30 of the injection device 10. The piston 70 is displaceable relative to the injection solution container 30 in a distal direction along a longitudinal axis of the piston 70 in order to eject the injection solution contained in the injection solution container 30 of the injection device 10 from the injection solution container 30. At its proximal end, which protrudes proximally from the injection solution container 30, the piston 70 carries an actuation button 72 which can be pressed by a user in order to displace the piston 70 relative to the injection solution container 30 in a distal direction along the longitudinal axis of the piston 70.

[0063] At its distal end, the piston 70 is provided with a tip element 74 which is attached to a piston rod 76 (see Fig. 13). Coupling between the piston rod 76 and the tip element 74 is achieved by the interaction of a tip barb 78 provided at the distal end of the piston rod 76 with a barb receptacle 80 of the tip element 74. Furthermore, the tip element 74 is provided with a sealing element 82, which is provided in the region of an outer peripheral surface of the tip element 74 and which cooperates in a sealing manner with an inner peripheral surface of the injection solution container 30.

[0064] The piston 70 of the injection device 10 can, as shown in the Fig. 33a to 33d, be arranged in a filling position. When the piston 70 is arranged in its filling position and the injection device 10 is engaged with the second connection port 22 of the adapter element 18 of the filling adapter 12, a distal tip of the piston 70, i.e., a distal end surface of the tip element 74 provided at the distal tip of the piston 70, is arranged at a desired small distance D from the distal tip of the cannula 27 of the filling adapter 12, see Fig. 14. For example, the injection device 10 and the filling adapter 12 can be designed such that the distance D between the distal tip of the piston 70 and the distal tip of the cannula 27 is set to approximately 1.5 mm + / - 0.5 mm. By arranging the distal tip of the piston 70 and the distal tip of the cannula 27 at a close distance, the injection solution supplied to the injection solution container 30 via the cannula 27 is reliably forced to flow toward the venting device 64. This ensures air-free filling of the injection solution container 30 with the injection solution.

[0065] Finally, the hollow sleeve 16 is provided with two observation windows 83 through which the filling of the injection device 10 with the injection solution from the syringe 14 can be observed. The observation windows 83 allow an unobstructed view of the interior of the injection device 10 and the distal tip of the cannula 27.

[0066] The piston 70 is slidably received by a housing 84 of the injection device 10, which has a Fig. 16 to 19, the first housing element 86 and a housing element 88 Fig. 20 to 23. Both the first and second housing elements 86, 88 are made of polycarbonate / acrylonitrile butadiene styrene, but have a different color. The first housing element 86 is provided with a piston through-hole 90 that receives the piston rod 76, so that the piston 70 is displaceable in a direction along its longitudinal axis relative to the first housing element 86. Guide elements 92 are provided on the first housing element 86 and extend into the piston through-hole 90. When the piston 70, ie the piston rod 76, is received in the piston through-hole 90 of the first housing element 86, each guide element 92 engages in a guide channel 94 which is provided in a peripheral surface of the piston 70, ie the piston rod 76, and which extends along the longitudinal axis of the piston 70, see in particular the Fig. 19a and Fig. 19b.

[0067] For mounting the piston 70 on the first housing element 86, mounting channels 96 are provided in the outer circumferential surface of the piston rod 76. These mounting channels branch off from the guide channels 94 in a distal region and extend substantially perpendicular to the guide channels 94 in a circumferential direction of the piston rod 76. During assembly of the piston 70 with the first housing element 86, the guide elements 92 are brought into engagement with the mounting channels 96.

[0068] The piston 70 is then rotated until the guide elements 92 are guided in the guide channels 94, see Fig. 19a and Fig. 19b. To simplify handling of the injection solution transfer system 100, the injection device 10 is delivered such that the piston 70 is arranged in its filling position, which corresponds to a proximal end position of the piston 70. A piston positioning mechanism 98 prevents the piston 70 from being moved in the proximal direction relative to the injection solution container 30 further than its proximal end position, i.e., its filling position. However, the piston positioning mechanism 98 allows movement of the piston 70 relative to the injection solution container 30 from its filling position in a distal direction. In particular, the piston positioning mechanism 98 is defined by a distal end surface 102 of the guide channels 94 provided in the peripheral surface of the piston rod 76 and the guide elements 92 provided on the first housing element 86.When the piston 70 is arranged in its proximal end position, which corresponds to its filling position, the guide elements 92 abut the distal end surfaces 102 of the guide channels 94. The interaction between the distal end surfaces 102 of the guide channels 94 and the guide elements 92 then prevents further movement of the piston 70 in the proximal direction and thus defines the proximal end position, ie, the filling position of the piston 70.

[0069] The second housing element 88 consists of two identical parts (see Fig. 20 and Fig. 21), each of which comprises an interference pin 104 and an interference socket 106. The two housing parts of the second housing element 88 are joined together by engaging the interference pins 104 with the respective interference sockets 106, as shown in Fig. 22. In order to align the parts of the second housing element 88 relative to one another during assembly, alignment pins 108 are provided, which are received in the respective alignment sockets 110 after the parts of the second housing element 88 have been connected. The injection solution container 30 and the protective outer cylinder 44 are connected to the second housing element 88 via the flange element 46, which extends from the outer cylinder 44 at a proximal end thereof. In particular, the flange element 46 is received in a correspondingly shaped and dimensioned receiving area 112 of the second housing element 88, see Fig. 23.

[0070] As particularly in Fig. 26, the second housing element 88 is provided with a piston guide 114 that clamps the piston rod 76 so that the piston 70 is prevented from rotating relative to the second housing element 88. A first locking mechanism 116 is designed to exert a holding force that holds the piston 70 in its current position relative to the second housing element 88. The first locking mechanism 116 thus prevents unintentional displacement of the piston 70 relative to the injection solution container 30, so that active manual actuation of the piston 70, for example by applying a compressive force to the actuation button 72, is required to displace the piston 70 relative to the injection solution container 30. The first locking mechanism 116 comprises a resettable locking element 118 provided on the second housing element 88. The resettable locking element 118 exerts a resettable holding force on the piston 70, ieThe resettable locking element 118 is resettably urged from a rest position into a preloaded position by interaction with the piston 70 and, due to its resettability, exerts a resettable holding force on the piston 70, which holds the piston 70 in its current position. In particular, the resettable locking element 118 cooperates with a locking rib 120 provided on the outer circumferential surface of the piston rod 76 and extending substantially parallel to the longitudinal axis of the piston 70.

[0071] The injection device 10 further comprises a piston locking mechanism 122, which cooperates with the filling adapter 12, i.e., the hollow sleeve 16 of the filling adapter 12, to prevent the piston 70 of the injection device 10 from being moved from its filling position relative to the injection solution container 30 in a distal direction, i.e., toward the distal tip of the cannula 27, when the injection device 10 is connected to the filling adapter 12. The piston locking mechanism 122 serves to prevent unintentional contact between the piston 70, i.e., the distal tip of the piston 70, and the distal tip of the cannula 27. The operation of the piston locking mechanism 122 will now be described with reference to the Fig. 27 to 32 are described in more detail.

[0072] In particular, the piston locking mechanism 122 comprises a lever element 124, see Fig. 27 and Fig. 28, which is movable within the second housing element 88 between an active position, which is in the Fig. 29 and Fig. 31, and an inactive position shown in Fig. 30. In its active position, the lever element 124 cooperates with the piston 70 and the hollow sleeve 16 of the filling adapter 12 to prevent the piston 70 from being moved from its filling position in a distal direction when the injection device 10 is connected to the filling adapter 12. In its inactive position, however, the lever element 124 allows movement of the piston 70 from its filling position in a distal direction when the injection device 10 is not connected to the filling adapter 12. The lever element 124 is mounted within the second housing element 88 such that it is rotatable between its active and inactive positions. Specifically, the lever element 124 is provided with a hinge 126 that rotatably fastens the lever element 124 to a pivot axis 128 provided on the second housing element 88.

[0073] The lever element 124 further comprises a pair of foot elements 130 which extend substantially parallel to each other and which are contacted by the filling adapter 12 when the injection device 10 is connected to the filling adapter 12 to hold the lever element 124 in its active position. In particular, as shown in Fig. 29, the foot elements 130 face the filling adapter 12 and are contacted by a locking edge 132 of the hollow sleeve 16, which faces the injection device 10 when the injection device 10 is connected to the filling adapter 12. Through the interaction between the locking edge 132 of the hollow sleeve 16 and the foot elements 130, the lever element 124 is pressed in the proximal direction substantially parallel to the longitudinal axis of the piston 70 into contact with the piston 70 and thus in its Fig. 29 and Fig. 31 shown active position.

[0074] The lever element 124 includes a stop device 134 comprising two tabs extending from a proximal end surface of the lever element 124. Furthermore, a proximal portion of the piston 70 extends further in a direction substantially perpendicular to the longitudinal axis of the piston 70 than a distal portion of the piston 70. Consequently, a shoulder defining a stop surface 136 is formed in a transition region between the distal portion and the proximal portion of the piston 70.

[0075] In particular, the stop surface 136 is defined by an outer portion of a distal end surface of the proximal piston part, which protrudes from an outer peripheral surface of the distal piston part. When the lever element 124 is arranged in its active position, as shown in Fig. As shown in Figure 29, the two tabs of the stop device 134 abut the stop surface 136 of the piston 70. This holds the lever element 124 in its active position and simultaneously prevents movement of the piston 70 from its filling position in the distal direction.

[0076] The piston locking mechanism 122 also includes a retaining device 138 which cooperates with the foot elements 130 of the lever element 124 to prevent the foot elements 130 from detaching from the locking edge 132 of the filling adapter 12 when the lever element 124 is held in its active position by the cooperation between the locking edge 132 and the foot elements 130, see Fig. 20 and Fig. 32. In particular, the retaining device 138 prevents the foot elements 130 from sliding around the locking edge 132 of the hollow sleeve 16 and thus from detaching from the filling adapter 12 when the lever element 124 is pressed into engagement with the piston 70. The retaining device is provided in the second housing element 88 and is designed in the form of a retaining rib that prevents the foot elements 130 of the lever element 124 from deforming away from the piston 70 in a direction substantially perpendicular to the longitudinal axis of the piston 70.

[0077] After completion of the transfer of the injection solution from the syringe 14 into the injection solution container 30 of the injection device 10, the piston 70 being moved as described above and in the Fig. 33a to 33c, the filling adapter 12 and the syringe 14 are detached from the injection device 10 by detaching the male Luer cone 48 provided at the distal end of the injection solution container 30 from the female Luer cone 50 provided at the second connection port 22 of the adapter element 18 and by detaching the Luer connection 52 provided at the distal end of the outer cylinder 44 from the complementary Luer connection 54 provided at the second connection port 22, see Fig. 33d.

[0078] As soon as the filling adapter 12 is released from the injection device 10, the filling adapter 12, i.e. the locking edge 132 of the hollow sleeve 16, no longer rests against the foot elements 130 of the lever element 124. Thus, when a compressive force is exerted on the piston 70 in order to displace the piston 70 in the distal direction within the injection solution container 30 of the injection device 10, the lever element 124 is returned to its Fig. 30. In particular, the lever element 124 is rotated about its rotation axis 128 from its active position to its inactive position and thus out of the path of the piston 70. This no longer impedes the displacement of the piston 70. Consequently, a needle (not shown in the drawings) can be attached to the injection device 10, for example, using the Luer connection 52 provided at the distal end of the outer cylinder 44, and the injection device 10 can be operated as described below.

[0079] In order to administer a precise dose to a patient, in particular a precise microdose of, for example, 10µl of the injection solution contained in the injection solution container 30, in a first step, excess injection solution must be expelled from the injection solution container 30 by displacing the piston 70 in the distal direction relative to the injection solution container 30, as shown in Fig. 34a.

[0080] The desired dose of the injection solution must then be injected into the patient. The injection device 10 therefore comprises a first piston stop mechanism 140, which is designed to stop displacement of the piston 70 relative to the injection solution container 30 in the distal direction in a first dosing position P1, see Fig. 34. Furthermore, the injection device 10 comprises a second piston stop mechanism 142, which is designed to stop a displacement of the piston 70 relative to the injection solution container 30 from the first dosing position P1 in the distal direction in a second dosing position P2, see Fig. 34d. The first and second dosing positions P1, P2 of the piston 70 are selected such that the piston 70, when displaced relative to the injection solution container 30 between the first and second dosing positions P1, P2, can eject a desired dose of the injection solution contained in the injection solution container 30 from the injection solution container 30.

[0081] Thus, during use of the injection device 10, a user can expel excess injection solution from the injection solution container 30 by displacing the piston 70 in the distal direction relative to the injection solution container 30 until the piston 70 reaches the first dosing position P1. Upon reaching the first dosing position P1, the first piston stop mechanism 140 stops further displacement of the piston 70 in the distal direction. This prevents the user from expelling too much injection solution from the injection solution container. The remaining injection solution located in the injection solution container can then be administered to a patient by further displacing the piston 70 in the distal direction until the piston 70 reaches the second dosing position P2.When the second dosing position P2 is reached, the second piston stop mechanism 142 stops the further displacement of the piston 70 in the distal direction and thus prevents too much injection solution from being administered to the patient.

[0082] As particularly in the Fig. 12, Fig. 16 and Fig. 18, the first piston stop mechanism 140 includes a metering element 144 that is attached to the piston 70 and is configured to engage a first metering surface 146 provided on the first housing member 86. The metering element 144 also forms part of the second piston stop mechanism 142 and, as part of the second piston stop mechanism 142, is configured to engage a second metering surface 148 also provided on the first housing member 86. The metering element 144 is formed integrally with the piston 70 and protrudes in the form of a rib from an underside of the actuating button 72 toward the inner solution container 30.

[0083] The first and second dosing surfaces 146, 148 extend substantially parallel to one another and parallel to a stop surface 150 of the dosing element 144 substantially perpendicular to the longitudinal axis of the piston 70, wherein the second dosing surface 148 is arranged offset in the distal direction parallel to the first dosing surface 146. A distance S between the first and second dosing surfaces 146, 148 in the distal direction corresponds to a desired travel path of the plunger 70 in the distal direction between the first and second dosing positions P1, P2, see in particular Fig. 18. The distance S between the first and the second dosing surface 146, 148 in the distal direction thus determines the desired injection solution dose to be ejected from the injection solution container 30 when the piston 70 is moved from the first to the second dosing position P1, P2.

[0084] Furthermore, the first and second metering surfaces 146, 148 are arranged offset from one another in the circumferential direction of the piston 70. In particular, the second metering surface 148 is defined by a bottom surface of a recess 152 formed in the first metering surface 146 on the first housing element 86.

[0085] If the piston 70 is moved out of its position during use of the injection device 10 Fig. 34a shown filling position in the distal direction, the stop surface 150 of the metering element 144 abuts the first metering surface 146 when the piston 70 reaches the Fig. 34b is reached. The interaction of the dosing element 144 with the first dosing surface 146 prevents the piston from being displaced further in the distal direction. The first piston stop mechanism 140 thus ensures a firm stop of the piston 70 in the first dosing position P1. The injection device 10 therefore further comprises a piston release mechanism 154, which is suitable for deactivating the first piston stop mechanism 140 in order to release the piston 70 and thus enable a displacement of the piston 70 relative to the injection solution container 30 from the first dosing position P1 in the distal direction, i.e., in the direction of the second dosing position P2.

[0086] The piston release mechanism 154 is adapted to enable a movement of the first dosing surface 146 relative to the dosing element 144, i.e., relative to the piston 70, in order to release the dosing element 144 from the first dosing surface 146. In particular, the piston release mechanism 154 is adapted to enable a rotational movement of the first dosing surface 146 relative to the dosing element 144, i.e., relative to the piston 70, in order to release the dosing element 144 from the first dosing surface 146. In order to effect the rotational movement of the first dosing surface 146 relative to the dosing element 144, the first housing element 86, which carries the first and second dosing surfaces 146, 148, is designed to be manually rotatable relative to the second housing element 88, see Fig. 34c. Since the piston 70 is prevented from rotating relative to the second housing element 88 by the piston guide 114, a rotation of the first housing element 86 relative to the second housing element 88 inevitably leads to a rotation of the first housing element 86 relative to the piston 70.

[0087] In order to be guided to rotate relative to the second housing element 88, the first housing element 86 is provided with a holding recess 156, see Fig. 17, Fig. 18 and Fig. 24, which receives a holding element 158 ​​formed on the second housing element 88, see Fig. 20. To simplify handling of the piston release mechanism 154, the first housing element 86 is provided with a gripping structure 159 in the region of its outer surface. The gripping structure 159 is designed in the form of a gripping rib array with individual gripping ribs that extend substantially in a direction along the longitudinal axis of the piston 70.

[0088] The extent of rotation of the first housing element 86 relative to the second housing element 88, and thus relative to the piston 70, is adjusted such that the recess 152 formed in the first metering surface 146 is aligned with the metering element 144 protruding from the actuating button 72 of the piston 70. The piston release mechanism 154 is thus adapted to displace the first and second metering surfaces 146, 148 in the circumferential direction of the piston 70 in order to release the metering element 144 from the first metering surface 146 and simultaneously align the second metering surface 148 with the metering element 144.

[0089] To ensure that, upon activation of the piston release mechanism 154, a user rotates the first housing member 86 relative to the second housing member 88 in the correct direction and by the correct amount of rotation required to release the dosing element 144 from the first dosing surface 146 and simultaneously align the second dosing surface 148 with the dosing element 144, the piston release mechanism 154 includes a marking system 160 adapted to indicate activation of the piston release mechanism 154. The marking system 160 includes a first marking element 162 provided on an outer surface of the first housing member 86. The marking system 160 further includes a second marking element 164 provided on an outer surface of the second housing member 88.The first and second marking elements 162, 164 are arranged on the first and second housing elements 86, 88 in such a position that they are arranged offset relative to one another in the circumferential direction of the piston 70 when the piston release mechanism 154 is not activated, but are arranged in alignment with one another when the piston release mechanism 154 is activated, cf. . Fig. 34b and Fig. 34c.

[0090] The injection device 10 further comprises a limiting mechanism 166 adapted to limit the movement of the first and second metering surfaces 146, 148 to release the metering element 144 from the first metering surface 146 and to align the metering element 144 with the second metering surface 146, see Fig. 16 and Fig. 20. The limiting mechanism 166 includes a first limiting element 168 provided on the first housing member 86, which supports the first and second metering surfaces 146, 148. The limiting mechanism 166 further includes a second limiting element 170 provided on the second housing member 88, which remains stationary when the first housing member 86 is rotated to deactivate the first piston stop mechanism 140. The first limiting element 168 abuts the second limiting element 170 when the metering element 144 is released from the first metering surface 146 and aligned with the second metering surface 148 due to rotation of the first housing member 86 relative to the piston 70. The limiting mechanism 166 prevents a user of the injection device 10 from excessively rotating the first housing member 86 relative to the second housing member 88.In addition, the limiting mechanism 166 provides the user with haptic feedback that the first piston stop mechanism 140 has been deactivated.

[0091] A second locking mechanism 172 serves to exert a holding force that holds the first housing element 86 in its current position relative to the second housing element 88. The presence of the second locking mechanism 172 requires active manual actuation to rotate the first housing element 86 relative to the second housing element 88. The second locking mechanism 172 thus prevents unwanted displacement of the first housing element 86 relative to the second housing element 88 and thus unwanted activation of the piston release mechanism 154. The second locking mechanism 172 comprises a friction element 174, which is provided on the first limiting element 168 of the limiting mechanism 166 and which is suitable for frictionally engaging the holding element 158 ​​of the second housing element 88.The injection device 10 further comprises an activation mechanism 176 which is suitable for preventing activation of the piston release mechanism 154 when the piston 70 is not arranged in the first dosing position P1, and which is suitable for enabling activation of the piston release mechanism 154 when the piston 70 is arranged in the first dosing position P1 (see . Fig. 12, Fig. 16 and Fig. 19a). In particular, the activation mechanism 176 prevents rotation of the first housing member 86 relative to the piston 70 and thus prevents movement of the metering element 144 and the first metering surface 144 relative to each other when the piston 70 is not arranged in the first metering position P1.

[0092] The activation mechanism 176 comprises the guide channel 94, which is provided on the circumferential surface of the piston 70, extends along the longitudinal axis of the piston 70, and accommodates the guide element 92 provided on the first housing element 86 such that the guide channel 94 is displaced relative to the guide element 92 upon displacement of the piston 70 relative to the injection solution container 30. An interaction between the guide element 92 and opposite side surfaces of the guide channel 94 prevents rotation of the piston 70 and the first housing element 86 relative to one another. The activation mechanism 176 thus fulfills the dual function of ensuring a guided displacement of the piston 70 in the direction of its longitudinal axis and, at the same time, preventing unintentional deactivation of the first piston stop mechanism 140 when the piston 70 is not arranged in the first dosing position.

[0093] The activation mechanism 176 further includes an activation channel 178, which branches off from the guide channel 94 and extends in a circumferential direction of the piston 70 substantially perpendicular to the guide channel 94. The activation channel 178 receives the guide element 92 when the piston 70 is arranged in the first metering position P1 and the first housing element 86 is rotated relative to the piston 70. The first metering position P1 of the piston 70 is thus defined by the position of the activation channel 178 along the longitudinal axis of the piston 70.

[0094] Finally, the piston release mechanism 154 also includes a locking assembly 180 that locks the first metering surface 146 in position relative to the metering element 144 after the first metering surface 146 has been moved relative to the metering element 144 to release it from the metering element 144, see Fig. 17, Fig. 21 and Fig. 25. In particular, the locking assembly 180 comprises a resilient locking clip 182 provided on the second housing member 88 and which, by cooperating with a locking member 184 provided on the first housing member 86, is resiliently pushed out from a rest position when the first metering surface 146 is moved relative to the metering member 144 to release it from the metering member 144, ie when the first housing member 86 is rotated relative to the second housing member 88.

[0095] The locking clip 182 deforms back to its rest position after the movement of the first metering surface 146 has ended, i.e., after the rotation of the first housing member 86 has ended, and cooperates with the locking element 184 to lock the first housing member 86 relative to the second housing member 88 and the piston 70. In particular, the locking clip 182 cooperates with the locking element 184 to prevent counter-rotation of the first housing member 86 relative to the second housing member 88 and the piston 70 after the first housing member 86 has been rotated once to release the first metering surface 146 from the metering element 144 and align the second metering surface 148 with the metering element 144. This locks the first metering surface 146 in position relative to the metering element 144.The locking arrangement 180 allows the piston release mechanism 154 to be used only once to deactivate the first piston stop mechanism 140. This prevents reuse of the injection device 10.

[0096] After completion of the rotational movement of the first housing element 86 relative to the second housing element 88 with the piston 70 arranged in its first dosing position P1, the dosing element 144 is aligned with the recess 152 formed in the first dosing surface 146. Consequently, the stop surface 150 of the dosing element 144 is arranged parallel to the second dosing surface 148 at a distance S. As a result, the piston 70 can be displaced further from the first dosing position P1 in the distal direction by the distance S into the second dosing position P2 until the dosing element 144, i.e. its stop surface 150, rests against the second dosing surface 148, cf. Fig. 34c and Fig.34d. Like the first piston stop mechanism 140, the second piston stop mechanism 142 also provides a hard stop for the piston 70, i.e., it prevents the piston 70 from being displaced distally from the second dosing position P2 relative to the injection solution container 30. The dose of the injection solution to be administered to a patient can thus be adjusted particularly precisely. points 1. Injection device (10) comprising: - an injection solution container (30); - a piston (70), at least a part of which is slidably received by the injection solution container (30), the piston (70) being displaceable relative to the injection solution container (30) in a distal direction in order to eject an injection solution contained in the injection solution container (30) from the injection solution container (30); - a first piston stop mechanism (140) designed to stop displacement of the piston (70) relative to the injection solution container (30) in the distal direction at a first dosing position (P1); and - a second piston stop mechanism (140) designed to stop a displacement of the piston (70) relative to the injection solution container (30) from the first dosing position (P1) in the distal direction at a second dosing position (P2), wherein the first and second dosing positions (P2) of the piston (70) are selected such that the piston (70), when displaced relative to the injection solution container (30) between the first and second dosing positions (P2), is suitable for ejecting a desired dose of the injection solution contained in the injection solution container (30) from the injection solution container (30). 2. Injection device according to point 1, wherein the first piston stop mechanism (140) comprises a metering element (144) attached to the piston (70) and configured to engage a first metering surface (146) provided on a housing element (86), and / or wherein the second piston stop mechanism (140) comprises a metering element (144) attached to the piston (70) and configured to engage a second metering surface (148) provided on a housing element (86). 3. Injection device according to point 1 or 2, wherein the first piston stop mechanism (140) is adapted to prevent the piston (70) from being displaced relative to the injection solution container (30) from the first dosing position (P1) in the distal direction, and wherein the injection device (10) further comprises a piston release mechanism (154) adapted to deactivate the first piston stop mechanism (140) to enable displacement of the piston (70) relative to the injection solution container (30) from the first closed position (P1) in the distal direction. 4. Injection device according to points 2 and 3, wherein the piston release mechanism (154) is adapted to enable movement of the dosing element (144) and / or the first dosing surface (146) to release the dosing element (144) from the first dosing surface (146), wherein the movement of the dosing element (144) and / or the first dosing surface (146) is in particular a rotational movement. 5. Injection device according to point 2 and one of points 3 or 4, wherein the first and second dosing surfaces (148) are arranged offset relative to one another in a circumferential direction of the piston (70), and wherein the piston release mechanism (154) is suitable for displacing the first and second dosing surfaces (148) in the circumferential direction of the piston (70) in order to release the dosing element (144) from the first dosing surface (146) and simultaneously align the second dosing surface (148) with the dosing element (144) such that the dosing element (144) bears against the second dosing surface (148) when the piston (70) reaches the second dosing position (P2) after having been displaced relative to the injection solution container (30) from the first dosing position (P1) in the distal direction. 6. Injection device according to one of points 2 to 5, wherein the first and second metering surfaces (148) are formed on a first housing element (86) which is rotatable relative to the piston (70), wherein the second metering surface (148) is defined in particular by a bottom surface of a recess (152) formed in the first metering surface (146). 7. Injection device according to one of points 3 to 6, wherein the piston release mechanism (154) comprises a marking system (160) configured to indicate activation of the piston release mechanism (154). 8. Injection device according to one of points 3 to 7, further comprehensive: - an activation mechanism (176) which is suitable for preventing activation of the piston release mechanism (154) when the piston (70) is not arranged at the first dosing position (P1) and which is suitable for enabling activation of the piston release mechanism (154) when the piston (70) is arranged at the first dosing position (P1). 9. Injection device according to point 8, wherein the activation mechanism (176) has a guide channel (94) which is provided on a circumferential surface of the piston (70), which extends along a longitudinal axis of the piston (70) and which receives a guide element (92) provided on a housing element (86) in such a way that the guide channel (94) is displaced relative to the guide element (92) upon displacement of the piston (70) relative to the injection solution container (30), wherein an interaction between the guide element (92) and opposite side surfaces of the guide channel (94) prevents rotation of the piston (70) and the housing element (86) relative to one another. 10. Injection device according to point 9, wherein the activation mechanism (76) further comprises an activation channel (178) branching off from the guide channel (94) and adapted to receive the guide element (92) when the piston (70) is arranged in the first dosing position (P1) and the housing element (86) carrying the guide element (92) is rotated relative to the piston (70). 11. Injection device according to one of points 3 to 10, wherein the piston release mechanism (154) further comprises a locking assembly (180) configured to lock the first metering surface (146) in position relative to the metering member (144) after the first metering surface (146) has been moved relative to the metering member (144) to disengage from the metering member (144). 12. Injection device according to point 11, wherein the locking arrangement (180) comprises a resilient locking clip (182) which is designed to be resiliently pushed out of a rest position by cooperation with a locking element (184) when the first metering surface (146) is moved relative to the metering element (144) so ​​that it detaches from the metering element (144), and which is further designed to deform back to its rest position after completion of the movement of the first metering surface (146) and to cooperate with the locking element (184) in order to lock the first metering surface (146) in its position relative to the metering element (144). 13. Injection device according to one of points 2 to 12, further comprehensive: - a limiting mechanism (166) adapted to limit movement of the dosing element (144) and / or the first dosing surface (146) and / or the second dosing surface (148) in order to release the dosing element (144) from the first dosing surface (146) and to align the dosing element (144) with the second dosing surface (148), wherein the limiting mechanism (166) comprises in particular a first limiting element (168) provided on a first housing element (86) carrying the first and second dosing surfaces (148), and adapted to abut against a second limiting element (170) provided on a second housing element (88) when the dosing element (144) is released from the first dosing surface (146) and aligned with the second dosing surface (148). 14. Injection device according to one of items 1 to 13, and at least one of the following elements: - a first locking mechanism (116) which is suitable for exerting a holding force which holds the piston (70) in its current position, wherein the first locking mechanism (116) comprises in particular a resettable locking element (118) which is suitable for exerting a resettable holding force on the piston (70), and - a second locking mechanism (172) which is suitable for exerting a holding force which holds the first housing element (86) in its current position, wherein the second locking mechanism (172) comprises in particular a friction element (174) which is provided on the first limiting element (168) of the limiting mechanism (166) and which is suitable for cooperating with a holding element (158) of the second housing element (88). 15. Injection device according to one of items 1 to 14, further comprehensive: - a piston positioning mechanism (98) designed to prevent displacement of the piston (70) relative to the injection solution container (30) from a proximal end position in a proximal direction. 16. Injection solution transfer system (100) comprising: - an injection device (10) according to one of items 1 to 15; and - a filling adapter (12) for connecting a syringe (14) containing an injection solution to the injection device (10) in order to fill the injection solution container (30) of the injection device (10) with the injection solution from the syringe (14). List of reference symbols 100 Injection solution transfer system 10 Injection device 12 filling adapters 14 syringes 16 hollow sleeve 18 Adapter element 20 first connection port 22 second connection port 23 holding shoulders 24 crush ribs 25 female Luer cone (of the first connection port) 26 passage opening 26a Inlet section (of the passage opening) 26b Intermediate section (of the passage opening) 26c Receiving section (of the through opening) L1 Longitudinal axis (of the filling adapter) L2 Longitudinal axis (of the injection device) 27 cannula 28 plunger (of the syringe) 30 injection solution containers 32 resettable clip 34 Collar (of the syringe) 36 Arm (of the resettable clip) 38 recess 40 locking lug (of the spring clip) 42 first gripping structure 44 outer cylinder 46 flange element 48 male Luer cone (of the injection solution container) 50 female Luer cone (of the second connection port) 52 Luer connection (of the outer cylinder) 54 Luer connection (of the second connection port) 56 second gripping structure 58 guide ribs 64 Ventilation device 66 Radial bore 68 air gap 70 pistons 72 operating button 74 top element 76 Piston rod 78 point barbs 80 barb receptacle 82 Sealing element D Distance distal tip of the plunger / distal tip of the cannula 83 observation windows 84 housings 86 first housing element 88 second housing element 90 piston through hole 92 guide element 94 guide channel 96 mounting channel 98 Piston positioning mechanism 102 distal end surface (of the guide channel) 104 Interference pin 106 Interference socket 108 Alignment pin 110 Alignment bushing 112 Mounting area (for mounting the flange element) 114 Piston guide 116 first inhibition mechanism 118 resettable locking element 120 inhibitory rib 122 Piston locking mechanism 124 Lever element 126 Hinge 128 axis of rotation 130 foot elements 132 locking edge 134 Stop device 136 Stop surface (of the piston) 138 Holding device 140 first piston stop mechanism 142 second piston stop mechanism P1 first dosing position P2 second dosing position 144 Dosing element 146 first dosing area 148 second dosing area S Distance first dosing area / second dosing area 150 Stop surface (of the dosing element) 152 recess 154 Piston release mechanism 156 Retaining recess 158 Holding element 159 Gripping structure 160 marking system 162 first marking element 164 second marking element 166 Limiting mechanism 168 first boundary element 170 second boundary element 172 second inhibition mechanism 174 Friction element 176 Activation mechanism 178 Activation channel 180 locking arrangement 182 resilient locking clip 184 locking element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2002 / 052578 A1

[0003] WO 2005 / 121176

[0014]

Claims

[1] Injection device (10), consisting of: - an injection solution container (30); - a piston (70), at least a part of which is slidably received by the injection solution container (30), wherein the piston (70) is displaceable relative to the injection solution container (30) in a distal direction in order to eject an injection solution contained in the injection solution container (30) from the injection solution container (30); - a first housing member (86) rotatable relative to the piston (70), a first metering surface (146) and a second metering surface (148) being formed on the first housing member (86), the second metering surface (148) being defined by a bottom surface of a recess (152) formed in the first metering surface (146); - a first piston stop mechanism (140) adapted to stop a displacement of the piston (70) relative to the injection solution container (30) in the distal direction in a first dosing position (P1), wherein the first piston stop mechanism (140) comprises a dosing element (144) attached to the piston (70) and adapted to bear against the first dosing surface (146); - a second piston stop mechanism (142) adapted to stop a displacement of the piston (70) relative to the injection solution container (30) from the first dosing position (P1) in the distal direction at a second dosing position (P2), wherein the second piston stop mechanism (142) comprises the dosing element (144) attached to the piston (70) and adapted to bear against the bottom surface of the recess (152) formed in the first dosing surface (146), wherein the first and second dosing positions (P1, P2) of the piston (70) are selected such that the piston (70), when displaced relative to the injection solution container (30) between the first dosing position (P1) and the second dosing position (P2), is adapted to dispense a desired dose of the injection solution contained in the injection solution container (30) from the injection solution container (30) emits; and - a locking arrangement (180) adapted to lock the first metering surface (146) in its position relative to the metering element (144) after the first metering surface (146) has been moved relative to the metering element (144) to release it from the metering element (144). [2] Injection device according to claim 1, wherein, when the piston (70) is arranged in its first dosing position (P1) and the dosing element (144) abuts the first dosing surface (146), the second dosing surface (148) can be aligned with the dosing element (144) by a rotational movement of the first housing part (86). [3] The injection device according to claim 1 or 2, wherein the first piston stop mechanism (140) is configured to prevent the piston (70) from being displaced relative to the injection solution container (30) from the first dosing position (P1) in the distal direction, and wherein the injection device (10) further comprises a piston release mechanism (154) configured to deactivate the first piston stop mechanism (140) to allow displacement of the piston (70) relative to the injection solution container (30) from the first dosing position (P1) in the distal direction. [4] Injection device according to claim 3, wherein the piston release mechanism (154) is designed to enable movement of the dosing element (144) and / or the first dosing surface (146) to release the dosing element (144) from the first dosing surface (146), wherein the movement of the dosing element (144) and / or the first dosing surface (146) is in particular a rotational movement. [5] Injection device according to one of claims 3 or 4, wherein the first and second dosing surfaces (148) are arranged offset from one another in a circumferential direction of the piston (70), and wherein optionally the piston release mechanism (154) is suitable for displacing the first dosing surface (146) and the second dosing surface (148) in the circumferential direction of the piston (70) in order to release the dosing element (144) from the first dosing surface (146) and at the same time to align the second dosing surface (148) with the dosing element (144) so ​​that the dosing element (144) abuts the second dosing surface (148) when the piston (70), after having been displaced relative to the injection solution container (30) from the first dosing position (P1) in the distal direction, reaches the second dosing position (P2). [6] An injection device according to any one of claims 3 to 5, wherein the piston release mechanism (154) comprises a marking system (160) configured to indicate activation of the piston release mechanism (154). [7] Injection device according to one of claims 1 to 6, further comprising a guide channel (94) which is provided on a peripheral surface of the piston (70), which extends along a longitudinal axis of the piston (70) and which receives a guide element (92) provided on the first housing element (86) in such a way that the guide channel (94) is displaced relative to the guide element (92) upon displacement of the piston (70) relative to the injection solution container (30), wherein an interaction between the guide element (92) and opposite side surfaces of the guide channel (94) prevents rotation of the piston (70) and the first housing element (86) relative to one another. [8] Injection device according to one of claims 3 to 7, further comprising: - an activation mechanism (176) which is suitable for preventing activation of the piston release mechanism (154) when the piston (70) is not arranged in the first dosing position (P1) and which is suitable for enabling activation of the piston release mechanism (154) when the piston (70) is arranged in the first dosing position (P1). [9] Injection device according to claim 8, wherein the activation mechanism (176) further comprises an activation channel (178) branching off from the guide channel (94) and adapted to receive the guide element (92) when the piston (70) is arranged in the first dosing position (P1) and the housing element (86) carrying the guide element (92) is rotated relative to the piston (70). [10] An injection device according to any one of claims 3 to 9, wherein the locking arrangement (180) is included in the piston release mechanism (154). [11] The injection device of claim 10, wherein the locking assembly (180) comprises a resilient locking clip (182) configured to be resettably urged out of a rest position by cooperation with a locking member (184) when the first metering surface (146) is moved relative to the metering member (144) so ​​as to disengage from the metering member (144), and further configured to deform back to its rest position upon completion of movement of the first metering surface (146) and to cooperate with the locking member (184) to lock the first metering surface (146) in position relative to the metering member (144). [12] Injection device according to one of claims 1 to 11, further comprising: - a limiting mechanism (166) adapted to limit movement of the dosing element (144) and / or the first dosing surface (146) and / or the second dosing surface (148) in order to release the dosing element (144) from the first dosing surface (146) and to align the dosing element (144) with the second dosing surface (148), wherein the limiting mechanism (166) comprises in particular a first limiting element (168) provided on the first housing element (86) carrying the first and second dosing surfaces (148), and adapted to abut against a second limiting element (170) provided on the second housing element (88) when the dosing element (144) is released from the first dosing surface (146) and aligned with the second dosing surface (148). [13] Injection device according to one of claims 1 to 12, which further comprises at least one of the following features: - a first locking mechanism (116) which is suitable for exerting a holding force which holds the piston (70) in its current position, wherein the first locking mechanism (116) comprises in particular a resettable locking element (118) which is suitable for exerting a resettable holding force on the piston (70), and - a second locking mechanism (172) which is suitable for exerting a holding force which holds the first housing element (86) in its current position, wherein the second locking mechanism (172) comprises in particular a friction element (174) which is provided on the first limiting element (168) of the limiting mechanism (166) and which is suitable for cooperating with a holding element (158) of the second housing element (88). [14] Injection device according to one of claims 1 to 13, further comprising: - a piston positioning mechanism (98) designed to prevent displacement of the piston (70) relative to the injection solution container (30) from a proximal end position in a proximal direction. [15] Injection solution transfer system (100) comprising: - an injection device (10) according to one of claims 1 to 14; and - a filling adapter (12) for connecting a syringe (14) containing an injection solution to the injection device (10) in order to fill the injection solution container (30) of the injection device (10) with the injection solution from the syringe (14).

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