Syringe device for easy automatic cannulation and withdrawal

Abstract

A syringe for use with a primary package. The syringe includes: a distal housing component and a proximal housing component in a stacked engagement; a rod configured to move axially with the distal housing component; and a mechanism for releasably securing the rod to a plunger to allow specified axial movement of the rod and plunger over a first distance during stacking of the distal and proximal housing components, and relative axial movement of the rod and plunger over a subsequent second distance during stacking of the distal and proximal housing components. The mechanism includes two or more flexible fingers on one of the rod and plunger and mating features on the other of the rod and plunger; and a locking member axially movable between a locked position and a released position during stacking, in which the locking member substantially surrounds the flexible fingers, and in the released position, the locking member is axially spaced from the locking fingers.

Description

Technical Field

[0001] The present invention relates to a syringe device that facilitates automatic cannulation retraction, and specifically, but not necessarily, to a syringe device that provides a manually injected dose from a sleeve or syringe. Background Technology

[0002] PCT / GB2019 / 050317 describes a so-called "primary package" which includes a sleeve for containing a drug or "pharmaceutical" that is combined with a cannulation component. This primary package 1, as shown... Figure 1 As shown, the sleeve is identified by reference numeral 2, and the cannula assembly by reference numeral 3. Considering each component in more detail, the sleeve comprises a generally cylindrical glass or plastic body 4 with a movable plug 5 located at an end of the body away from the end to be connected to the cannula assembly. The other end of the body 4 is shaped for connection to the cannula assembly 3 and is closed by a cap 6 comprising a sealing element 7 in the form of a disc-shaped elastic diaphragm. The cannula assembly 3 comprises a cannula 8 adhered to a bushing 9, which in turn is slidably located within a generally cylindrical body 9a. The cannula is enclosed within a safety cap or sheath 10 that engages with the bushing 9. The sheath has an opening therein closed by an antimicrobial barrier 11. The barrier 11 is permeable to air to prevent damage to the device from external pressure fluctuations.

[0003] The sleeve is typically filled with medication in a sterile environment before being sealed by the diaphragm. Then, in the same sterile environment, a cap 6 with an antimicrobial barrier is secured to the body 4, followed by the attachment of the cannula component 3. In this state, the end of the cannula 8 remains away from the sealing element 7, so that there is no fluid communication between the two components 2 and 3.

[0004] WO2019155202 describes an arrangement in which a primary package 1 is installed in a drug delivery device, such as a manually operated syringe or an autoinjector (“autoinjector”). After removing the sheath 10, the first stage of operation is to advance the primary package to a point where further advancement of the cannula component is prevented, while the sleeve continues to advance. This causes the tip of the cannula to penetrate the sealing element, thereby allowing the drug to enter the cannula. Injection can then be performed.

[0005] Known drug delivery devices may not be ideal when user dexterity is limited. For example, in an emergency, a user might experience anaphylactic shock and require an emergency injection of adrenaline. In such cases, a "manual injector" is helpful. This type of injector allows injection to be performed using only one hand, with essentially only the user's fist gripping the device in a "prick" motion. Manual injectors may also be more reliable and robust than auto-injectors.

[0006] One of the challenges in designing suitable manual syringes is ensuring proper protection of the cannula after injection to prevent cannula punctures and to prevent contamination and cross-infection. Similar challenges arise when designing manual syringes suitable for use with syringes.

[0007] WO9421316 describes an injection device for use with a syringe, which utilizes a main drive spring to facilitate cannula insertion and drug delivery. A return spring is configured to push the syringe and its cannula back into the main housing after injection is completed. Summary of the Invention

[0008] According to a first aspect of the invention, a syringe is provided for use with a primary package or syringe including a cannula and a body, the body containing a drug and a plug located within the body. The syringe includes: a substantially cylindrical proximal portion configured to receive at least a portion of the cannula and the body; and a substantially cylindrical distal portion for collapsing engagement with the proximal portion, the distal portion having a distal wall and a member extending axially from the distal wall into a central region of the distal portion.

[0009] The syringe is configured such that applying a force to stack the proximal and distal components together causes the plunger to:

[0010] Push the primary packaging or syringe component through the proximal component, thereby causing the cannula of the cannulation component to protrude from the proximal component;

[0011] The plug is then driven through the body of the sleeve or the syringe body to expel the drug through the cannulation component; and

[0012] The plunger is then disengaged from the distal component to allow the entire primary package or syringe to move distally through the syringe along with the plunger, thereby completely retracting the cannula into the proximal component.

[0013] One of the component and the plunger includes two or more flexible fingers extending in a substantially axial direction, and the other of the component and the plunger includes an engagement feature for engaging the fingers. The syringe also includes a locking member capable of axial movement within the distal component between a first position and a second position.

[0014] In the first position, the locking member surrounds the finger and the engagement feature to prevent relative radial movement of them, thereby securing the member to the plunger, and in the second position, the locking member allows the relative movement to at least partially disengage the member from the plunger.

[0015] During steps a) and b), the locking member is held in the first position, and in step c), the locking member is moved to the second position by means of axial abutment of the locking member with a feature disposed on the inner surface of the proximal member.

[0016] The proximal and distal components may each comprise a generally cylindrical housing, one of which has a larger diameter than the other to facilitate the overlapping engagement. The engagement feature may include one or more recesses. The locking member may be an annular ring positioned substantially coaxially with the distal component.

[0017] The proximal component can be configured to restrict the flexible finger during the collapsing movement of the proximal component and the distal component together from the first position to the second position.

[0018] The syringe may include a compression spring located within the proximal component and coupled to the primary package or syringe body in use, such that the spring is compressed by pushing the primary package or syringe body through the proximal component. The syringe is configured such that disengagement of the plunger and the component allows the spring to extend and cause movement of the entire primary package or syringe component and the plunger distally through the syringe, thereby completely retracting the cannula into the proximal component. The spring may optionally be a helical spring adjacent to the inner surface of the proximal end of the proximal component.

[0019] The syringe can be assembled around the primary package or syringe. The syringe is a manual syringe, whereby the force applied to stack the proximal and distal components together is a manually applied force.

[0020] The syringe may be an auto-injector and includes an energy storage mechanism and a release mechanism, the release mechanism being used to release energy from the storage mechanism to apply the force for stacking the proximal and distal components together.

[0021] The plunger may include a generally cylindrical body that supports the flexible finger, and the engagement feature is provided by means of a contour formed around the member, which may optionally be an elongated member, such as a rod.

[0022] The component can be further connected to the plunger by means of a mating helical thread, the thread optionally having an adhesive applied between them, wherein after the at least partial disengagement, the plunger and the component remain connected by the thread, such that further specified axial movement of the component and the plunger continues until the plunger touches the bottom, thereby causing relative rotation.

[0023] The syringe may include a locking member for preventing relative axial movement of the plunger and the syringe body during cannula insertion, the locking member being released upon completion of insertion. The locking member may include a surface abutting the syringe body and two or more flexible legs capable of deflecting to engage and disengage from the plunger.

[0024] According to a second aspect of the invention, a syringe is provided for use with a primary package or syringe including a cannula and a body containing a drug and a plug located within the body. The syringe has a plunger in the case of the primary package, or utilizes the plunger of the syringe in the case of the syringe. The syringe includes: a distal housing component and a proximal housing component in a stacked engagement; a rod configured to move axially together with the distal housing component; and a mechanism for releasably securing the rod to the plunger to allow specified axial movement of the rod and the plunger at a first distance during the stacking of the distal and proximal housing components, and relative axial movement of the rod and the plunger at a subsequent second distance during the stacking of the distal and proximal housing components. The mechanism includes two or more flexible fingers on one of the rod and the plunger and a mating feature on the other of the rod and the plunger, and a locking member capable of axially moving between a locked position and a released position during stacking, in which the locking member is substantially around the flexible fingers, and in the released position, the locking member is axially spaced from the locking fingers.

[0025] The syringe may include a helical spring capable of being compressed during the stacking of the distal housing component and the proximal housing component. The spring is configured to push the primary package and the plunger or the syringe in a distal direction at a moment after the rod is released from the plunger, to retract the cannula component into the proximal housing component.

[0026] According to a third aspect of the invention, a syringe for use with a syringe includes a cannulation component, a body, and a plunger, the body containing a drug and a plug located within the body. The syringe includes: a distal housing component and a proximal housing component in a collapsed engagement; and a rod configured to move axially with the distal housing component. The syringe further includes:

[0027] A first mechanism for releasably securing the rod to the plunger to allow specified axial movement of the rod and the plunger at a first distance during the stacking of the distal housing component and the proximal housing component, and relative axial movement of the rod and the plunger at a subsequent second distance during the stacking of the distal housing component and the proximal housing component;

[0028] A second mechanism is used to maintain engagement of the rod and the plunger after the first mechanism releases the rod and the plunger. The second mechanism includes mating threads on the rod and the plunger to prevent or limit relative axial movement of the rod and the plunger substantially until the plunger reaches the dose-end position, and thereafter allows the plunger and the rod to disengage by relative rotation.

[0029] The syringe may include a helical spring compressible during the stacking of the distal and proximal housing components. The spring is configured to push the primary package and the plunger or syringe in a distal direction at a moment after the rod has disengaged from the plunger by the relative rotation, to retract the cannula component into the proximal housing component.

[0030] According to another aspect of the invention, a syringe is provided for use with a primary package or syringe comprising a cannulation component and a body, the body containing a drug and a plug located within the body, the syringe having a plunger in the case of the primary package, or utilizing the plunger of the syringe in the case of the syringe, the syringe comprising:

[0031] Presented as a stacked joint of distal and proximal housing components;

[0032] A mechanism for releasably securing the plunger relative to the primary package or syringe body to allow for specified axial movement of the plunger and the primary package or syringe body during a needle insertion phase, and for releasing the plunger from the primary package or syringe body after needle insertion.

[0033] The mechanism may include two or more flexible legs suspended from a base member passing through the plunger, and mating features on the plunger for engaging with the flexible legs.

[0034] According to another aspect of the invention, a set of components for assembly into a syringe according to any of the foregoing aspects is provided, the components surrounding a primary package or syringe.

[0035] According to another aspect of the invention, a syringe is provided for use with a primary package, the primary package including a cannula and a sleeve, the sleeve including a body containing a drug and a plug located within the body. The syringe includes a proximal portion configured to receive at least a portion of the cannula and the sleeve, a distal portion for collapsing engagement with the proximal portion, and a plunger releasably engaged within the distal portion to engage the plug. The syringe is configured such that applying a force to collapsing the proximal and distal portions together causes the plunger to act on the plug to push the primary package through the proximal portion, thereby causing the cannula of the cannula to protrude from the proximal portion, subsequently driving the plug through the body of the sleeve to expel the drug through the cannula, and subsequently disengaging the plunger from the distal portion to allow the entire primary package and plunger to move distally through the syringe, thereby completely retracting the cannula into the proximal portion.

[0036] The proximal and distal components may each comprise a generally cylindrical housing, one of which has a larger diameter than the other to facilitate the stacked engagement. The syringe may also include one or more radially movable fingers coupled to the cylindrical housing of the distal component, and one or more features disposed in or on the plunger for engaging with the one or more radially movable fingers to facilitate the releasable engagement of the plunger with the distal component. The one or more radially movable fingers may be coupled to one or more corresponding flexible arms extending substantially axially from the distal end of the housing through the cylindrical housing of the distal component. Features disposed on the plunger may include one or more recesses.

[0037] The syringe may include a limiting member located within a distal component, the limiting member being movable distally from an initial pre-injection position to a post-injection position, wherein in the initial pre-injection position the limiting member restricts radially outward movement of the fingers, and in the post-injection position the limiting member does not restrict radially outward movement of the fingers. The limiting member may be an annular ring coaxially positioned with the cylindrical housing of the distal component. The device may be configured such that the proximal and distal components collapsing together for a first predetermined distance, corresponding to an injection end distance, such that the limiting member engages with one or more features of the proximal component, thereby moving the limiting member from the pre-injection position to the post-injection position. The cylindrical housing of the proximal component may be configured to further restrict one or more flexible fingers during a second predetermined distance of collapsing movement of the proximal and distal components together after the first predetermined distance of collapsing movement.

[0038] The syringe can be configured such that, after a first predetermined distance or a second predetermined distance of collapsing movement, a further collapsing movement of the proximal and distal components together releases one or more fingers to move radially outward, thereby causing the plunger and distal component to disengage. Disengagement of the plunger and distal component may allow the plunger to pass over the flexible arms or between each flexible arm.

[0039] The syringe may include a compression spring, such as a helical compression spring, located within the proximal component and coupled to the primary package in use, such that the spring is compressed by pushing the primary package through the proximal component. The syringe is configured such that the disengagement of the plunger and the distal component allows the spring to extend and causes the entire primary package and plunger to move through the syringe in the distal direction, thereby completely retracting the cannula into the proximal component.

[0040] According to one aspect of the invention, the syringe is provided as a set of components for assembly around a primary package. Alternatively, the syringe may be assembled around a primary package.

[0041] The syringe can be a manual syringe, whereby the force applied to stack the proximal and distal parts together is manual.

[0042] The syringe may be an auto-injector and includes an energy storage mechanism and a release mechanism for releasing energy from the storage mechanism to apply the force for stacking the proximal and distal parts together.

[0043] According to another aspect of the invention, a syringe is provided for use with a primary package, the primary package including a cannula and a sleeve, the sleeve including a body containing a drug and a plug located within the body. The syringe includes a generally cylindrical proximal part defining an internal space for receiving at least a portion of the cannula and the sleeve, a generally cylindrical distal part for collapsing engagement with the proximal part, and a plunger within the internal space defined by the distal part, the plunger having a proximal end for engagement with the plug. The syringe also includes one or more fingers fixed relative to the distal part, the fingers(plural) engaging one or more features defined at the distal end of the plunger to provide releasable engagement of the plunger within the distal part, and a locking mechanism disposed on the fingers(plural) to prevent disengagement from the features until the locking mechanism engages with the distal end of the proximal part and is pushed in a distal direction within the distal part. Attached Figure Description

[0044] Figure 1 It is a cross-sectional view of a known primary package including a sleeve and cannula for assembly in a sterile environment;

[0045] Figure 2 Is with Figure 1 A cross-sectional view of the proximal component of a manual syringe used in conjunction with the primary package;

[0046] Figure 3 Is with Figure 1 A cross-sectional view of the distal component of a manual syringe used in conjunction with the primary package;

[0047] Figure 4 It includes Figure 2 Proximal components and Figure 3 A cross-sectional view of a manual syringe with a distal component, wherein the syringe includes Figure 1 The (assembled) primary package is in a pre-use state;

[0048] Figure 5 The top cover of the far end was removed. Figure 4 A cross-sectional view of a manual syringe;

[0049] Figures 6 to 10 It is a cross-sectional view of a manual syringe at various stages of the injection operation;

[0050] Figure 11 This is a perspective view of an assembled manual syringe used with a primary package according to an alternative embodiment;

[0051] Figure 12 It includes primary packaging. Figure 11 An exploded view of a manual syringe;

[0052] Figure 13 It shows Figure 11 A series of states of a manual syringe during use;

[0053] Figure 14 It shows Figure 11 The plunger and rod of the syringe;

[0054] Figure 15 This is a perspective view of an assembled manual syringe according to an alternative embodiment and used with a syringe including a plunger;

[0055] Figure 16 It includes syringes. Figure 15 An exploded view of a manual syringe;

[0056] Figure 17 It shows Figure 15 A series of states of a manual syringe during use. Detailed Implementation

[0057] The above has been referenced Figure 1 A known primary package 1 for containing a drug or pharmaceutical agent is described. A manual syringe will now be described that facilitates injection using this known primary package or other primary packages with a similar configuration. For ease of understanding, reference is made to the proximal and distal ends of the syringe and package 1, where "proximal" refers to the end closest to the tip of the cannula and the skin during use, and "distal" refers to the end furthest from the tip of the cannula and the skin during use. Note that in the context of the following discussion, the terms "needle" and "cannula" are used interchangeably, and the use of one term encompasses the use of the other, although the exact technical meaning of each term may differ.

[0058] Figure 2 A proximal portion 20 of a manual syringe 21 is shown, comprising a generally cylindrical housing 22 shaped to receive and accommodate a primary package 1. While the housing is generally open at its distal end, it has an end wall 23 at its proximal end. The end wall has a centrally located circular opening 24. A compression spring 25 is located within the housing 22 and, in the unassembled state, is positioned as follows: Figure 2 The uncompressed state is shown. The top cover or "shelter removal piece" 26 is also generally cylindrical, concentrically located on the housing 22, and secured in place by, for example, a suitable snap-fit ​​or interference fit. The proximal end of the sheath removal piece 26 is closed to cover the circular opening 24. While the spring 25 may (but is not required to) be formed of metal, other parts of the proximal component may be formed using plastic materials and injection molding processes, but other materials and manufacturing processes may also be used.

[0059] Figure 3 The distal component 30 of a manual syringe 21 is shown. This distal component includes a generally cylindrical housing 31, which is closed at the distal end by a wall 32 and open at the proximal end. A pair of flexible arms 33a, 33b hang from the distal wall 32 and extend axially, partially passing through the cylindrical housing 31. [In some cases, three or more arms may be provided.] These arms terminate in corresponding fingers 34a, 34b, which extend radially inward and outward a small portion, i.e., the fingers have a “T-like” shape. A generally cylindrical plunger 35, concentrically located within the cylindrical housing 31, is formed to provide a substantially V-shaped recess 36 that extends circumferentially around a region near the distal end of the plunger. The innermost radial ends of the fingers 34a and 34b are formed with complementary V-shapes, such that during assembly, when the plunger is pushed into the housing 31 from the open end, the fingers 34a and 34b engage with and interlock in the recess 36. The plunger 35 is otherwise unrestricted within the housing 31. An annular ring 37, with an outer diameter slightly smaller than the inner diameter of the housing 31 and an inner diameter slightly larger than the outer extent of the fingers 34a and 34b (when the fingers are engaged in the recess 36 of the plunger), surrounds the fingers and is prevented from moving proximally within the housing 31 by one or more suitable features of the housing. The ring 37 is also prevented from moving distally within the housing by one or more features, but the resistance provided can be overcome to allow such movement, as described below. Similarly, all components of the distal component 30 may be formed using plastic materials and injection molding processes, but other materials and manufacturing processes may also be used.

[0060] Figure 4 A manual syringe 21 assembled around a primary package 1 is shown. Assembly involves first inserting the primary package into the open end of the proximal component 20. The primary package is pressed in such that features on the end of the sheath 10 engage with complementary features of the sheath removal member 26 in a known manner. The open end of the distal component 30 is positioned on and around the end of the proximal component such that the proximal end of the plunger 35 abuts against a movable plug 5 within the sleeve body 4. In this position, complementary features of the distal component housing 31 and the proximal component housing 22 engage to secure the two components together. These complementary features may be snap-fit ​​features, but other forms of engagement, such as threads, are also conceivable. Figure 4It is evident that, in this assembled, pre-use state, little or no force is applied between the sleeve 2 and the cannula bushing 9 (or cannula 8), keeping the distal end of the cannula 8 spaced apart from the sealing element 7. The spring 25 acting between the housing 31 and the cylindrical body 9a of the cannula assembly is relaxed and largely uncompressed. Features of the proximal and distal components (e.g., the same features securing the components together) provide resistance to further movement of the proximal component towards the distal component, resistance that must be overcome to initiate injection. Furthermore, any such movement is prevented by the sheath removal member 26, which engages in a blocking manner with the housing 31 of the distal component. Figure 4 The syringe configuration shown is typically the configuration in which the syringe is provided to the end user or healthcare professional. It will be understood that the design presented herein facilitates the use of low-cost and environmentally friendly materials due to the absence of a storage load.

[0061] Figure 5 The first step of operation of the manual syringe 21 is shown, in which the sheath removal member 26 has been pulled out from the proximal part 20. This action also pulls the sheath 10, captured by the sheath removal member, out from the cannula part 3, thereby exposing the proximal end of the cannula 8 within the proximal part 20. This breaks the sterile barrier. A latch or simple “bump” is provided between the bushing 9 and the body 9a of the cannula part to prevent the sheath removal step from pulling the bushing forward and potentially damaging the cannula or causing the cannula to come into contact with the sealing element 7.

[0062] Injection can then be performed. This typically involves the user grasping the distal part 30 within his or her fist and pressing against the proximal end of the syringe against the injection site. This is usually done with a piercing motion, allowing for rapid and continuous cannula penetration and injection. For illustrative purposes, Figures 6 to 10 The various stages of the injection process are shown.

[0063] Figure 6 This is illustrated in a stage where the force applied between the proximal and distal components causes the plunger 35, which engages with the fingers 34a, 34b, to advance into the proximal component, thereby applying force to the plug 5 as the plunger 35 proceeds. The spring 25 initially provides minimal resistance to the primary package 1, allowing it to advance through the proximal component. This causes the tip of the cannula 8 to exit through the opening 24 in the proximal component and penetrate the skin at the injection site. The tip of the cannula continues to advance until the needle liner 9 touches the end wall 23 of the housing 22. This is Figure 6 The location shown.

[0064] As the user continues to apply force between the distal component and the skin, the bushing 9 and the cannula 8 between the distal and proximal components are pushed back through the cylindrical body 9a, causing the distal tip of the cannula to pass through the sealing element 7, thereby enabling the flow channel of the cannula to communicate with the drug fluid. This position is as follows... Figure 7 As shown. Note that the fingers 34a and 34b remain trapped within the ring 37, and so far, the fingers 34a and 34b have not moved relative to the housing 31 of the distal component 30.

[0065] At this stage, further movement of the cannula and bushing is prevented, as is any movement of the primary package 1 in the proximal direction. Further force applied by the user will now cause the plunger 35 and plug 5 to pass through the sleeve body 4 of the primary package, thereby delivering the medication through the cannula 8 and into the injection site. During this process, the fingers 34a, 34b are held captive within the ring 37. Medication delivery is completed when the proximal component has advanced some predetermined distance into the distal component. This is in Figure 8 As shown in the diagram. At this stage, ring 37 abuts against the distal end 27 of the proximal component, where the continued applied force overcomes the resistance to distal movement of the ring within the housing 31, and moves the ring back within the housing. Now, the fingers pass through the distal end 27, in which case the fingers continue to be restricted from any outward radial movement. However, upon leaving the distal end 7, the fingers enter the central space within the proximal component, at which point any resistance to radial outward movement of the fingers 34a, 34b disappears. Figure 9 The diagram illustrates the operational state of the syringe with the finger positioned at the point of release from the recess 36 of the plunger 35. Continued relative movement between the proximal and distal components releases the finger, thereby substantially disengaging it from the housing 31 of the plunger 35 and the distal component 30.

[0066] In this operational phase, the spring 25, which is essentially fully compressed, extends freely, thereby pushing the entire primary package 1 and plunger 35 through the proximal component 20 in the distal direction. The fingers are now driven out of the V-shaped recess by the relative movement of the fingers and the plunger, in which the support arms 33a, 33b open outwards. The end of the plunger is received within the space between the fingers 34a, 34b and the arms 33a, 33b, while the cannula is fully retracted into the proximal component, where the tip of the cannula is no longer exposed. This operational state of the syringe is shown in... Figure 10 In this case, the possibility of puncture wounds and contamination / cross-infection is eliminated or at least greatly reduced.

[0067] Figure 11 It shows something like Figure 1 An alternative embodiment of the manual syringe 100 used with the primary package shown. Figure 11 The distal housing portion 101 and the sheath removal part 102 can be seen in the image. Figure 12 This is an exploded view of the manual syringe along the axis of the device. Besides the distal housing portion 101 and the sheath removal member 102, the primary package 103, which includes a sheath 104 (covering the invisible cannula), a plunger 105, a member or rod 106, an annular ring 107, a helical metal spring 108, and a proximal housing portion 109, is also visible in the exploded view. The various components are configured to facilitate assembly of the device around the primary package by bringing the components together along the axis and securing them together in a manner suitable for use, as will become apparent from the description below.

[0068] Figure 13 The operation of the manual syringe is illustrated in a series of steps a through h, where each illustration shows an axial cross-section of the device in the same plane:

[0069] a. The user receives the device in a fully assembled state, the device including a primary package 103 and a sheath removal member 102. As will be apparent from this and other views, the rearmost (i.e., distal) end of the rod 106 abuts the inner end surface of the distal housing portion 101, while the frontmost (i.e., proximal) end of the rod 106 is received by a pair of flexible legs 110a, 110b of a plunger 105, the flexible legs extending upward from the cylindrical body portion 111 of the plunger. The flexible legs are provided with respective protrusions 112a, 112b that extend radially inward to engage with an annular recess 113 formed around the outer surface of the rod 106. In the state shown in the figure, the flexible legs are in an unstressed or relaxed state. An annular ring 107 is positioned around the rod 106 and is releasably held in a desired axial position on the rod by a circumferential protrusion 114 formed on the rod and a mating groove 115 formed around the inner surface of the ring 107. Of course, alternative fixation methods can also be used. In this state, the ring 107 also surrounds the protrusions 112a and 112b of the flexible leg, thereby preventing the leg from bending outward.

[0070] b. The user prepares to use the device by grasping the distal housing portion 101 with one hand and the sheath removal member 102 with the fingers of the other hand, and pulling the two portions apart to remove the sheath removal member and the engaged sheath 104 from the rest of the device and expose the cannula 116 (but still protected within the proximal housing portion).

[0071] c. The user then presses the now exposed end of the proximal housing portion 102 against the skin at the injection site, applying sufficient force to compress the coil spring 108, which is located between the shoulder of the body of the primary package 103 and the end shoulder of the proximal housing portion 109, thereby folding the proximal and distal housing portions together. The distal housing portion has a larger inner diameter than the proximal housing portion, allowing the former to slide over the latter during this folding motion. This action causes the tip of the cannula to extend outward, through an opening in the lower end of the proximal housing portion 109, and through the user's skin. Note that during this phase of operation, the rod 106 is axially fixed relative to the plunger 105 by the annular ring 107, such that the rod, plunger, and primary package (and distal housing portion) move substantially as a single unit relative to the proximal housing portion until the cannula bushing touches the bottom of the end of the proximal housing portion, i.e., the spring is substantially fully compressed. As described with respect to the previous embodiment, since the bushing cannot move further, further movement of the body of the primary package causes the distal end of the cannula to penetrate the diaphragm of the primary package, thereby enabling fluid communication between the internal channels of the cannula and the internal fluid of the body, and allowing medication to flow into the user through the cannula. Note that during this operational phase, rotation of the proximal housing portion relative to the distal housing portion is prevented, for example, by positioning an anti-rotation protrusion of the proximal housing portion within a corresponding track extending coaxially along the inner surface of the distal housing portion.

[0072] d. Continue to apply force to the distal housing portion 101 so that the housing portions continue to stack together and deliver the drug.

[0073] e. When approaching the end of the drug delivery location, the uppermost end of the proximal housing portion 109 contacts the annular ring 107.

[0074] f. After overcoming the relatively small resistance presented by the engagement feature of the rod and the annular ring, continuing to stack the housing portions together causes the uppermost end of the proximal housing portion to push the annular ring 107 upward into the distal housing portion. Since the flexible legs 110a, 110b are no longer prevented from bending outward by the annular ring, the rod 106 is now able to move downward within the plunger, pushing the protrusions 112a, 112b outward as the rod 106 advances.

[0075] g. The flexible fingers and corresponding protrusions now bend inward toward the retaining recess below the protrusions formed on the rod. At this stage, without any mechanism to restrict the relative axial movement of the rod 106 and the plunger 105, the user cannot apply further force to the plunger, as the rod will only enter the plunger. This is undesirable because, due to manufacturing tolerances, the annular ring may prematurely release from the flexible fingers before reaching the dose-end position (and fully delivering the drug dose). Alternatively, the plunger may reach the dose-end position before the locking ring is released. To prevent either situation, the device is configured to ensure that the flexible fingers 111a, 111b are released before reaching the dose-end, taking into account the maximum possible manufacturing tolerances. To ensure that drug delivery can continue beyond this point, the plunger 105 includes short helical threads 117 on its inner surface, which engage with corresponding short threads 118 on the outer surface of the rod 107. The plunger is further shown in Figure 14 a (3D diagram) and Figure 14 In section b (axial section view), rod 106 is further shown in Figure 14 c (3D diagram) and Figure 14 In d (axial section view). By carefully selecting the thread pitch and, if necessary, introducing an adhesive to increase friction between the threads, it can be ensured that even after the release of the flexible fingers, the axial force applied to the rod 106 will continue to be transmitted to the plunger 105, and thus to the plug 119, without necessarily causing relative rotation of the rod and the plunger. When the plug 119 and the plunger 105 have reached the bottom, i.e., after (substantially) all the drug has been expelled, the force continuing to be applied to the rod will cause the rod to rotate relative to the plunger until the external thread 118 on the rod completely disengages from the internal thread 117 on the plunger and enters the internal space within the plunger. At this point, a pair of previously restricted flexible legs 120a, 120b disposed on the outer surface of the proximal housing engage with corresponding openings 121a, 121b disposed in the distal housing portion 101, thereby preventing or limiting further relative axial movement between the proximal and distal housing portions.

[0076] h. Since the threads on the plunger and rod are no longer engaged, the two parts can move freely axially relative to each other. This movement is driven by the now freely extending compression spring 108, which pushes the plunger 105 backward past the rod 106 and back into the distal housing portion 101. This causes the cannula 116 to be completely retracted into the proximal housing portion 109, so that no part of the cannula is exposed and the risk of cannula puncture to the user is prevented.

[0077] Figure 15This is a perspective view of another embodiment of a manual injection device 200, adapted for use with a syringe rather than a primary package. Thus, the plunger forms an integral part of the syringe, rather than the manual injection device itself. However, those skilled in the art will understand that the features and operation of this injection device are similar to those described above. Figures 11 to 14 The features and operation of the described embodiments are explained, and the following description should be understood in light of the foregoing embodiments.

[0078] exist Figure 15 What is visible are the distal housing portion 201 and the sheath removal part 202. Figure 16 This is an exploded view of the manual syringe along the axis of device 200. Besides the distal housing portion 201 and sheath removal member 202, the exploded view also shows a syringe 203, which includes a sheath 204 (covering the invisible cannula), a plunger 213, a member or rod 206, an annular ring 207, a helical metal spring 208, a proximal housing portion 209, and a rod end cap 210. A thin cylindrical metal extrusion 228 is also shown in the figure, which is held against the end cap 202 with outward-facing teeth and against the sheath with inward-facing teeth. This provides a reliable method for removing the sheath. The various components are configured to facilitate assembly of the device 200 around the syringe 203 by bringing the components together along the axis and securing them together in a manner suitable for use, as will become apparent from the following description.

[0079] Figure 17 The operation of the manual syringe is illustrated in the following series of steps a to h, where each illustration shows an axial cross-section of the device:

[0080] a. The user receives the fully assembled device, including the syringe 203 and the sheath removal component 202. As can be clearly seen from this and other views, the rear end of the rod 206 is secured to a rod end cap 210 abutting against the inner end surface of the distal housing portion 201, while the front end of the rod 206 is received by a pair of flexible legs 211a, 211b of the plunger 205 of the syringe, the flexible legs extending upward from the cylindrical body portion 212 of the plunger 213. The flexible legs are provided with corresponding radially inwardly extending protrusions 214a, 214b to engage with an annular recess 215 formed around the outer surface of the rod 206. In the illustrated state, the flexible legs are in an unstressed or relaxed state. An annular ring 207 is positioned around the rod 106 and is releasably held in the desired axial position on the rod by a circumferential protrusion 116 formed on the rod and a mating groove 217 formed around the inner surface of the ring 207. In this state, the ring 207 also surrounds the protrusions 214a and 214b of the flexible leg, thereby preventing the leg from bending outward.

[0081] b. The user prepares to use the device by grasping the distal housing portion 201 with one hand and the sheath removal member 202 with the fingers of the other hand, and pulling the two portions apart to remove the sheath removal member 202 and the engaged sheath 204 from the rest of the device and expose the cannula 218 (but still protected within the proximal housing portion).

[0082] c. and Figure 1 Compared to the primary package shown, the syringe typically includes a distal end of a cannula already in fluid communication with the interior of the syringe body. Therefore, to prevent fluid leakage through the cannula during the cannula insertion phase, a mechanism is provided to prevent axial relative movement between the syringe body and the plunger until this phase is complete. This mechanism includes a locking member 219 having a generally rectangular base 219a defining a central opening therethrough, and a pair of upright legs 220a, 220b extending from the base. In a pre-use state, the protrusions 221a, 221b engage within a recess 222 formed around the outer periphery of the plunger, which would otherwise pass through the central opening in the locking member. The base of the locking member 219 abuts the upper surface of a flange (finger gripper) 223 surrounding the end of the syringe body. During the initial forward movement of the distal housing portion 201 relative to the proximal housing portion 209, the legs 220a, 220b are prevented from outward deflection by the area surrounding the proximal housing portion 209. The compression spring 208 is located between the lower surface of the flange 223 and the shoulder 224 formed around the inner surface of the proximal housing portion 209, such that the spring 208 is compressed during cannula insertion.

[0083] d. After cannula insertion, the legs 220a, 220b move out of the confined area within the proximal housing portion 209 and into an area where they are not so confined. This allows the legs to extend outward, releasing the locking member 219 from the plunger 213, and thus releasing the syringe body. Further force applied by the user to the distal housing portion 201 causes the plunger 213, driven by the lever 206, to move forward within the syringe body, thereby expelling the drug through the cannula 218. It will be understood that the lever and plunger, as described above... Figures 11 to 13 The flexible legs and the annular ring mechanism are fixed together and move axially. Note that when deployed, the protrusions 221a, 221b of the corresponding legs now engage with corresponding recesses in the proximal housing portion 209. This prevents the syringe body from moving rearward into the proximal housing portion. This is important because it prevents withdrawal of the cannula (from the skin) if the user significantly reduces the applied force midway through the insertion process.

[0084] e. At the end of delivery, the protrusions 221a, 221b of each leg engage in the circumferential groove 225 extending around the distal portion of the plunger 213, thereby disengaging the locking member from the proximal housing portion and thus disengaging the syringe body from the proximal housing portion.

[0085] f. As for Figures 11 to 14 As described in the embodiment, the locking ring 107 is now pushed rearward relative to the rod 206, thereby releasing the engagement between the rod and the plunger. Continued force applied to the distal housing portion 201 causes the rod 206 to begin rotating through the plunger 213 via the mating helical threads.

[0086] g. When the mating threads disengage, the distal housing portion and the proximal housing portion reach a relative position, at which a pair of flexible lugs 226a, 226b extending from the outer surface of the proximal housing portion snap outward to engage corresponding openings 227a, 227b provided in the distal housing portion, thereby securing the distal housing portion and the proximal housing portion together.

[0087] h. Rod 206 is now completely disengaged from plunger 213. This allows spring 208 to extend, pushing the entire syringe, including plunger 213, back into the proximal housing portion, thereby completely protecting cannula 218.

[0088] Regarding the issues of post-injection cannulation withdrawal and protection, the mechanism described in the accompanying drawings provides a very simple and concise solution involving the release of the syringe from the device once the medication delivery is complete. While the mechanism is well-suited for use with manual syringes, it can also be effectively integrated into autoinjectors that include force transmission mechanisms (such as springs) to push the plunger through the device.

[0089] Those skilled in the art will understand that various modifications can be made to the above embodiments without departing from the scope of the invention.

Claims

1. A syringe for use with a primary package, the primary package including a cannula and a sleeve, the sleeve including a body containing a drug and a plug located within the body, the syringe comprising: A proximal component, the proximal component being configured to receive at least a portion of the cannulation component and the sleeve; A distal component, the distal component being configured to overlap and engage with the proximal component; as well as A plunger, releasably engaged within the distal component to engage with the plug, the syringe being configured such that applying a force to stack the proximal and distal components together causes the plunger to act on the plug to: Push the primary package through the proximal component, thereby causing the cannula of the cannulation component to protrude from the proximal component; The plug is then driven through the body of the sleeve to expel the drug through the cannulation component; and The plunger is then disengaged from the distal component to allow the entire primary package and the plunger to move distally through the syringe, thereby completely retracting the cannula into the proximal component. The proximal component and the distal component each include a cylindrical housing, and the syringe further includes: One or more radially movable fingers are coupled to one or more corresponding flexible arms that axially extend from the distal end of the housing of the distal component through the cylindrical housing of the distal component. One or more features disposed in or on the plunger, the one or more features engaging with the one or more radially movable fingers to facilitate the releasable engagement of the plunger with the distal component; and A limiting component is located within the distal component and is movable within the distal component in a distal direction from an initial pre-injection position to a post-injection position. In the initial pre-injection position, the limiting component restricts radial outward movement of the finger, and in the post-injection position, the limiting component does not restrict radial outward movement of the finger.

2. The syringe according to claim 1, wherein, One of the housings has a larger diameter than the other housing to facilitate the stacking joint.

3. The syringe according to claim 1 or 2, wherein, The feature provided on the plunger includes one or more recesses.

4. The syringe according to claim 1, wherein the limiting member is an annular ring coaxially positioned with the cylindrical housing of the distal member.

5. The syringe of claim 1, wherein the syringe is configured such that the proximal part and the distal part are moved together in a collapsed manner a first predetermined distance, the first predetermined distance corresponding to an injection end distance, such that the limiting part engages with one or more features of the proximal part, thereby moving the limiting part from the pre-injection position to the post-injection position.

6. The syringe of claim 5, wherein the cylindrical housing of the proximal component is configured to further restrict the one or more flexible fingers during a second predetermined distance of collapsing movement, after the proximal component and the distal component have collapsed and moved together, following a first predetermined distance.

7. The syringe according to claim 6, wherein, After a first predetermined distance or a second predetermined distance of collapsing movement, a further collapsing movement of the proximal component and the distal component together releases the one or more fingers to move radially outward, thereby causing the plunger and the distal component to disengage.

8. The syringe according to claim 6, wherein, The disengagement of the plunger and the distal component allows the plunger to pass over the flexible arm or between each flexible arm.

9. The syringe according to any one of claims 4-8, the syringe comprising a compression spring located within the proximal component and coupled in use to the primary package such that the spring is compressed by pushing the primary package through the proximal component, the syringe being configured such that disengagement of the plunger and the distal component allows the spring to extend and causes the entire primary package and plunger to move through the syringe in the distal direction, thereby completely retracting the cannula into the proximal component.

10. The syringe according to claim 9, wherein, The spring is a helical spring.

11. The syringe according to any one of claims 4-8, wherein the syringe is assembled around the primary package.

12. The syringe according to any one of claims 4-8, wherein the syringe is a manual syringe, and the force applied to stack the proximal part and the distal part together is manual.

13. The syringe of claim 1, wherein the syringe is an auto-injector and includes an energy storage mechanism and a release mechanism, the release mechanism being used to release energy from the storage mechanism to apply the force for stacking the proximal and distal parts together.

Images