Patent Application
20250235629
The present invention relates to an autoinjector.
In this application, the distal end of a component or of a device is to be understood as meaning the end furthest from the user's hand and the proximal end is to be understood as meaning the end closest to the user's hand. Likewise, in this application, the “distal direction” is to be understood as meaning the direction away from the user's hand, and the “proximal direction” is to be understood as meaning the direction toward the user's hand.
Automatic injection devices are designed for automatic injection of a medical product into an injection site. Autoinjectors usually comprise a housing for receiving a medical container. The medical container has a barrel defining a reservoir for containing the medical product, the barrel having a distal end provided with an injection needle and an opened proximal end receiving a plunger rod for pushing a stopper. The opened proximal end is usually provided with a flange.
Autoinjectors also include a safety shield mechanism moving from an extended to a retracted position to respectively shield or unveil the needle and an injection mechanism for automatically injecting the medical into an injection site. The injection mechanism usually includes a plunger rod for pushing a stopper inside the barrel of the medical container, and an initially compressed spring for moving the plunger in the distal direction. Locking means are provided for maintaining the plunger rod in an initial position in which the plunger rod is axially blocked despite the action of the compressed spring. A release member is typically arranged to release the plunger from the locking means and allow the spring to push the plunger rod in the distal direction to perform injection. A predetermined displacement of the safety shield towards the retracted position is required to allow the release member to unlock the locking means and release the plunger rod.
The document EP2921191 discloses a device for automatic injection of a medical product into an injection site. The device includes a two-part assembly having an upper sub-assembly assembled to a lower sub-assembly. The lower sub-assembly receives a syringe provided with an injection needle. The injection needle is covered by a rigid needle shield. The device further includes a needle cover movable relative to the housing between an extended and a retracted position. The plunger rod is coupled to a compressed spring and maintained in an initial position by a deflectable retainer of an inner cylinder. A push button is arranged at a proximal end of the device for releasing the plunger rod by deflecting the retainer outwardly. Activation of the push button only becomes possible when the needle cover has moved a predetermined distance in the proximal direction towards the retracted position. Besides, activation of the push button requires the end user to press the push button. That is, the end user must perform a specific additional operation to activate the device. Moreover, this operation may not be so easy since the end user must in the same time exert a distal force on the push button and hold the autoinjector pressed against his/her skin.
The document WO2016034407 discloses a signal delaying assembly for a medicament delivery device. The document US2013317432 discloses an autoinjector. The document WO2021094047 discloses a medicament delivery device.
There is therefore a need for an autoinjector allowing activation of the injection mechanism without requiring an additional operation from the end user.
Besides, in some prior art autoinjectors, the retainer that retain the plunger rod may creep over time under the stress of the compressed spring. Thus, there is also a need for an autoinjector that is less sensitive to material creep over long storage periods.
Furthermore, to assess the robustness of the autoinjectors, autoinjectors are subjected to drop tests as required in ISO11608. These drop tests usually consist in dropping the autoinjectors at least once from a height of 1 m onto a horizontal floor. There are three drop directions: a drop ‘cap upward’, a drop ‘cap downward’, and a drop with the autoinjector being horizontal. In the first case (drop ‘cap upward’), the push button of the autoinjector hits the floor first. Accordingly, the push button is pressed upon impact on the floor. This may lead to inadvertent activation of the autoinjector.
There is therefore a need for an autoinjector having an improved drop test resistance.
An aspect of the invention is an autoinjector, for automatic injection of a product into an injection site, said autoinjector comprising:
The autoinjector of the invention allows easier activation of the injection mechanism. Indeed, there is no need to manually press a push button, since the push button has been replaced by a rotative lock ring which automatically moves to an unlocking position when the needle cover moves to the retracted position. The end user has no additional operation to perform, the lock ring rotates automatically. Therefore, the triggering of the injection mechanism including the biasing means and the plunger rod is automatically achieved without need for an additional manual action from the end user.
Besides, the autoinjector provides a better resistance to the drop test ‘cap upward’ because the push button, which was pressed in the axial direction (i.e. the drop direction), has been replaced by the lock ring, which is axially blocked and which can only rotate around the longitudinal axis A. The rotative lock ring being less sensitive to an impact ‘cap upward’, the risks of inadvertently triggering the injection are reduced. It is also contemplated that the lock ring is arranged inside the housing, instead of being arranged at the proximal end thereof (as would be a push button). This arrangement further contributes to making the autoinjector less sensitive to a drop ‘cap upward’.
Eventually, the lock ring blocks outward deflection of the retainer so that the retainer cannot creep over time because of the force exerted by the biasing member on the plunger rod. The autoinjector of the invention is thus less sensitive to material creep over long storage periods.
The retainer preferably includes two diametrically opposite blocking legs provided with a proximal abutment surface for abutting against the plunger rod. Thus, the proximal abutment surface stops distal movement of the plunger rod. The proximal abutment surface may be defined at a proximal side of a radial hook. Preferably, the radial hook is inwardly protruding from a distal end of the blocking legs. The blocking legs axially extend inside the housing. They may be part of an inner sleeve distally protruding from a proximal end of the housing. The retainer may thus be part of the housing and fixed with regard to the housing.
The needle cover, the cam and the lock ring may be separate components.
The biasing means preferably include an injection spring which is compressed in the initial position of the plunger.
The housing is preferably made of a top body and a bottom body assembled to each other by any appropriate securing means, such as snap-fitting means.
The autoinjector of the invention may further include some or all of the features below.
In an embodiment, the lock ring has an axial groove configured to accommodate the retainer when the retainer moves to the deformed position.
In an embodiment, the axial groove includes at least one circumferential stop configured to prevent the retainer from moving back to the rest position when the retainer is engaged in the axial groove.
In an embodiment, the lock ring extends around the retainer. The axial groove may be an inner axial groove.
In an embodiment, the autoinjector includes an axial holder for blocking the lock ring in the axial direction. The autoinjector may include clipping means for allowing clipping of the lock ring to the top body or said axial holder.
In an embodiment, the lock ring includes a side surface configured to abut against the cam when the cam rotates from the blocking position to the release position.
In an embodiment, the side surface is arranged on a drive element engaged with a complementarily shaped drive element of the cam. The drive element may be an outwardly radially extending tab. The tab may be arranged on an axial rib, for instance at a proximal end thereof. The axial rib protrudes from an outer surface of the lock ring and may include a stiffening chamfer.
Possibly, the drive element of the lock ring includes an opposite side surface configured to abut against the cam when the rotates in the opposite direction.
In an embodiment, the drive element of the cam is a notch arranged at the proximal end of the cam. The notch defines a proximal opening for receiving the drive element of the lock ring.
In an embodiment, the lock ring is remote from a proximal end of the housing.
In an embodiment, the lock ring is arranged at a distal end of an inner sleeve axially protruding from the proximal end of the housing.
In an embodiment, the housing has a lateral wall and a transversal wall closing the proximal end of the housing, said transversal wall being integral with the lateral wall.
In an embodiment, the inner sleeve is integral with the transversal wall of the housing.
Possibly, the proximal end of the housing includes a proximally protruding circumferential rim.
In an embodiment, the plunger rod has a distal abutment surface configured to abut against the retainer in the initial position, said distal abutment surface being inclined with regard to the longitudinal axis A. That is, the distal abutment surface is not orthogonal to the longitudinal axis A, and tapers in the distal direction. The plunger rod is thus configured to outwardly deflect the retainer.
Possibly, the retainer includes a proximal abutment surface configured to abut against the plunger rod in the initial position, said proximal abutment surface being inclined with regard to the longitudinal axis A. That is, the proximal abutment surface is not orthogonal to the longitudinal axis A, and tapers in the proximal direction.
Possibly, the plunger rod and the retainer may therefore establish a line contact or conical contact against each other.
In an embodiment, the biasing means include an injection spring arranged around the plunger rod.
Possibly, the plunger rod is symmetrical around the longitudinal axis A.
In an embodiment, the biasing means include an injection spring arranged inside the plunger rod.
The terms Fig., Figs., Figure, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings.
The invention and the advantages arising therefrom will clearly emerge from the detailed description that is given below with reference to the appended drawings as follows:
With reference to
The lower sub-assembly 1A includes a bottom body 10A for receiving a medical container 100, a cap 2 removably attached to a distal end 11 of the bottom body 10A and configured for removing a needle shield 102, a needle cover 3 axially movable along the longitudinal axis A with respect to the bottom body 10A between a first extended position (pre-use position) in which the needle cover 3 at least partially or completely shields an injection needle, a retracted position (injection position) proximally located relative to said first extended position, in which the needle cover 3 moves inside the autoinjector 1 to allow triggering of the injection, and a second extended position (safety position) in which the needle cover 3 moves back in the distal direction so as to safely shield the injection needle. The lower sub-assembly 1A further includes a cam 4 pivotally mounted around the needle cover 3 and the longitudinal axis A, a safety spring 5 for urging the needle cover 3 in the distal direction towards the safety position, and a non-rotatable abutment ring 6 configured to be fixed to the medical container 100 for blocking axial movement of the medical container 100 in the distal direction before activation of the autoinjector 1.
The medical container 100 may be a syringe, for instance a prefilled syringe, and has a tubular barrel 101 defining a reservoir for containing a medical product to be injected. The barrel 101 has a distal end provided with an injection needle (not shown) and a needle shield 102 removably attached to said distal end for protecting and sealing the injection needle. Opposite said distal end, the barrel 101 has an opened proximal end 103 provided with a flange 104 and configured to receive a plunger rod 7.
The top sub-assembly 1B includes a top body 10B, a plunger rod 7 axially movable with respect to the top body 10B between an initial position, in which the plunger rod 7 may be away from a stopper 105 (see
With reference to
With reference to
The inner sleeve 15 may further includes bearing means for supporting and guiding rotation of the lock ring 9 around the inner sleeve 15. The bearing means may comprise two diametrically opposite bearing legs 151, which may each extend between the deformable blocking legs 16. The bearing legs 151 and the blocking legs 16 may be regularly distributed around the longitudinal axis A and separated from each other by axial slots 152. They may have the same length. However, the bearing legs 151 are devoid any radial hook and thus do not hamper axial movement of the plunger rod 7. The top body 10B or the inner sleeve 15 may further comprise one or more, for example two diametrically opposite, axial holders 17. As visible in
It is to be understood that the number of blocking legs 16, respectively bearing legs 151, may vary. For instance, the retainer, respectively, the bearing means, may comprise less or more than two blocking legs 16, respectively bearing legs 151.
The lock ring 9 is rotatable around the longitudinal axis A and around the inner sleeve 15 between a locking position (
As visible in
With reference to
With reference to
It is contemplated that the lock ring 9 may include two pairs of circumferential stops 920. The circumferential stops 920 extend at both sides of the axial grooves 92. The circumferential stops 920 are configured to abut against the blocking legs 16 so as to prevent the blocking legs 16 from going back to their rest position against the blocking lateral walls 93 of the lock ring 9 should the lock ring 9 further rotates in the clockwise or counterclockwise direction. The circumferential stops 920 may thus have a surface orthogonal to a circumferential direction. The circumferential length L1 of the axial grooves 92, i.e. the distance between two opposite circumferential stops 920, is preferably greater than the circumferential length L2 of the blocking legs 16.
With reference to
With reference to
With reference to the embodiment of
The injection spring 8 is transitionable between a compressed state and a stretched state in which the injection spring 8 is less compressed. When the autoinjector 1 is idle, the injection spring 8 is maintained in the compressed state by the plunger rod 7 abutting against the blocking legs 16 and the blocking legs 16 being prevented from outwardly deflecting by the lock ring 9 being in the locking position. When the autoinjector 1 is activated, i.e. when the lock ring 9 has rotated to the unlocking position, the injection spring 8 extends, thereby pushing the plunger rod 7 in the distal direction up to completion of the injection operation. When the injection is complete, the injection spring 8 is in the stretched state.
The operation of the autoinjector 1 according to the embodiment of
As visible in
The user first withdraws the cap 2 from the lower sub-assembly 1A. This withdrawal entails removal of the needle shield 102. During the cap 2 removal, the abutment ring 6 may abut against the proximal shoulder 410 of the cam 4 to avoid a back and forth movement of the medical container 100.
The user then places the autoinjector 1 against the injection site. The distal end 31 (
Since the tab 94 of the lock ring 9 is engaged with the notch 45 of the cam 4, rotation of the cam 4 towards the release position makes the cam 4 push the lock ring 9 in a circumferential direction. The lock ring 9 accordingly rotates from the locking position to the unlocking position.
It should be noted that the autoinjector 1 is activated only when the needle cover 3 moves towards the retracted position, i.e. when the lug 30 of the needle cover 3 moves in the oblique portion 42 towards the axial portion 43 of the first slot 40. If the user changes his/her mind and decides to cancel the injection before activation, then the user just moves the autoinjector 1 away from the injection site. As a result, the safety spring 5 will urge the needle cover 3 back towards the first extended position. The lug 30 of the needle cover 3 will slide against the lower ramp 421 of the oblique portion 42 and the cam 4 will thus rotate back towards the blocking position. The cam 4 will push the tab 94 of the lock ring 9 back in the opposite direction and the lock ring 9 will return to the locking position, still keeping the blocking legs 16 from outwardly deflecting. The injection spring 8 will thus not be released and the plunger rod 7 will still be prevented from moving in the distal direction.
If however the user goes on pressing the autoinjector 1 against the injection site until activation, the needle cover 3 goes on moving towards the retracted position, and the cam 4 eventually reaches the release position (
When the stopper 105 eventually abuts against a distal end of the reservoir defined by the barrel 101, the injection is complete. An indicator, such as a visual, tactile or audible indicator, may inform the user that the injection is complete.
The user then moves the autoinjector 1 away from the injection site. The needle cover 3 slides in the axial portion 43 of the cam 4, moving from the retracted to the second extended (safety) position under the action of the safety spring 5. A locking mechanism may lock the needle in the safety position to prevent needle stick injuries.
Turning now to
With reference to the embodiment of
Since the diameter of the plunger rod 7 is greater than the diameter of the injection spring 8 and since the injection spring 8 is inside the plunger rod 7, the blocking legs 16 do not abut against the injection spring 8 when the plunger rod 7 moves towards the injection end position. Instead, the blocking legs 16 abut against the tubular wall of the plunger rod 7. This avoids the noise that would be due to the friction between the hooks 160 of the blocking legs 16 and the coils of the injection spring 8. This also makes easier to provide the autoinjector 1 with an indicator, such as a visual, tactile or audible indicator for informing the user that the injection is complete. The injection spring 8 has a proximal end 80 abutting against the transversal wall 130 of the top body 10B and an opposite distal end 81 abutting against a distal end of the inner cavity 74.
The plunger rod 7 has two diametrically opposite windows 75 arranged through the tubular wall 76 for receiving the hooks 160 of the blocking legs 16. The windows 75 have an upper edge configured to abut against the proximal abutment surface 161 of the hooks 160 when the plunger rod 7 is in the initial position. This upper edge corresponds to the distal abutment surface 70 of the plunger rod 7 and may thus be inclined with regard to the longitudinal axis A. Therefore, the upper edge is configured to deflect the blocking legs 16 due to the action of the injection spring 8 when the lock ring 9 is in the unlocking position. The inclination of the upper edge may be similar to the inclination of the proximal abutment surface 161 of the hooks 160, thus establishing a conical contact between the plunger rod 7 and the blocking legs 16.
The operation of the autoinjector 1 according to the embodiment of
It is readily understandable from the above description that the autoinjector 1 of the invention permits to reduce the steps that are necessary to trigger the injection (the user has no need to push a button and the lock ring 9 automatically rotates when the autoinjector 1 is being pressed against the skin of the user), avoids creep of the blocking legs 16 because of the spring pressure (the lock ring 9 prevents any deformation of the blocking legs 16), and improves the resistance to the drop test ‘cap upward’ (since the injection is longer triggered at the proximal end 13 of the top body 10B).
It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22305521.1 | Apr 2022 | EP | regional |
This application is the United States national phase of International Patent Application No. PCT/EP2023/059046 filed Apr. 5, 2023, and claims priority to European Patent Application No. 22305521.1 filed Apr. 11, 2022, the disclosures of which are hereby incorporated by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/059046 | 4/5/2023 | WO |
