CN116897060A - Injection device - Google Patents

Abstract

Aspects of the present invention relate to an injection device including a drive device, a plunger, and an intermediate member disposed between the drive device and the plunger and releasably engaged with the plunger to thereby selectively transfer force from the drive device to the plunger.

Description

Injection device

Technical Field

The present disclosure relates to an injection device.

Background

One of the most common routes of administration for a pharmaceutical product is by injection, such as intravenous, subcutaneous or intramuscular. Syringes containing medications are used for injections, which are typically performed by trained medical personnel. In some cases, the patient is trained to use a syringe to allow self-injection. In addition, certain medications are formulated in pre-filled syringes for use by patients to avoid the need for the patient to fill the syringe. However, some patients may be adverse to self-injection, particularly if the patient is afraid of needles. Automatic injection devices provide an alternative to syringes for delivering pharmaceutical products.

Disclosure of Invention

Aspects and embodiments of the invention provide an injection device as claimed in the appended claims.

According to an aspect of the present invention there is provided an injection device comprising: a syringe carrier configured to receive a drug container; a housing having a proximal end and a distal end; the housing is configured to receive the syringe carrier and releasably engage a proximal end of the syringe carrier; and a proximal cap arranged to engage the proximal end of the housing and comprising a wall extending distally along the housing, the proximal cap being configured to maintain engagement between the proximal end of the syringe carrier and the housing. The wall acts to prevent proximal movement of the syringe carrier while at the same time having a proximal cap on the injection device and thus reducing the chance of the device being actuated before it is intended.

Optionally, the housing further comprises an abutment feature against which the syringe carrier abuts. The abutment feature may be a protrusion extending inwardly from an inner surface of the housing towards a central longitudinal axis of the injection device. The projection may be, for example, an annular projection extending around the inner circumference of the housing, a single projection, or a plurality of spaced projections.

Optionally, the syringe carrier may have a proximal end and a distal end, and the proximal end of the syringe carrier comprises resilient fingers; the proximal ends of the resilient fingers engage the housing.

The wall preferably extends distally and inwardly within the syringe carrier.

Preferably, the outer surface of the wall contacts and extends beyond the inner surface of the abutment feature.

Preferably, the wall further comprises at least one protrusion extending inwardly towards the central longitudinal axis. The protrusion may be arranged to engage with a rigid needle shield or a rigid needle shield covering the needle of the syringe and thus facilitate removal of the rigid needle shield together with the proximal cap.

Preferably, the proximal cap is provided with a radial wall at the proximal end of the wall. Preferably, the proximal cap is further provided with a second wall extending distally from the radial wall and spaced apart from the wall. The second wall facilitates removal of the cap from the device.

Preferably, the second wall is arranged to be removably engaged with the outer surface of the housing, optionally by frictional engagement with the outer surface of the housing.

According to another aspect of the present invention there is provided an injection device comprising: a driving device; a plunger; and an intermediate member disposed between the drive device and the plunger and releasably engaged with the plunger to thereby selectively transfer force from the drive device to the plunger. The selective transfer of force from the drive device to the plunger facilitates the use of the drive device for multiple functions.

Preferably, the intermediate drive has a compressed configuration in which the intermediate member engages the plunger to transfer force from the drive means to the plunger, and a relaxed configuration in which the intermediate member is released from engagement with the plunger such that force is not transferred from the drive means to the plunger.

Preferably, the injection device also comprises a housing arranged to selectively maintain the intermediate drive in the compressed configuration. This may be achieved by a housing having a distal length with a reduced inner diameter relative to a proximal portion of the housing, the reduced inner diameter maintaining the compressed configuration of the intermediate driver. This may be achieved by, for example, one or more support ribs, or an increased thickness of the wall of the housing.

The intermediate member may have an outer portion and an inner portion connected by a connecting portion. The outer portion may be made of one or more resilient fingers, or a discontinuous wall at least at its proximal end. The resilient fingers or discontinuous wall portions or a portion thereof are preferably closer together in the compressed configuration than in the relaxed configuration.

The intermediate member is preferably provided with an inclined surface, which contacts a corresponding inclined surface of the plunger. This facilitates disengagement of the plunger from the intermediate member.

Preferably, the intermediate member includes an outer portion and an inner portion connected by a connecting portion; the outer and inner portions extend distally from the connecting portion to receive a proximal end of the drive device. This provides a seat for accurately positioning the drive means relative to the intermediate member.

Preferably, the drive means is a spring. More preferably, the spring is a compression spring.

According to another aspect of the present invention there is provided an injection device comprising a drive device, an intermediate member arranged to receive the drive device, and a shield; wherein the intermediate member and the shield are engaged by the drive means. This allows the shield to be deployed using the drive means without requiring separate drive means to move the shield and the plunger.

The shroud and the intermediate member may be provided with complementary engagement features to assist in engagement of the shroud with the intermediate member. The engagement feature may be, for example, a protrusion on one of the intermediate member and the shroud, and a complementary recess on the other of the intermediate member and the shroud. Alternatively, the protrusion may have a truncated cone shape.

The shield may include a distally extending arm, and the engagement feature is present on a distal end of the distally extending arm. The intermediate member may be provided with a proximally extending arm arranged to contact the shield. Optionally, the engagement feature may be provided on the proximal end of the proximally extending arm.

Preferably, the injection device comprises a housing and at least a portion of the distally extending arm and/or the proximally extending arm is provided with an expanded outer section configured to be received in a complementary recess in the housing.

Optionally, the distally extending arm is provided with a laterally extending resilient arm configured to engage a portion of the housing to prevent distal movement of the shield when the shield is in its extended position.

Preferably, the shield comprises a continuous wall at its proximal end.

Those skilled in the art will appreciate that any of the features described above may be incorporated into any other aspect of the present invention, either alone or together.

Drawings

One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 shows a cross section through an injection device according to the invention;

fig. 2a and 2b illustrate the proximal end of the injection device with the proximal cap engaged and removed, respectively;

figures 3a and 3b show a cross section through the injection device with the intermediate drive in a compressed configuration.

Fig. 4a and 4b show a cross section through the injection device, wherein the intermediate drive and the shield are engaged.

Fig. 5 illustrates an intermediate drive and a shroud.

Detailed Description

The present invention relates to an injection device, components thereof, and methods for injecting substances such as liquid drugs or vaccines into a patient to control or cure medical conditions. In one embodiment, the automatic injection device is a pen, i.e., an auto injector pen or an auto injector pen (used interchangeably herein).

An injection device according to an embodiment of the present invention is described herein with reference to figure X.

Referring to fig. 1, an injection device 10 includes a housing 12 for containing a container, such as a syringe, containing a dose of a substance to be injected. The housing 12 preferably has a tubular configuration, but the housing 12 may have any suitable size, shape and configuration for a syringe or other container containing a substance to be injected. Although the present invention will be described with respect to a syringe mounted in the housing 12, those skilled in the art will recognize that the automatic injection device 10 may employ any suitable container for storing and dispensing substances. Unless otherwise indicated, references to radial and axial in this specification should be considered as referring to the longitudinal axis. The term axis may be considered as the longitudinal axis of the device unless stated otherwise or apparent from the context. The normal to the longitudinal axis is considered perpendicular to the longitudinal axis.

The syringe is preferably slidably mounted in the housing 12, as described in detail below. In the inactive position, the syringe is wrapped or sheathed within the housing 12 and retracted. When the device is actuated, the needle of the syringe protrudes from the first (proximal) end 20 of the housing 12 to allow for the injection of a substance from the syringe into a patient. As shown, the first (i.e., proximal) end of the housing 20 includes an opening through which the needle of the syringe protrudes during actuation of the device 10.

The second (distal) end 30 (i.e., distal end) of the housing 12 includes an actuation button 32 for actuating the syringe to move from a wrapped position within the housing 12 to a protruding position and then expel the substance from the needle into the patient. The housing 12 houses one or more actuators that perform the functions of moving the syringe and expelling the substance from the syringe.

A first removable cap 24 (or needle cap) is used to cover the first end 20 of the housing 12 to prevent exposure of the needle to the syringe prior to use. A second removable cap 34 (or actuator cap) covers the second end 30 of the housing 12 to prevent accidental actuation of the actuation button 32.

A syringe 50 or other suitable container for a substance is disposed within the interior of the housing 12. The illustrative syringe 50 includes a hollow barrel portion 53, the barrel portion 53 for holding a dose of a liquid substance to be injected. The exemplary barrel portion 53 is substantially cylindrical in shape, but those skilled in the art will recognize that the barrel portion 53 may have any suitable shape or configuration. A seal, illustrated as a plug 54, seals the dose within the barrel portion 53. The syringe 50 may also include a hollow needle 55 connected to and in fluid communication with the barrel portion 53, through which the dose may be ejected by applying pressure to the stopper 54. The hollow needle 55 extends from the proximal end of the barrel portion 53. The distal end of the barrel portion 53 includes a flange 56. Those skilled in the art will recognize that the present invention is not limited to the illustrative embodiment of syringe 50 and that any suitable container for holding a dose of a substance to be injected may be used in accordance with the teachings of the present invention.

The syringe 50 is received within a syringe carrier 40 slidably disposed within the housing 12. The syringe carrier 40 is provided at its distal end with an abutment surface arranged to engage with the flange 56 of the syringe. At its proximal end, the syringe carrier is provided with one or more resilient or flexible protrusions 44. The syringe 50 rests in the carrier 40 and both are contained in the housing 12. The syringe carrier 400 may have any suitable configuration and size suitable for carrying or guiding the syringe 50 within the housing 12.

The injection device further comprises an actuation mechanism comprising a plunger 70, an intermediate drive 80, and a biasing means. In the present invention, the biasing means is a compression spring 88, but it will be appreciated that the biasing means is any suitable means for biasing the plunger and the intermediate driver 80 distally.

The actuation mechanism selectively moves the syringe 50 and actuates the syringe 50 to inject a dose contained in the syringe 50 into a user. The exemplary plunger 70 includes a stem portion 71 having a first end 71a integral with the stopper 54, connected to the stopper 54, or in communication with the stopper 54, for selectively applying pressure to the stopper 54 to expel the dose from the needle 55. The plunger 70 may include a flanged second end 72.

The rod portion 71 is provided with a proximal portion 73 and a distal portion 74, the proximal portion 73 and the distal portion 74 having different outer diameters and being connected by an inclined portion 75. In this embodiment of the invention, the proximal portion 73 of the stem portion 71 has a larger outer diameter than the distal portion 74 of the stem portion 71.

The intermediate driver 80 is provided with a cylindrical inner part 81, and an outer part 82 connected by a connecting part 83. The circumference of the outer portion 81 is greater than the circumference of the inner portion 81, and the outer portion 81 extends further distally than the inner portion. The connecting portion 83 and compression spring 88 are configured such that the compression spring engages the connecting portion 83 and biases the intermediate driver 80 distally prior to use of the injection device 10. In addition, prior to use, the connecting portion 83 is positioned such that it communicates with the angled portion 75 of the plunger 70 such that any biasing force exerted by the compression spring 88 on the intermediate driver 80 is communicated to the plunger 70 and biases the plunger 70 distally.

The actuation button of the present embodiment maintains the plunger 70 and the first biasing device 88 in a retracted, latched position. In the exemplary embodiment, the flanged second end 72 of the plunger 70 extends through an opening in the distal end of the housing 12 and the flange abuts the outer distal wall of the housing. The flange is configured such that proximal pressure on the flange causes the flanged end of the plunger to flex inwardly and move through the opening in the distal end of the housing 12, thereby allowing the coil spring, i.e., coil spring 72, to move the intermediate driver 80 and the plunger distally. For example, the second flanged end 72 of the plunger 70 may include one or more proximally extending fingers provided with one or more flanges.

Any suitable alternative method of releasably holding the distal end of the plunger 70 distally may be used. The activation device may be of any suitable size, shape, configuration and location suitable for releasing the plunger 70 or otherwise activating the device 10. The activation means may be an activation button 32 formed on the distal end 30 of the housing 12, or may include another suitable means such as a latch, a twist activated switch, and other means known in the art. Although the exemplary activation device is positioned toward the distal end 30 of the device 10, one skilled in the art will recognize that the activation device may be positioned in any suitable location on the device 10.

Fig. 2a and 2b illustrate the proximal end 20 of the injection device 10 before and after the first removable cap 24 is removed from the device. In fig. 2a, the first removable cap 24 is engaged with the proximal end 20 of the injection device. The inner needle cover 22 encloses the syringe needle 55.

The housing 12 is provided with at least one radial projection or abutment feature 14 that extends inwardly toward the central longitudinal axis of the injection device 10. The proximal end of the syringe carrier is provided with one or more resilient protrusions 44 which engage at least one radial protrusion 14 before the injection device 10 is activated. Engagement of the at least one radial projection 14 with the proximal end of the one or more resilient projections 44 serves to retain the syringe carrier in its distal, pre-activated position.

The first removable cap 24 is provided with an inner wall 25 and an outer wall 26 having a larger diameter than said inner wall 25. The inner wall 25 and the outer wall 26 extend distally and are connected by a proximal wall 27. The inner surface of the outer wall 26 is configured to engage the outer surface of the proximal end of the housing 12 in any suitable manner. For example, the outer wall 25 may form a frictional engagement with the housing, or the outer wall 25 may be provided with threads.

The inner wall 25 extends distally within the proximal end of the housing and the proximal end of the syringe carrier. When the first removable cap 24 is engaged with the housing 12, the outer surface of the inner wall 25 is in contact with the radial projection 14. The inner wall 25 is sufficiently rigid to prevent the resilient projection of the syringe carrier 40 from flexing toward the central longitudinal axis of the injection device 10 and moving past the radial projection 14 when the first removable cap 24 is engaged with the housing 12. This helps prevent premature activation of the device by holding the syringe carrier 24 in its distal pre-activation position.

The inner wall 25 may be provided with one or more protrusions 28 extending inwardly towards the central longitudinal axis of the injection device 10. The protrusion 28 is configured to engage with a feature of the inner needle cover 22, such as a distal end of the inner needle cover 22, such that removal of the first removable cap 24 also results in removal of the inner needle cover 22, as shown in fig. 2 b. When the cap 24 is removed, the syringe needle 55 is exposed within the interior cavity 1012 of the housing 12. The cap 24 may also include an opening in its proximal end.

While the first removable cap 24 has been described as having a tubular wall, those skilled in the art will appreciate that the cap may be any suitable shape that engages the housing 12. In addition, the inner wall 25 may include one or more spatially separated sections. Furthermore, while the first removable cap 24 has been described as having an inner wall and an outer wall, those skilled in the art will appreciate that the outer wall is optional.

To actuate the device, the second removable cap 34 is removed from the device. The injection device 10 may then be introduced to an injection site. Pressing the button 32 causes the flanged end of the plunger 70 to move inwardly, thereby causing the flange to no longer be retained by the distal wall of the housing 12. This allows the spring 88, which has been held in a compressed state, to exert a proximal force on the intermediate driver 80.

Fig. 3 illustrates the interaction between the plunger rod 70 and the intermediate driver 80. As can be seen, the connecting portion 83 is provided on its proximal side with an inner inclined surface which engages with the inclined portion 74 of the plunger. The proximal end of the compression spring 88 is disposed on the distal side of the flange and is received between the inner portion 81 and a portion of the outer portion 82 that extends distally from the flange, forming a seat or socket for the proximal end of the compression spring 88.

When the compression spring 88 exerts a force on the distal side of the connecting portion 83, this force is transferred to the inclined surface of the connecting portion 83, which engages the inclined portion 74 of the plunger rod 70, thereby moving the plunger rod 74 proximally. The force applied to the plunger 70 causes a force to be applied to the syringe 50 via the stopper 54, causing the resilient projections 44 of the syringe carrier 40 to deflect inwardly and move past the abutment features 14 and thus move proximally, thereby inserting the needle into the user.

Once the needle 55 has been inserted, forward movement of the syringe carrier 40, and thus the syringe 50, is prevented by any suitable means, meaning that further proximal movement of the plunger rod causes proximal movement of the stopper 54 within the syringe 50, thereby causing medicament to be expelled from the container 18 through the needle 22.

In fig. 3a, the intermediate drive 80 is held in compressed form by the housing 12. At least the outer portion is movable from a compressed form of reduced diameter to a relaxed form of increased inner diameter. For example, this may be accomplished by providing one or more resilient fingers as the outer portion 82, at least a portion of the outer portion 82 being formed of a discontinuous wall, or by making the outer portion from at least two materials, one of which is more resilient than the other to allow the circumference of the outer portion to be reduced.

In compressed form, the intermediate driver 80 has an inner circumference smaller than the outer circumference of the proximal portion 73 of the plunger rod 70 and thus engages the plunger rod 70 at the inclined portion 75. In the relaxed form, the intermediate driver 80 has an inner circumference that is larger than the outer circumference of the proximal end portion 73 of the plunger rod 70 and is thus movable along the plunger rod.

The housing is provided with one or more support ribs (not shown) extending longitudinally down the inner surface of the housing. The ribs reduce the inner diameter of the housing, thereby maintaining the intermediate driver 80 in a compressed configuration.

Any other suitable means may be used to reduce the inner diameter of the housing. For example, if the longitudinal distance between the annular protrusions is smaller than the length of the elastic portion of the outer portion, the thickness of the housing wall may be increased, or a plurality of annular protrusions or a plurality of rings may be provided.

The inner diameter of the housing increases at the point where the intermediate drive 80 is to be moved to its relaxed form and thus disengaged from the plunger. This can be achieved by reaching the ends of the inner support ribs, reducing the thickness of the housing wall, terminating the annular projection. In the present device, the intermediate driver 80 is disengaged from the plunger 70 when the medicament has been delivered to the user, i.e. when the stopper 54 has reached the proximal end of the syringe 50. The skilled artisan will appreciate that any suitable location may be selected.

Fig. 3b shows that the intermediate drive 80 reaches, for example, the end of the support rib. When this occurs, the outer portion may move outwardly towards the relaxed position, as illustrated in fig. 4 b. The outward movement of the outer portion allows the inclined surfaces of the plunger and the connecting portion to move beyond each other, thereby disengaging the plunger 70 and the intermediate driver 80. Thus, the plunger 70 no longer has a proximal force applied thereto by the drive spring 88 and no longer moves forward. Furthermore, the drive spring 88 still applies a proximal force to the connecting portion of the intermediate driver 80, and thus the intermediate driver 80 continues to move proximally within the housing 12 of the injection device 10.

As the intermediate drive 80 continues to move proximally, it contacts the shield 90, as illustrated in fig. 4a and 4 b. When the intermediate driver is driven proximally by the drive spring 88, it also drives the shield 90 proximally. The shroud and the intermediate drive 80 are illustrated in more detail in fig. 5.

As can be seen in fig. 5, the shield 90 is provided with a shield portion 91 having a continuous wall to protect the user from the needle after the injection device has been used. The shroud is also provided with two rearwardly extending arms 92 configured to engage the intermediate drive. Each of the two rearwardly extending arms 92 is provided with a recess 93 which receives the radial projection 14 or abutment feature and allows the shroud 90 to move proximally along the radial projection. The radial projections 14 may guide the direction of movement of the shroud 90; however, those skilled in the art will also appreciate that the arms 92 may be positioned such that they do not engage the radial projections 14.

The distal ends of the shroud arms 92 and the proximal ends of the outer portion 82 of the intermediate driver 80 are provided with engagement features 84, 94. The engagement feature may be any suitable feature designed to assist in the engagement of the intermediate drive 80 with the shroud 90. For example, one of the intermediate driver 80 and the shroud 90 may be provided with a protrusion 84, and the other of the intermediate driver 80 and the shroud 90 may be provided with a complementary recess 94 to receive the protrusion. As illustrated in fig. 5, the protrusions have a frustoconical shape, however, the skilled artisan will appreciate that any suitable shape may be used.

Additionally, to assist in the alignment of the distal ends of the shield arms 92 with the proximal ends of the outer portions 82, the outer portions of the shield arms and/or the outer portions may be received in grooves in the housing 12.

Each shroud arm 92 is also provided with a resilient transverse arm 95. When the shield 90 is in its proximal position, the distal ends of the transverse arms 95 abut features in the housing 12 (not shown), thereby preventing the shield 90 from moving distally after the injection device has been used. Those skilled in the art will appreciate that a variety of alternative methods of preventing rearward movement of the shield may be used.

Certain terminology is used in the following description for convenience only and is not limiting. The term "proximal" or "proximal" refers to the front or patient end of the device. The term "distal" or "distal" refers to the back end of the device or the user end of the syringe. The term "longitudinal" with or without an axis refers to a direction through the axis of the device in the longest direction of extension of the device. The term "radial" or "transverse" with or without an axis refers to a direction that is substantially perpendicular to the longitudinal direction, e.g., "radially outward" would refer to a direction pointing away from the longitudinal axis.

It should be understood that the detailed description and specific examples, while indicating various changes and modifications within the spirit and scope of the disclosure, are given by way of illustration only, since various changes and modifications will become apparent to those skilled in the art from this disclosure.

Claims (12)

1. An injection device, comprising:

i) A driving device;

ii) a plunger;

iii) An intermediate member disposed between the drive device and the plunger and releasably engaged with the plunger to thereby selectively transfer force from the drive device to the plunger.

2. The injection device of claim 1, wherein the intermediate driver has a compressed configuration in which the intermediate member engages the plunger to transfer force from the drive device to the plunger, and a relaxed configuration in which the intermediate member is released from engagement with the plunger such that force is not transferred from the drive device to the plunger.

3. The injection device of claim 2, further comprising a housing arranged to selectively maintain the intermediate drive in the compressed configuration.

4. The injection device of claim 3, wherein the housing comprises a distal length having a reduced inner diameter relative to a proximal portion of the housing, the reduced inner diameter maintaining the compressed configuration of the intermediate driver.

5. The injection device of claim 4, wherein the reduced diameter is provided by one or more support ribs, or an increased thickness of the wall of the housing.

6. An injection device according to any preceding claim, wherein the intermediate member comprises an outer portion and an inner portion connected by a connecting portion.

7. An injection device according to any preceding claim, wherein the outer portion comprises one or more resilient fingers or a wall which is discontinuous at the proximal end of the outer portion.

8. An injection device according to claim 7 when dependent on claim 2, or any of claims 3 to 6 when dependent on claim 2, the resilient fingers or discontinuous wall portions being more closely together in the compressed configuration than in the relaxed configuration.

9. An injection device according to any preceding claim, wherein the intermediate member is provided with an inclined surface which contacts a corresponding inclined surface of the plunger.

10. An injection device according to any preceding claim, wherein the intermediate member comprises an outer portion and an inner portion connected by a connecting portion; the outer and inner portions extend distally from the connecting portion to receive a proximal end of the drive device.

11. An injection device according to any preceding claim, wherein the drive means is a spring.

12. The injection device of claim 11, wherein the spring is a compression spring.