Patent Application
20230070045
The present invention relates to an injection device for ejecting a predetermined plurality of fixed doses. Further, the present invention relates to such injection device having a plurality of integrated needle assemblies wherein each of the needle cannula assemblies can be brought to an injection position for ejecting one of the fixed doses.
The present invention thus relates to a so-called Multi-Use Fixed Dose Device which is able to deliver a predefined plurality (i.e. more than one) of fixed doses of a liquid drug to a user.
In a preferred example the number of fixed doses and the number of needle assemblies are the same.
Examples of injection devices provided with an integrated needle cannulae are disclosed WO 2001/93927 and in US 2012/0016315.
WO 2001/93927 discloses a needle magazine which in one example is formed as an integral part of an injection device. During use, the user manually pushes a shield axially. The manual axial movement of the shield in the proximal direction brings a needle cannula into a relative injection position wherein the entire front-end of the needle cannula is exposed outside the shield and the back-end of the needle cannula is penetrated into the cartridge which is secured in the injection device. With the needle cannula positioned in this injection position, the user can expel any number of doses wanted through the same needle cannula. The needle shield is preferably moved proximally by a spring when the user decides to manually release the shield. When the shield has been moved to its proximal position, the user can manually rotate the shield to thereby position the shield in the correct rotatable position for the next needle cannula. There is no automatic correlation between the release mechanism and the needle change mechanism as each mechanism is individually operated by the user.
US 2012/0016315 discloses an injection device with a needle magazine which in one example can form one unitary disposable assembly. The individual needle cannulae are placed in a hinged structure such that one individual needle cannula at the time can be brought into contact with the cartridge.
Common for such integrated solutions is that the injection device with the build-in needle magazine must be discarded either when all the needle cannulae are used or when the volume of liquid drug contained in the injection device is used. Depending on what occurs first, the user is forced to either discard unused needle cannulae or unused liquid drug.
Further, both the needle change, and the release of the dose are done as two individual user operations.
As an alternative to injection devices with integrated needle magazine are stand-alone needle magazines which the user manually attaches to an injection device. Examples of such separate needle magazines are disclosed in WO 2017/189164 and in U.S. Pat. No. 9,889,249.
After having attached such needle magazine to an injection device, the user must manually operate the needle magazine to bring the individual needle cannulae into an injection position. Since the needle magazine is a stand-alone unit there is no correlation between the needle change and the ability to inject a dose as these two actions are made separately.
Another drawback with such solution is that the user is faced with several kinds of handling issues. Firstly, it is not recommendable to move the needle magazine to a new injection device in case the injection device runs dry from liquid drug before all the individual needle cannulae are used since the sterility barrier protecting the back-end needle is broken first time the needle magazine is attached to an injection device. Moving the needle magazine from one injection device to another one would seriously expose the back-end of the needle cannulae entering the cartridge to contamination and in order to avoid this, the user is forced to discard the needle magazine when the injection device runs dry for liquid drug and hence discard unused needle cannulae.
Secondly, if all the needle cannulae in the attached needle magazine are used while there is still liquid drug left in the injection device, the user must replace the needle magazine with a new needle magazine where after the possibility of running dry for liquid drug in the injection device before all the needle cannulae in the new magazine are used is fairly high which would again lead to the user discarding unused needle cannulae.
A further obstacle with both the integrated solutions and the separate needle magazines are the fact that the changing of the individual needle cannulae is performed manually which means that the same needle cannula can accidentally be used for several injections should the user forget to change to a new needle cannula.
It is an object of the present invention to provide an injection device with integrated needle cannulae wherein the safety for the user has been optimized and wherein it is ensured that each dose is delivered using an unused needle cannula.
Accordingly, in a first aspect of the invention a pre-filled injection device for releasing a pre-defined plurality of fixed doses of a liquid drug is provided. The injection device comprises:
The user consequently has to activate the needle change mechanism and move a new needle assembly into the injection position before it is possible to release the next subsequent fixed dose.
The release of each dose can be foreseen in many different ways e.g. by activating a release button or by a spring driven mechanism which in one example could be triggered by the movement of a further mechanism such as a needle shield.
However, the release of each of the next doses following the first dose requires that the needle change mechanism has been operated at least once such that a new and unused needle assembly has been moved to the injection position prior to ejecting each of the next doses.
In this way it can be ensured that each of the doses in the injection device is ejected through an unused needle assembly.
A fixed dose is generally a dose having a fixed volume which is determined by the manufacturer of the injection device. When such injection device is capable of ejecting a plurality of fixed doses, the doses in the plurality can have minor variations due to mechanical tolerances in the injection device. However, all the fixed doses delivered by the injection device preferably has substantially the same volume and the term “fixed doses” are meant to cover a predetermined and fixed number of substantially equally sized dose volumes.
Further, it is preferred that the number of needle assemblies available in the plurality of needle assemblies is the same as, or more than, the predefined number of fixed doses of liquid drug available in the predetermined plurality of fixed doses. The last available dose is thus always injected with a new needle assembly where after the user discards the injection device.
Preferably, the first dose is injected using the first needle assembly where after the user activates the needle change mechanism thus bringing a new needle assembly into the injection position such that the second dose is injected by the second needle assembly and so forth. Each fixed dose in the predetermined plurality of doses are thus injected through a new needle assembly and the pre-filled injection device runs out of fixed doses before it runs out of needle assemblies.
In one example, four fixed doses are available and four (or more) needle assemblies are available. Hence each fixed dose can be injecting through a new and clean needle assembly.
In one example a needle shield can be provided which needle shield is telescopically movable in relation to the housing structure between a first position to a second position.
The first position of the needle shield is preferably a position wherein the needle shield is extended in an axial direction to cover the needle cannula. To cover is here meant that the needle shield extends over and covers the needle cannula in the axial direction, not necessarily in the radial direction.
The second position of the needle shield is preferably a position wherein the needle shield has been moved proximally to thereby expose at least the distal end of the needle cannula.
The release of each of the doses in the predefined plurality is preferably released when moving the needle shield axially from the first position and into the second position thus making the injection device a so-called shield triggered device i.e. an injection device wherein the axial movement of the needle shield activates the release of the dose.
In one example, the needle shield is guided translational in its movement from the first position to the second position.
In a further example, the release mechanism comprises a connector element and a torsion spring driven drive tube for driving a piston rod.
The connector thus connects the needle shield with the drive tube and the drive tube is further connected to the housing structure by a torsion spring. The drive tube is thus pushed proximally out of engagement with the housing structure by the connector which downstream is operated by the needle shield. Each time the drive tube is pushed out of engagement with the housing structure the drive tube is rotated by the torsion spring. In one preferred example, the drive tube rotates one full revolution each time it is pushed out of its engagement. The rotation of the drive tube generates a distal movement of the piston rod such that the fixed dose is expelled.
The dose volume being released is thus a result of the rotation of the drive tube and the transformation of this rotation to a movement of the piston rod in the distal direction. Since these interfaces are the same for all doses and the drive tube is moved the same distance for each release, the same dose volume will be expelled each time the drive tube is moved out of engagement with the housing structure. However, minor tolerances can occur.
The needle shield is in one example rotatable between a locked and an unlocked position when the needle shield is in the first position.
The user is thus able to lock and unlock the injection device by rotation of the needle shield once the needle shield is in its extended first position.
In the locked position it is not possible to activate the release mechanism since the needle shield in the locked position is hindered in any axial movement.
In a further example, the protective cap is used to rotate the needle shield between the locked and the unlocked position. This is preferably done by having the protective cap engage with the housing structure via a track interface that requires the user to rotate the protective cap in order to remove it (and attach it) and to transform this rotation of the protective cap to a rotation of the needle shield
Each needle assembly preferably comprising a hub adapted to hold a needle cannula such that a distal end points in a distal direction and a proximal end points in a proximal direction.
Further, in one example the container containing the liquid drug is a cartridge having an interior containing the liquid drug. The interior is defined by a movable plunger and a pierceable septum. In such construction which is well known from many different injection devices, the needle cannula used for injecting is pierced through the septum and the plunger is moved axially to thereby decrease the volume of the interior such that a quantum of the liquid drug is forced out through the lumen of the needle cannula.
When using a cartridge as the container, the cartridge is preferably permanently secured in the housing structure thereby making the injection device a pre-filled injection device.
Usually a drive mechanism is present for driving the plunger forward inside the cartridge. In the present example, the drive mechanism is a release mechanism which releases one fixed dose at the time.
First time the needle shield is rotated to unlock the injection device, all the proximal ends of all the needle cannulae in the plurality of needle assemblies are pierced through the septum of the container upon the first rotation of the needle shield from the locked position to the unlocked position.
Once the proximal ends of all the needle cannulae is inserted into the container, the proximal ends remain inserted into the container for the remaining life-time of the injection device. Whenever a needle cannula is moved distally to the injection position, the proximal end of that particular needle cannula remains inserted into the interior of the container but is translated a distance in the distal direction thus moving the proximal end of the needle cannula closer to the septum of the cartridge. Following an injection, the needle cannula is moved proximally such the proximal end of that particular needle cannula is moved back to its initial position. The distance the distal ends of the needle cannulae are moved when moved from the storage position and into the injection position must thus be shorter or at least the same as the distance the proximal ends are inserted into the cartridge the first time the user rotates the needle shield in order to maintain the proximal ends inserted into the container.
In a preferred example, both the release mechanism and the needle change mechanism are activated by movement of the needle shield.
The needle shield thus has two patterns of movements. During injection, the needle shield is translated forth and back and during locking and unlocking of the injection device, the needle shield is rotated relatively to the housing structure.
These two patterns of movements (translation and rotation) are used to both activate the release of a dose and to change the needle assembly.
In one example, a new and unused needle assembly is moved to the injection position upon each rotation of the needle shield from the locked position to the unlocked position.
The needle change mechanism is preferably such that whenever the user rotates the needle shield to the locked position, an old and used needle assembly is moved proximally into the storage position and whenever the user rotates the needle shield to the unlocked position in preparation of a new dose release, the next new and unused needle assembly is moved into the injection position.
The needle change mechanism preferably comprises a key and a carousel which both have a helical track used to move the needle assembly axially.
Translation of the needle shield forth and back as done during injection, generates a rotation the key such that the key is moved to the next unused needle assembly during injection.
Following an injection, once the needle shield is back in the first position, the user rotates the needle shield to the locked position. This rotation of the needle shield generates a simultaneously rotation of the carousel and the helical track inside the carousel moves the needle assembly.
The implications are that whenever the needle shield is rotated to the locked position, the old and used needle assembly is moved proximally and whenever the key and the carousel are rotated in the same rotational direction a new and unused needle assembly is moved into the injection position.
During rotation of the needle shield to the locked position, the key needs to be maintained in the new position it has been moved to during injection. It is thus desirable to have click means which rotates the key together with the needle shield and the carousel when moving a new needle assembly to the injection position but which maintains the key in its position whenever the needle shield and the carousel are rotated to the locked position and the old and used needle assembly is moved back to the storage position.
An “injection pen” is typically an injection apparatus having an oblong or elongated shape somewhat like a pen for writing. Although such pens usually have a tubular cross-section, they could easily have a different cross-section such as triangular, rectangular or square or any variation around these or other geometries.
The term “Needle Cannula” is used to describe the actual conduit performing the penetration of the skin during injection. A needle cannula is usually made from a metallic material such as e.g. stainless steel and preferably connected to a hub made from a suitable material e.g. a polymer. A needle cannula could however also be made from a polymeric material or a glass material.
As used herein, the term “Liquid drug” is meant to encompass any drug-containing flowable medicine capable of being passed through a delivery means such as a hollow needle cannula in a controlled manner, such as a liquid, solution, gel or fine suspension. Representative drugs could include pharmaceuticals such as peptides, proteins (e.g. insulin, insulin analogues and C-peptide), and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form.
“Cartridge” is the term used to describe the primary container actually containing the liquid drug. Cartridges are usually made from glass but could also be moulded from any suitable polymer. A cartridge or ampoule is preferably sealed at one end by a pierceable membrane referred to as the “septum” which can be pierced e.g. by the non-patient end of a needle cannula. Such septum is usually self-sealing which means that the opening created during penetration seals automatically by the inherent resiliency once the needle cannula is removed from the septum. The opposite end of the cartridge is typically closed by a plunger or piston made from a rubber composition or a suitable polymer. The plunger or piston can be slidable moved inside the cartridge. The space between the pierceable membrane and the movable plunger holds the liquid drug which is pressed out as the plunger decreased the volume of the space holding the liquid drug.
The cartridges used for both pre-filled injection devices and for durable injections devices are typically factory filled by the manufacturer with a predetermined volume of the liquid drug. A majority of the cartridges currently available contains either 1.5 ml or 3 ml of liquid drug.
Since a cartridge usually has a narrow distal neck portion into which the plunger cannot be moved not all of the liquid drug contained inside the cartridge can actually be expelled. The term “initial quantum” or “substantially used” therefore refers to the injectable content contained in the cartridge and thus not necessarily to the entire content.
By the term “Pre-filled” injection device is meant an injection device in which the cartridge containing the liquid drug is permanently embedded in the injection device such that it cannot be removed without permanent destruction of the injection device. Once the predetermined amount of liquid drug in the cartridge is used, the user normally discards the entire injection device. Usually the cartridge which has been filled by the manufacturer with a specific amount of liquid drug is secured in a cartridge holder which is then permanently connected in a housing structure such that the cartridge cannot be exchanged.
This is in opposition to a “Durable” injection device in which the user can himself change the cartridge containing the liquid drug whenever it is empty. Pre-filled injection devices are usually sold in packages containing more than one injection device whereas durable injection devices are usually sold one at a time. When using pre-filled injection devices an average user might require as many as 50 to 100 injection devices per year whereas when using durable injection devices one single injection device could last for several years, however, the average user would require 50 to 100 new cartridges per year.
A “Multi-Use Fixed Dose” injection device is meant to define an injection device which is able to deliver a predefined plurality (i.e. more than one) of doses which are substantially identical in volume. The liquid drug contained in the cartridge is thus expelled in a number of substantially identical dose volumes. In one example the cartridge could e.g. contain 3 ml of liquid drug which could e.g. be expelled in 6 identical doses each of 0.5 ml. The number of equally sized doses are often 2 to 8, and preferably 4 to 6 identical dose volumes. A multi-use fixed dose injection device can either be pre-filled such that the injection device is discarded after the predefined number of dose volumes has been expelled or it can be a durable injection device enabling the user to change the cartridge and expel a new series of equally sized doses volumes from the new cartridge.
Using the term “Automatic” in conjunction with injection device means that, the injection device is able to perform the injection without the user of the injection device delivering the force needed to expel the liquid drug during dosing. The force is typically delivered—automatically—by an electric motor or by a spring drive. The actual spring for the spring drive is e.g. strained by the user during dose setting, however, such springs are usually pre-strained with a low force in order to avoid problems of delivering very small doses. Alternatively, the spring can be fully preloaded by the manufacturer with a preloaded force sufficient to expel the full initial content (i.e. the entire injectable content) of liquid drug contained in the cartridge though a number of doses. Typically, the user activates a latch mechanism provided either on the surface of the housing or at the proximal end of the injection device to release—fully or partially—the force accumulated in the spring when carrying out the injection.
The term “Permanently connected” or “permanently embedded” as used in this description is intended to mean that the parts, which in this application is embodied as a cartridge permanently embedded in the housing structure, requires the use of tools in order to be separated and should the parts be separated it would permanently damage at least one of the parts thus rendering the injection device unable to operate.
All references, including publications, patent applications, and patents, cited herein are incorporated by reference in their entirety and to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
All headings and sub-headings are used herein for convenience only and should not be constructed as limiting the invention in any way.
The use of any and all examples, or exemplary language (e.g. such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability, and/or enforceability of such patent documents.
This invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.
The invention will be explained more fully below in connection with a preferred embodiment and with reference to the drawings in which:
The figures are schematic and simplified for clarity, and they just show details, which are essential to the understanding of the invention, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts.
When in the following terms as “upper” and “lower”, “right” and “left”, “horizontal” and “vertical”, “clock-wise” and “counter clock-wise” or similar relative expressions are used, these only refer to the appended figures and not to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as their relative dimensions are intended to serve illustrative purposes only.
In that context it may be convenient to define that the term “distal end” in the appended figures is meant to refer to the end of the injection device carrying the needle cannulae and pointing towards the user during injection, whereas the term “proximal end” is meant to refer to be the opposite end as indicated in
When referring to clock-wise and counter clock-wise in the following examples it is understood that the injection device is viewed from a position distal to the injection device. Clockwise is thus rotation following the direction of the arms on a clock and counter clock-wise is towards the opposite rotational direction as indicated by the arrow “Counter” in
To explain the various movements taken place in the injection device described, the following terminology are used throughout the following examples;
“Translational movement” is meant to be a strictly linear movement without any rotation.
“Rotational movement” is any movement of rotation around a centre which centre can be a centre point i.e. in one planar or a centre axis i.e. having a longitudinal extension.
“Axial movement” means any movement in an axial direction e.g. along the centre axis. Such movement can be a strictly translational movement or include a rotational movement which thus makes it a “Helically movement” as this is meant to be the combination of an axial movement and a rotational movement.
“Telescopic” is meant to cover the situation in which a movable element moves out from, or into, a base element. The movement can be translational i.e. without any rotation, or the movement can include a rotation thus making the movement helical.
In the following example reference is made to the dose expelling mechanism of the multi-use fixed dose injection device disclosed in International patent application No. PCT/EP2000/085271 which is henceforth included by reference.
In the example herein provided, the multi-use fixed dose device is designed to expel four (4) equally sized (i.e. fixed) dose volumes. However, any other random number of fixed doses can be envisaged, e.g. 2, 3, 5, 6 or more fixed dose volumes.
The protective cap 20 which is disclosed in further details in
As seen in
The needle shield 30, 35 which comprises the first shield 30 and the second shield 35 as will be explained is also provided with a window which can be rotated into alignment with the window 105 in the housing structure thus allowing the user to visually inspect the content of the cartridge before performing an injection.
In
The pierceable plug 65 is made from a suitable polymer which in one example could be the same TPE as used for the septum 8 in the cartridge 6. Preferably, the pierceable plug 65 also contains an anti-bacterial additive.
The needle unit 45 holds the individual needle assemblies 70 together with a needle change mechanism which comprises a key 80 and a carousel 90. The needle change mechanism is driven by the needle shield 30 as will be explained.
The above individual parts are disclosed in further details in the
The shield guide 10 is distally provided with a peripheral track 12 which guides the inner protrusion 21 provided inside the protective cap 20. This peripheral track 12 has at least one axial track opening 13. The user is henceforth required to rotate the protective cap 20 before the inner protrusion 21 inside the protective cap 20 is aligned with the axial track opening 13 and the protective cap 20 can be axially pulled off the housing structure.
The bottom of the peripheral track 12 preferably has a raised part such that the inner protrusion 21 inside the protective cap 20 encounters some resistance when the protective cap 20 is rotated relatively to the shield guide 10 and thus the housing structure. This provides the user with a tactile indication when the protective cap 20 is removed and attached.
The protective cap 20 which protects the distal part of the injection device between injections is disclosed in
When the user rotates the protective cap 20 in order to remove it, these longitudinal tracks 22 engages similar outwardly pointing bars 31 provided on the outer surface of the first shield 30 as disclosed in
The rotation of the protective cap 20 introduced by the peripheral track 12 is thus transferred to a similar rotation of the first shield 30.
The first shield 30 disclosed in
In the following the first shield 30 and the second shield 35 will together be named as the needle shield and referenced to as “30, 35”.
The first shield 30 is on the outer surface provided with a pair of protrusions 33 which together with guide surfaces 14 in the shield guide 10 makes the first shield 30 move helically when rotated as will be explained.
The guide surfaces 14 in the shield guide 10 connects to a helical guide part 101 provided in the housing part 100 such that a helical track 102 is formed between the shield guide 10 and the housing part 100 as e.g. seen in
The injection device is disclosed in different states in the
The housing part 100 of the housing structure is further provided with the before mentioned window 105 through which the user can visually inspect the content of cartridge 6. The window 105 is preferably divided into sections indicating the number of predetermined dose volumes.
Distally, the needle cannula 72 is hidden by the first shield 30 which is connected to the second shield 35 as explained.
The housing part 100 which is thus only partially disclosed, is distally connected to the shield guide 10 and proximally connected to a spring base 120 as indicated with broken lines in
The drive tube 130 engages and rotates a piston rod 2 during ejection as explained in International patent application No. PCT/EP2000/085271. In order to release one of the fixed doses, the user pushes the first shield 30 and consequently the second shield 35 in the proximal direction which moves the drive tube 130 proximally and releases the drive tube 130 to expel a fixed dose volume as explained in International patent application No. PCT/EP2000/085271.
When the drive tube 130 is released, the torsion spring 115 rotates the drive tube 130 and thus the piston rod 2 which is henceforth rotated helically in the distal direction due to its engagement with a nut element in the housing structure. In the disclosed example, the drive tube 130 is rotated approximately 360° every time it is proximally moved out of engagement with the housing part 100. The drive tube 130 engages a longitudinal track structure in the piston rod 2 such that the piston rod 2 rotate together with the drive tube 130. The piston rod 2 henceforth rotates simultaneously with, and the same angle as, the drive tube 30, and is moved helically forward a distance depending on the pitch of the thread on the piston rod 2 and the thread in the nut member in the housing part 100.
Preferably, a connector element 140 is provided for moving the drive tube 130 in the proximal direction during expelling of the fixed doses. The connector element 140 is provided between the second shield 35 and a connector spring 143 urging the connector element 140 in the distal direction. The second shield 35 and the connector element 140 are preferably hooked together in some situations as will be explained.
The uprights 52a,b,c,d are each provided with a longitudinal track structure 53 which engages the needle assemblies 70 as will be explained. The result is that the needle assemblies 70 can only move translationally in relation to the tower 50 and the housing structure. In the disclosed example the four uprights 52a,b,c,d are capable of guiding four needle assemblies 70 in the longitudinal direction. By using four needle assemblies it is assured that each of the four injections can be performed through a fresh and unused needle cannula 72.
However, the number of uprights and thus the number of longitudinal track structures can be changes to accommodate a different number of needle assemblies.
Distally the uprights 52a,b,c,d abuts four inserts 61a,b,c,d in the tip part 60 which are disclosed in details in
A perspective view of the needle unit 45 disclosed in
In
The key 80 which is disclosed in further details on
Between the key 80 and the tip part 60, a carousel 90 is provided. This carousel 90 is disclosed in further details in
The first shield 30 as disclosed in
Each needle cannula 72 has a distal end 73 and a proximal end 74 and a lumen there between. The needle cannula 72 is preferably glued and/or click fitted to the hub 71 and the hub 71 is further provided with a protrusion 75 on an outer surface.
The hub 71 is on the inwardly pointing surface provided with a rib configuration 76 which engage with the longitudinal track structure 53 in the uprights 52a,b,c,d on the tower 50 such that the needle assemblies 70 can only slide translational in relation to the needle unit 45 defined by the tower 50 and tip part 60. This also implies that the needle assemblies 70 can only slide translational in relation to the housing structure.
The working of the dose engine is described in the below example which is visualized on the
The dose engine itself is disclosed in an exploded view in
The drive tube 130 is proximally provided with a helical end surface 133 which terminates into an axial drive flange 132 extending in parallel with the centre axis “X” of the injection device. Further, an axial rib 131 is provided on an outer surface of the drive tube 130. The drive tube 130 is also described in further details in International patent application No. PCT/EP2000/085271. The centre of the drive tube 130 comprises a through-going opening which surrounds the piston rod 2.
The piston rod 2 has a longitudinal track structure 3 and an outer thread 4. The longitudinal track structure 2 is engaged by one or more radial teeth 134 provided in the through-going opening the drive tube 130, and the outer thread 4 on the piston rod 2 is threaded to a similar thread in the housing structure. The result being that the piston rod 2 is moved helically in relation to the housing structure whenever the drive tube 130 is rotated.
In the example disclosed on
To move the drive tube 130 in the proximal direction during dose activation a connector element 140 is provided which lies between the drive tube 130 and the needle shield 30, 35.
The connector element 140 is urged in the distal direction by a connector spring 143 which is provided between the spring base 120 and the connector element 140 and applies an axial force onto the connector element. Distally the connector element 140 is provided with a number of hooks 141 which are able to engage with similar hooks 36 provided proximally on the second shield 35 as will be explained.
As seen in the
In
On the inner surface, the connector element 140 is provided with an inwardly pointing knob 142 which thus follows all movements of the connector 140. In the
The inwardly pointing knob 142 operates a longitudinal rib 131 provided on the drive tube 130 during dose expelling as will be explained.
The drive tube 130 further has an axial drive flange 132 which abut the axial housing flange 111 inside the housing part 100 as disclosed in
In the
The pair of protrusions 33 provided on the first shield 30 is movable in the helical track 102, in the axial track 104 and in the peripheral track 103. The pattern of movement of the first shield 30 are the same as the pair of protrusions 33 as they are provided on the first shield 30. The position and the movement of the pair protrusions 33 in these tracks 102, 103, 104 defines the different states of the injection device as will be explained further.
The doses are released by moving the first shield 30 and thus also the second shield 35 in the proximal direction. This is preferably done by pressing the distal end of the first shield 30 against the skin of the subject to be injected. The proximal movement of the first shield 30 and the second shield 35 is via the connector element 140 transferred to a proximal movement of the drive tube 130. The axial length of the housing flange 111 and the axial drive flange 132 is henceforth decisive for how long the drive tube 130 most be moved in the proximal direction before a dose is released, and the pitch between the piston rod 2 and the nut member in the housing structure decides how far the piston rod 2 is rotated helically in the distal direction during release of the dose. Since these factors are the same for all the doses provided for, the piston rod 2 moves the same axial distance in the distal direction for each dose release why all the doses are identical in volume. However, minor variations can occur due to tolerances.
It is further to be understood that once the drive tube 130 is moved proximally and the axial drive flange 132 is moved out of engagement with axial housing flange 111, the helical end surface 133 of the drive tube 130 will rotate on the helical structure 112 of the bridge structure 110 inside the housing structure. The force providing this rotation is delivered by the torsion spring 115 which operates between the housing structure and the drive tube 130. The rotation of the drive tube 130 stops once the axial drive flange 132 abuts against the housing flange 111 which in the disclosed example means that the drive tube 130 rotates one full rotation i.e. 360° each time the drive tube 130 is activated to deliver one dose.
The torsion spring 115 is preferably loaded with a torque sufficient to rotate the drive tube 130 a predefined number of times to expel the same predefine number of dose volumes. In the example herein provided, the multi-use fixed dose device is designed to expel four equally sized dose volumes and the torsion spring 115 is thus pre-strained to deliver a torque sufficient to rotate the drive tube 130 four times. However, any other random number of fixed doses can be envisaged, e.g. 2, 3, 5, 6 or more fixed dose volumes and the torque stored in the torsion spring is preferably set to the chosen number of dose volumes. Do to this pre-straining of the torsion spring 115 it is not necessary for the user to manually strain the torsion spring 115 every time a new dose is to be expelled.
The fixed doses to be expelled are thus prepared by moving the axial drive flange 132 on the drive tube 130 axially out of engagement with the axial housing flange 111 and the fixed dose is expelled when the drive tube 130 rotates one full rotation down the helical structure 112 provided on the bridge structure 110 inside the housing structure. For each dose release, the piston rod 2 moves a certain, and pre-determined, distance in the distal direction and as explained in International patent application No. PCT/EP2000/085271 and a stop mechanism incorporated between the drive tube 130 and the piston rod 2 prevents the drive tube 130 from being moved further in the proximal direction when the last of the predetermined number of fixed doses has been prepared.
When the pair of protrusions 33 is provided in the start of helical track 102 (
Further, in the state disclosed in
The different states correlated with the different positions of the pair of protrusions 33 are described in further details below. In the
1. Unlocking the injection device for First Dose.
2. Preparing the First Dose.
3. Injecting the First Dose.
4. Sliding back the Needle Shield After First Injection.
5. Attachment of the Protective Cap Following First Injection and locking of the injection device.
6. Unlocking the Injection Device for Next Dose.
7. Injection of the Next Doses.
When the user rotates the protective cap 20 counter clock-wise to remove it, this rotation will be transformed to a similar rotation of the first shield 30 indicated by the arrow “U” in
In the locked position disclosed in
During rotation of the first shield 30 from the position in
This further helical rotation of the needle shield 30 and the second shield part 35 is thus transferred to a similar helical rotation of the connector element 140 which moves the inwardly pointing knob 142 inside the connector element 140 into alignment with the longitudinal rib 131 provided on the outer surface of the drive tube 130 as seen in
In the unlocked position of the needle shield 30, 35 disclosed in
Before an injection can be performed the user must remove the protective cap 20. In the position disclosed in
In
The inwardly pointing knob 142 on the connector element 140 is in this state positioned adjacent to and in abutment with the longitudinal rib 131 on the drive tube 130, and the second shield 35 is hooked 36, 141 to the connector element 140.
As the first shield 30 are pressed further against the skin “S” as disclosed in
At the same time, the connector element 140 moves translational in the proximal direction guided by the raised bar 106 and due to the abutment between the inwardly pointing knob 142 and the distal end of the longitudinal rib 131, the drive tube 130 is also moved proximally.
During this proximal movement of the drive tube 130, the axial drive flange 132 on the drive tube 130 slides proximally on the axial housing flange 111 provided on the bridge structure 110. However, as long as the axial drive flange 132 abuts the axial housing flange 110, the drive tube 70 is kept inrotatable.
The axial movement of the drive tube 130 compresses the compression zone provided on the torsion spring 115. This compression zone is best seen on
In
As seen in
The drive tube 130 (see e.g.
The nut member facilitating the rotation of the piston rod 2 is preferably carried by the housing structure. The nut member is either permanently attached e.g. by moulding it to the bridge structure 110 or the nut member can be attached thereto using alternatives means.
During the rotation of the drive tube 130 from the position in
In
The rotation of the connector element 140 also moves the end flange 144 of the connector element into contact with a sloped flange 39 proximally on the second shield 35. However, as the first shield 30 and the second shield 35 is in their most proximal position and the skin of the subject being injected hinders the first shield 30 from moving in the distal direction this has no consequence for the connector element 140 which thus remains in the same axial position.
Sliding back the Needle Shield after First Injection
In
Since the second shield 35 is prevented from rotation due to the engagement of the pair of protrusions 33 on the first shield 30 with the axial track 104, the abutment of the end flange 144 on the connector element 140 with the sloped flange 39 on the second shield 35 will force the connector element 140 to rotate further in the counter clock-wise direction as it moves distally and releases from the raised bar 106 (
In
At the same time; the engagement between the end flange 144 on the connector element 140 and the sloped flange 39 on the second shield 35 has rotated the connector element 140 further to a position wherein a carved-out portion 145 on the connector element 140 engages a raised bar 106 in the housing structure such that the connector element 140 is now hooked and secured to the housing structure.
In this position, the connector element 140 is prevented from being moved translational in the proximal direction due to the engagement between the carved-out portion 145 and the raised bar 106. It is henceforth not possible to move the needle shield 30, 35 in the proximal direction. Should the user try to activate a new dose when in this state it will not be possible to move the needle shield 30, 35 proximally as the connector element 140 is locked in the proximal direction. The first shield 30 is consequently locked from any movement in the proximal direction.
The inwardly pointing knob 142 is in this position located counter clockwise to the rib 131 such that should the connector 140 be moved proximally in this state, it will not release a further dose.
When the injection is finished, the user attaches the protective cap 20 by inserting the inner protrusion 21 on the protective cap 20 into the peripheral track 12 on the shield guide 10 through the axial opening 13 in the peripheral track 12 and starts to rotate the protective cap 20 in the clock-wise direction. All though the protective cap 20 is not shown in
This rotation is transferred to a similar rotation of the first shield 30 due to the engagement between the longitudinal ribs 22 inside the protective cap 20 and the outwardly pointing bars 31 on the first shield 30.
In
The carved-out portion 145 in the connector element 140 is proximally provided with a sloped flange 146. Consequently, when the connector element 140 is rotated in the clock-wise direction as disclosed in
Once the protective cap 20 has been rotated to its locked position in the peripheral track 12, the pair of protrusions 33 are located in the clock-wise end of the peripheral track 103 as shown in
As also seen in
Whenever the user wants to perform a new injection, the user must remove the protective cap 20 by rotating the inner protrusion 21 to a position wherein it is aligned with the radial opening 13 in the peripheral track 12 and remove the protective cap 20 as seen in
In
When rotating the second shield 35 from the position disclosed in
When unlocking the injection device by rotating the needle shield 30 (using the protective cap 20) from the position disclosed in
The result being that the inwardly pointing protrusion 142 provided on the inner surface of the connector 140 is moved into alignment and abutment with the rib 131 provided on the drive tube 130 such that the injection device is ready to release the next fixed dose.
Once the needle shield 30, 35 has been rotated to the position disclosed in
The next dose is prepared and released by pushing the first shield 35 against the skin of the subject to be injected as described in the above state named “Preparing the First Dose” and “Injecting the First Dose”. Actually, all the following fixed doses are prepared and released in this way.
Conclusively, the helical track 102 is only used in connection with the first fixed dose and between each of the following fixed doses the pair of protrusions 33 needs to be moved to the bottom of the peripheral track 103 as disclosed in
This pattern of movements is used to also guide the needle change mechanism such that for each preparation of a new fixed dose, a new and fresh needle assembly is being brought into the injection position.
During the various states described above the needle change mechanism moves one fresh and unused needle assembly into injection position at the time as will be explained in the following.
The following table shows the correlation between the figures showing the needle change mechanism and the figures showing the different states of the operation of the injection device in regards of expelling the doses.
Preparing the first needle for injection is schematically disclosed in
However, the tip part 60 is only shown with broken lines as it moves one layer below the first shield 30.
In the
Returning shortly to
The needle unit 45 is preferably guided translational by having a pair of radial protuberances 55 being guided in an axial track 15 provided in the shield guide 10 which is a part of the housing structure. This axial track 15 is best seen in
The rotation of the first shield 30 is also here introduced by the rotation of the protective cap 20 which engages the outwardly pointing protrusion 31 on the first shield 30. As the first shield 30 is rotated it moves helically in the proximal direction due to the guidance of the pair of protrusions 33 in the helical track 102. Further, as the first shield 30 in its helically movement also presses on the helical rib 63, the needle unit 45 is moved in the proximal direction with a high speed due to the double helical engagement (rotation of the first shield 30 drives the needle unit 45 translational in the proximal direction and rotation of the first shield 30 drives the first shield 30 helically in the proximal direction).
During the rotation of the needle shield 30 from the position disclosed in
The key 80 which is disclosed in
During rotation of the key 80 by the first shield 30, this curved flange 84 engages the protrusion 75 on the needle hub 71. As the user continues to rotate the first shield 30, the needle unit 45 moves in the proximal direction due to engagement of the first shield rib 41 with the helical rib 63 on the needle unit 45. However, due to the engagement of the curved flange 84 with the protrusion 75, one of the needle assemblies 70 is prevented from fully following the proximal movement of the remaining needle assemblies 70 in the needle unit 45.
In fact, all the needle assemblies 70 travels with a high speed in the proximal direction except one of the needle assemblies 70 which due to the engagement between the protrusion 75 on the needle hub 71 and the curved flange 84 in the key 80 travels with a lower speed. The result being that all the proximal ends 74 of the needle cannulae 72 penetrates through the septum 8 of the cartridge 6, however, one of the needle cannulae 72 are moved a smaller distance into the cartridge 6 whereas the distal end 73 of that particular needle cannula 72 is moved to its injection position which is a position wherein the distal end 73 of the needle cannula 72 lies outside and distal to the needle unit 45.
However, the continued rotation of the first shield 30 translates the needle unit 45 including the needle assemblies 70 in the proximal direction as disclosed in
The rotation of the key 80 moves the protrusion 75 on the needle hub 71 into the helical guiding track 92 in the carousel 90 as disclosed in
During the rotation occurring from
Once the needle unit 45 has been moved translational to the position disclosed in
Further, in the position depicted in
Once the first needle assembly 70 is in the injection position disclosed in
In the
Since the pair of protrusions 33 and the first shield rib 41 are free to translate in the proximal direction, the needle shield 30 will slide in the proximal direction when pushed against the skin. This proximal movement will thus compress the connector spring 143. As the first shield 30 moves proximally, the distal end 73 of the needle cannula 72 penetrates the skin of the subject being injected as the needle assembly 70 is prevented from movement in the proximal direction due to the engagement between the protrusion 75 on the needle hub 71 and the shelf 93 inside the carousel 90.
The key 80 which is disclosed in details on
In
As the needle shield 30 is moved further in the proximal direction as disclosed in
The longitudinal rib 34 is at the proximal end provided with an axial extension 43 and a sloped surface 44 which as the needle shield 30 is moved proximally engages with the radial protrusion 85 on the key 80 and as disclosed in
The protuberance 55 on the tower 50 of the needle unit 45 is distally provided with a blade 56. This blade 56 allows the flexible flap 82 to pass by the blade 56 in one direction (counter clockwise in this example) but prevents the flexible flap 82 from passing the blade 56 in the opposite direction (clock-wise).
In
Once the fixed dose volume has been delivered, the user removes the needle shield 30 from the skin of the subject being injected. The connector spring 143 will consequently move the first shield 30 in the distal direction as disclosed in
As seen e.g. in
As seen in
As explained earlier and shown on
As best seen in
As the carousel 90 rotates together with the needle shield 30, the sidewall 94 of the helical track (see
Once the protective cap 20 has been fully attached and the inner protrusion 21 inside the protective cap 20 has been moved to its locked position which is indicted by the arrow “21” in
This situation is reflected in
As best seen in
These openings 87a-b allows the protrusion 75 on the needle assembly 70 to move from the helical track 92 in the carousel 90 and back into key 80. Once the protrusion 75 is moved back into the carousel 90, the needle assembly 70 is fully retracted. This is e.g. seen in
In this stored position of the needle assemblies 70 are all the proximal ends 74 of the needle cannulae located inside the cartridge 6 and the distal ends 73 are all stored in the plug 65 which preferably contains an anti bacterial material.
Moving Next Needle into Injection Position
The injection device is hereafter unlocked by rotating the needle shield 30 in the counter clock-wise direction as indicated by the arrow “O” in
During this rotation which is disclosed in the transition from
It is noted that since the peripheral track 103 is a part of the housing part 100 it is not physically shown in the
When the user rotates the needle shield 30 in the counter clock-wise direction to unlock the injection device, the second shield rib 42 engages the flexible flap 82 and rotates the key 80 also in the counter clock-wise direction. This rotation lifts the protrusion 75 on the next needle assembly 70 in the distal direction as the curved flange 84 on the key 80 engages the protrusion 70 on the needle hub 71.
The radial flange 86 on the key 80 prevents the other needle assemblies 70 in moving axially as the radial flange 86 abut the protrusions 75 as seen in
The needle shield 30 also engages and rotates the carousel 90 such that the carousel rotates together with the needle shield 30 and with the key 80. This has the consequence that the protrusion 75 is first picked up by the curved flange 84 inside the key 80 and delivered into the helical track 91 of the carousel 90 and the next needle assembly 70 is thus lifted to the shelf 93. As seen in
The injection position is the position wherein the protrusion 75 on the individual needle hub 71 is located on the relevant shelf 93 and the distal end 73 of the needle cannula 72 has been moved out of the plug 65. This position is disclosed in
In this position which is the same position as disclosed in
A comparison between
The injection device is thus delivered to the user with the needle unit 45 decoupled from the housing structure as disclosed in
Then, first time the user removes the protective cap 20, the needle shield 30 is rotated and moved helically due to the engagement of the pair of protrusion 33 with the helical track 102 in the housing structure. This first rotation of the needle shield 30 translates the needle unit 45 in the proximal direction such that all the proximal ends 74 of the needle cannulae 72 penetrates the septum 8 of the cartridge 6 and thus gains liquid contact with the drug inside the cartridge 6. In the remaining lifetime of the injection device all the proximal ends 74 are maintained inserted into the cartridge 6.
Simultaneously with the insertion of the needle cannulae 72 into the cartridge 6, the needle change mechanism lifts the first needle assembly 70 into the injection position as disclosed in
During injection, the needle shield 30 translates proximally which starts to rotate the key 80 towards the next needle assembly 70 as disclosed in
Once the injection has been performed and the needle shield 30 is slided back to its extended position as disclosed in the
In order to re-align the dosing mechanism, the user needs to rotate the needle shield 30 to its locked position and back to its unlocked position. If this is not done, a new dose cannot be released. The rotation of the needle shield 30 is, as explained, facilitated by the attachment and the removal of the protective cap 20.
The locking of the injection device is disclosed in
The key 80 was thus rotated to the next needle assembly 70 during translation forth and back of the needle shield 30 as done during injection and the carousel 90 is rotated during rotation of the needle shield 30.
When the needle shield 30 is rotated to its locked position, the old and used needle assembly 70 is moved proximally back into the storage position and when the needle shield 30 is rotated to its unlocked position, the key 80 is already placed at the next needle assembly 70 which is thus lifted to the injection position as the key 80 and the carousel 90 are rotated simultaneously together in the counter clock-wise direction during the unlocking of the injection device.
The change of the needle assemblies 70 are thus done by translating the needle shield 30 forth and back followed by a locking and an unlocking of the injection device. This can in theory be done any number of times but in the shown example a proximal stop surface is provided in the track structure 3 in the piston rod 2 which determines how many times the drive tube 130 can be moved proximally which again determines how many fixed doses it is possible to release. This End-of-Content mechanism is further disclosed in International patent application No. PCT/EP2000/085271 and is in the preferred example set such that the number of fixed doses to be released is the same as the number of needle assemblies 70 which in the disclosed example is four (4).
It is thus, generally preferred for the described invention that the predetermined number of doses available is the same as the number of needle assemblies available such that each predetermine dose volume can be injected through a new and clean needle cannula and such that the pre-filled injection device can be discarded once the number of fixed doses and the number of needle assemblies has been used. Should the number of fixed doses and needle assemblies be different it is important that there are more needle assemblies than fixed doses thus maintaining the basic idea of having a new and clean needle assembly available for each fixed dose. In such example, the user must then discard an injection device with one or more unused needle assemblies.
Alternatively, the key 80 can be provided with an extra protrusion which engages an inner peripheral track in the housing structure such that the key 80 can only be rotated a little less than one full revolution in relation to the housing structure. This will assure that all the needle assemblies 70 can only be used once.
Some preferred examples have been shown in the foregoing, but it should be stressed that the invention is not limited to these, but may be embodied in other ways within the subject matter defined in the following claims. It is especially pointed out that all though the number of fixed doses and the number of needle assemblies are the same, the number of these can be any relevant number and is not limited to four (4) as in the disclose example.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20157959.6 | Feb 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/053752 | 2/16/2021 | WO |
