Patent Application
20230001101
The present invention relates to a drug delivery device for delivering a predefined plurality of fixed doses. The present invention especially relates to such a drug delivery device wherein the expelling of the fixed doses is driven by a pre-strained torsion spring.
Drug delivery devices for self-administration of different liquid drug formulation presently exist in various shapes and sizes. Some are adapted for connecting to an infusion set, and some are connectable or integrated with an injection needle. The latter type is referred to as injection devices. Some are durable devices comprising a cartridge with a drug reservoir, wherein the cartridge can be changed. Others are disposable devices that are discarded when the cartridge is empty. Disposable devices can be either multi-dose devices, in which the user can set the desired dose size prior to each injection, or single dose devices, capable of administering only a single dose of a given size. The latter exists with so-called “Shield activation”, where the cannula is covered by a shield in the front of the device that releases the dose when pressed. The cannula is then exposed only to enter the skin, when the user presses the device against the skin, and thereby depresses the shield, and releases the dose. These injection devices are disposed after a single injection.
Fixed dose devices are preferable to some users, since they may not feel comfortable with or be capable of operating the device to adjust the correct dose each time. When devices for instance are used by children or older people, simplicity and ease of use is important to avoid user error leading to over- or under dosing. In other cases, the treatment regimen prescribes a fixed dose of e.g. a GLP-1 type of drug.
However, the device itself is responsible for a considerably part of the costs of the unit, not to mention the amount of materials used and thus necessary to dispose. It would therefore be desirable to make a fixed dose device capable of delivering multiple doses of a fixed volume.
In existing multi-dose devices, the motor consists of a spring being wound up when adjusting the dose. One solution is to make a normal multi-dose device where the maximum dose size is limited, so it is only possible to dial up to the fixed dose size. This would however introduce a risk that the user does not dial up sufficiently and thus gets a smaller dose than expected, this problem has been solved in WO2020089167 filed by Novo Nordisk, wherein a ratchet tube is locked to the housing until the full dose has been set and the drive mechanism has been released.
Another fixed dose device is disclosed in WO2019/09179 filed by Sanofi-Aventis. The disclosure relates to an injection device with a longitudinally displaceable dose tracker, providing an automated dose setting in accordance to a preselected size of a dose. The disclosed injection device comprises an elongated housing 10 extending along a longitudinal axis (z), a piston rod 20, 120 to operably engage with a piston 7 of a cartridge 6 filled with the medicament. The injection device further comprises a dose tracker 60, 150, 250, 350, 450, 550 selectively operably engageable with the piston rod 20, 120, wherein the dose tracker is proximally displaceable relative to the housing 10 from an initial position (i), see
An alternative fixed dose device is disclosed in WO2018/007259 filed by Copernicus. The disclosure relates to an injection device for delivering a defined number of equal doses of a fluid substance. The disclosed injection device comprises a housing 1 with an arming mechanism and a dose delivery mechanism arranged along the longitudinal axis of the housing. The housing is coupled to an enclosure 3 for receiving a reservoir with the fluid substance. The arming mechanism comprises a setting sleeve 5, which is axially non-displaceable. The arming mechanism is rotatable about the axis of the housing in two opposite directions by a defined setting angle (a). The setting sleeve 5 is coupled with a torsion spring 10, which is strained by the rotation of the setting sleeve 5 during arming of the device. The dose delivery mechanism comprises a screw ring 6 and a piston rod 4 which is non-rotatable and axially displaceable within the setting sleeve 5. When the piston rod 4 cooperates with the screw ring 6, during arming of the device, the screw ring 6 and the piston rod 4 are immobilized. During delivery of each dose, the piston rod 4 is displaced along the housing 1 by a defined distance due to unwinding of the spring 10 and rotation of the screw ring 6. Displacement of the piston rod 4 causes the fluid substance to be discharged from the reservoir. As appears, to enable ejection of a dose the torsion spring must be strained. An alternative design utilizing the compression of a spring is described in WO 2017/098460 also filed by Copernicus. Another alternative device also utilizing the compression of a spring before each fixed dose is disclosed in WO94/26331 filed by Owen Mumford. However, arming the device between each dose is not always desirable, as it requires that the user can provide enough force to arm the device.
An alternative fixed dose device is disclosed in WO2013/034651 filed by Menarini. The disclosure relates to a device for the automatic injection of two doses of a medicament at two successive times. The disclosure describes an automatic injection device comprising a sliding sheath 30 which, when depressed with its front end 3 against the injection site, interacts with cam means 26, 27, 28 to activate the triggering of a plunger 8, controlling the delivery of a drug dose. Plunger guide means 44 are provided on the inner surface of an outer housing 1 for controlling the triggering sequence and a dose knob 4 is used for arming or setting the device in the dose delivery condition. The device is adapted for automatic needle re-sheathing and resetting of a lock-out condition after each dose is delivered are provided. The number of the device components is reduced resulting in a simpler structure and cost reduction. Devices of same applicant and with a similar functioning are disclosed in WO2013/034647 and WO2011/111006. As appears all alternatives utilize a compression spring as the power means for driving the plunger.
US 2013/0096513, WO 2014/060369, WO 2014/198858 all describe drug delivery devices driven by a torsion spring, wherein the torsion spring is strained during the setting of a dose. US 2013/0096513 relates to a fixed dose drug delivery device, whereas WO 2014/060369, WO 2014/198858 relates to drug delivery devices with a variable dose.
Therefore, an unmet need exists for delivering alternative injection devices for delivering a predefined fixed dose, which addresses the needs for simple, safe, user-friendly and robust drug delivery devices.
Having regard to the above, it is an object of the present invention to provide a user-friendly, safe and robust a drug delivery device for delivering a predefined plurality of fixed dose.
In the disclosure of the present invention, embodiments and aspects will be described which will address one or more of the above objects or which will address objects apparent from the below disclosure as well as from the description of exemplary embodiments.
In a first aspect is provided a drug delivery device for sequentially delivering a predefined plurality of fixed doses, wherein the drug delivery device comprises:
a housing assembly,
a drive mechanism comprising a drive tube, wherein the drive mechanism is adapted to sequentially deliver the predefined plurality of doses, and,
an activation mechanism for activating the drive mechanism,
wherein the drive mechanism comprises a pre-strained torsional drive spring (108, 208) conserving an initial amount of energy, and adapted for rotating the drive tube, wherein each activation of the drive mechanism, and completion of a drive tube dose sequence reduces the amount of conserved energy in the drive spring, and wherein the initial amount of conserved energy, which is the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses.
Hereby, is provided a drug delivery device for delivering a predetermined plurality of fixed doses without arming or straining the drive mechanism between doses, as the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses. A fixed dose drug delivery device according to the present invention is adapted to deliver a dose of a desired volume a plurality of times. The total content of drug divided with the desired volume of a fixed dose determines the predetermined plurality. Each activation of the drive mechanism reduces the stored energy, as the spring is not strained before each dose.
In a further aspect:
the housing assembly comprises a guide structure comprising a stop-and-activation-guide-portion, and a drive-guide-portion);
the drive tube is adapted to be guided along the stop-and-activation-guide-portion for activation of the drive mechanism, and along the drive-guide-portion for delivering a fixed dose, and to the stop-and-activation-guide-portion, wherein dosing is stopped, whereby the drive tube is adapted to be guided, in response to the conduction of a drive tube dose sequence comprising activation, dosing and stop of dosing;
the drive mechanism further comprises a piston rod operationally connected to the housing assembly and the drive tube,
the activation mechanism is adapted for moving the drive tube along the stop-and-activation-guide-portion in a first axial direction from a first axial position to a second axial position, and thereby activate the drive mechanism.
In a further aspect, the drive mechanism further is adapted for biasing the drive tube in a second axial direction opposite the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube along the drive-guide-portion to the stop-and-activation-guide-portion, in response to activation of the drive mechanism, whereby a fixed dose of the predefined plurality of fixed doses is delivered, and wherein the drive tube is operationally positioned to be guided along the stop-and-activation-guide-portion for delivering a subsequent fixed dose of the plurality of fixed doses.
In a further or alternative aspect, the housing further comprises an inner thread, wherein the piston rod further comprises and outer thread for threadably engaging the inner thread of the housing assembly, wherein the drive tube is axially splined to the piston rod, whereby the drive tube is axially movable and rotationally locked relative to the drive tube, whereby the piston rod is operationally connected to the housing assembly and the drive tube.
In a further or alternative aspect, the torsional drive spring is compressional, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction. Hereby, the drive spring is adapted to bias the drive tube towards the first position during dosing, whereby the guide surfaces are ensured to be intact during dosing.
In a further or alternative aspect, the drug delivery device comprises an axially movable spring base, wherein the drive mechanism comprises a compressional return spring positioned between the axially movable spring base and the housing, whereby the torsional drive spring and the return spring a serially coupled, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction.
In a further or alternative aspect, the drug delivery device is adapted for drug delivery at a distal end, wherein the drug delivery device comprises a central axial axis defined between the distal end and a proximal end, wherein the drug delivery device comprises a slidably arranged spring base, wherein the torsional spring is arranged between the spring base and the drive tube, wherein the drive tube, during activation and dosing, is to be positioned with a component of the central axial axis in a direction opposite the gravitational force, being the second axial direction, whereby the drive tube is biased in the distal direction, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction.
In a further or alternative aspect, the torsional drive spring is arranged between the drive tube and the housing assembly.
In a further or alternative aspect, the housing assembly comprises a fixed spring base, wherein an end of the torsional drive spring is attached to the fixed spring base. Hereby the spring base becomes a fixed part of the housing assembly.
In a further or alternative aspect, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a helical portion.
In a further or alternative aspect, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a transverse portion.
In a further or alternative aspect, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a step-wise portion comprising intervals of a portion from a first group comprising transverse, and helical portions and a portion from a second group comprising radial, helical and axial portions.
In a further or alternative aspect, the drive tube comprises a corresponding guide structure adapted for cooperating with the guide structure of the housing assembly.
In a further or alternative aspect, the guide structure of the drive tube comprises an axial portion and a helical portion.
In a further or alternative aspect, for the drive tube being in the first position, the axial portions of the guide structures of the housing assembly and the drive tube are in abutment, and the helical portions of the guide structures of the housing assembly and the drive tube are in abutment, and wherein, for the drive tube being in the second position, an axial clearance is provided between the axial portions of the housing assembly and the drive tube, whereby the helical portion of the drive tube can slide onto the helical portion of the housing assembly.
In a further or alternative aspect, each of the delivered doses are of equal volume.
In a further or alternative aspect, the drug delivery device comprises an initialization mechanism, whereby each of the delivered doses are of equal volume.
In a further or alternative aspect, drive spring is pre-strained to deliver the predefined plurality of doses with a constant force, wherein the force can be measured as the axial force transferred from the piston rod, and wherein a constant force is defined as a force varying less than 20 percent between the first and the last dose.
In a further or alternative aspect, the predefined plurality of fixed doses is 2, 3, 4, 5 or 6, and preferably 4.
In a further or alternative aspect, the drug delivery device comprises a drug filled cartridge with a proximally arranged piston, wherein the piston rod is operationally arranged to advance the piston.
In a further or alternative aspect, the drug delivery device comprises an integrated needle, and wherein the activation mechanism comprises an axially movable needle shield for covering and uncovering the needle, wherein the shield is adapted to activate the drive mechanism, in response to a movement in a proximal direction, whereby the needle is uncovered.
In a further or alternative aspect, the drug delivery device comprises a needle mount for an injection needle, and wherein the activation mechanism comprises an axially movable release button, adapted to activate the drive mechanism, in response to an axial movement.
In a further or alternative aspect, the activation mechanism comprises a connector operationally connected to the drive mechanism, wherein the connector is adapted to activate the drive tube in response to an axial movement.
In a further or alternative aspect, the activation mechanism comprises a shield for covering an integrated needle, and a connector operationally connected to the drive mechanism, wherein the shield is operationally arranged to engage the connector, in response to rotating the shield, and wherein the shield is axially movable and adapted to move the connector, and thereby adapted to activate the drive tube, in response to an axial movement.
In a further or alternative aspect, the first position of the drive tube is a distal position and the second position is a proximal position.
In a further or alternative aspect, the drug delivery device is an injection device.
In a further or alternative aspect, the drug delivery device further comprises a drug reservoir with a piston arranged to expel a drug from the reservoir, wherein the piston rod is adapted for axially advancing the piston, wherein the piston rod is axially splined to the housing assembly, whereby the piston rod is axially movable and rotationally locked relative to the housing assembly, wherein the drive tube further comprises an inner thread, wherein the piston rod further comprises an outer thread for threadably engaging the inner thread of the drive tube, whereby the piston rod is operationally connected to the housing assembly and the drive tube, wherein the drive mechanism further comprises a compressional drive spring for axially moving the drive tube and the piston, whereby the drive mechanism and the drive-and-return guide are adapted to return the drive tube to the first position.
In a further or alternative aspect, the drug delivery device further comprises an axially movable spring base, wherein the compressional drive spring is positioned between the spring base and the housing, whereby the torsional drive spring and the compressional drive spring are serially couples.
In a further or alternative aspect, the compressional drive spring is integral with the torsional drive spring.
In a further aspect, the drive spring is pre-strained to deliver the predefined plurality of doses with a constant force.
In a further aspect, the housing assembly comprises a guide structure comprising a stop-and-activation-guide-portion, and a drive-guide-portion.
In a further aspect, the drive tube is adapted to be guided along the stop-and-activation-guide-portion for activation of the drive mechanism, and along the drive-guide-portion for delivering a fixed dose, and to the stop-and-activation-guide-portion, wherein dosing is stopped, whereby the drive tube is adapted to be guided, in response to the conduction of a drive tube dose sequence comprising activation, dosing and stop of dosing;
In a further aspect the drug delivery device comprises a reservoir with a piston, wherein the drive mechanism further comprises a piston rod for engaging and advancing the piston rod to expel a dose.
In a second aspect of the present disclosure is provided a drug delivery device for sequentially delivering a predefined plurality of fixed doses, wherein the drug delivery device comprises:
a housing assembly comprising a guide structure comprising a stop-and-activation-guide-portion, and a drive-guide-portion;
a drive mechanism adapted to sequentially deliver the predefined plurality of doses, wherein the drive mechanism comprises:
a drive tube adapted to be guided along the stop-and-activation-guide-portion for activation of the drive mechanism, and along the drive-guide-portion for delivering a fixed dose, and to the stop-and-activation-guide-portion, wherein dosing is stopped, whereby the drive tube is adapted to be guided, in response to the conduction of a drive tube dose sequence comprising activation, dosing and stop of dosing,;
a torsional drive spring conserving an initial amount of energy, and adapted for rotating the drive tube,
a piston rod operationally connected to the housing assembly and the drive tube,
an activation mechanism adapted for moving the drive tube along the stop-and-activation-guide-portion in a first axial direction from a first axial position to a second axial position, and thereby activate the drive mechanism,
wherein the drive mechanism further is adapted for biasing the drive tube in a second axial direction opposite the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube along the drive-guide-portion to the stop-and-activation-guide-portion, in response to activation of the drive mechanism, whereby a fixed dose of the predefined plurality of fixed doses is delivered, and wherein the drive tube is operationally positioned to be guided along the stop-and-activation-guide-portion for delivering a subsequent fixed dose of the plurality of fixed doses,
wherein each activation of the drive mechanism, and completion of a drive tube dose sequence reduces the amount of conserved energy in the drive spring, and wherein the initial amount of conserved energy, which is the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses.
Hereby, is provided a drug delivery device for delivering a predetermined plurality of fixed doses without arming or straining the drive mechanism between doses, as the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses. As appears the volume of a fixed dose is determined by the guides of the housing and drive mechanism. Therefore, a fixed dose drug delivery device according to the present invention is adapted to deliver a dose of a desired volume a plurality of times. The total content of drug divided with the desired volume of a fixed dose determines the predetermined plurality. As also appears for a fixed dose drug delivery device according to the present invention, a fixed dose can only be adjusted by modifying the drive mechanism and the guides of the device.
In the following embodiments of the invention will be described with reference to the drawings:
In the figures like structures are mainly identified by like reference numerals. Reference numbers followed by the letter “a” is used to denote the distal end of the structure, and numbers followed by “b” is used to denote the proximal end. Reference numbers comprising a first number followed by a “.” and a second number is used to denote a functional or structural detail of a structure. In this way the first number indicates a primary (relatively large) structure and the second number indicates a secondary (relatively small) structure or a specific function. Reference numbers followed by the letters c, d and e indicate features with rotational symmetry.
When in the following terms such as “upper” and “lower”, “right” and “left”, “horizontal” and “vertical” or similar relative expressions are used, these only refer to the appended figures and not necessarily 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. When the term member is used for a given component it can be used to define a unitary component or a portion of a component, having one or more functions.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.
It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first subject could be termed a second subject, and, similarly, a second subject could be termed a first subject, without departing from the scope of the present disclosure. The first subject and the second subject are both subjects, but they are not the same subject. Furthermore, the terms “subject,” “user,” and “patient” are used interchangeably herein.
As used herein, the term “if” may be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.
As used herein, the term distal and proximal end is in analogy with the terminology from anatomy used to describe the end situated away from or nearest the point of attachment to the body. Therefore, the distal end of an injection device is defined in a context, where a user holds the device in a ready to inject position, whereby the end with the injection needle will be the distal end and the opposite end will be the proximal end. Furthermore, distal and proximal ends of individual components of the device is also defined in that context.
As used herein, a trailing edge and a front edge is used to describe the edges of a structure moving relative to another structure. The front edge is the edge in the moving direction and the trailing edge is the opposite. In this way, the front edge and the trailing edge defined according to the direction of the relative movement between structures.
As used herein, rotational symmetry, is a property of a structure when it appears the same or possess the same functionality after some rotation by a partial turn. A structure's degree of rotational symmetry is the number of distinct orientations in which it appears the same for each rotation. Rotational symmetry of order n, wherein n is 2 or more, is also called n-fold rotational symmetry, or discrete rotational symmetry of the nth order, with respect to a particular point (in 2D) or axis (in 3D), which means that rotation by an angle of 360°/n does not change the object. The property of the structure may both relate to the visible appearance and the functional capability of structural feature.
As used herein, the term clockwise direction is used to describe the direction that the hands of a clock rotate as viewed from in front. Therefore, the clockwise rotation of the injection device is the clockwise rotation observed, when viewing the device from in front of the distal end. Counterclockwise or anticlockwise rotation is defined as the opposite direction.
As used herein, a proximal face is a face of the device as viewed from the proximal end and in the distal direction, wherein a distal face is the face of the device as viewed from the distal end and in the proximal direction.
As used herein, a positive axial or longitudinal direction is defined from the proximal end towards the distal end. A positive axial direction and a distal direction are used interchangeably with the same meaning. Similar, the definitions a negative axial direction and proximal direction are used interchangeably with the same meaning. A central axis of the device is defined through the centre of the injection device in the positive axial direction, which is also referred to as a longitudinal axis, with the same meaning.
As used herein, a positive radial direction is defined along a radial axis originating at the central axis and with a direction perpendicular to the central axis.
A positive circumferential or positive angular direction is defined for a point positioned at a radial distance from the central axis, wherein the circumferential direction is counter-clockwise and perpendicular to the axial and radial direction. A direction can as used in the present disclosure be both positive and negative. For example the term axial direction covers the positive axial direction from the proximal end towards the distal end and the negative axial direction, which is in the opposite direction.
Both the radial and the circumferential direction are herein referred to as transverse directions, as they are transverse normal to the axial direction. The transverse plane is herein defined as a plane spanned by two vectors in the radial and circumferential direction, for a given coordinate along the axis, and with the central axis as the normal vector.
As used herein, axial movement of a structure is used to describe a movement, wherein the displacement vector of the structure has a component in the axial direction. A translational movement is used to describe a uniform motion in the axial direction only. A pure, strict or uniform axial movement is the same as a translational movement and the terms are used interchangeably.
Radial movement of a structure is used to describe a movement, wherein the displacement vector of the structure has a component in the radial direction. A pure or strict radial movement is used to describe a uniform motion in the radial direction only. Thus a pure, strict and uniform radial movement is the same and the terms are used interchangeably.
Circumferential, angular or rotational movement of a structure is used to describe a movement, wherein the displacement vector of the structure has a component in the circumferential direction. A pure or strict circumferential movement is used to describe a uniform motion in the circumferential direction only. Thus a pure, strict and uniform circumferential movement is the same as pure, strict and uniform angular or rotational movement, and these terms are used interchangeably. The definition of rotational movement for a structure also encompasses the special case, wherein the structure comprises a central axis defining the axis of rotation. In this special case, all the positions of the structure, which are off the central axis, are subject to a circular circumferential movement, whereas the displacement vector of the positions on the central axis is zero. Therefore, a structure rotating about its own central axis and moving in an axial direction is said to perform a rotational movement.
A helical movement of a structure is used to describe a combined axial and angular or rotational movement, wherein the displacement vector of the structure comprises a circumferential and an axial component. The definition of helical movement for a structure also encompasses the special case, wherein the structure comprises a central axis defining an axis of rotation. In this special case, all the positions of the structure, which are off the central axis, are subject to a helical movement, whereas the displacement vector of the positions on the central axis only comprises an axial component. Therefore, a structure rotating about its own central axis and moving in an axial direction is said to perform a helical movement.
In this context pure, strict and uniform movements are abstract mathematical definitions, and these terms are used to describe an ideal or abstract movement of the devices. Therefore, a structure in a real device should not be expected to exhibit this ideal behaviour, rather such a structure should be expected to move in a pattern approximating such an ideal movement.
As used herein a right-handed thread or helical portion is a thread or helix portion whose helix moves in the positive axial direction, when the screw is turned clockwise. A screw with a right handed-thread is by convention the default thread, and is screwed in the positive axial direction by counterclockwise rotation usually performed by the right hand. Similar, a screw with a left-handed thread is screwed in the positive axial direction by clockwise rotation, and can thus be performed with the left hand and mirror the movement of the right hand operating a right handed thread.
The embodiments of the present disclosure, wherein the injection device is adapted for providing a plurality of predefined fixed doses, are described in detail in relation to an injection device comprising a reusable integrated needle cannula with a cleaning chamber. However, in an alternative embodiment a needle magazine as described in EP20157959.6 titled an injection device with integrated needles could be integrated instead one single re-usable needle and filed by Novo Nordisk.
Housing Assembly
The injection device comprises a housing assembly, providing a rigid frame with guides and connectors for guiding and connecting the other components of the device. The housing assembly comprises the housing insert portion 160, the tubular elongate housing structure 140, the cartridge holder 130 and the spring base 165. After final assembly these structures are fixedly connected, and the housing assembly can provide a frame of reference for describing the relative movement and position of the other structures. The elongate housing structure 140 comprises an internal thread for engaging an outer thread of the piston rod. The internal thread may be provided in the form of an integral nut member, which is fixed to the housing structure 140 both rotationally and axially. In one example, the nut member is an integral part of the housing structure 140. Alternatively, the nut member can be a separate part which is fixed to the housing during assembly of the injection device e.g. by gluing or welding. The nut member is on an inner surface provided with an inner thread which engages with the outer thread of the piston rod 109 such that the piston rod is moved helically when it is rotated relatively to the housing structure. Alternatively, the inner thread is provided directly in the housing. The housing insert portion 160 comprises a cap snap at the end of a track for a bayonet with the cap. The housing insert portion 160 further comprises a proximal edge for guiding the shield. For further description, the housing assembly may in short be referred to as the housing, and the needle shield assembly as the needle shield.
The injection device 100 comprises a drive mechanism and a triggering or activation mechanism. The drive mechanism comprises the piston rod 109, the drive spring 108, and the drive tube 180, and for expelling a dose the structures are operationally arranged in the housing. The triggering mechanism comprises the elongate shield structure 110 and the connector 170, and for triggering the dose expelling mechanism the structures are operationally arranged in the housing.
Needle Shield Assembly
The injection device further comprises a needle shield assembly comprising the shield tip 119 and the elongate shield structure 110. The elongate shield structure 110 comprises a window 111 for inspection of the drug, the elongate shield can be arranged in a first position of overlapping with the cartridge holder window 131, and in a second position with no overlap, wherein a solid portion of the elongate shield structure covers the window 131 in the second position.
Cartridge Holder
The cartridge holder 130 is adapted for receiving the cartridge 135. The cartridge holder comprises a window 131 for inspecting the drug in the cartridge 135.
Cartridge
As further shown in
Needle Assembly
The injection device further comprises a needle assembly comprising a needle hub 125 and a reusable needle cannula 124. The cannula comprises a proximal end for piercing the pierceable septum and for establishing fluid communication with the reservoir, and a distal end for insertion into the skin of a subject or user of the device.
Piston Washer
A piston washer, although not shown on
Cap
The cap 105 is adapted for releasable mounting to the housing insert portion 160. The cap comprises an inner surface with a protrusion 105.2 (
Spring Base
The spring base 165 is fixedly mounted to the housing structure 140 at the proximal end and is adapted to receive and support a compressible torsional drive spring 108.
Drive Spring
The drive spring 108 is pre-strained or winded up and positioned between the spring base and the drive tube 180. The drive spring is further adapted to induce a torque on the drive tube, whereby the medicament can be expelled. The drive spring comprises torsional sections 108.3, 108.4, wherein the spacing between the coils is relatively small and a compressible section 108.4 adapted to transfer an axial force to the drive tube after compression and during expelling of the medicament. The ability to drive the drive tube in an axial direction enables an end of dose mechanism, and to enable a resetting of the drive tube.
Return Spring
The connector return spring 107 is positioned between the spring base 165 and the connector 170 and is adapted to urge the connector in the distal direction.
Cleaning Assembly
Cleaning the needle between injections allows the same integrated needle to be used a plurality of times in a clean condition. Therefore, in an alternative embodiment of the present disclosure, the injection device comprises a cleaning assembly 120, as illustrated in
The cleaning assembly 120 preferably contains a chamber with a liquid cleaning agent which in one example can be the same preservative as contained in the liquid drug in the cartridge 135. In a preferred example, the cleaning agent is the identical same preservative containing pharmaceutical liquid drug as contained in the cartridge 135, which is filled into the chamber of the cleaning module during the initiation of the injection device. In an alternative embodiment the cleaning agent is embedded in a porous plug. In a further alternative the cleaning agent is embedded in a matrix of a solid plug.
The shield can be arranged in different positions. An initial position defined by an initial angular position and a corresponding initial axial position. A locked position defined by a locked angular position and a corresponding locked axial position. An unlocked distal position defined by an unlocked angular position and a corresponding distal unlocked axial position. The movable shield can be changed by a combined rotational and proximal movement from the initial position to the locked position, wherein the shield is axially locked. In both positions the needle tip is covered by the shield and contained in the cleaning chamber assembly. During use the shield can be further rotated and moved further in the proximal direction to the unlocked distal position, whereby the tip is uncovered. By moving the shield further in the proximal direction the shield uncovers a larger portion of the needle and an injection can be made. After injection the shield is moved back to the locked position, whereby the needle tip is cleaned.
If it for some reason should be desired to reuse the needle without cleaning the needle, the cleaning module can be left out.
Returning to the illustrated embodiment 100.
As the plunger 136 in the cartridge 130 is positioned in abutment with the piston rod 109, a proximal movement of the cartridge relative to the cartridge holder (which is a part of the housing assembly) will induce an overpressure in the cartridge. If the reservoir is in fluid contact with the needle cannular, the liquid will flow into the cleaning chamber. The additional feature of pulling the plunger 122 out of the cleaning chamber housing 121, is provided to overcome stick friction between plunger and chamber housing 121, but the pulling will also add to the flow between reservoir and chamber housing 121, when fluid connection has been established.
Housing Structure
In
The distal guide 142 comprises a first axial portion 142.1, a first transverse portion 142.2, a second axial portion 142.3, a second transverse portion 142.4 and a third axial portion 142.5 providing a rotational stop. The middle guide comprises a proximal transverse portion 144.1, a first axial portion 144.2, a distal transverse portion 144.3 and a second axial portion 144.4. The proximal guide comprises a first axial portion 146.1, a first transverse portion 146.2, a second axial portion 146.3, a third axial portion 146.4, a ramp portion 146.5, a flush portion 146.6. Collectively, the guide surfaces provide a closed track allowing a cyclic guiding of the connector. The surface of the transverse portions extends in the radial and circumferential direction, the surface of the axial portion extends in the axial and radial direction, the surface of the ramp portion 146.4 extends from the bottom of the recess towards the surface of the flush portion 446.5. The flush portion extends in the axial and circumferential direction and is flush with the inner surface.
Therefore,
Zero-Point-Adjustment Mechanism
Furthermore, on the outer surface of the adjustment nut 106 is provided a ratchet arm 106.3. In the disclosed embodiment, two ratchet arms 106.3c and 106.3d are positioned in two-fold rotational symmetry at the distal end 106a of the adjustment nut 106. Any suitable number of ratchet arms 106.3 can be provided. However, to increase rotational stability of the adjustment nut 106 at least two ratchet arms in rotational symmetry is preferred. Two-fold rotational symmetry implies that rotation by a 180-degree angle about a central axis of the nut 106, does not change the appearance of the nut 106.
In some embodiments, the inner tubular portion 154 is further provided with the internal thread 154.2 having a direction such that the adjustment nut 106 is helically screwed in the proximal direction when rotated in the allowed clockwise direction. Thereby, the thread connection 106.2, 154.2 between the nut and the housing provides an additional gearing between rotation of the adjustment nut 106 and the axial displacement of the rotationally fixed piston rod 109, which for example can be useful to compensate for a relatively large pitch thread connection between the adjustment nut 106 and the piston rod 109.
During assembly of the injection device it is desirable to ensure that the distance or air gap between the piston rod 109 and the piston 136 inside the cartridge 135 is minimized. Minimization of the air gap ensures that the drug is expelled from the reservoir, in response to moving the piston rod 109 in the distal direction. If a washer 104 is attached to the piston rod 109 as disclosed in a preferred embodiment shown in
When the adjustment nut is rotated relatively to the housing structure during final assembly, the piston rod 109 is advanced helically in the distal direction until the piston rod 109 or the washer 104 abut the piston 136 inside the cartridge 135. In embodiments comprising the thread connection 106.2, 154.2 between the nut and the housing, the advancement of the piston rod relative to the housing is compensated or counteracted by the proximal movement of the adjustment nut relative to the housing.
The rotation of the adjustment nut is preferably done by using a special tool in the production line which is adapted to engage the adjustment nut and transfer a rotation to the adjustment nut. In one preferred example, the piston rod 109 is arranged in engagement with the adjustment nut to provide a subassembly, and the subassembly is then arranged in the inner tubular portion 154 of the housing. Hereafter, electronic computerized equipment is used to detect the relative position of the piston 136 in the cartridge 135 to be used for that specific injection device. When the position of the piston 136 and the position of the piston rod 109 has been obtained, the computer can determine the required angular displacement of the arranged adjustment nut 106 to position the piston rod in abutment with the piston 136, when the injection device is assembled.
During assembly, the position of the proximal end of the piston rod 104 is thus adjusted by rotating the adjustment nut in the one-way interface with the inner tubular portion 154. It is here important that the adjustment nut can rotate in the direction, which advances the piston rod 109 into contact with the piston 136.
After assembly, the piston rod 109 or washer 104 abuts the piston 136 it is not possible to rotate the adjustment nut further in the clockwise direction. Furthermore in any of the assembled states, there are no external interfaces between the nut 106 and the external surroundings. Therefore, there are no possibilities of contacting the external surfaces with an external tool, and applying an external torque to the nut.
The result of the above is that the adjustment nut 106 is self-locking in relation to the housing structure and it is not necessary to physically secure the nut 106 to the housing. It is henceforth not necessary to weld or glue the nut member 11 to the housing.
Drive Mechanism
The drive tube 180 is provided with inward protrusions 180.2 protruding from an inner surface and adapted to engage the axial track 109.2 of the piston rod 109. The piston rod 109 is adapted to be slidably arranged in the drive tube, whereby relative axial displacement is allowed, but relative rotation is prevented. The drive tube 180 is provided with a ratchet arm 181c for engaging a toothing 165.1 inside the tubular spring base 165, and thereby forming a one-way ratchet interface such that the drive tube 180 is only rotational in one direction, which in the disclosed example is the counterclockwise direction for dispensing a dose. The ratchet arm 181c thus prevents rotation of the piston rod 109 in the clockwise direction. In the illustrated example the drive tube comprises two ratchet arms 181c, 181d arranged in 2-fold rotational symmetry. The ratchets arms 181 provides a dose clicking sound during expelling, in response to the drive tube 180 and the piston rod 135 rotating in the counter clockwise direction.
The engagement between the piston rod 109 and the drive tube 180 prevents relative rotation. Therefore, as the adjustment nut 106 during zero-point adjustment is rotated in the clockwise direction, the nut induces a distal translation of the piston rod 109, since the drive tube is locked against rotation in the clockwise direction.
The torque delivering drive spring 108, shown in
Incorporating a torsion spring in the drive mechanism provides several advantages. The inventors of the present invention realized that for an embodiment constructed with a compression spring, the compression spring advances into the cartridge as it releases energy. If the injection device is designed without allowing the compression spring advancing into the cartridge, the overall length of the device will increase. Therefore, in a construction of limited length the diameter of the spring is limited by the diameter of the cartridge. The inventors of the present invention found that as a torsional spring does not have to extend into the cartridge in order to limit the overall length of the device. Therefore, the torsional drive spring is not limited by the diameter of the cartridge or the piston rod and is advantageous in a construction of limited length.
The torsional drive spring according to an embodiment of the present disclosure is arranged proximal to the cartridge and on the outside of the piston rod 109. Thereby, the torsional drive spring allows the spring to enclose a larger volume, and thereby increase the mass, i.e., the amount of spring material (e.g. steel). In other words, as the used material or mass can be increased, the performance relating to long term storage and dosing can be improved. With increased mass, internal stress of the spring can be reduced, and/or the spring profile can be flatter thus minimizing the variation in dose time between the first and last dose of the device. The inventors of the present invention also found that if the maximum internal stress of the spring is reduced, the stress induced in the plastic components supporting the spring is also reduced, which is necessary in order to allow long term storage.
The inventors of the present invention further found that in an embodiment, wherein the torsional drive spring is arranged inside the drive tube, the drive tube can be adapted to provide dose clicks and allows an increase of the number of dose clicks by increasing the diameter. Therefore, the number of dose clicks can be increased without extending the axial length of the device.
According to an embodiment of the present disclosure, the outer surface of the drive tube comprises a dose click providing structure adapted to provide dose clicks, e.g., a ratchet arm riding over teeth provided on a surrounding structure. Alternatively, the ratchet arm is provided on the surrounding structure and the teeth on the drive tube. As the circumference of the outer surface of the drive tube 180 increases with the diameter of the drive tube, so does the number of dose clicks. In the case of a rotational drive tube, the number of dose clicks is determined as the relation between the circumference of the drive tube and the distance between the dose click providing structures, e.g., distance between the teeth (number of dose clicks=2*pi*radius/distance between teeth). Therefore, the number of dose clicks can be increased by increasing the radius, but without increasing the length of the spring and thereby the device. In contrast, in order to increase the number of dose clicks for a piston driven by a compression spring arranged in the piston, the length of the compression spring has to be increased. In the case of a compression spring, the number of dose clicks is determined by the axial extension of the spring divided by the distance between the teeth (number of dose clicks=axial extension/distance between teeth).
Furthermore, the inventors of the present invention found, that the required energy to release a triggering mechanism, i.e., the activation energy, is a function of the internal stress of the drive spring. Therefore, activation of the dose engine enabled with a torsional drive spring requires less force than a similar design based on a compression spring.
In addition, the inventors found that an embodiment comprising a drive mechanism based on a torsional drive spring is easier to assemble than an embodiment based on an equivalent compression drive spring. Compared to the compression spring, the torsional spring is relatively short and is thus easier to handle.
The rotating drive tube is easily adapted to function with an electronic dose capturing device, which register a rotating structure during dosing, as described in WO 2019/110494, titled “Drug delivery system with multipolar magnet and sensor system”.
Housing Insert Portion
Elongate Shield structure
The shield structure 110 further comprises a step-wise helical guide 112 arranged on the outer surface and adapted for cooperating with the proximal guide 162 of the housing insert portion and the distal guide 142 of the housing. The step-wise helical guide 112 is provided in the annular space between the outer surface of the tubular portion of the shield structure 110 and the inner surface of the outer tubular portion 143 of the housing. The step-wise helical guide comprises a continuous protruding structure extending in the axial and circumferential direction and comprises a proximal transverse protruding portion, a proximal left-handed helical protruding portion, a middle transverse protruding portion, a distal left-handed helical protruding portion, a distal transverse protruding portion. The continuous protruding structure comprises a plurality of axially and circumferentially oriented surface portions providing the guide surfaces (a circumferential surface or a circumferentially oriented surface means that at least a component of the normal vector is oriented in the circumferential direction). The surface portions can be seen on
The elongate shield structure 110 further comprises a proximal guide 114 positioned at the proximal end of the shield structure 110. On
The guide portions 114.1-114.9 are all surface portions and the guide portions 114.1, 114.2, 114.3, 114.4 and 114.9 provides a proximal face of the proximal guide 114, and the surface portion 114.6 provides a distal face, i.e., viewable from proximal and distal position, respectively. The guide portions 114.1, 114.2, 114.3 and 114.4 of the proximal face are adapted for cooperating with the connector during activation operations.
The guide portion 114.6 of the distal face of the proximal guide is adapted for cooperating with the connector during dosing, in response to premature release of pressure on the shield, which will be explained in detail later in the application.
The third axial portion 114.8 is adapted for cooperating with the middle guide 144 of the housing and provides a rotational stop, preventing further counterclockwise rotation of the shield, with respect to the housing and during dosing. Similar, the second transverse portion 114.9 provides an axial stop cooperating with the middle guide 144 and prevents further proximal movement of the shield during dosing.
The proximal guide 114 comprises a locking structure 115 comprising the guide portions 114.4 and 114.5, in the illustrated embodiment the locking structure 115 is a part of a hook resembling structure. As will be explained in detail later, the locking structure 115 is adapted for releasably locking to a corresponding hook resembling structure of the connector 170 during dosing.
The shield further comprises a click-arm 113, with an axial surface portion 113.1 providing a rotational stop. In an initial state the click-arm is radially compressed by an inner surface of the housing insert portion 160.
Connector
The guide portions 172.1-114.5 are all surface portions and the guide portions 114.1 and 114.2 provides a distal face of the distal guide 172, and the surface portion 172.4 provides a proximal face. The guide portions 172.1 and 172.2 of the distal face are adapted for cooperating with the proximal guide of the shield during activation operations. The guide portion 172.4 of the proximal face is adapted for cooperating with the guide portion 114.6 of the proximal guide of the shield during dosing, in response to premature release of pressure on the shield, which will be explained in detail later in the application.
The return spring 107 urges the connector in the distal direction. Therefore, the left-handed helical portion urges the connector in a clockwise direction and the shield in a counterclockwise direction, in response to establishing an engagement between the left-handed helical portion 172.1 and the first left handed helical portion 114.1 of the proximal guide of the shield, or in response to establishing an engagement between the left-handed helical portion 172.1 and the second left handed helical portion 114.1 of the proximal guide of the shield.
The distal guide 172 comprises a locking structure 171 comprising the left-handed helical portion 172.1 and the first axial portion 172.3. The locking structure 171 is a part of the hook resembling structure adapted for releasably locking to the corresponding hook resembling structure of the proximal guide 114 of the shield. The releasable lock between the hook resembling structures is established, in response to the second left-handed helical portion 114.4 of the locking structure 115 of the shield is brought into abutment with the left-handed helical portion 172.1 of the locking structure 171 of the connector under axial compression from the return spring 107. Hereby, the shield is urged in the counterclockwise direction and the connector is urged toward the counterclockwise direction, and abutment is established between the first axial portion 172.3 of the connector and the first axial portion 114.5 of the shield. In order to release the lock, the friction established in the abutment between the two left-handed helical portions 114.4 and 172.1 has to be exceeded, in response to a counter clockwise rotation of the connector.
The connector 170 comprises a tubular portion 170.1 with a full 360 degree circumference, and two axially extending tube portions 170.2 formed by two cut-outs in the tube and thereby only providing a fraction of the circumference. The connector 170 is having an outer surface with an outer diameter and an inner surface with an inner diameter. As illustrated on
The connector further comprises a middle guide 174 adapted to cooperate with the middle guide 144 of the housing and thereby control the position of the connector relative to the housing. The middle guide of the connector extends in the axial and circumferential direction and comprises: a first axial portion 174.1 providing a rotational stop, a first transverse portion 174.2, a second axial portion 174.3, a left-handed helical portion 174.4, a third axial portion 174.5., a fourth axial portion 174.6, and a second transverse portion 174.7.
The middle guide 174 of the connector defines a blocking structure comprising the second transverse portion 174.7 adapted to prevent unintended axial movement of the connector and thereby unintended activation of the drive tube 180.
The middle guide 174 further defines a seat or locking structure 173 comprising the first transverse portion 174.2 and the second axial portion 174.3, wherein the locking structure is adapted to provide a rotational lock to prevent rotation and distal movement of the connector in an initial position. In the initial position the connector 170 is in its distal most position.
The connector 170 further comprises an activation tab 178 arranged on and extending radially from the inner surface in a negative radial direction. The activation tab 178 comprises a first transverse portion 178.1 providing a proximal contact surface adapted for activating the drive tube 180. The activation tab further comprises an axial portion 178.2 adapted for releasing the automatic relock mechanism, in response to an impact in the clockwise direction from the drive tube 180, and a second transverse portion 178.3 providing a retention portion preventing a split-dose in response to premature release of pressure on the shield.
The connector further comprises a proximal guide in the form of a click arm 176 adapted to cooperate with the proximal guide 146 of the housing. A circle circumscribing the two-fold symmetrically arranged click arms 176c and 176d in their relaxed state defines a diameter larger than the outer diameter of the connector and larger than the inner diameter of the housing. Therefore, in response to arranging the connector 170 inside the outer tubular portion 143 of the housing with the click arms 176 contacting the inner surface, deflects the click arm in the negative radial direction. In this position, the click arms 176 exerts a radial force in the radial direction on the inner surface of the housing. The click arm comprises a first axial portion 176.1 for cooperating with the axial guide portions 146.1 and 146.3 of the proximal guide of the housing, and an outer surface portion 176.2 extending in the axial and circumferential direction adapted for cooperating with the axial portion 146.4, the ramp portion 146.5 and the flush portion 146.6.
Proximal Portion of Injection Device
Returning to
The first tubular portion 185 is also the distal tubular portion and is arranged inside the inner tubular portion 154 of the housing. The distal tubular portion comprises an outer tubular portion 185.1 in contact with the inner tubular portion 154. The outer tubular portion 185.1 is connected to the second tubular portion 186 and further comprises the axial surface portion 182c adapted for cooperating with the housing during activation and for defining the end of the dose. The outer tubular portion 185.1 further comprises a distal helical surface portion 189c adapted for cooperating with a proximal helical surface portion of the inner tubular portion 154 of the housing during dosing (see also
The second tubular portion 186 comprises the protruding helical structures 184c and 184d on the outer surface. The second tubular portion 186 further comprises the axial surface portion 182d, arranged in two-fold rotational symmetry with axial surface portion 182c, adapted for cooperating with the housing during activation and for defining the end of the dose. The second tubular portion 186 further comprises a distal helical surface portion 189d, arranged in two-fold rotational symmetry with distal helical surface portion 189c, adapted for cooperating with a proximal helical surface portion 157d of the inner tubular portion 154 of the housing during dosing (see also
The second tubular portion 186 and the third tubular portion 187 is surrounded by the return spring 107. Together with an inner tubular portion 165.2 of the spring base 165, the second and third tubular portions 186, 187 defines an annular space accommodating a portion of the drive spring 108. The fourth tubular portion 188 of the drive tube 180 is also the proximal tubular portion and comprises ratchet arm 181c for engaging the toothing 165.1 inside an outer tubular portion 165.3 of the spring base.
Activation Mechanism
Cross Sections of Injection Device in Initiated State
Operation of the Device
As illustrated in
In the following step the user pulls the cap 105 of, whereby the injection device is arranged in the cap-off state (C1), and wherein the shield is locked against axial translation.
Hereafter, the user manually turns the shield in the counterclockwise direction, whereby the device is arranged in a shield unlocked state (D1), the shield is arranged in an unlocked position and can be pressed proximally into the housing. Due to the guides between the shield and the housing 112, 162, the shield is subject to a combined proximal and rotational movement when operated between the cap-of state and the shield unlocked state. During the rotational unlocking movement of the needle shield, the needle shield uncovers the cartridge inspection window 141 in the housing, whereby the drug in the cartridge can be inspected. In addition, the piston 136 is also visible in the inspection window 141, and the position of the piston 136 relative to a fixed dose scale on the housing indicates the progression of the piston during use, and thereby indicates the remaining number of fixed doses in the reservoir. In
Hereafter, the user presses the needle shield against the injection site, whereby the shield and the connector 170 is proximally displaced against the force of the shield return spring 107. Hereby, the needle is inserted into the skin or subcutaneous layer of a patient. By this operation, the axial movement of the shield triggers the drive mechanism, and a fixed dose is delivered through the needle cannula in a dosing state (E1). At the end of dose, the piston 136 has moved to the next position, which is indicated by the fixed dose residual scale on the housing, and the injection device can be removed from the injection site. The cut-out window of the residual scale shows the piston in the next position. As the piston 136 progresses under the dosing state it can be useful to define to substates for a respective dosing state: an initial dosing state (E2.1) and a final dosing state (E2.2), wherein the piston is in a pressurized proximal position and a relaxes distal position, respectively.
After the dose has been completed, the user removes the device from the skin, and the pressure is thereby released from the shield. Consequently, the shield moves in the distal direction due to the action of a return spring 107. Due to guides 112, 162 between the shield and the housing, and guides 114, 142 between the shield and the connector 170, the shield is subject to a distal movement followed by a combined distal and rotational movement, whereby the shield automatically returns to a relocked state (F1).
Hereafter, the user puts on the cap 105 by an axial movement to put the device in a cap-on state (G1), which is the last state shown in the sequence shown in
Finally, the cap is turned, and thereby snap locked to the housing assembly to enter a cap locked state (A2), which is illustrated in
The cap locked state (A2) differs from the out-of-box state (A1) in that the device has been initiated. This is illustrated in
Detailed Description of the Operation of the Device
In an embodiment of the present disclosure, the injection device 100 for sequentially delivering a plurality of fixed dosses comprises: a housing comprising an elongate housing structure 140, a cartridge holder 130, and a housing insert portion 160, an internal thread, a shield comprising the elongate shield structure 110 and the needle tip 119, a needle hub 125 comprising the fixedly attached needle cannula 104, a cap 105 removably mounted on the housing and adapted for covering a distal end of the shield, a cartridge 135 with a movably arranged cartridge plunger 136 and a drive mechanism comprising a torsional drive spring 108, a drive tube 180 and a piston rod 109 with an outer thread for cooperating with the internal thread of the housing, the piston rod is arranged in connection with the plunger 136, and wherein the torsional spring is adapted to provide a torque for rotating the drive tube 180 relative to the housing. The drive tube comprises a ratchet mechanism ensuring rotation in a dosing direction and blocking in a non-dosing direction. The drive tube is axially splined with the piston rod, whereby relative axial movement is allowed, and relative rotation is prevented. The drive tube is adapted to advance the piston rod, in response to rotating the drive tube in the dosing direction, and due to the threaded connection with the housing, the piston rod is adapted to advance the plunger 136 in the cartridge 135 to expel a fixed dose. The drive mechanism is adapted to be activated, by changing the drive tube from a distal position, wherein the drive mechanism is in a stationary mode, to a proximal position, wherein the drive mechanism is in a dosing mode. In the distal position, the drive tube is rotationally locked to the housing. In the proximal position, the drive tube is rotationally unlocked from the housing, and the provided torque can rotate the drive tube a predetermined angel to expel the fixed dose. In the stationary mode of the drive mechanism, the piston rod is rotationally and axially locked, and the piston rod is rotationally locked to the housing through the splined connection with the drive tube 180, and axially locked through the threaded connection with the housing.
The torsion spring is pre-strained to deliver the plurality of doses without restraining during use. The drive mechanism is adapted to change mode upon activation, and as explained later the drive mechanism is adapted to be repeatably activated until the last dose has been expelled.
The cap can be arranged in an axially locked position and an axially unlocked position. The cap can be changed between the positions by turning the cap relative to the housing. For the cap being in the axially unlocked position, the cap can be removed from the housing.
The needle hub 125 is movably arranged on the housing and can be moved between the distal position and the proximal position relative to the housing. The needle hub 125 is arranged in connection with the cartridge and is rotationally locked relative to the housing. For the needle hub being in the distal position the proximal end of the needle cannula is arranged distally to a pierceable septum of the cartridge. For the needle hub 125, being in the proximal position, the needle cannula extends through the septum and is positioned in fluid communication with the reservoir of the cartridge. I response to moving the needle hub from the distal to the proximal position, the needle cannula pierces the septum of the cartridge, and moves the cartridge a proximal distance relative to the housing and the axially locked piston rod.
The shield can be arranged in different positions. An initial position defined by an initial angular position and a corresponding initial axial position. A locked position defined by a locked angular position and a corresponding locked axial position. An unlocked distal position defined by an unlocked angular position and a corresponding distal unlocked axial position. An unlocked proximal position defined by the unlocked angular position and a corresponding proximal unlocked axial position. In the initial position, the shield is adapted to prevent an axial and clockwise movement, and adapted to allow a counterclockwise movement. In the locked position, the shield is adapted to prevent clockwise and axial movement. In this position, the shield is further adapted to allow a counterclockwise rotation. In the unlocked distal position, the shield is adapted to prevent counterclockwise and distal movement of the shield, and further adapted to allow proximal movement. In the unlocked distal position, the shield is further adapted to allow a clockwise rotation, if the applied torque exceeds a predefined threshold. For the shield being in the initial position and the locked position the needle tip is covered by the shield. In the unlocked position, the shield is adapted to be moved from the unlocked distal position, wherein the needle tip is uncovered by the shield and wherein pressure in the reservoir can be released, and proximally to the unlocked proximal position, wherein the needle tip extends further from the shield and can be inserted into the subcutaneous layer of a subject. The shield can be manually operated between the different positions by the user. As appears for the shield being in the initial position, the locked position, the distal unlocked position and the proximal unlocked position, defines four different sets of angular and axial positions: three different angular position and four different axial positions.
The connector can be arranged in an initial position initial position defined by an initial angular and initial axial position, wherein it is positioned rotationally locked to the middle guide 144 of the housing, wherein the middle guide 144 also prevents a distal movement of the connector. The connector is biased in the distal direction by return spring 107.
Out-of-Pack State
The first user operation is to turn the cap counterclockwise until it reaches the cap axially unlocked position, whereby the shield is changed from the initial position to the locked position, and whereby the device is changed from the out-of-pack state through a number of intermediate arrangements to the cap unlocked state, also referred to as the shield initiated state.
In more details,
In a second intermediate arrangement of the injection device illustrated in
In a third intermediate arrangement of the injection device illustrated in
In a fourth intermediate arrangement of the injection device illustrated in
Cap Unlocked, Shield Initiated and Locked State
In the cap unlocked and shield locked state, as illustrated in
Cap-Off State
The second user operation is to pull the cap in a distal direction, whereby the device is changed from the cap unlocked state to the cap-off state.
In the cap of state, as illustrated in
Shield Unlocked State
The third user operation is to turn the shield, being in the locked position, in the counterclockwise direction until it reaches the unlocked position, and whereby the device has been changed from the cap-off state through a number of intermediate arrangements to the shield unlocked state.
From the first intermediate arrangement shown in
Dosing State
The fourth user operation is to push the shield, being in the unlocked distal position, in a proximal direction until it reaches the unlocked proximal position, and whereby the device has been changed from the shield unlocked state through a number of intermediate arrangements to the dosing state.
From the shield unlocked state shown in FIG. 16K1 to the first arrangement of the injection device in the dosing state shown in FIG. 16L1, the shield has been pushed in the axial direction from the unlocked distal position to the unlocked proximal position, whereby the activation tab 178 has been pushed though the transverse opening in the outer helical structure 184. By the proximal movement of the shield, the shield has moved the interlocked connector 170. The connector abutting the drive tube 180, has moved the drive tube 180 from a distal stationary position, wherein the drive tube is rotationally locked by the housing, to a proximal rotational position, wherein the drive tube will rotate relative to the housing. By the proximal movement the torsionally strained drive spring 109 has been compressed and brought into a compressed state. From the first arrangement of the device in the dosing state (FIG. 16L1) to the last illustrated arrangement in the dosing state (FIG. 16N1), the drive tube has turned 360 degrees during a distal helical movement, i.e., a full rotation, and returned to the initial position in the housing (
Initialization of Automatic Relock Mechanism
During the rotation of the drive tube 189 from the intermediate shield unlocking position to the stop dosing position the drive tube has provided a torque to the connector, which exceeds the release threshold torque. Hereby, the locking structure 171 of the connector has been released from the locking structure 115 of the shield, and the connector has been rotated until abutment with a rotational stop provided in the housing. By releasing the locking structures from each other the automatic shield relocking mechanism has been initiated.
During the counterclockwise rotation, a trailing edge of the left-handed helical portion 172.1 moves slightly in the proximal direction along the second left-handed helical portion until a proximal edge of the second left-handed helical portion 114.1 has been exceeded. Thereby, the connector has shifted from abutment with the left-handed helical portion 114.4 of the shield to abutment with the right-handed helical portion 114.3 of the shield, i.e., the abutment between the right-handed helical portion 172.2 of the connector and the second right-handed helical portion 114.3 of the shield has been re-established. Due to the right-handed helical abutment, the connector is urged in the counterclockwise direction under the distally oriented biasing force of the return spring 107. However, during the rotation of the connector, the connector arm 176 rotates along the first transverse portion 146.2 of the proximal guide of the housing and until an angular position of abutment between the axial surface 176.1 of the connector arm and second axial portion 143.3 of the proximal guide of the housing. Optionally and additional abutment is provided between the third axial portion 174.5 of the middle guide of the connector the first axial portion 144.2 of the middle guide of the housing. Hereby, further counterclockwise rotation of the connector 170 is prevented. As the shield 110, in this unlocked proximal position, is prevented from clockwise rotation due to the abutment between the distal axial guide portion 112.12 of the step-wise helical guide of the shield and the second axial portion 142.3 of the distal guide of the housing, and possibly also due to an optional abutment between the third axial portion 114.8 of the proximal guide of the shield and the second axial portion 144.4 of the middle guide of the housing, the connector can only move the shield in the axial direction in a pure axial movement.
Split-Dose-Prevention
During activation of the drive tube 180, the connector has been moved in a pure proximal axial direction, until the activation tab 178 has reached the position indicated with the patterned rectangle in FIG. 16L3. As previously described, by this movement of the connector, the drive tube 180 is consequently moved between the distal stationary position, wherein the drive tube is rotationally locked by the housing, to the proximal rotational position, wherein the drive tube will rotate relative to the housing due to the torsion provided by the drive spring 108. By this axial movement the activation tab has been moved through the transverse opening in the helical structure 184, and as the drive tube reaches the proximal rotational position the drive tube starts to rotate, and the outer helical structure 184 protruding from the outer surface of the drive tube rotates into a transverse overlap with the activation tab 178, whereby the activation tab and the connector is retained in a position proximal to the helical structure 184. During the rotational movement of the connector from the start dosing position, as seen in FIG. 16L3 to the stop dosing position seen in FIG. 16N3, the activation tab 178 is retained on the proximal side of the helical structure 184 of the drive tube, whereby a split-dose has been prevented. If the pressure is released premature, i.e., before the stop dosing position is reached, the connector and the shield is moved in the distal direction until axial abutment between the distally oriented retention portion 178.3 of the activation tab 178 and the helical structure 184. Hereafter, if the axial proximal force on the shield is not re-established, the activation tab will slide along the helical structure 184 as the drive tube rotates to the stop dosing position, whereby the activation tab will be moved in a pure distal axial direction through the transverse opening in the helical structure 184.
FIG. 16M1-M3 illustrate the same arrangement of the injection device 100. FIG. 16M2 illustrates the device from the same angle as in FIG. 16M1, but an angular portion of the connector has been cut away. FIG. 16M2 and M3 are seen from opposite sites (180 degrees rotation about the central axial axis). FIG. 16M4 illustrates the arrangement of FIG. 16M3 in gray scale.
FIG. 16N1-N3 illustrate the same arrangement of the injection device 100. FIG. 16N2 illustrates the device from the same angle as in FIG. 16N1, but an angular portion of the connector has been cut away. FIG. 16N2 and N3 are seen from opposite sites (180 degrees rotation about the central axial axis).
Relocked State
The fifth user operation is to release the axially oriented force on the shield, by lifting the needle tip 119 from the skin, whereby the shield being in the unlocked proximal position, is moved in the distal direction until it reaches the locked position, and whereby the device has been changed from the dosing state through a number of intermediate arrangements to the relocked state.
From the last arrangement in the dosing state shown in FIG. 16N1 to the intermediate arrangement shown in
During the distal movement the right-handed helical portion 172.2 of the connector abuts the second right-handed helical portion 114.2 of the shield. Due to the helical abutment between connector and shield the shield is urged in the clockwise direction, whereby the distal axial portion 112.12 is urged towards the second axial portion 142.3 of the housing. Therefore, the shield is axially guided along the distal guide of the housing until a trailing edge of the helical portion 172.2 has reached a distal edge of the second axial portion 142.2, whereby the shield can rotate in the clockwise direction, in response to further distal movement, as illustrated in the intermediate arrangement shown in
During the distal movement of the shield, the connector 170 has moved in the distal direction guided by the first axial portion 144.2 of the middle guide of the housing preventing counterclockwise rotation, as illustrated in the last arrangement in the dosing state (FIG. 16N1) and the intermediate arrangements in
Cap-On State Cap Locked State
The fifth user operation is to put the cap on as illustrated in
Housing Assembly
The injection device comprises a housing assembly, providing a rigid frame with guides and connectors for guiding and connecting the other components of the device. The housing assembly comprises the housing cap portion 260, the tubular elongate housing structure 240, the cartridge holder 230 with a window 231 and the spring base 265. After final assembly these structures are fixedly connected, and the housing assembly can provide a frame of reference for describing the relative movement and position of the other structures. The elongate housing structure 140 comprises an internal thread 254.3 for engaging an outer thread of the piston rod.
The injection device 200 comprises a drive mechanism and a triggering or activation mechanism. The drive mechanism comprises the piston rod 209, the drive spring 208, and the drive tube 280, and for expelling a dose the structures are operationally arranged in the housing. The triggering mechanism comprises the elongate shield structure 210 and the connector 280, and for triggering the dose expelling mechanism the structures are operationally arranged in the housing.
The tubular portion 254 comprises a middle guide 244 comprising an outer axial portion 244.1 arranged symmetrically around the longitudinal axis at a first radial position and thereby defining a first diameter and an inner axial portion 244.2 arranged symmetrically around the longitudinal axis a second radial position, and thereby defining a second diameter.
Needle Shield Assembly
The injection device further comprises a needle shield assembly comprising the shield tip 219 and the elongate shield structure 210. The elongate shield structure 110 comprises a window 211 for inspection of the drug, the elongate shield can be arranged in a first position of overlapping with the cartridge holder window 231, and in a second position with no overlap, wherein a solid portion of the elongate shield structure covers the window 231 in the second position.
Cartridge and Cartridge Holder
The cartridge holder 230 is adapted for receiving the cartridge 235. The cartridge holder comprises the window 231 for inspecting the drug in the cartridge 235. The cartridge 135 and the cartridge holder 230 is structurally and functionally similar to the cartridge 135 and cartridge holder 130 of the first embodiment, respectively.
Needle Assembly
The needle assembly comprising needle hub 225 and needle 224 are structurally and functionally similar to the needle assembly of the first embodiment.
Cap
The cap 205 is adapted for releasable mounting to the housing cap portion 260. The cap comprises an inner surface with a protrusion adapted to couple with a bayonet coupling track. The inner surface of the cap 105 further comprises an axially extending rib (not shown) protruding from the inner surface and adapted for transferring a torque to the shield structure 110 through an axially extending rib 216 on the outer surface of the shield. The cap 205 is structurally and functionally similar to the cap 105 of the first embodiment, with an exception that the cap 205 also encloses a main portion of the shield and the cartridge.
Spring Base
The spring base 265 is fixedly mounted to the housing structure 240 at the proximal end and is adapted to receive and support a compressible torsional drive spring 108.
Drive Spring
The drive spring 208 is pre-strained or winded up and positioned between the spring base and the drive tube 280. The drive spring is further adapted to induce a torque on the drive tube, whereby the medicament can be expelled. The drive spring comprises torsional and compressible sections. The ability to drive the drive tube in an axial direction enables an end of dose mechanism, and to enable a resetting of the drive tube.
Return Spring
The connector return spring 207 is positioned between the spring base 265 and the relock tube 279 and is adapted to urge the relock tube in the distal direction. In a return arrangement, the relock tube 279 abuts the shield 210, and the shield engages the connector, whereby the shield 210 and the connector 270 can be returned together with the relock tube 279.
Cleaning Assembly
The cleaning assembly is structurally and functionally similar to the cleaning assembly of the first embodiment.
Housing Structure
The housing structure 240 comprises a guide structure comprising an axial surface portion 256 providing a sliding surface and a rotational stop, and a helical surface portion 257 providing a sliding surface adapted for guiding the drive tube 280 during dosing.
Zero-Point Adjustment Mechanism
As seen in
Drive Mechanism
The construction and functionality of the drive mechanism of the second embodiment is similar to the first embodiment. In particular, the drive tube 280 is axially splined to the piston rod.
The same considerations for incorporating a torsion spring in the drive mechanism in the second embodiment provides the same advantages as mentioned for the first embodiment.
Elongate Shield Structure
The shield structure 210 further comprises a radial guide 212 arranged at the proximal end and extending radially, whereby the shield is adapted for cooperating with the connector 270.
The elongate shield structure 210 further comprises a proximal guide 214 positioned at the proximal end of the shield structure 210. On
Connector
The connector further comprises a step-wise helical track 274 for cooperating with the radial guide 212 of the shield. The step-wise helical track comprises a distal transverse portion 274.1, a distal helical portion 274.2, a middle transverse portion 274.3, a proximal helical portion 274.4 and a proximal transverse portion 274.5. Due to the helical portions of the step-wise helical track, a rotational movement of the shield 210 can be transferred into a proximal movement of the shield, and due to the transverse portions of the step-wise helical track 274, a distally oriented force on the shield can be transferred to the connector 270, whereby the shield can move distally. If the shield exerts a distal force on the helical portions of the step-wise helical track 244, the connector may move distally or both distally and rotationally.
The connector 270 comprises a first tubular portion 270.1 with a full 360 degree circumference, and a second tubular portion 270.2 with two cut-outs, whereby the remaining portions of the second tubular portion forms two axially extending tube portions 276. The first tubular portion comprises the step-wise helical track 274, and the two axially extending tube portions 276 comprises a distal transverse surface 272.1 forming the distal guide 272, a first axial surface providing a first axial guide 276.1, and a second axial surface, positioned clockwise to the first surface, providing a second axial guide 276.2. The shield can be arranged within, the first tubular portion 270.1 with the radial guide 212 extending through the step-wise helical track 274. The axially extending tube portions 276 extends in the proximal direction from the inner surface of the first tubular portion 270.1, and therefore has a smaller diameter. The transverse surface portion 272.1 is provided on the distally oriented surface of the axially extending tube portions 276, and as the diameter of the tube portions 276 corresponds to the diameter of the shield 210, the proximal guide 214 having a proximally oriented surface is adapted to cooperate with the transverse guide portion 272.1. The diameter of the axially extending tube portions 276 further corresponds to the diameter of the inner axial portion 244.2 of the middle guide, whereby the axially extending tube portions 276 can cooperate with the inner axial portion 244.2. The connector 270 is having an outer surface with an outer diameter and an inner surface with an inner diameter. As illustrated on
The connector 270 further comprises an activation tab 278 arranged at the proximal end of the axially extending tube portions 270.2, and extending radially from the inner surface in a negative radial direction, i.e., towards the centre of the tubular portion. The activation tab 278 extends into the closed guide track 284 of the drive tube. The activation tab 278 comprises a first transverse portion 278.1 providing a proximally oriented contact surface adapted for engaging the distally oriented surface 283.1 of the abutment structure in the transverse portion 284.1 of the closed guide track, and thereby enabling a proximal movement and activation of the drive tube 280. The activation tab 278 further comprises a proximally oriented surface portion 278.2 adapted to engage a distally oriented surface of the closed guide track 284, whereby the connector can be guided during a dose cycle, and whereby a split dose can be prevented in response to immature release of the proximal pressure on the shield. In response to guiding the proximal portion 278.2 of the activation tab along the left-handed helical guide portion 284.3, a shield relock mechanism is initiated.
Relock Tube
The relock tube 279 comprises a first tubular portion 279.1, and a second tubular portion with two cut-outs, whereby the remaining portions of the second tubular portion forms two axially extending tube portions 279.2. The relock tube comprises an axially extending guide track 279.4 extending from a relatively small distance from the proximal end (e.g. 1/10 of the length of the relock tube) to the distal end. The two axially extending tube portions 279.2 comprises an axial guide portion 279.5, a first transverse guide portion 279.6, a right-handed helical portion 279.7, and a second transverse portion 279.8. The axially extending tube portions 279.2 further comprises an axial portion 279.9 providing a rotational stop and axial guide for the connector. The axially extending tube portions 279.2 extends in the proximal direction from the inner surface of the first tubular portion 279.1, and therefore has a smaller diameter. The helical and transverse guide portions 279.6-279.8 is provided on the distally oriented surface of the axially extending tube portions 279.2, and as the diameter of the tube portions 279.2 corresponds to the diameter of the shield 210, the proximal guide 214 having a proximally oriented surface is adapted to cooperate with the helical and transverse guide portion 279.8-279.8. The diameter of the axially extending tube portions 279.2 further corresponds to the diameter of the inner axial portion 244.2 of the middle guide. The diameter of the first tubular portion corresponds to the diameter of the outer axial portion 244.1 of the middle guide. The axially extending guide track 279.4 is adapted to cooperate with the outer portion 244.1 of the middle guide, whereby the relock tube 279 is rotationally locked and axially guided between a distal position defined by the proximal end of the guide track 279.4 and a proximal position (
Detailed Description of the Operation of the Device
In an embodiment of the present disclosure, the injection device 200 for sequentially delivering a plurality of fixed dosses comprises: a housing comprising an elongate housing structure 240, a cartridge holder 230, and a housing cap portion 260, an internal thread, a shield comprising the elongate shield structure 210 and the needle tip 219, a needle hub 225 comprising the fixedly attached needle cannula 204, a cap 205 removably mounted on the housing and adapted for covering a main portion of the shield, a cartridge 235 with a movably arranged cartridge plunger or piston 236 and a drive mechanism comprising a torsional drive spring 208, a drive tube 280 and a piston rod 209 with an outer thread for cooperating with the internal thread of the housing, the piston rod is arranged in connection with the piston 236, and wherein the torsional spring is adapted to provide a torque for rotating the drive tube 280 relative to the housing. The drive tube comprises a ratchet mechanism 281, 265.1 ensuring rotation in a dosing direction and blocking in a non-dosing direction. The drive tube is axially splined with the piston rod, whereby relative axial movement is allowed, and relative rotation is prevented. The drive tube is adapted to advance the piston rod, in response to rotating the drive tube in the dosing direction, and due to the threaded connection with the housing, the piston rod is adapted to advance the piston 236 in the cartridge 235 to expel a fixed dose. The drive mechanism is adapted to be activated, by changing the drive tube from a distal position, wherein the drive mechanism is in a stationary mode, to a proximal position, wherein the drive mechanism is in a dosing mode. In the distal position, the drive tube is rotationally locked to the housing. In the proximal position, the drive tube is rotationally unlocked from the housing, and the provided torque can rotate the drive tube a predetermined angel to expel the fixed dose. In the stationary mode of the drive mechanism, the piston rod is rotationally and axially locked, and the piston rod is rotationally locked to the housing through the splined connection with the drive tube 280, and axially locked through the threaded connection with the housing.
The torsion spring 208 is pre-strained to deliver the plurality of doses without restraining during use. The drive mechanism is adapted to change mode upon activation, and as explained later the drive mechanism is adapted to be repeatably activated until the last dose has been expelled.
The cap can be arranged in an axially locked position and an axially unlocked position. The cap can be changed between the positions by turning the cap relative to the housing. For the cap being in the axially unlocked position, the cap can be removed from the housing.
The shield can be arranged in different positions. An initial position defined by an initial angular position and a corresponding initial axial position. An unengaged position defined by an unengaged angular position and a corresponding unengaged axial position. An engaged distal position defined by an engaged angular position and a corresponding distal engaged axial position. An engaged proximal position defined by the engaged angular position and a corresponding proximal engaged axial position. In the initial position, the shield is adapted to allow a counterclockwise movement. In the unengaged position, the shield is adapted to prevent clockwise movement and to allow clockwise movement. The shield is not engaged with the connector, in the sense that a proximal movement of the shield is not transferred to a proximal movement of the connector, whereby the shield cannot activate the drive tube in this position. In the engaged distal position, the shield is adapted to prevent counterclockwise and distal movement of the shield, and further adapted to allow proximal movement. In the engaged distal position, the shield is further adapted to allow a clockwise rotation, if the applied torque exceeds a predefined threshold. For the shield being in the initial position and the unengaged position the needle tip is covered by the shield. In the engaged position, the shield is adapted to be moved from the engaged distal position, wherein the needle tip is uncovered by the shield and wherein pressure in the reservoir can be released, and proximally to the engaged proximal position, wherein the needle tip extends further from the shield and can be inserted into the subcutaneous layer of a subject. In this position further proximal movement may be prevented by the shield tip 119 being blocked against the needle hub 125. The shield can be manually operated between the different positions by the user. As appears for the shield being in the initial position, the unengaged position, the distal engaged position and the proximal engaged position, defines four different sets of angular and axial positions: three different angular position and four different axial positions.
The connector can be arranged in an initial or first position defined by a first angular and a corresponding distal position, wherein the connector is allowed to move to a proximal position, guided along the rotationally locked relock tube 279 until the connector 270 meets an axial stop on the housing or the shield tip 219 abuts the hub 225. The connector can therefore further be arranged in a second position defined by the first angular position and the proximal position. Even further, the connector can be arranged in a third position defined by a second angular position and a corresponding distal position, wherein the first and the third positions are defined by the same axial positions.
Out-of-Pack State
Cap Unlocked State
The first user operation is to turn the cap counterclockwise until it reaches the cap axially unlocked position, whereby the shield is changed from the initial position to the unengaged position, and whereby the device is changed from the out-of-pack state to the cap unlocked state, as shown in FIG. 25B1 and B2. In the cap unlocked state, the cap can be moved axially. The cap unlocked state is also referred to as the shield-initiated state, as the shield has initiated the device, or the shield unengaged state, as the shield is not engaged with the connector to activate the device or the non-activation state as the shield cannot activate the drive mechanism. In contrast to the embodiment 100, the shield 210 in the embodiment 200 is not necessarily axially locked to the housing in this state, but as the shield does not engage the connector, an axial movement cannot be transferred from the shield to the connector, and the connector cannot be moved to activate the drive tube 280. As the radial guide 212 of the shield engages the step-wise helical track 274 of the connector 270, during the proximal helical movement of the shield from the initial to the unengaged position, the radial guide 212 abuts a proximal surface of the distal helical guide portion 274.2 of the step-wise helical track. In the unengaged position the radial guide rests on the middle transverse portion 273.4, wherein there are no proximal sides on the track 274. During the proximal helical movement of the shield, the shield has moved the relock tube 279 proximally against the biasing force of the return spring 208, and in the unengaged position the axially extending portions 279.2 of the relock tube has moved into the cut-out 214.5 whereby a rotational lock is provided. For the shield being in the unengaged position, the right-handed helical portion 279.7 of the relock tube abuts the right-handed helical guide portion 214.6 of the cut-out, and the right-handed helical portion 214.3 of the proximal guide, and thereby urges the shield in the distal direction. The distal force is transferred from the shield to the connector, through the abutment between the radial guide 212 and the track 274, whereby the connector is also biased in the distal direction. Therefore, in the following states the relock tube 279, the shield 210 and the connector are distally biased. On
Cap-Off State
The second user operation is to pull the cap in a distal direction, whereby the device is changed from the cap unlocked state to the cap-off state.
As the cap is not shown on the
Shield Engaged State or Activation State
The third user operation is to turn the shield, being in the unengaged position or non-activation position (as it cannot activate the drive mechanism), in the counterclockwise direction until it reaches the engaged distal position or activation position, and whereby the device has been changed from the cap-off state to the shield unlocked state.
From the shield unengaged position to the shield engaged distal position shown in FIG. 25C1 and C2, the shield rotates in a proximal helical movement guided by the distal helical portion 274.4 followed by a pure rotational movement guided by the proximal transverse portion 274.5. During the proximal helical movement of the shield along the distal helical portion 274.4, the right-handed helical guide portion 214.6 of the cut-out and the right-handed helical portion 214.3 of the shield slides in abutment with the right-handed helical portion 279.7 of the relock tube, whereby the rotationally locked relock tube 279 is forced in the proximal direction. During the pure rotational movement of the shield, the abutment between the helical portion 279.7 of the relock tube and the helical portions 214.7, 214.3 of the shield, shifts to an abutment between the right-handed helical portions 214.3, 279.7 only and then to an abutment between the second transverse portion 214.4 of the proximal guide and the first transverse guide portion 279.6 of the relock tube. As the abutment surface between the second transverse portion 214.4 of the shield and the first transverse portion 279.6 of the relock tube extends in a direction normal to the biasing force of the return spring, the abutment provides a static position of the relock tube 279 and the shield 210. Due to the biasing force and the abutment between the transverse portions 214.4, 279.6, a releasable locking mechanism is provided between the shield 210 and the relock tube 279. To release the lock, a torque exceeding a release threshold torque is required. During the helical movement of the shield, the first transverse surface portion 214.1 of the proximal guide of the shield and the transverse surface portion 272.1 are brought into abutment, and during the pure rotational movement the shield slides relative to the connector until abutment between the axial portion 276.1 of the axially extending portion 276 and the axial portion 214.2 of the proximal guide. Therefore, releasing the lock and thereby establishing an abutment between the helical portions 214.3, 279.7 of the shield and the relock tube will also disengage the transverse portions 214.1, 272.1 of the shield and the connector. Another axial portion 276.2 of the axially extending tube portions 276 of the connector is rotationally locked in the counterclockwise direction against the axial portion 279.9 of the rotationally locked relock tube, which is slidably arranged with the middle guide 244 engaged in the axial track 279.4. The activation tab 278 of the connector is seated in the transverse portion 284.1 of the closed guide track in the drive tube. In the engaged distal position, the shield is adapted to move the connector in the proximal direction to activate the drive tube.
Dosing State
The fourth user operation is to push the shield, being in the engaged distal position, in a proximal direction until it reaches the engaged proximal position, and whereby the device has been changed from the shield unlocked state to the dosing state. The dosing state is illustrated by the arrangements shown in
From the shield engaged distal position to the shield engaged proximal position shown in FIGS. 25D1 and D2, the shield moves in a proximal and pure axial movement guided by the relock tube travelling along the middle guide 144. During the proximal movement of the shield, the, by the shield, engaged relock tube 179 translates proximally to compress the return spring 208 even further, and the, by the shield, engaged connector translates proximally, whereby the activation tab 278 engages a proximal surface of the transverse portion 284.1 of the closed guide track, and wherein the drive tube also is translated proximally. Thereby, the drive tube has been moved from the distal position, wherein the drive tube is rotationally locked to the housing to the proximal position, wherein the drive tube is rotationally unlocked from the housing. As illustrated in FIG. 25D2, the torque provided by the drive spring 207 has rotated the drive tube, whereby the activation tab has slided out of the transverse portion 284.1 and into the right-handed helical portion 284.2 of the closed guide track.
Initialization of Automatic Relock Mechanism
As the drive tube stops rotating by reaching an end of dose, the proximal portion 278.2 of the activation tab 278 is brought out of abutment with the right-handed helical track, whereby the connector is no more prevented in moving in a distal direction. As axial movement of the connector is not prevented by the drive tube, the connector will move axially in a distal direction and rotate, in response to releasing the pressure from the shield, whereby the connector will move into engagement with the left-handed helical portion 184.3 of the drive-tube. Hereby, the automatic relock mechanism has been initiated.
Split Dose Prevention
During a dosing cycle the activation tab 278 is engaged in the closed guide track 284. Therefore, in response to lifting the shield from the skin, before the dose is completed, the activation tab will be blocked by the first transverse portion 284.1, or the right-handed helical portion 284.2, of the guide track 284 and the drive tube will continue to rotate until the dose has been completed. At completion of rotation, the connector will push the connector with the activation tab and the shield distally, but a split or interrupted dose has been prevented, whereby it is ensured that the next dose can be taken correctly. If the shield was extended to a distal position, the needle tip would be placed in the cleaning chamber, whereby an overpressure could be generated in the cleaning chamber. The overpressure could unintentionally stop the dosing.
Relocked State
The fifth user operation is to release the axially oriented force on the shield, by lifting the needle tip 219 from the skin, whereby the shield being in the engaged proximal position, is moved in the distal direction until it reaches the unengaged position, and whereby the device has been changed from the dosing state through an intermediate arrangement shown in
Automatic Relock Mechanism
Cap-On State Cap Locked State
The fifth user operation is to put the cap on, which is not illustrated for the injection device 200, hereby the protrusion on the inner surface of the cap is inserted into an axial track portion on the housing, whereby it can be turned in order to arrange the device in the cap locked state. The cap locked state for injection device 200 is not illustrated. The cap 205 does not engage the shield, when rotated back to the locked state, and the shield is therefore not pushed toward the initial position.
The described additional alternative embodiments are not individually illustrated and are not provided with reference numbers. However, features of the alternative embodiments correspond to features of the illustrated embodiments, whereby the features of the alternative embodiments provide one or more functions that are similar or equal to the features of the illustrated embodiments.
In an alternative embodiment is provided, a drug delivery device for sequentially delivering a predefined plurality of fixed doses, wherein the drug delivery device comprises:
a housing assembly,
a drive mechanism comprising a drive tube, wherein the drive mechanism is adapted to sequentially deliver the predefined plurality of doses, and,
an activation mechanism for activating the drive mechanism,
wherein the drive mechanism comprises a pre-strained torsional drive spring 108, 208 conserving an initial amount of energy, and adapted for rotating the drive tube, wherein each activation of the drive mechanism, and completion of a drive tube dose sequence reduces the amount of conserved energy in the drive spring, and wherein the initial amount of conserved energy, which is the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses.
Hereby, is provided a drug delivery device for delivering a predetermined plurality of fixed doses without arming or straining the drive mechanism between doses, as the conserved energy before the first activation, is sufficient to deliver the predefined plurality of fixed doses. A fixed dose drug delivery device according to the present invention is adapted to deliver a dose of a desired volume a plurality of times. The total content of drug divided with the desired volume of a fixed dose determines the predetermined plurality.
In an alternative embodiment:
the housing assembly further comprises a guide structure comprising a stop-and-activation-guide-portion, and a drive-guide-portion;
the drive tube is adapted to be guided along the stop-and-activation-guide-portion for activation of the drive mechanism, and along the drive-guide-portion for delivering a fixed dose, and to the stop-and-activation-guide-portion, wherein dosing is stopped, whereby the drive tube is adapted to be guided, in response to the conduction of a drive tube dose sequence comprising activation, dosing and stop of dosing;
the drive mechanism further comprises a piston rod operationally connected to the housing assembly and the drive tube,
the activation mechanism is adapted for moving the drive tube along the stop-and-activation-guide-portion in a first axial direction from a first axial position to a second axial position, and thereby activate the drive mechanism,
The drive-guide-portion corresponds to the helical portions 157, 257 of the first and second embodiment, and the stop-and-activation-guide-portion corresponds to axial portion 156, 256 of the first and second embodiment. The drive tube, the torsional drive spring and the piston rod corresponds to the drive tube 180, 280, the torsional drive spring 108, 208, and the piston rod 109, 209.
As appears the volume of a fixed dose is determined by the guides of the housing and drive mechanism. Therefore, a fixed dose drug delivery device according to the present invention is adapted to deliver a dose of a desired volume a plurality of times. As also appears for a fixed dose drug delivery device according to the present invention, a fixed dose can only be adjusted by modifying the drive mechanism and the guides of the device.
The drive mechanism is further adapted for biasing the drive tube in a second axial direction opposite the first axial direction, wherein the drive mechanism is adapted to rotate the drive tube 180, 280 along the drive-guide-portion 157, 257 to the stop-and-activation-guide-portion 156, 157, in response to activation of the drive mechanism, whereby a fixed dose of the predefined plurality of fixed doses is delivered, and wherein the drive tube is operationally positioned to be guided along the stop-and-activation-guide-portion for delivering a subsequent fixed dose of the plurality of fixed doses.
In an alternative embodiment, the housing further comprises an inner thread, wherein the piston rod further comprises an outer thread for threadably engaging the inner thread of the housing assembly, wherein the drive tube is axially splined to the piston rod, whereby the drive tube is axially movable and rotationally locked relative to the drive tube, whereby the piston rod is operationally connected to the housing assembly and the drive tube.
In an alternative embodiment, the torsional drive spring is compressional, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction.
In an alternative embodiment, the drug delivery device comprises an axially movable spring base, wherein the drive mechanism comprises a compressional return spring positioned between the axially movable spring base and the housing, whereby the torsional drive spring and the return spring are serially coupled, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction. The spring base correspond to the spring base 165, 265 of the first and second embodiment.
In an alternative embodiment, the drug delivery device is adapted for drug delivery at a distal end, wherein the drug delivery device comprises a central axial axis defined between the distal end and a proximal end. The drug delivery device further comprises a slidably arranged spring base, wherein the torsional drive spring is arranged between the spring base and the drive tube. The drive tube, during activation and dosing, is to be positioned with a component of the central axial axis in a direction opposite to the direction of the gravitational force, being the second axial direction, whereby the drive tube is biased in the distal direction, whereby the drive mechanism is adapted for biasing the drive tube in the second axial direction, i.e., the gravitational force is utilized as a biasing force. The spring base correspond to the spring base 165, 265 of the first and second embodiment.
In an alternative embodiment, the torsional drive spring is arranged between the drive tube and the housing assembly.
In an alternative embodiment, the housing assembly comprises a fixed spring base, wherein an end of the torsional drive spring is attached to the fixed spring base. The spring base corresponds to the spring base 165, 265 of the first and second embodiment.
In an alternative embodiment, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a helical portion. The axial portion corresponds to the axial portion 156, 256 and the helical portion corresponds to the helical portion 157, 257 of the first and second embodiment.
In an alternative embodiment, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a transverse portion. The axial portion corresponds to the axial portion 156, 256 and the transverse portion corresponds to the helical portion 157, 257 of the first and second embodiment.
In an alternative embodiment, the stop-and-activation-guide-portion of the guide structure is an axial portion, and wherein the drive-guide-portion of the guide structure of the housing assembly comprises a step-wise portion comprising intervals of a portion from a first group comprising transverse, and helical portions and a portion from a second group comprising radial, helical and axial portions. The axial portion corresponds to the axial portion 156, 256 and the step-wise portion corresponds to the helical portion 157, 257 of the first and second embodiment.
In an alternative embodiment, the drive tube comprises a corresponding guide structure 182, 189, 282, 287 adapted for cooperating with the guide structure 156, 157, 256, 257 of the housing assembly. The corresponding guide structure of the drive tube corresponds to the corresponding guide structure 182, 189, 282, 287 of the drive tube of the first and second embodiment. The guide structure of the housing assembly corresponds to the guide structure of the housing assembly 156, 157, 256, 257 of the first and second embodiment.
In an alternative embodiment the guide structure of the drive tube comprises an axial portion and a helical portion. The axial portion corresponds to the axial portion 182, 282 and the helical portion corresponds to the helical portion 189, 289 of the first and second embodiment.
In an alternative embodiment, for the drive tube being in the first position, the axial portions of the guide structures of the housing assembly and the drive tube are in abutment, and the helical portions of the guide structures of the housing assembly and the drive tube are in abutment, and wherein, for the drive tube being in the second position, an axial clearance is provided between the axial portions of the housing assembly and the drive tube, whereby the helical portion of the drive tube can slide onto the helical portion of the housing assembly. The axial portions of the guide structures of the housing assembly and the drive tube corresponds to the axial portions 156, 256, 182, 282 of the guide structures of the housing assembly and the drive tube. The helical portions of the guide structures of the housing assembly and the drive tube correspond to the helical portions 157, 257, 189, 289 of the guide structures of the housing assembly and the drive tube of the first and second embodiment.
In an alternative embodiment, each of the delivered doses are of equal volume.
In an alternative embodiment, the drug delivery device comprises an initialization mechanism, whereby each of the delivered doses are of equal volume.
In an alternative embodiment, the drive spring is pre-strained to deliver the predefined plurality of doses with a constant force, wherein the force can be measured as the axial force transferred from the piston rod, and wherein a constant force is defined as a force varying less than 20 percent between the first and the last dose. The force can be measured by placing a force measuring sensor between the piston rod and the piston of the cartridge, during dosing of the predefined plurality of fixed doses.
In an alternative embodiment, the predefined plurality of fixed doses is 2, 3, 4, 5 or 6, and preferably 4.
In an alternative embodiment, the drug delivery device comprises a drug filled cartridge with a proximally arranged piston, wherein the piston rod (109, 209) is operationally arranged to advance the piston. The cartridge corresponds to the cartridge 135, 235, and the piston corresponds to the piston 136, 236 of the first and second embodiment.
In an alternative embodiment, the drug delivery device comprises an integrated needle cannula, and wherein the activation mechanism comprises an axially movable needle shield for covering and uncovering the needle. The shield is adapted to activate the drive mechanism, in response to a movement in a proximal direction, whereby the needle is uncovered. The needle cannula corresponds to the needle cannula 124, 224, the shield corresponds to the elongate shield structure 110, 210 of the first and second embodiment.
In an alternative embodiment, the drug delivery device comprises a needle mount for releasably mounting an injection needle, and wherein the activation mechanism comprises an axially movable release button, adapted to activate the drive mechanism, in response to an axial movement. The release button corresponds to the shield of the first and second embodiment.
In an alternative embodiment, the activation mechanism comprises a connector operationally connected to the drive mechanism, wherein the connector is adapted to activate the drive tube in response to an axial movement. The connector corresponds to the connector 170, 270 of the first and second embodiment.
In an alternative embodiment, the activation mechanism comprises a shield for covering an integrated needle, and a connector operationally connected to the drive mechanism, wherein the shield is operationally arranged to engage the connector, in response to rotating the shield, and wherein the shield is axially movable and adapted to move the connector, and thereby adapted to activate the drive tube, in response to an axial movement. The needle cannula corresponds to the needle cannula 124, 224, the shield corresponds to the elongate shield structure 110, 210 of the first and second embodiment. The connector corresponds to the connector 170, 270 of the first and second embodiment.
In an alternative embodiment, the first position of the drive tube is a distal position and the second position is a proximal position.
In an alternative embodiment, the drug delivery device is an injection device.
In an alternative embodiment, the drug delivery device further comprises a drug reservoir with a piston arranged to expel a drug from the reservoir, wherein the piston rod is adapted for axially advancing the piston, wherein the piston rod is axially splined to the housing assembly, whereby the piston rod is axially movable and rotationally locked relative to the housing assembly. The drive tube further comprises an inner thread, and the piston rod further comprises an outer thread for threadably engaging the inner thread of the drive tube, whereby the piston rod is operationally connected to the housing assembly and the drive tube, and can be advanced during rotation of the drive tube. The drive mechanism further comprises a compressional drive spring for axially moving the drive tube and the piston, whereby the drive mechanism and the drive-guide-portion are adapted to drive the drive tube to the first position. During activation, the drive tube is moved together with the piston rod, whereby the piston rod is separated from the piston. During dosing, the drive tube performs a combined axial and rotational movement which moves the piston rod in the axial direction with a contribution from the axial movement of the drive tube and a contribution from the rotational movement.
In an alternative embodiment, the drug delivery device further comprises an axially movable spring base, wherein the compressional drive spring is positioned between the spring base and the housing, whereby the torsional drive spring and the compressional drive spring are serially coupled. The spring base corresponds to the spring base 165, 265 of the first and second embodiments.
In an alternative embodiment, the compressional drive spring is integral with the torsional drive spring corresponding to the drive spring 108, 208 of the first and second embodiment, wherein the drive spring is a torsional drive spring with compressional sections.
In an alternative embodiment is provided a drug delivery device for sequentially delivering a predefined plurality of fixed doses, wherein the drug delivery device comprises a housing assembly, a drive mechanism and an activation mechanism.
The housing assembly comprises a guide structure comprising a stop-and-activation-guide-portion and a drive-guide-portion. The drive-guide-portion corresponds to the helical portions 157, 257 of the first and second embodiment, and the stop-and-activation-guide-portion corresponds to axial portion 156, 256 of the first and second embodiment.
The drive mechanism is adapted to sequentially deliver the predefined plurality of doses, and comprises a drive tube, a torsional drive spring and a piston rod. The drive tube is adapted to be guided along the stop-and-activation-guide-portion for activation of the drive mechanism. The drive tube is further adapted to be guided along the drive-guide-portion for delivering a fixed dose, and to the stop-and-activation-guide-portion, wherein dosing is stopped by stopping the rotation of the drive tube. Hereby, the drive tube is adapted to be guided, in response to the conduction of a drive tube dose sequence comprising activation, dosing and stop of dosing. The torsional drive spring is adapted for conserving an initial amount of energy, and adapted for rotating the drive tube, i.e., in an out-of-pack state the torsional spring is pretensioned by winding it up, and thereby conserves the initial amount of energy. The piston rod is operationally connected to the housing assembly and the drive tube. The drive tube, the torsional drive spring and the piston rod corresponds to the drive tube 180, 280, the torsional drive spring 108, 208, and the piston rod 109, 209.
The activation mechanism is adapted for moving the drive tube along the stop-and-activation-guide-portion in a first axial direction from a first axial position to a second axial position, and thereby activate the drive mechanism. In some embodiment the drug delivery device may comprise a shield or a push button adapted to operate the activation mechanism to activate the drive mechanism.
The drive mechanism is further adapted for biasing the drive tube in a second axial direction being opposite to the first axial direction. The drive mechanism is adapted to rotate the drive tube along the drive-guide-portion to the stop-and-activation-guide-portion, in response to activation of the drive mechanism, whereby a fixed dose of the predefined plurality of fixed doses is delivered, and wherein the drive tube is operationally positioned to be guided along the stop-and-activation-guide-portion for delivering a subsequent fixed dose of the plurality of fixed doses. In some embodiments the biasing means may be a compressible torsional drive spring, or a compressible return spring serially coupled with the torsional drive spring.
Each activation of the drive mechanism, and completion of a drive tube dose sequence reduces the amount of conserved energy in the torsional drive spring. The initial amount of conserved energy, which is the conserved energy before the first activation, is sufficient or larger than the energy required to deliver the predefined plurality of fixed doses.
In the above description of exemplary embodiments, the different structures and means providing the described functionality for the different components have been described to a degree to which the concept of the present invention will be apparent to the skilled reader. The detailed construction and specification for the different components are considered the object of a normal design procedure performed by the skilled person along the lines set out in the present specification.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19217323.5 | Dec 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/085212 | 12/9/2020 | WO |
