HK1153155B - Medication delivery device - Google Patents

Description

Drug delivery device

Technical Field

The present invention relates to a drug delivery device, the use of the device and a method of manufacturing or assembling the device. The present invention relates in particular to a dosing mechanism suitable for use in a drug delivery device, in particular a pen-type injector, preferably having a dose setting means and a drive device, allowing administration of a drug product from a single-dose or multi-dose drug cartridge. In particular, the present invention relates to a medication delivery device in which a user may set a dose of medication delivered from a multi-dose cartridge and the multi-dose cartridge may be replaced after the medication has been fully dispensed.

The invention further relates to an actuation means for a medication delivery device, and in particular to an actuation means designed to set a guiding means of said medication delivery device to a guiding position.

Background

The drug delivery device has great use in the case of regular injections by persons not receiving formal medical training, i.e. patients. This is becoming increasingly common among patients with diabetes where self-treatment allows these people to effectively manage their diabetes.

This situation sets many requirements for such a drug delivery device. The device must be structurally sound but convenient to use in terms of component handling, user understanding of its operation, and delivery of the required dose of medicament. Dose setting must be easy and clear. In the case of patients suffering from diabetes, many users are physically infirm and may also have impaired vision, requiring a dosing mechanism with a drive device requiring less dispensing force and a drug delivery device with an easily readable dose setting display.

Due to environmental and economic factors, such drug delivery devices have been designed to allow only a portion of the device, typically only a drug cartridge, to be discarded after complete drug delivery. This puts an additional requirement on the drug delivery device that the resetting of the drive mechanism should be easy and clear when a new cartridge is connected or inserted into the drug delivery device, without the user having to directly touch any part of the drive mechanism, thereby reducing the likelihood of damage to the drive mechanism, e.g. due to contamination.

Another requirement of the reusable device is that the stopper inside the cartridge should not move when a new cartridge is connected, so that the cartridge contents are not pressurized before dose setting and dose delivery. If this happens, the accuracy of the device may be affected.

User operated drug delivery devices are well known in the medical field.

WO2004/078239a1 discloses a drive mechanism for a medication delivery device comprising: a housing having a helical thread; a dose dial sleeve having a helical thread engaging the helical thread of the housing; a drive sleeve releasably connected to the dose dial sleeve; and a clutch means located between the dose dial sleeve and the drive sleeve. When the dose dial sleeve and the drive sleeve are coupled via the clutch means, both are allowed to rotate relative to the housing. When the dose dial sleeve and the drive sleeve are disengaged, the dose dial sleeve is allowed to rotate relative to the housing and the drive sleeve is not allowed to rotate relative to the housing, thereby allowing the drive sleeve to move axially such that a force is transmitted in the longitudinal direction to the piston rod for delivering the medicament. This document does not describe the replacement of the cartridge nor the resetting of the drive mechanism.

The following prior art documents address the problem of reuse of such devices by using disposable and replaceable medicament cartridges that can be connected/disconnected to a reusable (resettable) drive mechanism.

In EP0554996B1 an injection device is disclosed comprising a housing and means to mount a fluid containing cartridge containing an internal piston to said housing. A lead screw is movably mounted in the housing and dose setting means are provided for selecting the amount of fluid to be delivered with the device. The device provides a solution for replacing a cartridge and resetting the dosing mechanism of a reusable injection device. A new cartridge is inserted into the housing and then screwed into place while the piston of the cartridge pushes the screw into the device, which has the disadvantage that pressure is applied to the piston at the end of screwing.

US5,827,232 teaches a medication delivery pen comprising a disposable drug containing barrel assembly. The cartridge assembly includes a cartridge having a pierceable sealed distal end and a plunger forming a sliding fluid-tight engagement in the cartridge for dispensing medication from the cartridge upon sliding of the plunger in a distal direction. In addition, the medication delivery pen includes a reusable body assembly having a housing, a lead screw disposed within the housing, and a drive means for moving the lead screw distally within the body assembly a selected amount. While this device provides a solution for resetting the drug delivery pen drive mechanism, the user is required to align the cartridge holder with the slot at the distal end of the piston rod, which may cause difficulties for visually impaired and/or handicapped users.

WO1997/010864a1 describes a medication delivery pen comprising a cartridge holder assembly for holding a cartridge with a plunger, the cartridge holder assembly having a plurality of threads at a proximal end. The distal end of the body assembly includes a plurality of threads for engaging threads in the cartridge holder assembly. A lead screw extends from the distal end for engaging a plunger within the barrel. Means are provided for driving the screw into the barrel so as to move the plunger in the distal direction. In addition, means are provided for disengaging the drive means from the lead screw to allow the lead screw to be automatically and conveniently retracted into the pen body as the pen body assembly approaches the cartridge retaining assembly and is threaded onto the cartridge retaining assembly.

However, the disclosed solution for mounting a new cartridge holder assembly to a reusable pen body assembly suffers from the drawback of applying pressure to the plunger at the end of assembly.

Disclosure of Invention

It is an object of the present invention to avoid the drawbacks of the known medicament delivery devices, in particular to provide a flexible reset mechanism for use in a medicament delivery device, by means of which the medicament delivery device can be reset for reuse when a medicament cartridge is replaced.

The dosing mechanism for a medication delivery device according to the present invention provides a valuable technical alternative to the known dosing mechanism. The dosing mechanism according to the invention has the advantage, for example, that when a new cartridge is connected, the piston rod is pushed back into the device body without the user needing to touch any part of the dosing mechanism and without any movement of the cartridge stopper. The dosing mechanism according to the present invention further provides the advantage that the medicament cartridge is easy to replace and that little pressure is exerted on the cartridge bung during resetting of the device, and therefore no pressure is exerted on the medicament in the cartridge until the first dose is set and dispensed.

According to the present invention, there is provided a drug delivery device comprising: a housing having a proximal end and a distal end; a medicament container designed to engage with the housing by engaging first and second engagement means; and a dosing mechanism, the dosing mechanism comprising:

a piston rod movable in a distal direction for delivering a medicament; and

a drive device for moving the piston rod (17) in the distal direction for delivering the drug.

The medicament container of the medicament delivery device comprises actuation means for bringing guiding means into a guiding position in which the guiding means guides the piston rod for delivering medicament.

The first and second engagement means may be movable into engagement by movement of the medicament container which terminates in rotational movement without axial movement of the medicament container relative to the housing (and preferably in rotational movement without axial movement of the actuation means), whereby the actuation means brings the guide means into the guide position. During the rotational movement of the medicament container, the guiding means is brought into the guiding position while the medicament container does not move axially relative to the housing.

The medicament delivery device may be designed such that, by means of movement of the actuation means, the actuation means interacts directly or indirectly with the guiding means for bringing the guiding means into the guiding position and thus into an operational state for delivering medicament, in which state the guiding means is prevented from rotating relative to the housing.

Preferably, the medicament delivery device according to the present invention is designed such that, when the guiding means is in the guiding position, the piston rod is axially movable in a distal direction relative to the housing for delivering the medicament by means of the drive device of the dosing mechanism, and the piston rod is prevented from axially moving in a proximal direction relative to the housing. Most preferably, the medicament delivery device according to the present invention is designed such that, when the guiding means is in the guiding position, the piston rod is axially movable in a distal direction and rotatable in one direction with the drive device of the dosing mechanism relative to the housing for delivering the medicament, and the piston rod is prevented from axially moving in a proximal direction relative to the housing.

According to a preferred embodiment of the invention, the medicament delivery device is designed such that the guiding means is prevented from rotating relative to the housing, more preferably any movement (translational as well as rotational) relative to the housing, when the guiding means is normally used in the guiding position. Preferably, the guide is mounted within the housing such that it is prevented from moving axially relative to the housing at any time, and further the guide is prevented from rotating only in the guide position. Most preferably, the guide is mounted within the housing such that when the guide is not in the guide position, the guide remains rotationally movable and remains limited axially relative to the housing, and when the guide is in the guide position, the guide is prevented from axially moving and rotating relative to the housing.

Additionally or alternatively, the medicament delivery device may be designed such that the piston rod is free to move axially in the proximal direction (preferably while rotating in the other direction) relative to the housing when the guiding means is not in the guiding position. Most preferably, the medicament delivery device is designed such that the piston rod is rotated back in a proximal direction with respect to the housing when the guiding means is not in the guiding position, e.g. for resetting the piston rod when a medication container for a heart (e.g. a new cartridge or a cartridge holder with a new cartridge) is mounted at the distal end of the housing of the device.

In a preferred embodiment of the invention, the first and second engagement means are designed such that, for moving the medicament container into engagement with the housing, the actuation means are first rotated and moved axially relative to the housing and thereafter rotated without being moved axially, thereby bringing the guiding means into the guiding position. When the first and second engagement means are disengaged (and thus when the medicament container is disengaged from the housing), the guiding means preferably leave the guiding position to another position in which the piston rod is no longer guided.

Furthermore, in the medication delivery device according to the invention,

the drive device may comprise a drive sleeve

The piston rod may comprise a threaded section, wherein a first threaded section is for threadedly engaging the guide and a second threaded section is for threadedly engaging the drive sleeve, and wherein a pitch direction of the second threaded section is directed opposite to a pitch direction of the first threaded section.

In this embodiment, the medicament delivery device may be designed such that the drive sleeve engages with the piston rod and that upon driving the piston rod in the distal direction by the drive sleeve for delivering medicament, the drive sleeve is axially moved and prevented from rotating relative to the housing during delivery of medicament, thereby causing the piston rod to be axially moved and rotated.

Furthermore, the dosing mechanism of the drug delivery device according to the present invention may comprise:

a dose dial sleeve having a helical thread that engages the helical thread of the housing, the drive sleeve being releasably coupled to the dose dial sleeve; and

a clutch arrangement located between the dose dial sleeve and the drive sleeve, wherein:

a) when the dose dial sleeve and the drive sleeve are coupled (by means of the clutch means), both are allowed to rotate relative to the housing; and

b) when the dose dial sleeve and the drive sleeve are decoupled, the dose dial sleeve is allowed to rotate relative to the housing, whereas the drive sleeve is not allowed to rotate relative to the housing, and the drive sleeve is allowed to move axially in a distal direction, thereby transmitting a force to the piston rod in the distal direction.

In all embodiments of the invention, the guiding means is preferably a nut means in threaded engagement with the piston rod. According to a preferred embodiment of the invention, the guiding means is a nut means threadedly engaged with the piston rod and engaged with the locking means in the guiding position.

The locking means and the guide means may comprise face teeth which interlock when the locking means and the guide means are engaged on the guide means.

In all of the above embodiments, the medicament delivery device may comprise locking means which is non-rotatable relative to the housing and which may engage with the guiding means, thereby locking the guiding means against rotation relative to the housing. Preferably, the locking means is splined to the housing or an insert of the housing, thereby being allowed to move axially but prevented from rotating relative to the housing. Preferably, the locking means is only allowed limited axial movement relative to the housing.

When the guiding means and the locking means are engaged in the guiding position, the piston rod is preferably prevented from rotating in one rotational direction and axially moved in a proximal direction with respect to the housing, but allowed to rotate in the other rotational direction and axially moved in a distal direction with respect to the housing for delivering the medicament.

The guiding means or the locking means of the medicament delivery device according to the present invention may comprise a shape interacting with the shape of the actuation means for driving the locking means and the guiding means into engagement by means of a rotational movement (without axial movement) of the actuation means relative to the housing.

Preferably, at least one inclined surface may be arranged on the actuating means and at least one corresponding inclined surface may be arranged on the guiding means or the locking means, wherein the inclined surfaces are formed such that they can slide along each other for the interaction of the actuating means and the guiding means or the interaction of the actuating means and the locking means.

Preferably, the actuating means comprises at least one protrusion with an inclined surface fixedly or movably arranged on the actuating means; or at least one with a sloping surface for interacting with the guiding means or the locking means by rotational movement of the actuating means relative to the housing in one direction, thereby driving the guiding means and the locking means into engagement.

Furthermore, the medicament delivery device is preferably designed such that, upon disengagement of the medicament container from the distal end of the housing, the locking means is disengaged from the guiding means under the force of the biasing means. The biasing means is preferably a spring, which forces the guiding means and the locking means when the medicament container is disengaged from the housing of the medicament delivery device. Most preferably, the biasing means moves the locking means axially away from the guiding means when the medicament container is disengaged from the distal end of the housing, thereby disengaging the locking means from the guiding means.

Additionally or alternatively, the medicament delivery device may be designed such that, when the medicament container is disengaged from the housing, the locking means is disengaged from the guiding means, whereby the guiding means is free to rotate relative to the housing. In this embodiment, when the locking means and the guiding means are disengaged, the guiding means are no longer in the guiding position. According to a preferred embodiment of the invention, the piston rod is free to move proximally when the locking full-time is disengaged from the guide.

Preferably, the medicament container is a cartridge holder designed to receive a cartridge filled with medicament. The medicament container is designed to engage with the distal end of the housing. Alternatively, the medicament container may for example be a cartridge having first engagement means for engaging the second engagement means of the housing.

According to a preferred embodiment of the invention, the medicament container or the insert of the medicament container comprises the first engagement means and the housing or the insert of the housing comprises the second engagement means.

The first engagement means may for example be a thread, preferably an external thread, of the medicament container and the second engagement means is an engagement element of the housing or of an insert of the housing for engagement with the thread of the medicament container, wherein a distal end of the thread of the medicament container merges into an annular groove for engaging the medicament container with the housing by first rotating and moving proximally relative to the housing and then only rotating relative to the housing. The pure rotational movement occurring at the end of the engaging movement is achieved with the engaging element moving along an annular groove without pitch (i.e. with a zero lead). Preferably, the annular groove is a partial annular groove running around a portion (e.g. 1/6) of the circumference of the substantially tubular end of the medicament container.

Alternatively, the distal end of the housing may be provided with, for example, an insert comprising second engagement means and being designed to engage with first engagement means at the proximal end of the medicament container, said insert being secured against rotation but being free to move axially (limited axial movement) relative to the housing, wherein axial movement of said insert towards the distal end is limited by the retaining means. In particular, the insert of the housing may comprise an internal thread as second engagement means for engaging an external thread as a proximal end of a medicament container, the medicament container comprising actuation means and being rotatable and axially movable relative to the insert and the housing in a first step for engaging the medicament container with the housing, and in a second step for engaging the medicament container with the housing, the medicament container being prevented from axial movement relative to the housing while being rotated, the insert being moved in a distal direction by rotation of the medicament container in the second step. The insert may be moved in the distal direction, for example until the insert abuts the retaining means, or until the internal thread of the insert ends.

According to a preferred embodiment of the invention, the insert is an internally threaded shifting sleeve and the retaining member is a retaining ring limiting the axial shifting of the sleeve towards the distal end. The retaining ring is connected to the distal end of the housing such that rotational and axial movement thereof relative to the housing is prevented. Furthermore, a spring member is provided to move the sleeve against a proximal axial stop means (e.g. an annular rib) in the housing when the medicament container is not engaged with the housing of the device. The spring member preferably abuts on one side against the proximal side of the retaining ring and on the other side against the distal side of the moving sleeve. The sleeve is engaged with the housing such that it is permitted to move linearly but is constrained from rotating. External threads on the proximal end of the medicament container engage internal threads of the sleeve when the housing and the medicament container are brought into engagement. Thus, the medicament container is screwed into the distal end of the housing until the proximal edge or shoulder of the medicament container abuts the distal side of the retaining ring. This abutting relationship prevents further proximal linear movement of the medicament container. However, the medicament container is allowed to rotate further, thereby causing the sleeve to move linearly in a distal direction against the force of the spring means until the sleeve abuts the proximal side of the retaining ring. The abutting relationship terminates the engaging movement of the housing with the medicament container. At the end of the engagement movement, a pure rotation of the medicament container is used to bring the guiding means into a guiding position in which the guiding means guides the piston rod for delivering the medicament.

According to a preferred embodiment of the invention, the medicament container (or the insert of the medicament container) and the housing (or the insert of the housing) may additionally be provided with snap features by means of which the medicament container and the housing remain engaged during normal use of the medicament delivery device, in particular during medicament delivery. Further, the snap feature may provide audible and/or tactile feedback to a user when the drug container is securely connected to the housing.

The drug delivery device may be a pen-type device and/or an injector-type device. The drug delivery device may comprise a needle or be a needle-free device.

The term "drug delivery device" according to instant invention shall mean a single-dose or multi-dose, disposable or reusable device designed to dispense a dose, preferably a plurality of selected doses, of a pharmaceutical product, such as insulin, growth hormone, small molecular weight heparin, their analogues and/or derivatives, and the like. The device may be of any shape, for example of the box type or of the pen type. The dose delivery may be achieved by a mechanical (optionally manual) or electrical or electromechanical or energy storing dosing mechanism such as a spring or the like. Dose selection may be achieved by manual or electronic or electromechanical means. Furthermore, the device may contain components designed to monitor physiological characteristics such as blood glucose levels and the like. Further, the device may include a syringe, or may be a syringe-less device. Preferably, the term "drug delivery device" should be understood as a reusable multi-dose pen-type device, having mechanical and manual dose selection and dose delivery mechanisms, which is designed to be used by persons not receiving formal medical training, such as patients. Preferably, the drug delivery device is of the syringe type.

In the context of the present invention, the term "medicament container" should preferably be understood as a cartridge or cartridge assembly containing a medicament, most preferably a cartridge holder for receiving a cartridge containing a medicament. Furthermore, the terms "medicament container" and "cartridge assembly" may be used interchangeably in the context of the present invention. This means that the use of the term "medicament container" includes the meaning of "cartridge" or "cartridge assembly" and vice versa.

According to the present invention, the term "cartridge holder" should be understood as any component and/or components designed to accommodate a medicament cartridge containing a medicament to be delivered by the medicament delivery device. The cartridge holder may have any shape, such as cylindrical and/or tubular. In general, the cartridge holder may be a cylindrical tubular or cylindrical non-tubular one-piece or multi-part component. Any suitable material known to those skilled in the art may be used, such as a transparent material. Furthermore, the cartridge holder or the insert of the cartridge holder is preferably provided with engagement means, such as a helical thread or partial thread or bayonet or the like, on the outer and/or inner surface of the distal and/or proximal end of the cartridge holder or the insert, for engaging corresponding engagement means on the outer and/or inner surface of the housing, the housing insert and/or the needle cannula assembly. In a preferred embodiment, the cartridge holder is of one-piece tubular design with external threads at its proximal end.

According to the present invention, the term "housing" should preferably be understood as an outer housing ("housing", "body", "outer housing") or an inner housing ("insert", "inner body") with engagement means, such as helical threads, splines or any other suitable means known to the person skilled in the art. The housing may be designed to allow safe, correct and comfortable operation of the drug delivery device or any mechanism thereof. Typically, the housing is designed to engage any internal components of the medicament delivery device (e.g. dosing mechanism, barrel, plunger, piston rod) for containing, securing, guiding and/or protecting by limiting exposure to contaminants such as liquid, dust, dirt, etc. In general, the housing may be a single or multi-part component, tubular or non-tubular. The outer housing may also be used to house a cartridge from which a number of doses of a pharmaceutical product may be dispensed.

According to the present invention, the term "guiding means" should preferably be understood as any component designed to guide the piston rod of the medicament delivery device when the guiding means is in a guiding position. In order to achieve the guiding function of the guiding means, the guiding means preferably comprises a shape interacting with a corresponding shape of the piston rod, for example an internal thread for engaging an external thread of the piston rod, or a non-annular opening for holding a piston rod having a corresponding non-annular shape or a piston rod having a corresponding segment of a non-annular form.

According to the present invention, the term "guiding position" should preferably be understood as a position or state in which the guiding means guides the piston rod and directly or indirectly prevents a proximal backward movement of the piston rod. The guiding means is preferably in the guiding position when the drug delivery device is used for dose setting and drug delivery. The guiding means may be in another position or state than the guiding position, which allows resetting the medicament delivery device with a proximal movement of the piston rod.

According to the invention, the term "nut means" should preferably be understood as any component designed to threadedly engage the piston rod, preferably serving as a piston rod guide. Furthermore, according to the invention, the term "nut means" should be understood as any component with a circular opening provided with a thread, either as a single component or as a multi-part component. According to a preferred embodiment of the invention, the guiding means is a nut means. In a further more specific embodiment, the nut means is free to rotate relative to the housing when not engaged with the locking means of the drug delivery device. According to an embodiment of the invention, the nut means is free to rotate relative to said housing and is secured against linear axial movement relative to said housing when not engaged by locking means of the medication delivery device, but is secured against rotation and linear axial movement relative to said housing when engaged by said locking means. More preferably, the nut means is free to rotate while remaining constrained against linear axial movement relative to the housing when not engaged by locking means of the medicament delivery device, but is secured against rotation and linear axial movement relative to the housing when engaged by the locking means. In a more specific embodiment, the nut means has a textured surface, such as a set of face teeth (saw tooth, dog tooth, crown tooth, etc.) or any other suitable friction surface, preferably a textured surface for engaging another component of the device, most preferably a textured surface for engaging the locking means.

According to the present invention, the term "locking means" should preferably be understood as any part which engages the housing or an insert of the housing such that the locking means is prevented from rotational movement relative to the housing, most preferably such that the locking means is allowed to move longitudinally but is prevented from rotational movement relative to the housing. In a preferred embodiment, the locking means has a textured surface, such as a set of face teeth (saw tooth, dog tooth, crown tooth, etc.) or any other suitable friction surface. In a further preferred embodiment, a non-rotatable locking means is designed to engage the guiding means, thereby preventing rotation of the guiding means relative to the housing. In a more specific preferred embodiment of the invention, the textured surface of the non-rotatable locking means engages with the textured surface of the guiding means (preferably nut means) in the guiding position to prevent rotation of the guiding means as long as the medicament container (preferably a cartridge holder) is engaged with the housing.

According to the present invention, the term "actuation means" should preferably be understood as any component of the drug delivery device and/or a part of a component of the drug delivery device, designed to move any other component of the drug delivery device into and/or out of engagement with another component of the drug delivery device and/or a plurality of components of the drug delivery device; and/or to maintain any components of the drug delivery device in an engaged state. Preferably, the actuating means is means for actuating a locking means so as to move the locking means into engagement with the guide means. In a preferred embodiment of the invention, the actuation means should form an integral part of the proximal end of the medicament container, e.g. of a cartridge holder of the medicament delivery device.

According to the present invention, the term "stop means" shall be understood as any feature and/or component of a drug delivery device designed to prevent axial movement and/or rotational movement of any component and/or components at least in one direction. In a preferred embodiment of the invention, the term "stop means" should be understood as any feature perpendicular to the distal-proximal axis of the medication delivery device (in particular any planar surface feature perpendicular to the distal-proximal axis of the medication delivery device) designed to prevent axial movement of a component in one direction when the component abuts said perpendicular feature. According to another preferred embodiment of the invention, the term "stop means" should be understood as any feature providing a radial or rotational stop action, so as to prevent a rotational movement of a part in one direction when an abutment element of the part abuts against said radial or rotational stop feature.

In a further preferred embodiment of the invention, the term "stop means" is to be understood as a component of the dosing mechanism ("end stop") which prevents setting of a dose which exceeds the amount of medicament left in the medicament container. Preferably, the end stop is a part which is secured against rotation but which allows axial movement relative to the housing and which should prevent at least one part of the dosing mechanism from rotating and/or axially moving when a final dose has been delivered, so as to prevent setting of a dose which exceeds the amount of medicament remaining in the cartridge. Furthermore, the "end stop" should preferably have a helical thread on its outer surface, which is designed to engage the internal helical thread of the dose dial sleeve of the dosing mechanism or the internal helical thread of the insert of the dose dial sleeve of the dosing mechanism. Preferably, the lead of the external helical thread of the dose dial sleeve for threadedly engaging the housing is greater than the lead of the internal helical thread of the dose dial sleeve for threadedly engaging the end stop.

According to the present invention, the term "engaged" shall be understood as interlocking two or more components of the dosing mechanism/drug delivery device by means of e.g. a spline, a thread, a snap tooth connection, preferably a threaded interlocking ("threaded engagement") of the components.

According to the present invention, the term "engagement means" should preferably be understood as any means known to a person skilled in the art that may be used to engage two or more components of a drug delivery device, such as a full or partial thread, a groove, an engagement element that engages with a thread and/or a groove or means forming a bayonet lock.

According to the present invention, the term "disengage" shall be understood as unlocking two or more components of the dosing mechanism/drug delivery device. According to an example, "disengaging" according to the present invention shall be understood as unlocking two or more components of the dosing mechanism/drug delivery device under the force of the biasing means. The two parts may also be disengaged by the force of the user of the device, for example by the patient unscrewing the medicament container from the housing.

The term "biasing means" should preferably be understood to mean any means for exerting a force on the component and/or components to ensure that said component and/or components are forced to mate (e.g. engage) or forced to separate (e.g. disengage) according to the invention. Preferably, the biasing means may be made of any suitable flexible energy storing material known to those skilled in the art (e.g. metal, rubber or plastic) and may take any suitable form, e.g. a spring. In a further preferred embodiment, the biasing means is a spring member, for example located between the return element and the locking means. In another preferred embodiment, said biasing means is a spring member located between the nut means and the locking means and within said housing.

According to the invention, the term "distal end" is understood to mean the end of the device or the end of a component of the device closest to the dispensing end of the device. Preferably, a needle cannula assembly is arranged at said distal end of the medicament delivery device of the invention, the needle cannula of said needle cannula assembly being insertable into the skin of a patient for delivery of the medicament.

According to the invention, the term "proximal end" should be understood as the end of the device or the end of a component of the device that is furthest away from the dispensing end of the device. Preferably, a button is provided at said proximal end of the inventive drug delivery device, said button being depressible for delivering a dose.

According to the present invention, the term "dosing mechanism" shall be understood as any component and/or components and/or assembly designed to allow a user to select and/or set a dose to be dispensed and/or to provide and/or transfer the force required to dispense a dose of medicament. The dosing mechanism may be constituted by mechanical and/or electromechanical and/or electrical components. Furthermore, the dosing mechanism may be housed by or engaged with the housing of the device, or may be a separate component. The dosing mechanism of the present invention comprises a piston rod and a drive device for moving the piston rod in a distal direction for delivering the drug. Preferably, the dosing mechanism of the present invention comprises a drive sleeve and a dose dial sleeve. More preferably, the dosing mechanism of the present invention comprises a drive sleeve, a dose dial sleeve, clutch means, a dose dial handle and button means.

According to the present invention, the term "piston rod" should be understood as a component adapted to operate through/within the housing, designed to transfer axial movement (preferably towards the distal end) through/within the drug delivery device, preferably from the drive sleeve to the piston of the cartridge, in order to expel/dispense a drug, preferably an injectable product, from the cartridge. The piston rod may or may not be flexible. The piston rod may be a simple rod, a lead screw, a part of a rack and pinion system, a part of a worm gear system, etc. Piston rod "should further be understood as a component having a circular or non-circular cross-section. The piston rod may be made of any suitable material known to those skilled in the art.

In a preferred embodiment, the piston rod comprises at least two, more preferably two, external and/or internal helical threads (thread sections). In another preferred embodiment of the piston rod according to the invention a first helical thread (first thread section) is located at the distal end of the piston rod and a second helical thread (second thread section) is located at the proximal end of the piston rod, whereby the threads of the thread sections have an opposite configuration. In another preferred embodiment the piston rod according to the invention comprises at least two thread sections with the same lead and the same pitch at the distal and proximal end. In another preferred embodiment of the invention the lead and pitch of the second helical thread of the piston rod should be larger than the lead and pitch of the first helical thread. More preferably, the lead ratio of the helical threads of the first and second helical threads is in the range of 1: 1.01 to 1: 20, even more preferably in the range of 1: 1 to 1: 10, most preferably 1: 2.3. Preferably, one of the threads (the thread of the second threaded section) is designed to engage the drive sleeve. Preferably, the thread further (of the first thread section) is designed to engage the guiding means, more preferably to engage nut means. According to a most preferred embodiment of the invention, the first external thread section of the piston rod with the thread of the smaller lead is designed to engage the internal thread of the nut means, while the second external thread section of the piston rod with the thread of the larger lead is designed to engage the internal thread of the drive sleeve. In a further preferred embodiment of the invention, the piston rod is provided with a stop means designed to limit the axial movement of the end stop towards the proximal end. The stop means may for example be the start of one of the external threads of the piston rod.

According to the present invention, the term "dose dial sleeve" should preferably be understood as a component of the drug delivery device which is directly or indirectly used for selecting/dialing a dose of drug to be delivered. Additionally or alternatively, the dose dial sleeve is designed to indicate a selected dose of the dispensable product (medicament). This may be accomplished using, for example, indicia, symbols, numbers, etc. printed on the outer surface of the sleeve or using a pedometer, etc. In a preferred embodiment of the invention, the dose dial sleeve is a substantially tubular member having a substantially circular cross-section, having either:

internal and external threads, or

Internal screw threads, or

And (4) external threads.

Preferably, the dose dial sleeve comprises an external thread for engaging an internal thread of the housing or an internal thread of an insert of the housing. Preferably, the dose dial sleeve according to the present invention comprises an external helical thread having a lead similar to, preferably identical to, the lead of the internal helical thread of the drive sleeve. In a more specific embodiment of the invention, the dose dial sleeve is provided with a plurality of radially extending members adapted to abut a corresponding plurality of radial stops provided within the housing or an insert of the housing. The radial stop means is preferably adapted to stop further screwing of the dose dial sleeve out of the housing after dose setting and/or to stop further screwing of the dose dial sleeve into the housing after dose dispensing.

According to the present invention, the term "drive device" should preferably be understood as any component and/or components and/or assembly designed to transfer a force to said piston rod for dispensing a dose of medicament. The drive device can be formed by mechanical and/or electromechanical and/or electronic components. The drive device may be received by and/or engaged with the housing, or may be a separate component. Preferably, the drive device of the invention comprises a drive sleeve. More preferably, the drive device of the present invention comprises a drive sleeve, a clutch means and a button means.

According to the present invention, the term "drive sleeve" should preferably be understood as any means for directly or indirectly driving the piston rod in the distal direction for delivering the medicament, most preferably for directly driving the piston rod. According to a preferred embodiment of the invention, said drive sleeve is a substantially tubular member having a substantially circular cross-section. In a preferred embodiment, the drive sleeve is engaged with the piston rod. Preferably, the drive sleeve comprises an internal thread for engaging an external thread of the piston rod. The drive sleeve is further preferably releasably coupled to the dose dial sleeve, most preferably by a clutch means.

According to the present invention, the term "thread" or "helical thread" should preferably be understood as a full or partial thread, e.g. cylindrical helical ribs/grooves, on the inner and/or outer surface of the components of the medication delivery device, having a substantially triangular or square or circular cross-section designed to allow continuous free rotation and axial movement between the components. Alternatively, the threads may be further designed as non-overhaulable components, thereby preventing certain components from rotating or moving axially in one direction

According to the present invention, the term "lead" should preferably be understood as the axial distance the nut travels in a complete revolution, preferably "lead" should be understood as the axial distance the component having a helical thread travels in one revolution, i.e. the dose dial sleeve, the drive sleeve, the piston rod, etc. of the dosing mechanism. Thus, the lead is a function of the thread pitch of the associated component.

According to the invention, the term "pitch" should preferably be understood as the distance between successive profiles on a helical thread, measured parallel to the axis of the helical thread.

According to the present invention, one aspect of the present invention provides a drug delivery device for dispensing a pharmaceutical product, preferably for dispensing a formulation (e.g. solution, suspension, etc.) comprising an active compound selected from: insulin, growth hormone, small molecular weight heparin, their analogs, and their derivatives.

The invention further relates to a method of manufacturing or assembling a drug delivery device according to one of the above embodiments. The method preferably comprises the steps of: the medicament container is moved into engagement with the distal end of the housing of the device by engaging the first engagement means with the second engagement means. The first and second engagement means engage with movement of the medicament container that terminates in rotational movement of the medicament container without axial movement relative to the housing. Such rotational movement of the medicament container relative to the housing without axial movement causes the actuation means of the medicament container to bring the guiding means into a guiding position in which the guiding means guides the piston rod of the medicament delivery device for delivering medicament.

According to the present invention there is also provided a use of a medication delivery device according to one of the above-described embodiments of the medication delivery device for dispensing a pharmaceutical product. The use preferably comprises dispensing a formulation (e.g. a liquid medicament such as a solution, suspension, etc.) comprising an active compound selected from: insulin, growth hormone, small molecular weight heparin, their analogs and their derivatives.

Drawings

Without being considered limiting in any way, the invention is described in more detail with reference to the accompanying drawings, in which:

figures 1a to 1c show cross-sectional views of an embodiment of a medicament delivery device according to the invention in three different states;

figures 2a to 2c schematically show three different states of an embodiment of the actuating means interacting with the locking means according to an embodiment of the invention;

fig. 3 shows an enlarged cross-sectional view of a central part of the embodiment according to fig. 1a to 1c, showing the actuation means and the guiding means of the medication delivery device;

figure 4 schematically shows a different embodiment of a medication delivery device according to the present invention provided with different arrangements of actuation means, locking means and guiding means;

fig. 5 shows another embodiment of a medication delivery device according to the present invention.

Reference numerals

1 drug delivery device

2 tube holder

3 case

3A shell plug-in

3B housing insert

4 second engaging means

5 first engaging means

6 pipe barrel

7 piston

8 joining device

9 locking device

10 end face teeth of locking device

11 reduction element/nut device

End face teeth of 12 nut device

13 opening of nut device

14 biasing device

15 first thread of piston rod

16 second thread of piston rod

17 piston rod

18 pressure foot

19 drive sleeve

20 flange of driving sleeve

21 internal thread of the driving sleeve

22A shoulder

22B extension

23 Flange

24 clutch

25 Clutch plate

26 biasing device

27 dose dial sleeve

28 end stop

29 distal clutch teeth

30 flange of clutch

31 serrations on proximal end of clutch

32 flexible arm

33 saw teeth of clutch plate

34 flange at the distal end of the end stop

35 rotate

36 axial movement

37 screw thread

38 annular groove

39 inclined surface

40 window

External helical thread of 41 dose dial sleeve

43 screw thread of housing insert

44 stop feature of dose dial sleeve

45 radially extending member

46 dosage dial handle

47 Central opening of dose dial handle

Annular recess of 48 dose dial grip

49 push button

51 button stem

51 push-button head

52 push button skirt

53 dose dial sleeve threaded insert

54 end cap

55 stop feature of insert 43

56 stop feature of insert 43

57 web

58 recess

59 proximal direction

60 radial stop on piston rod

63 holding device

64 biasing device

65 stop device

70 actuating device

71 ramp

72 inclined surface

Detailed Description

Referring first to fig. 1a to 1c, a medicament delivery device according to the present invention is shown in three different positions.

The drug delivery device 1 comprises a cartridge holder 2 and an (outer) housing 3. Preferably, the housing 3 is painted. The distal end of the housing 3 is provided with an insert 3A, the insert 3A being fixedly connected to the housing. The insert 3A is provided with second engagement means 4 for engaging the first engagement means 5 of the cartridge holder 2. In the illustrated embodiment, the insert 3A of the housing 3 is provided with a series of partial threads formed on the inner surface of the insert 3A. The proximal end of the cartridge holder 2 is provided with first engagement means 5 for engaging the second engagement means 4 of the insert 3A. In the exemplified embodiment, the cartridge holder 2 is provided with a thread, the distal end of which merges into a (part of a) annular groove (not shown) formed on the outer surface of the cartridge holder 2. The cartridge holder 2 is secured within the distal end of the housing 3 by the engaging action of the second engaging means 4 of the insert 3A of the housing 3 with the first engaging means 5 of the cartridge holder 2. In the preferred embodiment of the invention shown in the figures, the proximal end of the cartridge holder 2 is further provided with an actuating means 70 designed to activate the guiding means (nut means 11) and lock it in the guiding position (described below and shown in fig. 3).

A cartridge 6 from which a number of doses of a pharmaceutical product can be dispensed is provided in the cartridge holder 2. The piston 7 remains in the barrel 6.

A removable end cap (not shown) is releasably retained on the distal end of the cartridge holder 2. Preferably the end cap includes a clip which snaps onto the end cap.

The distal end of the cartridge holder 2 is provided with suitable engagement means 8, such as a helical thread, bayonet or the like, for engaging a suitable needle assembly (not shown) to dispense and inject the medicament from the cartridge 6.

The medicament delivery device 1 according to fig. 1a to 1c comprises a dosing mechanism comprising a piston rod 17. The piston rod 17 is generally circular in cross-section. A pressure foot 18 is located at the distal end of the piston rod 17. The pressure foot 18 is preferably made in two separate parts which snap together around the distal end portion of the piston rod 17. The pressure foot 18 is arranged against the proximal face of the piston 7. The piston rod 17 may be moved in the distal direction by means of the drive device, thereby pushing the piston 7 to move axially in the distal direction in the barrel 6 for delivering the medicament. A first thread 15 is formed at the distal end of the piston rod 17. A second thread 16 is formed at the proximal end of the piston rod 17. The first thread 15 and the second thread 16 are oppositely arranged. Preferably at least one of the first and second threads 15, 16 is a multi-start thread, most preferably both are double start threads.

The drive device comprises a drive sleeve 19 which extends around the piston rod 17. The drive sleeve 19 is generally cylindrical. The distal end of the drive sleeve 19 is provided with a radially extending flange 20. A helical groove (thread) 21 extends along the inner surface of the drive sleeve 19. The second thread 16 of the piston rod 17 is adapted to work in the helical groove 21 of the drive sleeve 19.

A shoulder 22A and an extension 22B are formed at the proximal end of the drive sleeve 19. The extension 22B is reduced in inner and outer diameter compared to the remainder of the drive sleeve 19. The proximal end of the extension 22B is provided with a radially outwardly directed flange 23.

The clutch 24 is disposed around the drive sleeve 19 between the drive sleeve 19 and an end stop 28 (described below). The clutch 24 is located near the proximal end of the drive sleeve 19. The clutch 24 is generally cylindrical and is provided at its distal end with a series of circumferentially directed serrations 29. Each serration includes a longitudinally directed surface and an inclined surface. Towards the proximal end of the clutch 24, a radially inwardly directed flange 30 is located. The flange 30 of the clutch 24 is arranged between the shoulder 22A of the drive sleeve 19 and the radially outwardly directed flange 23 of the extension 22B. The proximal end of the clutch 24 is provided with a plurality of serrations 31. The clutch 24 is keyed to the drive sleeve 19 using splines (not shown) to prevent rotation between the clutch 24 and the drive sleeve 19. The clutch 24 is provided with a plurality of flexible arms 32 (not shown) that engage a plurality of splines on the inner surface of the dose dial sleeve 27 (described below).

A clutch plate 25 and a biasing means 26 are located between the distal end of the clutch 24 and the proximal end surface of the radially extending flange 20 of the drive sleeve 19. In the illustrated embodiment, the biasing device 26 is a spring. The proximal surface of the clutch plate 25 is provided with a series of circumferentially directed serrations 33. The clutch plate 25 is secured against rotation relative to the housing 3. During dose setting (described below), the serrations 33 of the clutch plate 25 interact with the serrations 29 at the distal end of the clutch 24.

An end stop 28 is arranged around the drive sleeve 29 between the drive sleeve 19 and the dose dial sleeve 27. The end stop 28 is secured against rotation relative to the housing 3 and is free to move axially relative to the housing 3. At the distal end of the end stop 28, a radially extending flange 34 is provided to engage a spline feature (not shown) on the inner surface of the housing 3. In the exemplified embodiment, the outer surface of the end stop 28 is provided with a helical groove (thread) extending the full length of the end stop 28. The helical groove (thread) engages with the threaded insert 53 of the dose dial sleeve 27. The inner surface of the end stop 28 is provided with a plurality of spline features (not shown). The clutch plate 25 engages these spline features and is thereby secured against rotation relative to the housing 3.

A dose dial sleeve 27 is provided between the clutch 24 and the housing 3. A helical groove (thread) 41 is provided around the outer surface of the dose dial sleeve 27. The housing 3 is provided with helical ribs (threads) 42 adapted to seat in helical grooves (threads) 41 of the dose dial sleeve 27. In the illustrated embodiment, helical ribs (threads) 42 are formed on the inner surface of the insert 43. The threaded insert 43 is secured against rotation and axial movement relative to the housing 43. The helical rib 42 extends to sweep the inner surface of the insert 43 a single time. The proximal end of the dose dial sleeve 27 is provided with an inwardly directed flange in the form of a plurality of radially extending members 45.

The housing 3 is further provided with a window 40 (not shown) through which a portion of the outer surface of the dose dial sleeve 27 is visible. Visual indicia of the dose that can be dialled is provided on the outer surface of the dose dial sleeve 27. The window 40 conveniently allows only the currently dialed dose indicia to be viewed. The window may be designed to allow it to act as a magnifying glass to view the magnified visual indicia of the currently dialed dose. Preferably, the window 40 is filled with a transparent polymer. Most preferably, the window 40 is part of an insert of the housing 3 made by two-component injection molding, wherein the section with black polymer surrounds the section with transparent polymer. The insert is immovably fixed to the housing.

The threaded insert 43 of the housing 3 is provided with a series of radial stop features 55, 56 (not shown). The distal end of the dose dial sleeve 27 is provided with a plurality of stop features 44 (not shown), said stop features 44 abutting against stop features 56 of the insert 43 to prevent the dose dial sleeve 27 from being screwed further out of the housing 3 when a maximum dose is set.

A dose dial grip 46 is provided around the outer surface of the proximal end of the dose dial sleeve 27. The outer diameter of the dose dial grip 46 preferably corresponds to the outer diameter of the housing 3. A dose dial grip 46 is secured to the dose dial sleeve 27 to prevent movement therebetween. The dose dial grip 46 is provided with a central opening 47. An annular recess 48 in the proximal end of the dose dial grip 46 extends around the opening 47.

A button 49 is provided at the proximal end of the medication delivery device 1. In the illustrated embodiment of the invention, the button 49 has a generally T-shaped cross-section with a stem 50. The button 49 is preferably free to rotate relative to the housing 3. Preferably, the button 49 comprises a spacer (not shown) made of a friction reducing material, such as a friction modifying polymer material, in order to reduce friction between the button and the dose dial grip 46 during dose delivery. The stem 50 of the button 49 extends through the central opening 47 of the dose dial grip 46 and through the inner diameter of the extension 22B of the drive sleeve 19. The stem 50 of the button 49 remains within the drive sleeve 19 and the clutch 24 for limited axial movement. In the illustrated embodiment, the head 51 of the button 49 is generally circular. A skirt 52 depends from the periphery of head 51. The skirt 52 is adapted to seat within the annular recess 48 of the dose dial grip 46.

The inner surface at the distal end of the dose dial sleeve 27 is provided with a helical thread (not shown). In the exemplified embodiment, the helical thread of the dose dial sleeve 27 is provided on the inner surface of the threaded insert 53. The insert 53 is retained within the dose dial sleeve 27 by an end cap 54 secured to the distal end of the dose dial sleeve 27. The end cap 54 is secured against rotation and axial movement relative to the dose dial sleeve 27. The helical groove (thread) of the end stop 28 engages the threaded insert 53 of the dose dial sleeve 27.

The medication delivery device 1 further comprises nut means 11 which is guiding means and has a series of face teeth 12 on a distal surface and a threaded annular opening 13. The first thread 15 of the piston rod 17 extends through and is in threaded engagement with the threaded annular opening 13 of the nut means 11. The nut means 11 is prevented from axial movement in the distal and/or proximal direction relative to the housing 3, for example by means of webs 57 in the housing 3. The web 57 may be a separate component or may form part of the housing 3. In the device shown in fig. 1a to 1c, the nut means 11 is in a guiding position, in which the nut means 11 is prevented from rotating relative to the housing 3 by the locking means 9, thus guiding the piston rod 17 during dose delivery.

In the exemplified embodiment, the drug delivery device 1 is further provided with locking means 9. The locking means 9 is secured against rotational movement relative to the housing 3, but the locking means 9 is free to undergo limited axial movement relative to the housing 3 when the housing 3 is engaged with or disengaged from the cartridge holder 2. The locking means 9 is provided with a series of face teeth 10 on a proximal face for engaging face teeth 12 of nut means 11. A biasing means 14 in the form of a spring is provided between the proximal surface of the locking means 9 and a web 57 in the housing.

In the shown embodiment according to fig. 1a to 1c, the cartridge holder 2 (medicament container) comprises an actuating means 70 with a ramp 71, the inclined surface of the ramp 71 interacting with an inclined surface 72 of the locking means 9 when the cartridge holder 2 is connected with the housing 3 (described later with reference to fig. 2a to 2c and 3). With this interaction the locking means 9 is moved into engagement with the nut means 11. Whereby the actuating means 70 brings the nut means 11 into the guiding position. This interaction is described in more detail below.

The operation of the medication delivery device 1 according to the present invention is described below.

To dial a dose, the user rotates the dose dial grip 46, thereby rotating the dose dial sleeve 27. During dose dialing, the clutch 24 engages with the dose dial sleeve 27 via serrations 31 at the proximal end of the clutch 24. When the clutch 24 is engaged with the rotating dose dial sleeve 27, the clutch 24 and the drive sleeve 19 rotate together with the dose dial sleeve 27 due to the splined engagement of the clutch 24 and the drive sleeve 19.

Audible and perceptible feedback of the dialing dose is provided by clutch plate 25 and clutch 24. This feedback is provided by the serrations 29 of the clutch 24 slipping past the serrations 33 of the clutch plates 25 during rotational movement of the clutch 24 relative to the housing 3. During dialling of a dose, the clutch plate 25 is urged axially towards the proximal end of the device by the biasing means 26, thereby ensuring that the teeth 29 and 33 of the clutch plate 25 and clutch 24 remain in contact. Since the clutch plate 25 is secured against rotation by the spline feature on the inner surface of the end stop 28 and the end stop 28 is secured against rotation relative to the housing, the clutch 24 rotates relative to the clutch plate 25 during dose setting. The saw teeth 29 of the clutch 24 can slip over the saw teeth 33 of the clutch plate 25 when the clutch 24 rotates, due to the triangular profile, which is preferred due to the profile of the saw teeth 29 and 33. Preferably, the angular spacing ratio of the serrations 29 of the clutch 24 to the serrations 33 of the clutch plate 25 is such that the pitch of each tooth corresponds to a conventional unit dose, and so on.

When setting a larger dose, the dose dial sleeve 27 is screwed out of the housing 3 (rotational movement and axial movement in the proximal direction) due to the fact that the dose dial sleeve is engaged with (the insert 43 of) the housing 3 via the threads 41, 42. The helical groove 41 of the dose dial sleeve 27 and the internal thread 21 of the drive sleeve 19 have the same lead. This allows the dose dial sleeve 27 to extend from the housing 3 at the same rate as the drive sleeve 19 creeps along the second thread 16 of the piston rod 17.

At the limit of travel, a radial stop (not shown) on the dose dial sleeve 27 engages a stop feature 56 provided on the insert 43 of the housing 3 to prevent further movement. During dose setting, the piston rod 17 is prevented from rotating due to the first and second threads 15, 16 on the piston rod 17 being in opposite directions, the first thread 15 engaging the nut means 11 and the second thread 16 engaging the drive sleeve 19.

During dose setting, when the dose dial sleeve 27 is rotated and moved in the proximal direction, the end stop 28, which is preferably prevented from rotating relative to the housing 3 by a spline feature (not shown), is moved axially towards the proximal end of the housing 3. When setting the maximum dose that can be dispensed from the cartridge 6, the radially extending flange 34 abuts a radial stop 60 formed on the piston rod 17, preventing further proximal axial movement of the end stop 28 and preventing further rotation of both the dose dial sleeve 27 and the drive sleeve 19 in the direction to set a larger dose.

If the user inadvertently dials more than the desired dose, the medication delivery device allows the dose to be dialed down without dispensing the drug product from the cartridge 6. To this end, the dose dial grip 46 is rotated in the opposite direction. This causes the system to reverse. The reverse rotation of the clutch 24 causes the saw teeth 29 and 33 of the clutch 24 and the clutch plate 25 to pass each other to generate a click sound corresponding to a reduction in the dial dose. Preferably, the serrations 29 and 33 are arranged such that the circumferential span of each serration corresponds to a unit dose.

Fig. 1a shows the drug delivery device in a state before the first dose has been set. Fig. 1b shows the drug delivery device according to fig. 1a in a dose set state. The dose dial sleeve 27 is extending proximally from the housing 3.

Upon dialing the desired dose, the user dispenses the dose by pressing the button 49. This causes the clutch 24 to be displaced axially towards the distal end of the device relative to the dose dial sleeve 27, thereby disengaging the clutch 24 from the dose dial sleeve 27. However, the clutch 24 remains keyed to the drive sleeve 19 for rotation. Thus, disengagement of the clutch 24 causes the dose dial sleeve 27 to disengage from the drive sleeve 19. The dose dial sleeve 27 and associated dose dial grip 46 are free to rotate, guided by the helical ribs 42 of the insert 43 located in the helical groove 41 of the dose dial sleeve 27. During dose delivery, the dose dial sleeve 27 is screwed back into the housing 3 in the distal direction.

The pressure of the user pressing on the button 49 further causes the clutch 24 to move axially in a distal direction without rotating relative to the housing 3. Axial movement of the clutch 24 moves the clutch plates 25 distally against the force of the biasing means 26 until the clutch plates 25 abut a shoulder of the drive sleeve 19 and the clutch 24 and clutch plates 25 engage such that relative rotation between the clutch 24 and clutch plates 25 is prevented, thereby preventing rotation of the clutch 24 and drive sleeve 19 relative to the housing 3 during dose delivery. Since the clutch plates 25 are splined to the end stop 28 to prevent rotation of the clutch plates 25 relative to the housing 3, the clutch plates 25 and the clutch 24 travel together distally, but do not rotate.

Axial movement of the clutch 24 causes axial movement of the drive sleeve 19 in the distal direction. The longitudinal axial movement of the drive sleeve 19 towards the distal end further causes (by means of the internal thread 21 of the drive sleeve 19 and the second thread 16 of the piston rod 17) the piston rod 17 to rotate and thereby to wind around the opening 13 through the nut means 11, thereby advancing the piston 17 in the barrel 6.

Once the dialed dose is dispensed, the dose dial sleeve 27 is prevented from further rotation by a plurality of rotation stop features (not shown) extending from the dose dial grip 46 engaging stop features 55 on the insert 43 of the housing 3. In the exemplified embodiment, the whirl-stop feature extends axially from the dose dial grip 46 and has a sloped end surface. The zero position is determined by one of the axially extending edges of the whirl-stop feature (not shown) abutting a corresponding stop 55 on the insert 43.

The rotational movement of the dose dial sleeve 27 during dose delivery causes the end stop 28 to move axially in the distal direction back to its initial position within the housing 3.

Fig. 1c shows the medication delivery device according to fig. 1a and 1b after dispensing of a dose. The piston rod 17 and the piston 7 in the barrel 6 have been advanced in the distal direction. The dose dial sleeve 27 and the end stop 28 are in their original positions relative to the housing 3.

When the dose has been dispensed, the spent cartridge 6 can be removed and discarded. To remove the cartridge 6, the cartridge holder 2 is disengaged from the housing 3 by disengaging the first and second engagement means 5, 4. Once the cartridge holder 2 is disengaged from the housing 3, the spent cartridge 6 may be removed from the cartridge holder 2 and a new cartridge 6 may be placed in the cartridge holder 2.

Disengagement of the cartridge holder 2 from the housing 3 causes the locking means 9 to disengage from the nut means 11 under the force of the biasing means 14. The nut means 11 is no longer in the guiding position. This allows the nut means 11 to rotate freely and thus allows the piston rod 17 to be screwed back in the proximal direction.

In order to connect the cartridge holder 2 containing the new cartridge 6 to the housing 3, the piston rod 17 has to be moved axially in the proximal direction. When the user moves the cartridge holder 2 with the cartridge 6 towards the housing 3, the piston 7 of the cartridge 6 is brought to abut against the end of the piston rod 17 and the piston 7 of the cartridge 6 is moved proximally relative to the housing 3, thereby producing the above-mentioned proximal movement. Alternatively, the user may push the piston rod 17 in the proximal direction with a finger and then connect the cartridge holder 2 with the cartridge 6 to the housing 3. When the nut means 11 (threadedly engaging the piston rod 17) is free to rotate relative to the housing 3, the piston rod 17 is free to rotate and translate proximally until the locking means 9 and the nut means 11 are engaged. Pushing back the piston rod 17 by means of the piston 7 of the new cartridge 6 being pushed against the pressure foot 18 of the piston rod 17 has the advantage that when the device is reset, the pressure foot 18 of the piston rod 17 already abuts the piston 7 of the cartridge 6. Thus, the priming movement of the piston rod 17 (to remove air from the barrel 6) can be very small and the loss of medicament due to priming can be kept to a minimum.

The cartridge holder 2 containing the new cartridge 6 is engaged with the housing 3 by bringing the first and second engagement means 5, 4 into engagement. When the cartridge holder 2 is brought into engagement with the housing 3, the cartridge holder 2 is first rotated and moved axially in the proximal direction, since the second engagement means 4 of the insert 3A of the housing 3 are moved along the threaded section of the first engagement means 5 of the cartridge holder 2 until the second engagement means 4 reach the annular groove section of the first engagement means 5. The second engagement means 4 moves further in the annular groove, causing the cartridge holder 2 to rotate without moving axially relative to the housing 3. Thus, the first and second engagement means 5, 4 can be moved into engagement by movement of the cartridge holder 2, the movement of the cartridge holder 2 ending in a rotational movement without axial movement of the actuation means 70 relative to the housing 3. Further rotation of the cartridge holder 2 (without axial movement) causes the ramp 71 of the actuating means 70 to slide along the inclined surface 72 of the locking means 9. Thus, the locking means 9 is axially moved in the proximal direction against the force of the biasing means 14 until the face teeth 10 of the locking means 9 engage the face teeth 12 of the nut means 11, thereby setting the nut means 11 (guide means) in the guiding position. In this position the nut means 11 is secured against axial movement and rotation. In this guiding position, the piston rod 17 is prevented from rotating in one rotational direction and axially moving in a proximal direction with respect to the housing 3, but is allowed to rotate in the other rotational direction and axially move in a distal direction with respect to the housing 3 for delivering the medicament.

Upon engagement of the cartridge holder 2 and the snap feature (not shown) of the insert 3A of the housing 3, a pure rotational movement of the cartridge holder 2 and the actuating means 70, i.e. the movement of the locking means 9 into engagement with the nut means 11, is terminated. In this position, the actuating means 70 hold the nut means 11 in the guiding position.

A rotational movement (no axial movement) of the cartridge holder 2 relative to the housing 3, i.e. a movement to move the locking means 9 into engagement with the nut means 11, has the advantage that no pressure builds up on the piston 7 of the cartridge 6 before the medicament delivery device 1 is used.

Thus, the dosing mechanism of the medication delivery device 1 according to the present invention is reset to a zero (or non-dose delivered) position, as shown in fig. 1 a.

Fig. 2a to 2c schematically show an embodiment of the actuating means interacting with the locking means in three different states according to one embodiment of the invention.

Fig. 2a shows the locking means 9 and the actuating means 70 before interaction between the two takes place. In the illustrated embodiment, the actuation means 70 is for example part of a medicament container (e.g. a cartridge holder 2) of a medicament delivery device. In the shown embodiment, the component of the medicament delivery device comprising the actuation means 70 further comprises first engagement means 5 for engaging with second engagement means 4, preferably part of a housing of the medicament delivery device or part of an insert of the housing. The first and second engagement means 5, 4 are designed such that in order to move the two parts comprising the engagement means 5, 4, preferably the housing and the medicament container, into engagement, the two parts are first rotated and moved axially relative to each other (first step) and then only rotated and not moved axially relative to each other (second step). The interaction between the actuation means 70 and the locking means 9 only takes place in the second step, i.e. when the two components (e.g. the medicament container and the housing) and the actuation means 70 and the locking means 9 are only rotated relative to each other. The locking means 9 preferably does not rotate relative to the housing of the medication delivery device.

Fig. 2a shows the actuating means 70 and the locking means 9 in a first step, i.e. when a rotational movement (arrow 35) and an axial movement (arrow 36) between the two takes place. In this step, the second engagement means 4 is moved along a first section of the first engagement means 5, indicated with a thread 37. The distal end of the thread 37 merges into a second section of the first engagement means 5, which is represented by a portion of an annular groove 38. In this simplified view, the annular groove 38 appears as a straight section, as the figure shows a view on the outer surface of the substantially cylindrical part.

The second engagement means 4 is at least one engagement element which engages with the thread 37 and the annular groove 38. The engaging elements shown have a parallelogram shape.

In the illustrated embodiment, the locking means 9 and the actuating means 70 have a particular shape for interaction. The actuating means comprise a ramp 71 with an inclined surface for interacting with a corresponding inclined surface 39 of the locking means 9 forming the triangular recess 58.

In fig. 2a, the axial movement 36 of the actuation means 70 relative to the locking means 9 in combination with the rotation 35 causes the actuation means 70 to approach the locking means 9 until the actuation means 70 abuts the locking means 9 in a position in which the ramp 71 engages the triangular recess 58 of the locking means 9, as shown in fig. 2 b. In this position, the second engagement means 4 has reached the point where the thread 37 of the first engagement means 5 merges with the annular groove 38 of the first engagement means 5. The combined axial movement 36 and rotation 35 of the actuating device 70 relative to the locking device 9 (first engagement step) is now switched such that only the rotation 35 of the actuating device 70 relative to the locking device 9 is present (second engagement step).

During this rotation, the inclined surface of the ramp 71 and the recess 58 slide along each other. This interaction of the actuation means 70 and the locking means 9 drives the locking means 9 (which may not rotate relative to the housing (not shown)) axially in the proximal direction (arrow 59) during the course of only rotational movement without axial movement, as shown in fig. 2 c. With such an axial movement of the locking means 9, preferably against the force of a biasing means not shown, the locking means 9 is driven into engagement with a guiding means (e.g. nut means) not shown, thereby setting the guiding means into a guiding position, in which the guiding means guides the piston rod 17 during delivery of the medicament with the medicament delivery device. The locking means 9 and the guiding means are engaged, for example, by interlocking face teeth of the locking means 9 and the guiding means.

Fig. 3 shows an enlarged cross-sectional view of a central part of the embodiment according to fig. 1a to 1c, showing the actuation means, the locking means and the guiding means of the medicament delivery device.

The cartridge holder 2 of the medication delivery device is connected to the housing 3 of the medication delivery device by means of the first engagement means 5 engaging with the second engagement means 4 (not shown). The cartridge holder 2 includes a first engagement means 5, and the insert 3A of the housing 3 includes a second engagement means 4. A two-part pressure foot 18 is mounted to the distal end of the piston rod 17 and abuts the piston 7 of the medicament cartridge 6.

According to this embodiment, the cartridge holder 2 comprises an actuating means 70 comprising a ramp 71 with an inclined surface for interacting with a corresponding inclined surface 72 of the locking means 9. The locking means 9 engages with nut means 11, which are guiding means in a guiding position for guiding the piston rod 17. The tip of the ramp 71 of the actuator means 70 is pushed against the distal surface of the locking means 9, thereby holding the nut means 11 in the guiding position. The face teeth 10 of the locking means 9 engage with the face teeth 12 of the nut means 11. By means of the engagement of the nut means 11 with the locking means 9, the nut means 11 is prevented from rotating relative to the housing 3. The nut means 11 is in threaded engagement with the first thread 15 of the piston rod 17. With said threaded engagement and the engagement of the (oppositely arranged) second thread 16 of the piston rod 17 with the drive sleeve (not shown), the piston rod 17 is prevented from moving in the proximal direction as long as the nut means 11 is in the guiding position. The biasing means 14 is arranged to urge apart the nut means 11 and the locking means 9 when the cartridge holder 2 is disengaged from the housing 3.

Fig. 4 schematically shows a different embodiment of a medication delivery device according to the present invention, provided with different arrangements of actuation means and guiding means.

The actuation means 70 comprises a ramp 71 and the medicament container 2 comprises the first engagement means 5 with the threaded section 37 and the annular groove 38. The guide means 11 has an inclined surface 39 which interacts with the ramp 71 of the actuating means 70. In the second engagement step, when the inclined surface of the ramp 71 and the guide 11 abut against and slide along each other during the rotational movement of the actuation device 70 relative to the housing 3, the guide 11 is pushed against the locking device 9, whereby the face teeth 12 of the guide 11 engage the face teeth 10 of the locking device 9. The locking device 9 of this embodiment does not necessarily have to be a separate component. It may also be part of the housing 3.

Fig. 5 shows another embodiment of a medication delivery device according to the present invention.

The drug delivery device 1 according to fig. 5 comprises a cartridge holder 2 and an (outer) housing 3. The distal end of the housing 3 is provided with an insert 3B, the insert 3B being designed to engage the proximal end of the cartridge holder 2. The insert 3B is secured against rotation relative to the housing 3 but is free to move axially relative to the housing 3. The extent of axial movement of the insert 3B is limited by the retaining means 63, the retaining means 63 being engaged with and secured to the housing 3 so as to be neither axially movable nor rotatable relative to the housing 3.

The inner surface of the insert 3B is provided with second engagement means 4. The second engagement means 4 may be any suitable means known to the person skilled in the art, such as a bayonet, a screw thread or the like. Preferably, the second engagement means 4 is a helical thread and corresponds to the first engagement means 5 at the proximal end of the cartridge holder 2, the first engagement means 5 preferably also being a helical thread.

In the shown embodiment of the invention, the proximal end of the cartridge holder 2 is further provided with an actuating means (not shown) designed to activate the guiding means (not shown) and lock it in the guiding position.

The biasing means 64 is disposed between a proximal face of the retaining means 63 and a distal face of the insert 3B. The biasing device 64 may be made of any suitable flexible material known to those skilled in the art, such as stainless steel, rubber, etc., and may take any suitable form, such as a spring, spacer, etc. In the illustrated embodiment of the invention, the biasing device 64 is a wave spring. The biasing means 64 is designed to ensure that the insert 3B does not abut against the retaining means 63 when the cartridge holder 2 is not engaged with the housing 3.

The other components of the drug delivery device will not be described in detail, but are preferably similar to the components described above with reference to fig. 1a to 1 c.

The operation of the medication delivery device according to the present invention will now be described.

Dose dialling and dose dispensing may for example operate in a similar manner to that described above with reference to figures 1a to 1 c.

When the final dose dispensing position is reached, the spent cartridge 6 may be removed and discarded. To remove the cartridge 6, the cartridge holder 2 is disengaged from the housing 3, preferably the cartridge holder 2 is screwed off the housing 3. Once the cartridge holder 2 is disengaged from the housing 3, the cartridge 6 may be removed from the cartridge holder 2 and a new cartridge 6 may be placed in the cartridge holder 2.

Disengaging the cartridge holder 2 from the housing 3 causes the guide means (not shown) of the device to disengage from the guide means, for example by means of a locking means, under the force of the biasing means, and leave its guide position. This allows, for example, the guide to rotate freely and thus the piston rod may be moved in the proximal direction for resetting the device.

After removal of the cartridge holder 2, the insert 3B is moved away from the distal end of the housing 3 (away from the holding means 63) in the proximal direction by a limited distance due to the force exerted by the biasing means 64.

To connect the cartridge holder 2 to the housing 3, the piston rod is axially moved in the proximal direction relative to the housing 3. When the cartridge holder 2 with the cartridge is moved towards the housing 3, the piston of the new cartridge abuts against the end of the piston rod and moves proximally in relation to the housing 3, thereby causing the above-mentioned movement in the proximal direction. Since the guiding means is not yet in the guiding position, the piston rod is free to translate proximally until the guiding means reaches the guiding position, e.g. until the locking means and the guiding means are engaged. Pushing the piston rod back with the piston of the new cartridge 6 pushed against the pressure foot 18 of the piston rod 17 has the advantage that the pressure foot 18 of the piston rod 17 already abuts the piston 7 of the cartridge 6 when the device is reset. Thus, the priming movement of the piston rod 17 (to remove air from the barrel 6) can be very small and the loss of medicament due to priming can be kept to a minimum.

The cartridge holder 2 containing the new cartridge 6 is then engaged, preferably threadedly engaged, with the housing 3. As the cartridge holder 2 is moved into engagement with the housing 3, first engagement means 5 at the proximal end of the cartridge holder 2 engage with second engagement means of the insert 3B. The cartridge holder 2 is allowed to rotate and move axially in the proximal direction (first engagement step) until a stop means 65 (e.g. an annular outer periphery) located on the cartridge holder 2 abuts the retaining means 63. The stopper 65 prevents the cartridge holder 2 from further axial movement, but allows the cartridge holder 2 to rotate (second engagement step). As the cartridge holder 2 is rotated further, the insert 3B moves axially towards the distal end of the housing 3 and towards the retaining means 63 against the force of the biasing means 64.

Such a simple rotation of the cartridge holder 2 additionally causes the activation means to set the guiding means into a guiding position (not shown), for example axially displaced in the proximal direction against the force of the biasing means by the locking means until the face teeth of the locking means engage the face teeth of the guiding means.

Thus, the drive mechanism is reset to a zero (or no dose delivered) position.

The rotational movement (without axial movement) of the cartridge holder 2, which sets the guiding means to the guiding position, has the advantage that no pressure builds up on the piston of the cartridge after insertion of a new cartridge, before the first use of the medication delivery device 1.

Claims (31)

1. A drug delivery device (1) comprising:

a housing (3) having a proximal end and a distal end;

a medicament container (2) designed to engage with the distal end of the housing (3) by means of a first engagement means (5) in combination with a second engagement means (4); and

a dosing mechanism, the dosing mechanism comprising:

a piston rod (17) movable in a distal direction for delivering the medicament; and

a drive device for moving the piston rod (17) in a distal direction for delivering the drug;

characterized in that the medicament container (2) comprises actuation means (70) for bringing guide means (11) into a guide position in which the guide means (11) guides the piston rod (17) for delivering medicament, wherein the first engagement means (5) and the second engagement means (4) are movable into engagement by means of a movement of the medicament container which is terminated by a rotational movement of the medicament container relative to the housing (3) without axial movement, whereby the actuation means (7) brings the guide means (11) into the guide position.

2. A drug delivery device (1) according to claim 1, characterized in that in the guiding position the guiding means (11) is prevented from rotating relative to the housing (3).

3. A drug delivery device (1) as in claim 1, characterized in that the piston rod (17) is axially movable by the drive device in a distal direction relative to the housing (3) and the piston rod (17) is prevented from axially moving in a proximal direction relative to the housing (3) when the guiding means (11) is in the guiding position.

4. The drug delivery device (1) according to claim 1, characterized in that the piston rod (17) is free to move axially in the proximal direction with respect to the housing (3) when the guiding means (11) is not in the guiding position.

5. A drug delivery device (1) according to claim 1, characterized in that the first and second engagement means are designed such that, for moving the drug container and the housing into engagement, the actuation means are first rotated and axially moved relative to the housing and thereafter rotated without axial movement, thereby bringing the guiding means into the guiding position.

6. The medicament delivery device (1) according to claim 1, wherein the guiding means (11) is a nut means in threaded engagement with the piston rod (17).

7. The medicament delivery device (1) according to claim 1, characterized in that the drive device comprises a drive sleeve (19) and the piston rod (17) comprises two thread sections (15, 16), wherein a first thread section (15) is for threadedly engaging the guiding means (11) and a second thread section (16) is for threadedly engaging the drive sleeve (19), and wherein a pitch direction of the second thread section (16) is directed opposite to a pitch direction of the first thread section (15).

8. The drug delivery device (1) according to claim 7, characterized in that the drive sleeve (19) is engaged with the piston rod (17) for driving the piston rod (17) in a distal direction during drug delivery, whereas the drive sleeve (19) is axially moved but prevented from rotating relative to the housing (3) during drug delivery, thereby causing the piston rod (17) to be axially moved and rotated.

9. The drug delivery device (1) according to claim 7, characterized in that the dosing mechanism comprises:

a dose dial sleeve (27) having a helical thread engaging with the helical thread of the housing (3), the drive sleeve (19) being releasably coupled to the dose dial sleeve (27); and a clutch means (24) located between the dose dial sleeve (27) and the drive sleeve (19), wherein,

a) -when the dose dial sleeve (27) and the drive sleeve (19) are coupled, both the dose dial sleeve and the drive sleeve are allowed to rotate relative to the housing (3); and

b) when the dose dial sleeve (27) and the drive sleeve (19) are disengaged, rotation of the dose dial sleeve (27) relative to the housing (3) is allowed, rotation of the drive sleeve (19) relative to the housing (3) is not allowed, and the drive sleeve (19) is allowed to move axially in a distal direction, thereby transmitting a force in a distal direction to the piston rod (17).

10. A drug delivery device (1) according to claim 1, characterized in that the drug delivery device (1) comprises locking means (9) which is non-rotatable relative to the housing (3) and which is engageable with the guiding means (11), thereby locking the guiding means (11) against rotation of the guiding means (11) relative to the housing (3).

11. The medicament delivery device (1) according to claim 10, wherein the piston rod (17) is prevented from rotating and axially moving in a proximal direction with respect to the housing (3) but is allowed to rotate and axially move in a distal direction with respect to the housing (3) for delivering the medicament when the guiding means (11) is engaged with the locking means (9) in the guiding position.

12. The drug delivery device (1) according to claim 10, characterized in that the guiding means (11) or the locking means (9) comprises a shape interacting with the shape of the actuation means (70) for driving the locking means (9) and the guiding means (11) into engagement with a rotational movement of the actuation means (70).

13. A drug delivery device (1) according to claim 11, characterized in that at least one inclined surface is arranged on the actuation means (70) and at least one corresponding inclined surface (39) is arranged on the guiding means (11) or the locking means (9), which inclined surfaces are formed such that the inclined surfaces slide along each other for the interaction of the actuation means (70) and the guiding means or for the interaction of the actuation means (7) and the locking means (9).

14. The drug delivery device (1) according to claim 13, characterized in that the actuation means (70) comprises at least one protrusion having the inclined surface fixedly or movably arranged on the actuation means (70); or at least one ramp (71) with an inclined surface, which interacts with the guiding means (11) or the locking means (9) by means of a rotational movement of the actuating means (70) in one direction, thereby driving the guiding means (11) and the locking means (9) into engagement.

15. The medicament delivery device (1) according to claim 10, wherein the guiding means (11) is nut means threadedly engaging the piston rod (17) and the nut means engages the locking means when in the guiding position.

16. A medication delivery device (1) according to claim 10, characterized in that the locking means (9) and the guiding means (11) comprise face teeth (10, 12) which interlock when the locking means (9) and the guiding means (11) are engaged in the guiding position.

17. The medicament delivery device (1) according to claim 10, wherein the locking means (9) and the guiding means (11) are disengaged under the force of a biasing means (14) when the medicament container (2) is disengaged from the distal end of the housing (3).

18. The drug delivery device (1) according to claim 10, characterized in that the locking means (9) and the guiding means (11) are disengaged when the drug container (2) is disengaged from the housing (3), whereby the guiding means (11) is free to rotate relative to the housing (3).

19. The drug delivery device (1) according to claim 1, characterized in that the drug container (2) is a cartridge holder designed to receive a cartridge (6) filled with a drug.

20. A drug delivery device (1) according to claim 1, characterized in that the drug container (2) or an insert of the drug container (2) comprises the first engagement means (5) and the housing (3) or an insert (3A) of the housing (3) comprises the second engagement means (4).

21. The drug delivery device (1) according to claim 1, characterized in that the first engagement means (5) is a thread of the drug container (2) and the second engagement means (4) is an engagement element of the housing (3) or of an insert (3A) of the housing for engagement with the thread of the drug container, wherein a distal end of the thread of the drug container (2) merges into an annular groove for engaging the drug container (2) with the housing (3) by first rotating and moving proximally relative to the housing (3) and then only rotating relative to the housing (3).

22. A medicament delivery device (1) according to claim 1, wherein the housing (3) is distally provided with an insert (3B) comprising second engagement means (4) designed to engage the first engagement means (5) at the proximal end of the medicament container (2), the insert (3B) being secured against rotation but free to move axially relative to the housing (3), wherein axial movement of the insert (3B) towards the distal end is limited by retaining means (63).

23. The drug delivery device (1) according to claim 22, the insert (3B) of the housing comprises an internal thread as second engagement means (4) for engaging a first engagement means (5) as an external thread of the proximal end of the medicament container (2), the medicament container (2) comprising actuation means (70) and being rotatable and axially movable relative to the insert and the housing (3) in a first step for engaging the medicament container (2) with the housing (3), and in a second step for engaging the medicament container (2) with the housing (3), the medicament container (2) is rotated while axial movement of the medicament container (2) relative to the housing (3) is prevented, in the second step, the insert (3B) is moved in a distal direction by rotation of the medicament container (2).

24. The drug delivery device (1) according to claim 1, characterized in that the drug container (2) and the housing (3) are provided with snap features by means of which the drug container (2) and the housing (3) remain engaged during drug delivery.

25. The drug delivery device (1) according to claim 1, characterized in that it is a pen-type device.

26. The drug delivery device (1) according to claim 1, characterized in that the drug delivery device is a syringe type device.

27. The drug delivery device (1) according to claim 1, characterized in that the drug delivery device (1) comprises a needle cannula.

28. The drug delivery device (1) according to claim 1, characterized in that it contains a drug product.

29. The drug delivery device (1) according to claim 1, characterized in that it contains a formulation comprising an active compound selected from: insulin, growth hormone, small molecular weight heparin, their analogs, and their derivatives.

30. A drug delivery device (1) according to claim 2, characterized in that the piston rod (17) is axially movable by the drive device in a distal direction relative to the housing (3) and the piston rod (17) is prevented from axially moving in a proximal direction relative to the housing (3) when the guiding means (11) is in the guiding position.

31. A method of manufacturing or assembling a drug delivery device according to any of claims 1 to 30.