Drug Delivery Device

Abstract

A drug delivery device for selecting and dispensing a number of user variable doses of a medicament includes a housing having an opening, a dose selector operable to set a dose by rotation relative to the housing, a release member controlling movement of a piston in a dispensing direction, and a display comprising a units number wheel and a tens number wheel which are coupled to each other such that a continuous rotation of the units number wheel is translated into an intermittent rotary motion of the tens number wheel. The release member rotates, during dose dispensing, an angle corresponding to the dose set by the dose selector, thereby allowing a piston to move in a dispensing direction.

Claims

1-16. (canceled)

17. A drug delivery device for selecting and dispensing a number of user variable doses of a medicament, the drug delivery device comprising: a housing; a dose selector operable to set a dose by rotation relative to the housing; a release member operable to control movement of a piston in a dispensing direction; and a display comprising at least one number wheel or number sleeve, wherein the release member rotates, during dose dispensing, an angle corresponding to the dose set by the dose selector to allow the piston to move in the dispensing direction, wherein the device further comprises a clutch mechanism which rotationally couples the number wheel or the number sleeve to the dose selector and de-couples the number wheel or the number sleeve from the release member during dose setting, and which rotationally de-couples the number wheel or the number sleeve from the dose selector and couples the number wheel or the number sleeve to the release member during dose dispensing.

18. The drug delivery device according to claim 17, wherein the clutch mechanism is operable to be switched between a dose setting position and a dose dispensing position, wherein, when the clutch mechanism is in its dose setting position, the number wheel or the number sleeve is rotationally coupled via the clutch mechanism to the dose selector and the number wheel or the number sleeve is rotationally de-coupled from the release member, and wherein, when the clutch mechanism is in its dose dispensing position, the number wheel or the number sleeve is rotationally de-coupled from the dose selector and the number wheel or the number sleeve is rotationally coupled via the clutch mechanism to the release member.

19. The drug delivery device according to claim 17, wherein the display comprises at least one number wheel, wherein the number wheel is a units number wheel, and wherein the units number wheel is coupled to a tens number wheel by a gear mechanism, and wherein the gear mechanism comprises a driving dog provided on the units number wheel and a plurality of corresponding driven dogs provided on the tens number wheel.

20. The drug delivery device according to claim 19, wherein the units number wheel comprises one single driving dog and is provided with the FIGS. 0 to 9.

21. The drug delivery device according to claim 19, wherein the units number wheel (51) comprises a raised circular blocking disc that locks the tens number wheel in position between the steps of intermittent rotary motion of the tens number wheel.

22. The drug delivery device according to claim 17, further comprising a dose ring gear which is rotationally coupled to the dose selector during dose setting and which is rotationally coupled to the release member during dose dispensing.

23. The drug delivery device according to claim 22, wherein the dose ring gear is permanently rotationally coupled to the at least one number wheel or the number sleeve.

24. The drug delivery device according to 22, wherein the clutch mechanism rotationally couples the dose ring gear to the at least one number wheel or the number sleeve, rotationally couples the dose ring gear to the dose selector during dose setting and rotationally couples the dose ring gear to the release member during dose dispensing.

25. The drug delivery device according to 17, wherein the clutch mechanism comprises a clutch gear having a first gear wheel and a second gear wheel which is rotationally constrained to the first gear wheel.

26. The drug delivery device according to claim 25, wherein the clutch gear is axially movable between a dose setting position, in which the first gear wheel is rotationally coupled to the dose selector and the at least one number wheel or the number sleeve, and in which the second gear wheel is rotationally coupled to the dose ring gear, and a dose dispensing position, in which the first gear wheel is rotationally coupled to the at least one number wheel or the number sleeve, and in which the second gear wheel is rotationally coupled to the dose ring gear and the release member.

27. The drug delivery device according to claim 26, wherein the clutch gear is rotatable about a first axis and wherein the dose selector, the dose ring gear and the release member are rotatable about a second axis which is parallel to and offset from the first axis.

28. The Drug delivery device according to claim 17, further comprising a trigger for actuating the clutch mechanism, the trigger comprising a clutch lever pivot-mounted within the housing.

29. The drug delivery device according to claim 28, wherein the clutch lever comprises a guiding sleeve at least partially surrounding a part of the clutch mechanism for axially displacing the clutch mechanism upon actuation of the trigger.

30. The drug delivery device according to claim 17, further comprising a spring acting on the piston, wherein a cable is attached to the piston and to a cable spool of the release member, such that upon rotation of the release member the piston is allowed to be pushed by the spring.

31. The drug delivery device according to claim 17, further comprising a stop element preventing rotation of the release member during dose setting and allowing rotation of the release member during dose dispensing.

32. The drug delivery device according to claim 17, further comprising a cartridge containing a medicament.

33. The drug delivery device according to claim 32, wherein the medicament comprises a pharmaceutically active compound.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0056] Non-limiting, exemplary embodiments of the disclosure will now be described with reference to the accompanying drawings, in which:

[0057] FIG. 1 shows a cut away view of the drug delivery device of the present disclosure;

[0058] FIG. 2 shows a cut away view of the cable and spring of the device of FIG. 1;

[0059] FIG. 3 shows a detail view of the clicker mechanism of the device of FIG. 1;

[0060] FIG. 4a shows a partial section view of the release mechanism of the device of FIG. 1 before dialing;

[0061] FIG. 4b shows a partial section view of the release mechanism of the device of FIG. 1 during dialing;

[0062] FIG. 5 shows a cut away view of the release mechanism during dose setting of the device of FIG. 1;

[0063] FIG. 6 shows a cut away view of the release mechanism during dose dispensing of the device of FIG. 1;

[0064] FIGS. 7a & b show partial section view of the dose stop of the device of FIG. 1 during dose setting and dose dispensing;

[0065] FIG. 8 shows a cut away view of the last dose lock-out mechanism of the device of FIG. 1;

[0066] FIG. 9 shows a view of the last dose nut engaged with the last dose spool; and

[0067] FIGS. 10a, b show top and bottom views of the dose counter mechanism.

DETAILED DESCRIPTION

[0068] The mechanism comprises the following key components as depicted in FIG. 1: a housing 10, a chassis 20, a dose button 30, a dose selector in the form of a dial grip 40, a dose counter mechanism 50 with a units number wheel 51 and a tens number wheel 52, a clutch 60, a last dose spool 70, a last dose nut 80, a dose ring gear 90, a release gear 100, a cable 110 with a piston 111 or bearing disc, a piston spring 120, a clutch lever 130 with and a cartridge 140.

[0069] The medicament cartridge 140 is housed within a cartridge holder component 11 of housing 10. The cartridge holder 11 is rigidly connected to the housing 10 of the pen injector during assembly. The piston 111 is a bearing component located on the main axis I of the pen injector, and is rigidly connected to the cable 110 and the piston spring 120 on its proximal face, and on its distal face abuts the bung 141 of the medicament cartridge 140. The proximal end of the piston spring 120 reacts on the chassis 20.

[0070] The proximal end of the cable 110 is terminated on and wrapped around a cable spool 101 of the release gear 100. As the cable spool 101 rotates, a controlled length of the cable 110 is released, forced by the action of the piston spring 120 via the piston 111, causing the piston 111 to advance into the medicament cartridge 140 and dispel some of the medicament. The cable spool 101 is attached and locked in rotation to the release gear 100. The release gear 100 is able to rotate relative to the chassis 20 and the dose counter mechanism 50 about a fixed axis II, perpendicular to the main medicament cartridge axis I. The amount that the release gear 100 rotates during dispense of a dose is defined by the user, and controlled by the release mechanism. This consists of the dose ring gear 90, a clutch gear 61 with a first gear wheel 62 and a second gear wheel 63 connected via a shaft portion, a clutch lever 130, the dial grip 40 and dose stop element 150. As can be seen in FIGS. 5 and 6, the clutch gear 61 has a rotational axis III which is parallel to and off-set from the rotational axis II of the release gear 100.

[0071] The clutch lever 130 is pivotably supported in the chassis 20 such that actuation of the button 30 swivels the clutch lever 30, thus raising or lowering the clutch gear 61 as shown in FIGS. 5 and 6 via a sleeve-like end of the clutch lever 130 supporting the clutch gear 61. The opposite end of clutch lever 130 actuates stop element 150 by raising it from the blocking position in which release member 100 is prevented from rotation for dose dispensing or lowering it into the locking position after dispensing.

[0072] When the device is in its “dose setting mode” as shown in FIG. 5, i.e. the button 30 is not pressed by the user, the teeth of clutch gear 61 are engaged with the dial grip 40 and the dose ring gear 90. This engagement causes the dose stop face on the dose ring gear 90 to be rotated away from the dose stop element 150 as the dose is dialed. The position of the dial grip 40 mid-dose is controlled by a dial clicker element which is biased to single-unit detent positions on the dial grip 40 (see FIG. 3). Each of these detent positions corresponds to a single-unit during dialing. The set dose can be dialed both up and down (increasing and decreasing the dose number). An audible click will be produced by the dial clicker, once per unit increment.

[0073] The rotational position of release gear 100 is locked via the dose stop element 150 to the housing 10 and chassis 20 throughout dose setting mode and in storage. A maximum, fixed dose limit stop feature between dose ring gear 90 and dose stop element 150 ensures the dose ring gear 90 is not dialed above the maximum permissible dose.

[0074] To dispense the user-selected dose, the dose button 30 is pressed in, acting on the clutch lever 130, causing it to rotate about its central pivot and move the clutch gear 61 axially into the dispense position (see FIG. 6). In the dispense position, the clutch gear 61 is engaged with the release gear 100 and the dose ring gear 90, and disengaged from the dial grip 40. The axial movement of the clutch gear 61 is limited by features which act on the release gear 100 and the dial grip 40.

[0075] The order in which the clutch gear 61 disengages and engages with the other release mechanism components is important to ensure that the spring energy is not released in an unsafe manner. As the clutch lever 130 moves from the set position, it first locks the rotation of the dial grip 40 by moving the dial clicker into a position whereby it requires a very high torque to dial either up or down. As the clutch lever 130 continues to move it causes the clutch gear 61 to axially engage the release gear 100. The clutch gear 61 and the release gear 100 have chamfered teeth for ease of engagement to accommodate moulding and positional tolerances. As the clutch lever 130 continues to move further, it causes the clutch gear 61 to disengage from the dial grip 40 so that the last dose mechanism is not rewound and the dial grip 40 does not spin during dispense (preventing the user from jamming the device by touching it). Finally, the clutch lever 130 causes the dose stop element 150 to disengage from the release gear 100 (see FIG. 7), allowing the cable spool 101 and the release gear 100 to rotate, releasing some cable 110 and permitting the piston spring 120 to move the bung 141 by piston 111. The cable spool 101 of the release gear 100 rotates (keyed to the dose ring gear 90) until the stop face on the dose ring gear 90 contacts the dose stop element 150, preventing any further rotation and ending dispense.

[0076] When the dose button 30 is released after the dose has been expelled, the action of the release mechanism is reversed. The dose stop element 150 re-engages with the release gear 100, then the clutch gear 61 engages with the dial grip 40, then the clutch gear 61 disengages with the release gear 100, and finally the dial clicker is released, allowing the dial grip 40 to be dialed again.

[0077] Preferably, there is a return spring integrated into the clutch lever 130 that provides the return force to move the components during this operation. A separate integrated spring on the dose button 30 returns it to its default position. Both springs act on the mechanism chassis 20.

[0078] When the medicament cartridge 140 has been emptied, the mechanism locks to prevent the user from setting another dose. As shown in FIGS. 8 and 9, the last dose spool 70 is restrained in the chassis 20 so that it is only able to rotate. It is geared to the dial grip 40 assembly. The last dose nut 80 is engaged with the thread on the last dose spool 70 and prevented from rotating by a spline engagement with the chassis 20. When a dose is dialed, the dial grip 40 rotation causes the last dose spool 70 to rotate via their geared engagement. This rotation causes the last dose nut 80 to move axially up the thread of the last dose spool 70. When a dose is dispensed, as the dial grip 40 is stationary, the last dose mechanism is also held stationary. Eventually, as the total number of doses dialed reaches the capacity of the medicament cartridge, the last dose nut 80 is so far up the thread on the last dose spool 70 that corresponding stop faces on the two components contact each other. This prevents the last dose spool 70 rotating and, therefore, prevents the dial grip 40 rotating, locking out the device.

[0079] The size of the dialed dose is displayed to the user via a dose counter mechanism 50. This consists of the following components: a counter drive gear 53 with a smaller pinion and a larger pinion, the units number wheel 51, and the tens number wheel 52 (see FIGS. 10a, b). The mechanism is clutched to and is actuated by the dial grip 40 during dose setting, and is de-clutched from the dial grip 40 and actuated by the release gear 100 during dispense mode, both via the clutch gear 61. This ensures the remaining dose is displayed throughout the whole dispense operation.

[0080] The counter mechanism is situated in a recess within the dial grip 40. The units number wheel 51 has gear teeth that are permanently engaged with the counter drive gear 53, and a protrusion 54 (driving dog) that acts on the gear tooth-like features 55 (corresponding driven dogs) on the tens number wheel 52. The counter chassis 21 allows the number wheel axes to remain fixed relative to the device housing 10 while the dial grip 40 rotates around them.

[0081] Between indexed movement, the tens number wheel 52 is locked from rotating by scalloped recesses on the tens number wheel 52 which are restrained against the circular outer diameter of the units number wheel 51. The tens number wheel 52 is indexed to display the next number by the rotating action of the protrusion on the units number wheel 51 which engage on every rotation of the units number wheel 51. The counter drive gear 53 is in permanent toothed engagement with the clutch gear 61 so that it is rotated during dose setting and dispensing.

[0082] As an alternative embodiment the aforementioned device with the cable 110 can also be embodied as a timing belt (not shown). This alternative concept differs predominantly as described below. In this embodiment, the cable 110 and cable spool 101 are replaced with a toothed timing belt, and a toothed belt drum. This has advantages in terms of assembly and robustness in use. The belt drum increases the radius of curvature of the timing belt, thus reducing the stress that it is subjected to. The piston may be of a different design to allow integration with the timing belt. The timing belt has toothed regions at both ends of a plain cross section region, which makes up the majority of the length of the belt. The toothed regions allow permanent attachment to the piston at the distal end and the belt drum at the proximal end of the device. The plain region is wrapped around approximately 75% of the belt drum, and then runs down the inside of the piston spring 120 to the piston. The inner surface of the belt drum is in toothed engagement with the smaller pinion region of the release gear 100.

[0083] This alternative embodiment shares the other major functionality with the embodiment comprising the cable 110. This includes, but is not limited to: the dialing and dose setting mechanism, action of the clutch gear 61, zero and maximum unit dose stops, last dose lockout and dose display.

TABLE-US-00001 Reference Numerals: 10 housing 11 cartridge holder 20 chassis 21 counter chassis 30 dose button (trigger) 40 dial grip (dose selector) 50 dose counter mechanism 51 units number wheel 52 tens number wheel 53 counter drive gear 54 protrusion (driving dog) 55 tooth-like feature (driven dog) 60 clutch 61 clutch gear 62 first gear wheel 63 second gear wheel 70 last dose spool 80 last dose nut 90 dose ring gear 100 release gear 101 cable spool 110 cable 111 piston 120 piston spring 130 clutch lever 140 cartridge 141 bung 150 dose stop element I main axis II axis of rotation III axis of clutch gear