US-12616798-B2 - Drug delivery device

US12616798B2US 12616798 B2US12616798 B2US 12616798B2US-12616798-B2

Abstract

A drug delivery device comprises a housing adapted to receive a medicament container, a plunger and a plunger release mechanism that comprises a first plunger boss arranged on the plunger, a profiled slot arranged on the housing and adapted to be engaged by the first plunger boss so as to inhibit movement of the plunger in a distal direction. The plunger is rotatable about a longitudinal axis to release the first plunger boss from the profiled slot so as to allow movement of the plunger in the distal direction. A sleeve is coupled to the housing to permit movement of the sleeve relative to the housing. A sleeve ramp is arranged on the sleeve and adapted to engage a rib or boss on the plunger to rotate the plunger to release the first plunger boss from the profiled slot when the sleeve is moved in a proximal direction.

Inventors

Jim Bradford
Thomas Mark Kemp
William Timmis
Andrew LABAT-ROCHECOUSTE
Hugo Revellat

Assignees

SANOFI

Dates

Publication Date: 20260505
Application Date: 20230120
Priority Date: 20171103

Claims (19)

1 . An assembly for a drug delivery device comprising: a plunger configured to displace a piston of the drug delivery device, having arranged on the plunger a plunger boss; and a plunger holder, wherein the plunger holder comprises a profiled slot, wherein the profiled slot is adapted to be directly engaged by the plunger boss to inhibit movement of the plunger relative to the plunger holder in a distal direction, and wherein the profiled slot is adapted to induce a rotation to the plunger when an axial force is applied to the plunger, in order to rotate the plunger relative to the plunger holder in a rotational direction, wherein the profiled slot comprises an angled surface, wherein the angled surface is adapted to engage the plunger boss to induce the rotation; and wherein the plunger boss is axially and/or rotationally fixed relative to the plunger.
2 . The assembly according to claim 1 , wherein the plunger boss comprises an angled plunger boss surface, adapted to engage the angled surface, and wherein the angled plunger boss surface is adapted to induce the rotation, when engaged to the angled surface.
3 . The assembly according to claim 1 , wherein the plunger boss comprises several straight side faces.
4 . The assembly according to claim 1 , wherein the profiled slot comprises a wall adapted to limit movement of the plunger boss in the rotational direction when engaged to the angled surface, or wherein the plunger boss comprises two plunger boss side surfaces, and wherein the plunger boss side surfaces extend in the distal direction and are oriented parallel.
5 . The assembly according to claim 1 , wherein the angled surface is a first angled surface, wherein the profiled slot comprises a second angled surface adapted to engage the plunger boss to induce the rotation to disengage the plunger boss from the profiled slot to allow movement of the plunger in the rotational direction and the distal direction.
6 . The assembly according to claim 5 , wherein the plunger boss comprises an angled plunger boss surface, wherein the angled plunger boss surface is adapted to engage the second angled surface to induce the rotation to disengage the plunger boss from the profiled slot to allow movement of the plunger in the rotational and distal directions.
7 . The assembly according to claim 5 , wherein the profiled slot comprises a wall adapted to limit movement of the plunger boss in the rotational direction when engaged to the first angled surface, and wherein the first angled surface is adjacent to the second angled surface and the wall is arranged between the first and second angled surfaces such that the wall separates the first angled surface from the second angled surface.
8 . The assembly according to claim 7 , wherein the rotational direction is a first rotational direction, and wherein the wall is adapted to allow movement of the plunger boss in a second rotational direction, opposite the first rotational direction, when the plunger boss is engaged to the first or second angled surface.
9 . The assembly according to claim 7 , wherein the first angled surface, the second angled surface and the wall form a sawtooth shape.
10 . The assembly according to claim 5 , wherein the second angled surface extends further in the distal direction than the first angle surface.
11 . The assembly according to claim 5 , wherein the plunger boss is a first plunger boss and the plunger comprises a second plunger boss, and wherein the first and second plunger boss have different shapes.
12 . The assembly according to claim 11 , wherein the assembly comprises a needle sleeve movable mounted relative to the plunger holder along a longitudinal axis, wherein the needle sleeve comprises a sleeve rib on the needle sleeve, and wherein the plunger comprise a plunger rib, wherein the plunger rib is adapted to abut the sleeve rib with the plunger for moving the first plunger boss from the first angled surface of the profiled slot to the second angled surface of the profiled slot.
13 . The assembly according to claim 12 , wherein the profiled slot comprises a wall adapted to limit movement of the first plunger boss in the rotational direction when engaged to the first angled surface, and wherein the plunger rib is adapted to abut the sleeve rib to induce the rotation of the plunger in the rotational direction and push the plunger in a proximal direction when the first plunger boss is engaged to the first angled surface and to the wall of the profiled slot.
14 . The assembly according to claim 12 , wherein the sleeve rib comprises a distal face adapted to engage the second plunger boss of the plunger to limit movement of the sleeve rib in the distal direction relative to the plunger, or wherein the sleeve rib has a longitudinal face adapted to engage the second plunger boss preventing rotation of the plunger in the rotational direction to keep the first plunger boss engaged to the second angled surface.
15 . The assembly according to claim 14 , wherein the sleeve rib is adapted to disengage the second plunger boss from the longitudinal face when the sleeve rib is moved in a proximal direction thereby allowing the plunger to rotate in the rotational direction and the first plunger boss to disengage the second angled surface.
16 . The assembly according to claim 1 , wherein the assembly comprises a drive spring, and wherein the drive spring is arranged within the plunger holder and adapted to bias the plunger in the distal direction, and wherein the plunger is hollow and the drive spring is arranged within the plunger.
17 . The assembly according to claim 1 , wherein the plunger boss is an integral part of the plunger.
18 . A drug delivery device comprising: the assembly according to claim 1 ; a medicament container, wherein the medicament container contains a medicament; and a housing, wherein the housing houses the medicament container and the assembly.
19 . The drug delivery device according to claim 18 , wherein the drug delivery device is an auto-injector.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of U.S. patent application Ser. No. 16/758,781, filed Apr. 23, 2020, which is the national stage entry of International Patent Application No. PCT/EP2018/079918, filed on Nov. 1, 2018, and claims priority to Application No. EP 17306523.6, filed on Nov. 3, 2017, the disclosures of which are incorporated herein by reference. TECHNICAL FIELD The disclosure generally relates to a drug delivery device having a plunger release mechanism. BACKGROUND Drug delivery devices (i.e. devices capable of delivering medicaments from a medication container) typically fall into two categories—manual devices and auto-injectors. In a manual device—the user must provide the mechanical energy to drive the fluid through the needle. This is typically done by some form of button/plunger that has to be continuously pressed by the user during the injection. There are numerous disadvantages to the user from this approach. If the user stops pressing the button/plunger then the injection will also stop. This means that the user can deliver an underdose if the device is not used properly (i.e. the plunger is not fully pressed to its end position). Injection forces may be too high for the user, in particular if the patient is elderly or has dexterity problems. Auto-injectors are devices which completely or partially replace activities involved in parenteral drug delivery from standard syringes. These activities may include removal of a protective syringe cap, insertion of a needle into a patient's skin, injection of the medicament, removal of the needle, shielding of the needle and preventing reuse of the device. This overcomes many of the disadvantages of manual devices. Injection forces/button extension, hand-shaking and the likelihood of delivering an incomplete dose are reduced. Triggering may be performed by numerous means, for example a trigger button or the action of the needle reaching its injection depth. In some devices the energy to deliver the fluid is provided by a spring. Plunger release mechanisms are applied to control motion of a plunger in a drug delivery device in a manner keeping the plunger in a defined position until a condition is met suddenly allowing the plunger to move within the drug delivery device thus delivering a dose of a drug from a syringe. SUMMARY The present disclosure provides a drug delivery device with an improved plunger release mechanism as well as a method for assembling a drug delivery device. According to the present disclosure, a drug delivery device comprises a housing adapted to receive a medicament container, a plunger and a plunger release mechanism comprising: a first plunger boss arranged on the plunger, a profiled slot arranged on the housing and adapted to be engaged by the first plunger boss so as to inhibit movement of the plunger in a distal direction, wherein the plunger is rotatable about a longitudinal axis to release the first plunger boss from the profiled slot so as to allow movement of the plunger in the distal direction, a sleeve coupled to the housing to permit movement of the sleeve relative to the housing, wherein a sleeve ramp is arranged on the sleeve, the sleeve ramp adapted to engage a projection such as a rib or boss on the plunger to rotate the plunger to release the first plunger boss from the profiled slot when the sleeve is moved in a proximal direction. In an exemplary embodiment, the profiled slot is adapted to induce a torque to the plunger when an axial force is applied to the plunger, wherein the profiled slot comprises at least one angled surface adapted to engage the first plunger boss to induce a torque in a first rotational direction to the plunger to release the first plunger boss from the profiled slot. In an exemplary embodiment, the profiled slot further comprises a wall for limiting movement of the first plunger boss in the first rotational direction when engaged to the first angled surface and a second angled surface adjacent the wall and adapted to induce a torque in the first rotational direction to the plunger to release the first plunger boss from the profiled slot. This allows for preventing the plunger from being released while the first plunger boss is engaged to the first angled surface and the wall. This state is particularly useful for storing and transporting a drug delivery device or a part thereof comprising the plunger and optionally a drive spring so that the drive spring cannot inadvertently advance the plunger, e.g. if the drug delivery device or the part thereof comprising the plunger is dropped. In order to transition the plunger into a state in which it may be released, the plunger may be moved away from the first angled surface along the wall and rotated so that the first plunger boss engages the second angled surface. The transition into this state may be performed during final assembly of a drug delivery device. If the plunger is not otherwise pre