Drug delivery device with plunger rod having nonuniform stopper interface
Inventors
Bendix, Klaus • True, Daniel Patrick Godskesen • Soerensen, Dan Noertoft
Assignees
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Publication Number
US-12427264-B2
Publication Date
2025-09-30
Expiration Date
Abstract
The present invention provides a drug delivery device (1) comprising: a drug reservoir (20) comprising a reservoir body (21) extending along a reference axis and an elastomeric stopper (30) arranged in the reservoir body (21), the elastomeric stopper (30) comprising a stopper body (31) extending between a front stopper end (32) and a rear stopper end (34) and having a plurality of axially spaced apart circumferential ribs (33) for sealing interaction with an interior wall (22) of the reservoir body (21), and a plunger rod structure (10) for displacing the elastomeric stopper (30) relative to the interior wall (22), the plunger rod structure (10) extending along the reference axis and comprising a distal end face (12, 14) adapted to interface with the rear stopper end (34). The distal end face (12, 14) comprises a first force transferring portion (14) and a second force transferring portion (12), the first force transferring portion (14) axially leading the second force transferring portion (12) and being adapted to interact with a peripheral portion of the rear stopper end (34).
Core Innovation
The invention relates to a drug delivery device comprising a drug reservoir having a reservoir body extending along a reference axis and a first elastomeric stopper arranged in the reservoir body. The first elastomeric stopper includes a stopper body extending between a front stopper end and a rear stopper end and having a plurality of axially spaced apart circumferential ribs for sealing interaction with an interior wall of the reservoir body. A plunger rod structure displaces the first elastomeric stopper relative to the interior wall and extends along the reference axis to include a distal end face adapted to interface with the rear stopper end.
The distal end face includes a first force transferring portion and a second force transferring portion, where the first force transferring portion axially leads the second force transferring portion and is adapted to interact with a peripheral portion of the rear stopper end. The second force transferring portion is orthogonal to the reference axis, and the first force transferring portion forms part of a stud that protrudes distally from the second force transferring portion. The stud is adapted to interact with the peripheral portion of the rear stopper end as part of the force transferring interface.
In further defined embodiments, the stud abuts the rear stopper end at an interface between one of the axially spaced apart circumferential ribs and the interior wall of the reservoir body. The document describes that this leading-edge force transferring interaction can reduce break-loose force and make the expelling force profile more uniform by sequential detachment of circumferential ribs. Additional embodiments include a housing and a spring-loaded plunger rod mechanism where the plunger rod structure has a hollow interior configured to receive a releasable compression spring element for moving the plunger rod structure distally relative to the housing.
Claims Coverage
The provided independent claims are clm-00001, clm-00007, and clm-00013. They define 3 inventive features centered on a drug reservoir with an elastomeric stopper and a plunger rod structure whose distal end face includes orthogonal force transferring portions forming a stud to interface with a rear stopper end.
Stud-based distal force transferring interface for displacing elastomeric stopper ribs
A drug delivery device with a drug reservoir comprising a reservoir body along a reference axis and a first elastomeric stopper having a plurality of axially spaced apart circumferential ribs for sealing interaction with an interior wall, and a plunger rod structure for displacing the first elastomeric stopper relative to the interior wall, wherein the distal end face of the plunger rod structure interfaces with the rear stopper end and comprises a first force transferring portion and a second force transferring portion, the first force transferring portion axially leading and adapted to interact with a peripheral portion of the rear stopper end.
Orthogonal second force transferring portion forming a distally protruding stud
A device where the distal end face includes a second force transferring portion that is orthogonal to the reference axis, and wherein the first force transferring portion forms part of a stud that protrudes distally from the second force transferring portion, the stud configured to interact with the peripheral portion of the rear stopper end as part of the interface.
Stud abutting at a rib-to-interior-wall interface on the rear stopper end
A device where the stud is adapted to abut the rear stopper end at an interface between one of the plurality of axially spaced apart circumferential ribs and the interior wall of the reservoir body.
Across the independent claims, the core inventive coverage lies in a distal end face force transferring arrangement that axially leads and uses an orthogonal second force transferring portion to define a protruding stud engaging the rear stopper end at a peripheral portion and, in further definition, at an interface between a circumferential rib and the interior wall.
Stated Advantages
Reduces break-loose force.
Makes the expelling force profile more uniform.
Sequentially detaches circumferential ribs from the reservoir wall.
Documented Applications
A drug delivery device that interfaces a plunger rod structure with a rear elastomeric stopper end for displacing the stopper during expelling.
A device variant that includes a bypass section enabling fluid flow past a distal elastomeric stopper during displacement.
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