# US 2025/0144307 A1 · Auto-Injector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0144307 A1 - Document ID: US20250144307A1 - Status: Published application - Kind: A1 - Application number: 19/017,947 - Filed: 2025-01-13 - Published: 2025-05-08 - Earliest claimed: 2011-02-18 - Assignees: Sanofi-Aventis Deutschland GmbH - Applicants: Sanofi-Aventis Deutschland GMBH - Inventors: Simon Francis Brereton; Thomas Kemp; Rosie Burnell; Matthew Ekman - Web page: https://patentgrep.com/patent/US20250144307A1 ## CPC - A61M 5/31501: {Means for blocking or restricting the movement of the rod or piston (A61M5/5013 takes precedence)} - A61M 5/20: Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically (A61M5/142 takes precedence) - A61M 5/2033: {Spring-loaded one-shot injectors with or without automatic needle insertion (multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287)} - A61M 5/3157: {Means providing feedback signals when administration is completed (A61M5/20 takes precedence)} - A61M 5/3158: {the component being manually operated or triggered by an axially moving actuator operated by user, e.g. an axially movable injection button} - A61M 5/322: {Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston (devices for protecting guide needles in combination with catheters A61M25/0612)} - A61M 5/326: {Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user} - A61M 5/46: having means for controlling depth of insertion - A61M 5/206: {with automatic needle insertion} - A61M 2005/208: {Release is possible only when device is pushed against the skin, e.g. using a trigger which is blocked or inactive when the device is not pushed against the skin} - A61M 2205/581: by audible feedback - A61M 2205/582: by tactile feedback - A61M 2205/583: by visual feedback - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract An auto-injector for administering a dose of a liquid medicament (M) is present having a tubular chassis telescopable in a tubular case, a carrier subassembly comprising a tubular carrier slidably arranged relative to the chassis inside the case, where the carrier is adapted to contain a syringe with a hollow injection needle. The injector also has a drive spring and a plunger for forwarding load of the drive spring to a stopper of the syringe, wherein the syringe is lockable for joint axial translation with the carrier. A control spring is arranged around the carrier for translating the carrier in a proximal direction (P) for insertion of the needle through the chassis into an injection site. ## Claims ### Claim 1 (canceled) ### Claim 2 A plunger rod for an auto-injector, the plunger rod comprising: an inner proximal portion located symmetrically about a first plane of the plunger rod, a proximal end of the inner proximal portion being configured to contact a stopper of a syringe for dispensing a medicament from the syringe when the plunger rod moves proximally relative to a member of the auto-injector; an outer distal portion located symmetrically about the first plane, the outer distal portion configured to releasably latch to the member to limit proximal movement of the plunger rod relative to the member such that a radial inward deflection of at least two portions release the plunger rod from the member, the at least two portions being spaced apart from one another about the first plane; and a flange located axially between the inner proximal portion and the outer distal portion and being substantially perpendicular to the first plane such that at least a portion of a proximal side of the flange extends along a second plane substantially perpendicular to the first plane and at least a portion of a distal side of the flange extends along a plane parallel to the second plane, an outer portion of the flange extending outward from the outer distal portion and being configured to contact a compression spring for biasing the plunger rod in a proximal direction relative to the member to dispense the medicament from the syringe, and the inner proximal portion of the plunger rod extends from the inner proximal portion of the flange, wherein the inner proximal portion of the flange and the outer distal portion of the plunger rod define a first opening extending from the inner proximal portion of the flange to a distal end of the outer distal portion. ### Claim 3 (depends on 2) The plunger rod of claim 2, wherein an outer dimension of the inner proximal portion of the plunger rod is less than an inner dimension of the outer distal portion of the plunger rod, and an axial length of the inner proximal portion of the plunger rod is greater than an axial length of the outer distal portion of the plunger rod. ### Claim 4 (depends on 3) The plunger rod of claim 3, wherein the inner proximal portion of the plunger rod extends proximally from the proximal side of the flange, and the distal side of the flange directly opposite to the proximal side at least partially defines the first opening. ### Claim 5 (depends on 2) The plunger rod of claim 2, wherein the inner proximal portion comprises a proximal region and a distal region axially connected to one another, the proximal region has a larger outer dimension than the distal region, and the distal region is axially longer than the proximal region. ### Claim 6 (depends on 2) The plunger rod of claim 2, wherein the inner proximal portion of the plunger rod is sized to allow an axial gap between the flange of the plunger rod and a distal flange of the syringe when the plunger rod is fully inserted into the syringe. ### Claim 7 (depends on 6) The plunger rod of claim 6, wherein when the plunger rod is fully inserted into the syringe, all portions of the plunger rod within the syringe are symmetric about the first plane. ### Claim 8 (depends on 7) The plunger rod of claim 7, wherein when the plunger rod is fully inserted into the syringe, all portions of the plunger rod within the syringe are symmetric about a third plane that is perpendicular to the first and second planes. ### Claim 9 (depends on 2) The plunger rod of claim 2, wherein the first opening allows the inner proximal portion of the flange to be viewed from the distal end of the plunger rod along a central axis of the plunger rod, the central axis defined by an intersection of (i) the first plane and (ii) a third plane that is perpendicular to the first and second planes. ### Claim 10 (depends on 2) The plunger rod of claim 2, wherein the plunger rod is symmetric about the first plane. ### Claim 11 A plunger rod for an auto-injector, the plunger rod comprising: an inner proximal portion located symmetrically about a first plane, a proximal end of the inner proximal portion being configured to contact a stopper of a syringe; an outer distal portion located symmetrically about the first plane, the outer distal portion configured to releasably latch to a member of the auto-injector to limit proximal movement of the plunger rod relative to the member of the auto-injector such that a radial inward deflection of at least two portions releases the plunger rod from the member, the at least two portions being located symmetrically about the first plane; and an outer flange located axially between the inner proximal portion and the outer distal portion and substantially perpendicular to the first plane, the outer flange configured to contact a compression spring for biasing the plunger rod in a proximal direction relative to the member, wherein the outer distal portion of the plunger rod defines a first opening (i) extending from an axial location of the outer flange of the plunger rod to a distal end of the outer distal portion. ### Claim 12 (depends on 11) The plunger rod of claim 11, wherein the at least two portions are not located on the plunger rod. ### Claim 13 (depends on 11) The plunger rod of claim 11, wherein the outer distal portion of the plunger rod has a notched distal end. ### Claim 14 (depends on 11) The plunger rod of claim 11, wherein when the plunger rod is fully inserted into the syringe, all portions of the plunger rod within the syringe are symmetric about the first plane. ### Claim 15 A plunger rod for a syringe, the plunger rod comprising: an inner proximal portion centered about at least two planes that are perpendicular to one another, the inner proximal portion being configured slide from (i) a first position relative to the syringe in which a majority of the inner proximal portion is distal to a distal flange of the syringe to (ii) a second position relative to the syringe in which the majority of the inner proximal portion is proximal to the distal flange of the syringe; an outer distal portion centered about the at least two planes, the outer distal portion configured such that a radially inward deflection towards one of the at least two planes releases the plunger rod from being held in the first position relative to the syringe; and a flange located axially between the inner proximal portion and the outer distal portion, the flange being configured to contact a compression spring for biasing the plunger rod relative to the syringe towards the second position relative to the syringe. ### Claim 16 (depends on 15) The plunger rod of claim 15, wherein when the plunger rod is in the second position relative to the syringe, all portions of the plunger rod within the syringe are centered about a first plane of the at least two planes. ### Claim 17 (depends on 16) The plunger rod of claim 16, wherein when the plunger rod is in the second position relative to the syringe, all portions of the plunger rod within the syringe are symmetric about a second plane of the at least two planes. ### Claim 18 (depends on 17) The plunger rod of claim 17, wherein an intersection of the first and second planes of the at least two planes define a longitudinal axis of the syringe. ### Claim 19 (depends on 17) The plunger rod of claim 17, wherein the distal flange of the syringe has (i) a first portion extending radially outward from a barrel of the syringe in a direction perpendicular to the first plane of the at least two planes, and (ii) a second portion extending radially outward from the barrel of the syringe in a direction perpendicular to the second plane of the at least two planes. ### Claim 20 (depends on 15) The plunger rod of claim 15, wherein the flange of the plunger rod is distally spaced from the distal flange of the syringe when the plunger rod is in the first position relative to the syringe. ### Claim 21 (depends on 20) The plunger rod of claim 20, wherein the flange of the plunger rod is distally spaced from the distal flange of the syringe when the plunger rod is in the second position relative to the syringe. ### Claim 22 (depends on 21) The plunger rod of claim 21, wherein an outer-most portion of the flange of the plunger rod is outward of the distal flange of the syringe when the plunger rod is in the first position relative to the flange and the second position relative to the syringe. ### Claim 23 (depends on 15) The plunger rod of claim 15, wherein the inner proximal portion and the outer distal portion are symmetric about the at least two planes. ### Claim 24 A plunger rod comprising: an inner proximal portion centered about a first plane, a proximal end of the inner proximal portion being configured to contact a stopper of a syringe; an outer distal portion centered about the first plane, the outer distal portion configured such that an inward radially deflection towards the first plane releases the plunger rod from a member of an auto-injector; and an outer flange located axially between the inner proximal portion and the outer distal portion and substantially perpendicular to the first plane, the outer flange configured to contact a compression spring for biasing the plunger rod in a proximal direction relative to the member of the auto-injector, wherein the inner proximal portion extends from the outer flange to the proximal end of plunger rod. ### Claim 25 (depends on 24) The plunger rod of claim 24, wherein the outer distal portion of the plunger rod defines a first opening extending from an axial location of the outer flange of the plunger rod to a distal end of the outer distal portion. ### Claim 26 (depends on 25) The plunger rod of claim 25, wherein the first opening is located radially between two members that produce the inward radially deflection towards the first plane. ### Claim 27 (depends on 24) The plunger rod of claim 24, wherein the outer distal portion of the plunger rod defines a second opening extending completely through the plunger rod. ### Claim 28 (depends on 24) The plunger rod of claim 24, wherein a distal flange of the syringe has (i) a first portion extending radially outward from a barrel of the syringe in a direction perpendicular to the first plane, and (ii) a second portion extending radially outward from the barrel of the syringe in a direction perpendicular to a second plane perpendicular to the first plane. ### Claim 29 (depends on 28) The plunger rod of claim 28, wherein the outer flange of the plunger rod is distally spaced from the distal flange of the syringe when the plunger rod is fully inserted into the syringe. ### Claim 30 (depends on 28) The plunger rod of claim 28, wherein an outer-most portion of the outer flange of the plunger rod is outward of the distal flange of the syringe when the plunger rod is fully inserted into the syringe. ### Claim 31 (depends on 24) The plunger rod of claim 24, wherein the plunger rod is symmetric about the first plane.