Convertible plungers and methods for assembling the same in a medical barrel
Inventors
Lilly, Brian Russell • Kelly, Kenneth Wade • Rogers, Joseph W. • Giraud, Jean-Pierre • Rabinne, Bruce • Pichot, Herve • Hunt, Benjamin • Freeman, Zachary Dean • Roe, Dalton • Abrams, Robert S.
Assignees
Sio2 Material Products Inc • Bama Sas • SiO2 Medical Products LLC
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Publication Number
US-10918800-B2
Publication Date
2021-02-16
Expiration Date
Abstract
Disclosed are plunger assemblies including various convertible plungers and methods of making the same. Each plunger assembly is configured for disposition within a barrel of a medical container, e.g., a syringe, and displaced within the barrel from an engagement position to a release position. The engagement position is configured to provide a compression seal between a storage sealing section of the plunger and an inner wall of the syringe barrel. In the release position, the compression seal is reduced or eliminated. Also disclosed are methods for making convertible plungers and assembling them into syringes, e.g., pre-filled syringes.
Core Innovation
The invention relates to a convertible plunger for disposition within a barrel of a medical container, including a pre-filled syringe, where the plunger is moved along a central axis from a storage mode to a dispensing mode. The convertible plunger includes a ring carrier having a compressible and resilient storage ring disposed thereon, with the storage ring configured for axial displacement along the ring carrier between load, engagement, and release positions.
The ring carrier comprises an annular storage platform that is comparatively more rigid than the storage ring, an annular dispensing platform having a narrower cross-sectional width or diameter than the storage platform, and an annular insertion platform having a smaller maximum diameter or cross-sectional width than the storage platform. In an engagement position, the storage ring is in an expanded state and a storage sealing section applies outward radial pressure on the interior wall of the barrel to provide gas-tight sealing and container closure integrity, while in a release position the storage ring is in a constricted state and provides less radial pressure or no outward radial pressure on the interior wall.
The convertible plunger further includes a plunger head at a distal end, where the plunger head has a liquid sealing section configured to contact and provide a seal against the interior wall and is a separate component assembled with the ring carrier. The disclosure also includes oil-free operation without flowable silicone lubricant, including use of a fluoropolymer film/cap or lubricious materials for low-friction liquid sealing performance, and assemblies and materials for setting the storage ring and converting between modes.
The document further addresses geometry of the storage sealing section, including annular ribs and annular valleys and transition region geometry to retain the storage ring about the dispensing platform in the release position. Supporting experimental results are described using very low and consistent breakout and glide forces without flowable lubricant, vacuum-decay container closure integrity testing across shaft-diameter variants, and high-altitude vacuum simulation showing no storage ring/plunger movement.
Claims Coverage
The provided portion includes three independent claims covering a convertible plunger, a pre-filled syringe incorporating the convertible plunger, and a method for assembling the convertible plunger into a pre-filled syringe. Across the independent claims, three main inventive features are emphasized: a storage-ring/ring-carrier mechanism that changes outward radial pressure between engagement and release, a separate distal plunger head with a liquid sealing section, and a load-to-engagement assembly sequence using cooperating platforms and articles.
Convertible plunger with storage-ring pressure conversion between engagement and release
A ring carrier having a compressible and resilient storage ring disposed thereon, the storage ring configured for axial displacement along the ring carrier, wherein an annular storage platform supports an expanded state corresponding to an engagement position applying outward radial pressure on the interior wall of the barrel, and an annular dispensing platform with narrower cross-sectional width or diameter supports a constricted state corresponding to a release position with less radial pressure or no outward radial pressure on the interior wall.
Load-position insertion platform to enable insertion while reducing radial pressure
An annular insertion platform having a smaller maximum diameter or cross-sectional width than the storage platform, where the storage ring is in a load position when disposed about the insertion platform to facilitate insertion of the ring carrier and storage ring into the barrel, and wherein the storage sealing section provides less radial pressure than in the engagement position or provides no outward radial pressure on the interior wall, with the storage ring movable between load position, engagement position and release position.
Separate distal plunger head with a liquid sealing section
A plunger head mounted at a distal end of the plunger, the plunger head having a liquid sealing section configured to contact and provide a seal against the interior wall, where the plunger head is a separate component assembled with the ring carrier to form the convertible plunger.
Pre-filled syringe using the convertible plunger with storage-to-dispensing movement
A pre-filled syringe comprising a medical barrel having an inner wall and an injectable product disposed in a product containing area, and a convertible plunger disposed within the medical barrel movable along the axis from a storage mode to a dispensing mode, the plunger comprising a ring carrier with a compressible and resilient storage ring disposed thereon with an expanded engagement position applying outward radial pressure and a constricted release position providing less radial pressure or no outward radial pressure.
Assembling the convertible plunger by loading articles into the open top and moving the storage ring to engagement
A method for assembling a convertible plunger into a pre-filled syringe by providing a syringe barrel pre-filled with an injectable product, providing first and second articles where the first article comprises at least a plunger head and the second article comprises a ring carrier with a compressible and resilient storage ring, loading the first article into the syringe barrel through the open top, positioning the storage ring about an insertion platform and axially aligning the second article with the first article, disposing the second article into the open end to a depth where the storage ring is disposed within the syringe barrel, assembling the first and second articles to form the convertible plunger and moving the storage ring from load position to engagement position.
Across the independent claims, the document claims a convertible plunger in which a compressible and resilient storage ring changes between expanded engagement and constricted release states to vary outward radial pressure on the barrel interior wall, while a separate distal plunger head provides a liquid sealing section. A pre-filled syringe and an assembly method are claimed that use this convertible plunger and its load-to-engagement convertible ring-carrier arrangement.
Stated Advantages
Maintains container closure integrity and gas-tight sealing in a storage mode.
Transitions to a dispensing mode to reduce plunger force.
Enables oil-free operation without flowable silicone lubricant.
Enables very low and consistent breakout and glide forces.
Improved liquid sealing via a film configuration for the liquid sealing section.
Reduced wetted area variation and steeper relief angle without molding parting line.
Simplified manufacture.
Reduced leaching risk via a film barrier.
Breakout and maintenance forces are described as 2–5 N and below 5 N without flowable lubricant.
Vacuum-decay container closure integrity testing is described across shaft-diameter variants.
High-altitude vacuum simulation is described showing no storage ring/plunger movement.
Documented Applications
A convertible plunger disposed within a barrel of a medical container, including a pre-filled syringe, with storage-mode to dispensing-mode operation.
A method for assembling the convertible plunger into a pre-filled syringe.
Use in a pre-filled syringe having a medical barrel with an injectable product, a distal dispensing end, an open proximal end, and a convertible plunger movable from a storage mode to a dispensing mode.
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