United States Patent 5,435,076: Scope, Claim Construction, and US Landscape
US Drug Patent 5,435,076 covers a dual-chamber injection cartridge system and, separately, a method of preparing that system by freeze-drying a drug in a front chamber while using a sleeve-and-stopper arrangement to ensure the cartridge’s front opening is not sealed during freeze-drying and is sealed after freeze-drying by rearward displacement of the sleeve/stopper.
The claims are tightly structured around a single functional sequence:
1) freeze-dry in the front chamber with the front opening open,
2) retract-displace the sleeve so the stopper becomes inserted and seals the front opening,
3) then use a rear piston system to drive liquid from the rear chamber and mix with the sealed freeze-dried drug.
What is claimed, in plain scope terms?
Claim 1 (Device): What components and functions are required
Claim 1 recites a device for an injection apparatus with these core elements:
| Required element in Claim 1 |
Claim language anchor |
Functional role |
| Dual-chamber injection cartridge |
“front chamber… including a drug freeze-dried in said front chamber” and “rear chamber including a liquid component” |
Stores freeze-dried drug (front) and diluent/liquid (rear) |
| Front opening near front end |
“a front opening in the vicinity of a front end” |
Provides access region for sealing during/after freeze-drying |
| Movable wall separating chambers |
“a movable wall separating said front chamber and said rear chamber” |
Enables fluid separation and later transfer |
| Bypass transferring liquid between chambers |
“a bypass for transferring said liquid component between said front chamber and said rear chamber” |
Allows controlled fluid transfer path |
| Rear piston |
“and a rear piston” |
Applies force to move rear chamber liquid |
| Cylindrical sleeve, same length as cartridge, slidably arranged |
“a cylindrical sleeve substantially the same length… said cartridge being slidably arranged within said sleeve” |
Holds cartridge during freeze-drying; later displacement performs sealing |
| Stopper directed rearwardly coaxially with cartridge |
“a stopper… directed rearwardly coaxially with said cartridge” |
Moves relative to cartridge to seal front opening |
| Sealing event triggered by rearward sleeve displacement after freeze-drying |
“as said sleeve is displaced rearwardly after the freeze-drying… said stopper enters the front opening… to sealingly close” |
Ensures freeze-drying happens with front opening unsealed |
| Attaching/actuating interface for rear piston |
“means… for attaching means for actuating said rear piston” |
Connects to injection mechanism |
Claim 1 is therefore a cartridge-in-sleeve with coordinated stopper insertion after freeze-drying.
Claim 2 (Method): Preparation sequence is the novelty driver
Claim 2 recites a method for preparing the injection apparatus described in Claim 1, with an explicit procedural timing requirement:
| Required method step in Claim 2 |
Claim language anchor |
Timing constraint |
| Provide dual-chamber cartridge with bypass and piston |
“dual-chamber injection cartridge… movable wall… bypass… and a piston” |
Baseline cartridge structure |
| Provide solution/dispersion in front chamber |
“providing a solution or dispersion… in a front chamber” |
Drug loading pre-freeze-drying |
| Arrange cylindrical sleeve around cartridge |
“arranging a cylindrical sleeve around the cartridge” |
Sleeve present during freeze-drying |
| Provide stopper at front end of sleeve pointing rearward/coaxial |
“providing a front end of the sleeve with a stopper… rearwardly toward and coaxially” |
Stopper aligned for later insertion |
| Insert cartridge into freeze-drying apparatus |
“inserting the cartridge into a freeze-drying apparatus” |
Setup |
| Freeze-dry while stopper position leaves front opening not sealed |
“subjecting… to freeze-drying… carried out with the stopper in a position where a front opening of the cartridge is not sealed” |
Critical non-sealing condition during freeze-drying |
| Displace sleeve and stopper rearward to insert stopper into front opening for sealing |
“displacing the sleeve and the stopper rearwardly such that the stopper is inserted… to sealingly close” |
Seal after freeze-drying |
| Remove sealed cartridge from freeze-drying apparatus |
“removing… from the freeze-drying apparatus” |
Transition to injection use |
| Provide liquid component in rear chamber |
“providing a liquid component in the rear chamber” |
Dosing assembly |
| Provide attachment for actuating rear piston |
“providing the rear end… with means for actuating the rear piston” |
Final assembly |
The claim ties together structure and a sequence: the stopper must not seal during freeze-drying, then seals via rearward displacement.
Claims 3-7: Closure integrity refinements and sleeve/environment access
Claims 3, 4, 5, 6, and 7 add narrower structural constraints.
| Dependent claim |
Added limitation |
What it changes in scope |
| Claim 3 |
“spacing… between exterior wall of the cartridge and interior wall of the sleeve” providing connection to exterior environment |
Creates an environmental communication gap at the sleeve-cartridge interface |
| Claim 4 |
“openings… in the sleeve near its front end” providing connection between cartridge interior and exterior |
Enables front-end environmental access via sleeve ports |
| Claim 5 |
Stopper has “sealing ridges” cooperating with an interior wall area such that it “does not seal completely… until… fully inserted” |
Introduces a controlled/gradual sealing profile tied to insertion depth |
| Claim 6 |
Stopper has “thinned central part… as a septum for affording fluid contact” |
Adds a septum function for puncture/access while front chamber remains sealed |
| Claim 7 |
Bypass area is defined so movable wall “does not seal completely” against interior wall |
Ensures bypass behavior by requiring incomplete sealing at bypass region |
Claims 11 and 12 mirror the environmental communication features of Claims 3 and 4.
Claims 13-17 restate Claim 5-7’s structure around sealing ridges and septum/thinned central part, with some claim redundancy across device variants.
Claim 8: Protective gas during freeze-drying
Claim 8 adds an operational condition:
- “a protective gas is introduced into the freeze-drying apparatus before the cartridge is sealingly closed.”
This increases process coverage around inerting/atmosphere control until after the stopper seals the cartridge.
Claims 9-10: Injection apparatus prepared in accordance with the method
Claims 9 and 10 cover an injection apparatus comprising the same device structure as Claim 1 and is “prepared in accordance with claim 2” for the method-dependent version.
Claim 10 therefore extends process-defined preparation into an apparatus product-by-process style formulation.
How should the claims be construed for scope boundaries?
1) The “not sealed during freeze-drying” limitation is central
Claim 2 explicitly requires:
- freeze-drying “with the stopper in a position where a front opening of the cartridge is not sealed.”
That means any accused process must maintain the stopper such that it does not seal the front opening until after freeze-drying is complete. The scope is procedural but anchored to the relative positional state of the stopper.
2) The sealing is caused by rearward sleeve displacement after freeze-drying
Claim 1 requires:
- “as said sleeve is displaced rearwardly after the freeze-drying… said stopper enters the front opening… to sealingly close.”
Thus, the mechanism is not simply a manually placed stopper. It is the rearward displacement of the sleeve (and attached stopper) after freeze-drying.
3) Dual-chamber cartridge with bypass and movable wall are mandatory
Claim 1 is not satisfied by a standard two-chamber cartridge without the bypass / movable wall arrangement as recited. The bypass is a required “area” and transfer route.
Dependent Claim 7 further narrows bypass function:
- movable wall does not seal completely against interior wall in the bypass region.
4) Dependent claims define sealing mechanics and fluid access
- Sealing ridges: controlled sealing that is incomplete until full insertion (Claims 5/13/14).
- Thinned central part/septum: provides fluid contact with sealed front chamber (Claims 6/15/16/17).
5) Environmental communication via sleeve spacing/openings is optional unless taken by a dependent claim
The independent Claim 1 does not require sleeve spacing/openings. Claims 3/11 and 4/12 add them.
This matters for design-around: if a system avoids environmental communication features while still meeting the independent structure (dual-chamber + sleeve + stopper rearward sealing after freeze-drying), it may fall outside dependent claim limitations while still implicating Claim 1.
US patent landscape: where 5,435,076 sits and what it blocks
Core “technology cluster” implied by the claims
The patent occupies a niche at the intersection of:
- freeze-dried drug reconstitution packaging,
- dual-chamber cartridge systems (drug + liquid separated),
- in-process sealing strategy during freeze-drying, and
- actuation-driven piston-based injection from the rear chamber.
Within this cluster, the likely competitive design patterns are:
1) “traditional stopper sealed during freeze-drying” systems (which risk failing the “not sealed during freeze-drying” limitation),
2) “pre-sealed lyophilization vials” that do not use a sleeve/stopper displacement after freeze-drying, and
3) reconstitution devices that mix without a movable wall + bypass transfer architecture.
Claim scope and enforceability pressure points
For infringement and validity, the high-probability pressure points are:
- Functional timing: “stopper not sealing during freeze-drying” (Claim 2).
- Structural actuation of sealing: rearward sleeve displacement after freeze-drying (Claim 1).
- Cartridge architecture: movable wall + bypass + rear piston and the two-chamber arrangement (Claim 1).
As a result, the most direct competitive threat to the patent is any prior art or later development that replicates the same combination of:
- sleeve-mounted coaxial stopper,
- front opening left unsealed during lyophilization,
- sealing triggered by rearward displacement after lyophilization,
- dual-chamber cartridge with bypass and piston actuation.
What the claims likely do not cover (scope non-coverage)
Based on the literal claim structure, the patent does not read broadly on:
- lyophilization systems without a coaxial stopper on a sleeve that inserts into a cartridge front opening post-lyophilization,
- single-chamber lyophilized containers with reconstitution through a different mechanical pathway,
- devices lacking a bypass defined between chambers,
- injection assemblies that omit the rear piston / attachment structure recited.
Landscape mapping by claim theme
A. Device architecture (independent Claim 1 and product Claim 9)
Coverage is for devices that include the sleeve/stopper sealing scheme and dual-chamber bypass/piston architecture.
Design-compatibility signals in the claims:
- Cartridge is “slidably arranged within” a sleeve.
- Stopper is coaxial and directed rearwardly.
- Sealing happens only when sleeve is displaced rearward after freeze-drying.
B. Process architecture (independent Claim 2 and process-derived Claim 10)
Coverage is for a preparation method with the freeze-drying timing constraint.
Key process checkpoints:
- Sleeve and stopper present during freeze-drying,
- Front opening explicitly “not sealed” during freeze-drying,
- Post-freeze-drying rearward displacement seals the cartridge,
- Rear chamber liquid introduced after sealing.
C. Sealing mechanics and access (dependent Claims 3-7, 11-17)
These narrow the patent’s reach to specific engineering choices:
- environmental access via sleeve spacing/openings,
- controlled sealing ridges and insertion-depth-dependent sealing,
- septum-like thinned central stopper for later fluid contact,
- bypass region’s incomplete wall sealing.
Key Takeaways
- Claim 1 is a structural system: a dual-chamber cartridge with movable wall, bypass, and rear piston, housed in a slidable cylindrical sleeve with a coaxial stopper that seals the cartridge front opening only after rearward displacement post-freeze-drying.
- Claim 2 is a process definition: freeze-drying occurs while the stopper is positioned so the front opening is not sealed, then the sleeve/stopper are displaced rearward to sealingly close the front opening after freeze-drying.
- Dependent claims add narrower design features: sleeve-to-cartridge environmental communication, sealing ridges with incomplete-to-complete sealing progression, septum thinned central part for fluid access, and bypass region incomplete sealing.
- The practical landscape impact is concentrated around competitors using post-lyophilization sealing via sleeve/stopper displacement in a two-chamber bypass + piston injection platform.
FAQs
1) Does claim coverage depend on the identity of the drug?
No. The claims require “a drug freeze-dried” in the front chamber but do not limit the drug type.
2) Is sealing during freeze-drying allowed in the method claim?
No. Claim 2 requires freeze-drying “with the stopper… where a front opening… is not sealed.”
3) Is the sleeve required to move rearward after freeze-drying?
Yes. Claim 1 requires the sealing event to occur “as said sleeve is displaced rearwardly after the freeze-drying.”
4) Do all claims require sleeve environmental access openings or spacing?
No. Sleeve spacing (Claims 3/11) and sleeve openings (Claims 4/12) are in dependent claims; Claim 1 does not require them.
5) Do dependent claims cover both sealing ridges and a septum feature?
Yes across the set: sealing ridges appear in Claims 5/13/14 and septum thinned central part appears in Claims 6/15/16/17.
References
[1] United States Patent No. 5,435,076, “Device and method for preparing an injection apparatus with dual-chamber cartridge and freeze-drying sealing,” claims 1-17 (as provided).
