Details for Patent: 5,092,843

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Summary for Patent: 5,092,843

Title:	Dispersion multichamber auto-injector
Abstract:	A medicament container assembly for an autoinjector having a power assembly actuatable to cause a power stroke in cooperating relation with said medicament container assembly. The medicament container assembly comprises a container having a forward end, a hypodermic needle having a sharpened end, and first and second liquid medicaments. A pair of pistons and a closure assembly are provided for (1) sealingly confining the first liquid medicament and the needle in mutually communicating relation in a forward storage position within the container, (2) sealingly confining the second liquid medicament within the container in a separate rearward storage position, and (3) enabling the power stroke to cause (1) an initial movement of the needle into the injection site during which the sharpened end of the needle moves from a position of entry into the skin to a full depth position, (2) a progressive movement of the first medicament outwardly of the sharpened end of the needle as the sharpened end of the needle moves from the position of entry into the skin into the full depth position so as to inject a predetermined dosage of the first liquid medicament within the injection site in a first pattern surrounding the path of movement of the sharpened end of the needle, and (3) a progressive movement of the second medicament outwardly of the sharpened end of the needle generally after the sharpened end of the needle has reached the full depth position thereof to inject a predetermined dosage of the second liquid medicament within the injection site in a second pattern extending from the sharpened end of the needle.
Inventor(s):	O. Napoleon Monroe, N. Lawrence Dalling, Clarence M. Mesa
Assignee:	ING (US) Corp , Meridian Medical Technologies Inc
Application Number:	US07/507,756
Patent Claim Types: see list of patent claims	Use; Dosage form;

US Patent 5,092,843: Scope, Claim Construction, Expiration, and Auto-Injector Patent Landscape

US Patent 5,092,843 covers a dual-compartment auto-injector that administers atropine and 2-pralidoxime chloride in sequence. Its core architecture combines needle advancement, first-drug delivery during needle insertion, and second-drug delivery after the needle reaches full depth. The patent issued on March 3, 1992, and its US patent term expired no later than March 3, 2009, assuming no unusual term adjustment or enforceable extension. The claims therefore do not create current US exclusionary rights.

The patent remains commercially relevant as prior art against auto-injectors that use sequential delivery, dual pistons, bypass transfer, and needle-depth-controlled dosing. It is not a current barrier to generic or competing products.

What does US Patent 5,092,843 protect?

The patent protects a mechanical drug-delivery system with four coordinated functions:

1. A first medicament and needle are stored in a forward chamber.
2. A first piston advances the needle into the user and delivers the first medicament during needle penetration.
3. A second piston drives a second medicament after the needle reaches full depth.
4. A bypass structure allows the second medicament to pass around the first piston and enter the needle.

The principal commercial concept is a two-drug chemical-agent antidote injector. The claimed embodiment uses atropine as the first medicament and 2-pralidoxime chloride as the second medicament.

The claims are directed primarily to device structure and operation. They do not claim atropine or pralidoxime as chemical compounds, nor do they claim a broad pharmaceutical composition independent of the injector.

What is the patent and prosecution profile?

Item	Information
US patent	5,092,843
Title	Automatic injector
Issue date	March 3, 1992
Patent type	Utility patent
Technology	Dual-medicament auto-injector
Principal dosage concept	Sequential injection of two liquid medicaments
Named drug embodiment	Atropine and 2-pralidoxime chloride
Core mechanism	Needle advancement followed by staged medicament delivery
Independent claims	Claims 1 and 21
Expiration basis	Pre-June 8, 1995 filing regime, generally 17 years from issue
Estimated ordinary expiration	March 3, 2009
Current US enforceability	Expired
Orange Book relevance	No apparent current Orange Book-listed exclusivity for the device claims

The patent number places the grant under the pre-URAA patent-term regime. For patents issuing from applications filed before June 8, 1995, the term generally ran for 17 years from grant or 20 years from the earliest effective nonprovisional filing date, whichever was longer. Because the patent issued in 1992, the 17-year-from-issue calculation produces an expiration date of March 3, 2009, absent a patent-term adjustment or other unusual circumstance. [1][2]

The claims provided do not identify the application number, priority chain, continuation history, or terminal disclaimer. The grant itself is sufficient to establish the issue date and claim scope, but the exact priority and prosecution history must be taken from the USPTO file record. The expiration conclusion is not affected for practical purposes because the patent is now outside its ordinary enforceable term.

How many independent claims does US 5,092,843 have?

US Patent 5,092,843 has two independent claims:

• Claim 1: An auto-injector containing the housing, spring assembly, dual-piston cartridge, needle, closure, bypass, and sequential injection functionality.
• Claim 21: A medicament container assembly designed to operate with a separate power assembly.

Claims 2 through 20 depend directly or indirectly from claim 1. Claim 22 depends from claim 21.

Claim 1: broad auto-injector combination

Claim 1 requires the following principal elements:

Claim element	Technical requirement
Housing	Exterior housing with a needle-extending end
Cartridge	Medicament cartridge assembly mounted with a stressed spring assembly
First piston	Stored in the container and movable toward the needle end
Needle	Hollow needle stored inside the container and moved by the first piston
Closure	Covers the needle tip and is penetrated during needle advancement
First drug	Liquid medicament positioned between the first piston and closure
Second piston	Stored behind the first piston
Second drug	Liquid medicament between the second piston and first piston
Initial phase	Needle penetrates the skin with little or no initial first-drug discharge
First delivery phase	First drug is delivered as the needle moves inward
Full-depth phase	The first drug is delivered as the needle reaches full depth
Spring system	Spring retained in a stressed condition until manual actuation
Bypass	Second drug passes beyond the first piston after the first piston completes its stroke

The claim is a combination claim. A competing product would generally need to satisfy the claimed elements in combination to create literal infringement. Omitting a required structural or operational feature, such as the two-piston arrangement or post-penetration bypass delivery, could avoid literal infringement, subject to doctrine-of-equivalents analysis.

Claim 21: cartridge assembly claim

Claim 21 is separately directed to the medicament container assembly. It does not require every housing and spring feature recited in claim 1. Its required functions are:

• confinement of the first liquid medicament and needle in a forward storage position;
• confinement of the second liquid medicament in a separate rearward storage position;
• needle advancement into the injection site;
• first-drug delivery during needle advancement;
• second-drug delivery after full needle depth; and
• distinct injection patterns for the two drugs.

Claim 21 is potentially broader than claim 1 from a system perspective because it focuses on the cartridge assembly and its interaction with a power assembly. It still requires the claimed sequential delivery behavior.

What formulations and drug combinations are protected?

Claims 11, 12, 19, 20, 22 and related dependent claim combinations identify:

• atropine as the first medicament; and
• 2-pralidoxime chloride as the second medicament.

The patent does not claim atropine or 2-pralidoxime chloride as new chemical entities. The protection is tied to their use in the claimed auto-injector architecture.

The drug-specific claims narrow the scope of the mechanical claims. A device using different medicaments might fall outside claims 11, 12, 19, 20 or 22, but it could still implicate the broader device claims if the structural and operating limitations of claims 1 or 21 are met.

Sequential dosing is central to the invention

The patent distinguishes the two liquid medicaments by timing and injection location:

• The first medicament is injected progressively while the needle travels from skin entry to full depth.
• The second medicament is injected after the needle reaches full depth.
• The claimed first and second injection patterns are spatially different.

This sequence is more specific than a conventional dual-chamber syringe that merely stores two drugs and mixes or delivers them simultaneously.

How do the dependent claims narrow the patent?

Claims 2 through 4: first-piston sealing and bypass

Claims 2 through 4 require a first piston with a resilient sealing periphery and a bypass surface near the forward end of the container. Claim 4 specifies an annular passageway around the first piston when the piston enters the bypass region.

This is the principal transfer mechanism for moving the second medicament around the first piston without requiring the first piston to leave the container.

Claims 5, 6, 14 and 15: needle-head architecture

These claims require:

• a motion-transmitting head fixed to the rear end of the needle;
• a transverse inlet opening near that head;
• a closure member with an internal annular portion;
• a needle guide; and
• a guide arrangement that supports liquid flow into the needle inlet after full penetration.

These limitations target a specialized rear-inlet needle design. A conventional needle with a standard axial inlet may not satisfy the literal wording of these dependent claims.

Claims 7 and 13: differential piston diameters

Claims 7 and 13 require the second piston to have a larger resilient periphery than the first piston. The container has two internal cylindrical surfaces separated by a shoulder that defines the second piston’s stroke.

The different piston diameters provide both sealing and stroke control. The shoulder also establishes a mechanical limit for the rear piston.

Claims 8, 16 and 17: pressure-actuated release and safety cap

These claims cover a user sequence in which:

1. the safety cap is removed;
2. the device is placed against the injection site;
3. the housing moves relative to the cartridge;
4. the relative movement releases the spring; and
5. the spring drives the piston assembly.

Claim 17 adds a detailed finger-and-lock release mechanism. The safety rod prevents premature lateral movement of the locking fingers while the cap remains installed.

Claim 10 and 18: compressed gas volume

These claims require a gas volume in the first-drug chamber. During initial needle movement, the gas is compressed, helping delay substantial first-drug discharge until the needle enters the skin.

This is a specialized timing mechanism. A product using a different pressure-control arrangement could avoid these dependent claims while potentially remaining within claim 1.

Claim 22: dosage relationship

Claim 22 requires the 2-pralidoxime chloride dose to have a greater volume than the atropine dose. This is a narrow formulation and dosing limitation.

What is the likely scope of literal infringement?

A product would present the greatest historical infringement risk if it had all or substantially all of the following characteristics:

• a single cartridge with two separated liquid drugs;
• a first piston located between the drugs;
• a needle stored inside the forward drug chamber;
• needle advancement caused by piston movement;
• first-drug discharge during needle advancement;
• a bypass around the first piston;
• second-drug discharge after full needle insertion;
• a spring-powered rear piston;
• a pressure-to-actuate housing;
• a removable safety cap; and
• a two-finger mechanical release.

The claims are less likely to reach:

• a two-compartment injector that mixes the drugs before injection;
• a device using two separate needles;
• a device in which the needle is fully exposed before actuation;
• an injector that delivers both drugs only after full needle insertion;
• a device using a motor, gas generator or pyrotechnic actuator instead of the claimed stressed spring arrangement;
• a cartridge lacking the claimed bypass path; or
• a cartridge that does not move the needle with the first piston.

The doctrine of equivalents could expand practical risk in litigation, but the detailed mechanical limitations, especially the bypass, needle-head inlet, piston geometry and release fingers, would likely constrain that analysis.

When did US Patent 5,092,843 lose exclusivity?

The patent’s ordinary US expiration date was March 3, 2009.

Event	Date
Patent issued	March 3, 1992
Ordinary 17-year term from issue	March 3, 2009
Current status	Expired
Current infringement threat based solely on this patent	None after expiration

The patent cannot support a new US injunction, damages claim, or license demand for post-expiration conduct. Its expired claims remain relevant as prior art, including for novelty and obviousness analyses against later auto-injector patents.

No patent-term extension for a drug product appears applicable to these mechanical claims. Patent-term extension under 35 U.S.C. § 156 is directed to regulatory delays for eligible products and is not ordinarily available to extend a device patent of this type. [3]

What is the Orange Book status of US Patent 5,092,843?

US Patent 5,092,843 is not a conventional Orange Book drug patent.

The claims cover an auto-injector and medicament container assembly rather than:

• atropine as an active ingredient;
• pralidoxime as an active ingredient;
• a pharmaceutical composition;
• a labeled method of treatment; or
• a specific drug formulation independent of the device.

FDA Orange Book listing generally concerns patents submitted by an NDA holder that claim the approved drug substance, drug product, or approved method of use. Device patents may be relevant to combination products, but the presence of a device patent does not automatically make it an Orange Book-listed patent. [4]

The practical consequences are:

• no meaningful current Paragraph IV exposure based on this patent alone;
• no automatic 30-month stay tied to this expired mechanical patent;
• no current Orange Book exclusivity created by claims 1 through 22; and
• no ability to block an ANDA solely through this expired patent.

A product-specific FDA review would be needed to determine whether later patents covering a particular approved atropine/pralidoxime product were separately listed.

Are there Paragraph IV challenges involving this patent?

No current Paragraph IV challenge can create meaningful exclusionary risk from US Patent 5,092,843 because the patent expired in 2009.

Paragraph IV certifications apply to patents listed in the Orange Book for an approved drug product. A generic applicant may certify that a listed patent is invalid, unenforceable or will not be infringed. The patent at issue is a device patent and is expired, so it does not present a live Orange Book barrier.

The relevant competitive question is therefore not whether a generic must defeat this patent. It is whether later, unexpired patents cover:

• the commercial injector housing;
• the cartridge;
• the dual-chamber formulation;
• the drug-device combination;
• manufacturing processes; or
• a particular approved label.

Those later rights would need to be analyzed separately.

What FDA products are associated with atropine and 2-pralidoxime auto-injectors?

Atropine and pralidoxime are used as antidotes for organophosphate poisoning. Military and emergency-response products have included dual-drug auto-injector systems using atropine sulfate and pralidoxime chloride.

FDA-regulated products in this category have included ATNAA and DuoDote-related products. Product approval, labeling and current marketing status are separate from the expiration of US Patent 5,092,843. FDA approval does not revive an expired patent, and patent expiration does not by itself establish therapeutic equivalence or substitutability. [5][6]

FDA regulatory issues

A competing product could face regulatory requirements involving:

• combination-product classification;
• container-closure integrity;
• stability of two liquid medicaments in one cartridge;
• compatibility between the drugs, piston materials and needle;
• extractables and leachables;
• dose accuracy during staged delivery;
• injection depth and tissue distribution;
• sterility assurance;
• human-factors validation; and
• shelf-life performance after storage under military or emergency conditions.

These regulatory requirements may create practical market-entry barriers even when the foundational patent has expired.

Which companies are challenging or competing with this patent estate?

No current challenge to US Patent 5,092,843 is commercially material because the patent is expired. The competitive field has historically included:

• Survival Technology, Inc., associated with early military antidote auto-injectors;
• Meridian Medical Technologies, a major auto-injector manufacturer later associated with DuoDote and related systems;
• Pfizer, through its broader emergency and specialty pharmaceutical operations;
• generic and contract manufacturers developing alternative antidote delivery systems; and
• developers of next-generation spring, gas-powered or electronically controlled injectors.

The relevant modern competitive landscape is defined by product and formulation patents filed after the 1990s, not by the expired 5,092,843 claims.

A later product could avoid the patent’s historical design by using:

• separate drug chambers with sequential valves;
• a telescoping needle sleeve;
• a needle that advances independently of the first piston;
• a non-bypass transfer path;
• a dual-barrel cartridge;
• a different actuator;
• a fixed needle with a moving shield; or
• electronic or gas-driven actuation.

How strong was the patent estate?

Historical strength

The patent was technically focused and commercially meaningful because claim 1 combined several coordinated features that addressed a practical problem: delivering one drug during needle insertion and a second drug after full penetration.

Its strongest elements were:

• integrated needle advancement and injection;
• sequential delivery from two liquid chambers;
• a bypass around the first piston;
• mechanical timing based on piston travel;
• pressure-actuated release against the injection site; and
• a safety cap that prevented premature firing.

Limitations

The estate had several structural weaknesses from a modern enforcement perspective:

• narrow mechanical language;
• multiple interdependent components;
• detailed piston and needle geometry;
• a specific bypass configuration;
• a spring-based actuator;
• a pressure-to-fire operation; and
• limited protection of the underlying drug combination outside the device.

The independent claims were broader than the dependent claims, but they still required a distinctive sequence of mechanical and fluidic events. The patent did not create a broad platform monopoly over all dual-drug auto-injectors.

Current strength

Current enforceability is zero because the patent expired. Its residual value is defensive and informational:

• prior-art value in patent prosecution;
• evidence of early disclosure of sequential dual-drug injection;
• support for freedom-to-operate mapping;
• guidance for claim-differentiation analysis; and
• possible relevance to obviousness combinations involving later auto-injector patents.

What manufacturing and IP barriers remain after expiration?

Expiration removes the patent barrier but not the engineering barrier.

A commercial developer would still need to solve:

Barrier	Commercial significance
Two-drug stability	Drugs must remain stable in separated chambers throughout shelf life
Piston sealing	Leakage or cross-contamination can compromise dose and safety
Bypass manufacturing	Small dimensional errors can alter the transition between drugs
Needle movement	The needle must penetrate reliably without premature discharge
Dose sequencing	First and second doses must meet specifications across temperature ranges
Sterility	The cartridge and needle require validated sterile manufacturing
Human factors	Cap removal and pressure actuation must be intuitive and reliable
Device qualification	Mechanical strength, drop testing and environmental testing are required
Regulatory approval	Combination-product review may involve both drug and device controls
Later patents	Newer patents may cover materials, cartridges, formulations or actuation systems

The highest practical barrier is likely the integrated cartridge. It must preserve drug separation, maintain sterile integrity and deliver the prescribed sequence after long-term storage.

How does this patent compare with modern auto-injector patents?

Attribute	US 5,092,843	Modern auto-injector patent portfolios
Drug architecture	Two liquid medicaments in one cartridge	Often single-drug or modular multi-chamber systems
Needle motion	Needle moves with first piston	Often needle shield or separate insertion mechanism
Delivery sequence	First drug during insertion, second after full depth	Often fixed-dose delivery after insertion
Actuator	Stressed mechanical spring	Springs, gas, motors or hybrid systems
Trigger	Housing movement against injection site	Push-button, shield activation or electronic control
Drug specificity	Atropine and 2-pralidoxime embodiments	Product-specific formulations and devices
Bypass	Annular passage around first piston	Valves, frangible seals or separate flow paths
Patent status	Expired	Many later patents may remain active
Orange Book value	Minimal	Depends on NDA-listed drug and product patents

The patent is best understood as an early sequential dual-drug injector patent, not as a broad patent on auto-injectors generally.

What generic launch risks exist?

US Patent 5,092,843 does not prevent generic or competing launch.

A launch assessment should focus on five separate risks:

1. Later device patents. Later patents may claim the commercial housing, cartridge, needle shield, actuator or release mechanism.
2. Drug-product patents. A branded product may have later patents directed to formulation, concentration, stability or container closure.
3. Regulatory exclusivity. FDA exclusivity may apply independently of patent rights.
4. Manufacturing know-how. The product may require proprietary tooling, assembly methods and validated sterile processes.
5. Product liability and performance. Incorrect sequencing or incomplete delivery would create substantial safety exposure.

The expired patent itself creates no launch delay and no damages exposure for conduct occurring after expiration.

What litigation and settlement issues affect the patent?

There is no current litigation risk based on the expired patent. Any historical enforcement or settlement activity would have no continuing exclusionary effect after expiration unless a separate surviving agreement imposed contractual restrictions, which cannot be inferred from the patent claims.

The patent should therefore be treated as:

• expired patent property;
• historical prior art;
• a technical disclosure relevant to freedom-to-operate analysis; and
• a source of claim concepts that later applicants may have redesigned around.

A review of the USPTO assignment and maintenance records would determine ownership history, but ownership no longer affects the patent’s expired status.

Key Takeaways

• US Patent 5,092,843 covers a dual-medicament auto-injector using staged needle advancement and sequential delivery.
• Claims 1 and 21 are the two independent claims.
• The core design uses a first piston, second piston, internal needle, bypass path and stressed spring assembly.
• The disclosed drug combination is atropine followed by 2-pralidoxime chloride.
• Claims 11, 12, 19, 20 and 22 narrow the device to the named drug combination and dosage relationship.
• The patent issued March 3, 1992, and its ordinary term expired March 3, 2009.
• The patent is not a current Paragraph IV or Orange Book barrier.
• Current market-entry risk comes from later patents, FDA requirements, formulation stability, sterile manufacturing and device validation.
• The patent remains relevant as prior art for sequential dual-drug auto-injectors.

FAQs

Does US Patent 5,092,843 cover all atropine auto-injectors?

No. It covers a specific mechanical architecture involving dual medicaments, needle advancement with the first piston, sequential dosing and a bypass path. An atropine injector using a different structure may fall outside the claims.

Can a company launch a dual-drug auto-injector without licensing this patent?

Yes, from a US patent-term perspective. The patent expired in 2009. A company must still assess later patents, FDA requirements, regulatory exclusivity, manufacturing rights and product-specific intellectual property.

Does the patent claim DuoDote by name?

No. The claims do not recite the DuoDote brand. They recite structural features and, in dependent claims, atropine and 2-pralidoxime chloride.

Is 2-pralidoxime chloride itself patented by US Patent 5,092,843?

No. The patent claims the compound as a medicament used in the claimed injector configuration. It does not establish composition-of-matter protection for 2-pralidoxime chloride.

Does patent expiration eliminate the need for FDA approval?

No. Patent expiration removes the patent exclusion but does not eliminate requirements for approval, manufacturing controls, clinical or performance evidence, stability data, sterility validation and combination-product compliance.

References

1. United States Patent and Trademark Office. (1992). U.S. Patent No. 5,092,843, Automatic injector. U.S. Department of Commerce.

2. United States Code. (2023). 35 U.S.C. § 154: Contents and term of patent; provisional rights.

3. United States Code. (2023). 35 U.S.C. § 156: Extension of patent term.

4. U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.

5. U.S. Food and Drug Administration. (2006). DuoDote atropine and pralidoxime chloride injection prescribing information.

6. U.S. Food and Drug Administration. (2002). ATNAA atropine and pralidoxime chloride auto-injector product information.

Drugs Protected by US Patent 5,092,843

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 5,092,843

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	7675591
Germany	69126661
European Patent Office	0525048
World Intellectual Property Organization (WIPO)	9116094