Details for Patent: 6,862,473

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Summary for Patent: 6,862,473

Title:	Iontophoretic drug delivery device and reservoir and method of making same
Abstract:	A reservoir electrode assembly of the present invention for an iontophoretic drug delivery device includes an electrode and a hydrophilic reservoir situated in electrically conductive relation to the electrode. The hydrophilic reservoir is formed from a bibulous hydrophilic cross-linked polymeric material having a first surface and a second surface that is adhesively adherent to the electrode. The first surface of the polymeric material is releasably adhesively adherent when applied to an area of a patient's skin. The polymeric material has a cohesive strength forms an adhesive bond with a bond strength between the second surface of the polymeric material to the electrode that is greater than the cohesive strength of the polymeric material. Additionally, an adhesive bond strength of the first surface of the polymeric material to the applied area of the patient is less than the cohesive strength of the polymeric material so that upon removal of the reservoir assembly of the invention from the applied area of the patient, substantially no polymeric material remains on the applied area and the hydrophilic reservoir remains substantially intact and adhesively adherent to the electrode.
Inventor(s):	Preston Keusch, Vilambi Nrk, Bruce Michael Eliash
Assignee:	Vyteris Inc
Application Number:	US10/085,428
Patent Claim Types: see list of patent claims	Compound; Delivery; Device;

United States Patent 6,862,473: Claim Scope, Expiration, FDA Status, and Iontophoretic Patent Landscape

U.S. Patent No. 6,862,473 covers a prepackaged iontophoretic electrode assembly using a working reservoir containing lidocaine and epinephrine and a return reservoir containing an electrolyte. Both reservoirs must independently contain at least one crosslinked water-soluble polymer. The patent also claims specific concentrations, stabilizers, additives, electrode areas, and polymer classes.

The patent’s earliest priority date is May 24, 2000, and its statutory 20-year term therefore expired in 2021, subject to any patent-term adjustment. The patent does not create a current enforceable exclusivity barrier for generic or competing iontophoretic products. Its historical scope was narrow because infringement required the accused product to practice the full combination of drug composition, polymeric reservoirs, electrode configuration, and ready-to-use packaging. [1]

What does U.S. Patent 6,862,473 protect?

The patent protects a device rather than lidocaine, epinephrine, or a method of administering local anesthesia in isolation. The independent claim requires all of the following:

Claim element	Required scope
Delivery technology	Iontophoretic drug delivery device
Electrode structure	A single electrode assembly
Working electrode	Connected to a working reservoir
Working reservoir	Contains lidocaine and epinephrine
Return electrode	Connected to a return reservoir
Return reservoir	Contains an electrolyte
Polymer requirement	Each reservoir independently contains at least one crosslinked water-soluble polymer
Product format	Electrode assembly is prepackaged as a ready-to-use device

The combination is materially narrower than a general claim to an iontophoretic device or a general claim to a lidocaine patch. A competing device that lacks any one required element may avoid literal infringement of claim 1.

What is the core inventive combination?

The core combination is a disposable or preassembled iontophoretic system in which the drug reservoir and return reservoir are polymeric reservoirs, with the active reservoir carrying lidocaine and epinephrine. The patent focuses on formulation stability, adhesion, conductivity, handling, and immediate clinical readiness.

The “prepackaged as a ready to use device” limitation excludes many systems that require a clinician or patient to fill a reservoir, mix ingredients, attach electrodes, or assemble the delivery patch before use.

The claim does not expressly require a particular current, voltage, treatment duration, adhesive layer, backing layer, battery, controller, or skin-contact protocol. Those features may be present in commercial embodiments, but they are not required by claim 1 unless incorporated through another claim or a separate patent.

How do claims 2 through 16 narrow the patent scope?

Claims 2 through 16 create narrower species within claim 1. They do not broaden the independent claim.

Claim	Additional limitation	Commercial or technical significance
2	Same crosslinked water-soluble polymer in both reservoirs	Narrows the device to a matched-polymer construction
3	Epinephrine at about 0.1 wt.%	Targets the commercial formulation range
4	Lidocaine at about 10 wt.%	Adds the principal anesthetic concentration
5	Glycerin, sodium metabisulfite, and EDTA	Adds excipients and stabilizers
6	About 10 wt.% glycerin, 0.05 wt.% sodium metabisulfite, and 0.01 wt.% EDTA	Claims a specific formulation
7	About 0.1 wt.% epinephrine and about 10 wt.% lidocaine	Restates the principal active concentrations
8	Specific glycerin, metabisulfite, and EDTA disodium amounts	Further narrows claim 7
9	One to three return electrodes	Covers multi-return-electrode embodiments
10	Return electrode area of 1 to 5 cm² and working electrode area of 2 to 10 cm²	Claims physical electrode geometry
11	At least one stabilizer	Functional formulation limitation
12	Stabilizer is sodium metabisulfite or EDTA	Narrows the stabilizer class
13	At least one additive	Adds formulation components
14	Glycerin, propylene glycol, polyethylene glycol, or conductive salts	Defines additive categories
15	Crosslinked polymer acts as an adhesive	Links reservoir polymer to skin attachment
16	Polymer is polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, or polyacrylamide	Defines a closed polymer group

Claims 3, 4, and 6 use “about,” which creates numerical claim-construction questions. Courts generally interpret “about” in light of the specification, technical measurement practices, prosecution history, and the required precision of the formulation. A product with 9.5% or 10.5% lidocaine cannot automatically be classified as either inside or outside the claim.

The text supplied for claim 6 contains apparent typographical errors, including “05 wt.%” and “01 wt.%,” which are conventionally understood from claim 8 as 0.05 wt.% sodium metabisulfite and 0.01 wt.% EDTA. The issued patent and prosecution history control the legally operative wording.

What formulation is protected by U.S. Patent 6,862,473?

The most commercially specific formulation is represented by claims 7 and 8:

Component	Claimed concentration
Lidocaine	About 10 wt.%
Epinephrine	About 0.1 wt.%
Glycerin	About 10 wt.%
Sodium metabisulfite	About 0.05 wt.%
EDTA disodium	About 0.01 wt.%

The formulation is directed to a lidocaine-epinephrine anesthetic reservoir. Sodium metabisulfite and EDTA function as stabilizing agents, while glycerin can contribute to solvent balance, humectancy, reservoir properties, and skin-contact performance.

Claims 1 and 2 do not require the precise claim 8 formulation. They require lidocaine, epinephrine, electrolyte, and crosslinked water-soluble polymer reservoirs. A product with different stabilizers or additives could still implicate claim 1 if every other limitation is present.

What polymer systems are covered?

Claim 16 identifies four polymer classes:

• Polyethylene oxide
• Polyvinyl pyrrolidone
• Polyvinyl alcohol
• Polyacrylamide

The polymer must be crosslinked and water soluble. The claim therefore does not cover every hydrogel, adhesive, or water-containing polymer system. A non-crosslinked polymer, an insoluble polymer, or a reservoir using a different material may fall outside the literal wording of claim 16, although it could remain within claim 1 if it satisfies the broader “at least one crosslinked water soluble polymer” limitation.

Claim 15 separately requires that the crosslinked polymer act as an adhesive. That limitation is narrower than merely using the polymer as a drug reservoir matrix. A reservoir may contain a crosslinked polymer without the polymer itself providing the principal adhesive function.

How many patents cover the claimed iontophoretic technology?

The relevant patent position is broader than U.S. Patent 6,862,473 because iontophoretic products can be exposed to several patent families covering different technical layers:

Patent layer	Typical subject matter	Relevance to the claimed device
Device architecture	Electrodes, current control, batteries, controllers	Potentially relevant but not required by every claim here
Reservoir chemistry	Hydrogels, polymer matrices, electrolytes, adhesives	Central to claims 1, 2, 15, and 16
Drug formulation	Lidocaine, epinephrine, antioxidants, chelators, humectants	Central to claims 3 through 8 and 11 through 14
Electrode geometry	Working and return electrode size and placement	Central to claims 9 and 10
Packaging	Preassembled and ready-to-use patch systems	Central to claim 1
Manufacturing	Mixing, crosslinking, filling, sealing, sterilization	Not expressly required by the listed claims
Clinical use	Anesthesia, local analgesia, dermatologic procedures	Not claimed as an independent method in the listed claims

A freedom-to-operate review would need to examine the complete family and related patent families held by the original product developer, competitors, and suppliers of iontophoretic patch components. U.S. Patent 6,862,473 alone does not define the entire freedom-to-operate position for an iontophoretic lidocaine product.

When did U.S. Patent 6,862,473 lose exclusivity?

The patent’s 20-year term ran from its earliest nonprovisional priority date, subject to patent-term adjustment under 35 U.S.C. § 154. Based on the May 24, 2000 priority date, the ordinary term ended in 2021. [1][2]

Event	Date or period
Earliest priority date	May 24, 2000
Patent issued	2005
Ordinary 20-year term endpoint	May 24, 2021
Current status	Expired by term, subject to any recorded adjustment

An expiration-based freedom-to-operate conclusion should be checked against the USPTO patent record for any patent-term adjustment, terminal disclaimer, reexamination certificate, or other recorded event. Patent-term extension under 35 U.S.C. § 156 is generally associated with qualifying regulatory review and must be separately established in the official record. [2]

Because the claims are expired, they no longer support an infringement action for post-expiration commercial activity. They remain relevant as prior art, prosecution-history evidence, technical disclosure, and a record of the original commercial formulation.

What is the Orange Book status of U.S. Patent 6,862,473?

U.S. Patent 6,862,473 is not properly characterized as an Orange Book drug patent. The claims are directed to an iontophoretic delivery device and reservoir assembly, not to a new drug substance or a drug product eligible for ordinary Orange Book patent listing.

The FDA Orange Book lists approved drug products and certain patents submitted by new drug application holders. Device patents generally do not provide the basis for a Paragraph IV certification unless they are properly listed in connection with an eligible approved drug application. [3]

For a lidocaine-epinephrine iontophoretic product, regulatory rights may be divided between:

1. The drug formulation and its approved labeling.
2. The iontophoretic device.
3. Combination-product review.
4. Manufacturing and quality-system controls.
5. Any remaining patent or regulatory exclusivity associated with the approved product.

The expiration of this device patent does not eliminate the need for FDA authorization of a competing product.

Are there Paragraph IV challenges or generic entry barriers?

A conventional Paragraph IV challenge is unlikely to be the central pathway for this patent because the patent claims a device rather than a listed drug product patent. A competing product would more likely require an appropriate device or combination-product submission, depending on its formulation, intended use, delivery mechanism, and regulatory classification. [3][4]

The principal entry barriers are therefore regulatory and technical rather than current patent exclusivity:

• Demonstrating equivalent or acceptable delivery performance.
• Establishing dose uniformity and current-control performance.
• Showing formulation stability for epinephrine and lidocaine.
• Validating reservoir adhesion and skin contact.
• Demonstrating biocompatibility and electrical safety.
• Establishing manufacturing controls for crosslinked polymer reservoirs.
• Addressing combination-product responsibilities.

A generic topical lidocaine product is not automatically a substitute for a ready-to-use iontophoretic lidocaine-epinephrine device. The delivery system affects dose, treatment time, application procedure, and clinical performance.

What generic launch scenarios exist?

Scenario 1: Same formulation and same reservoir architecture

A competitor using approximately 10% lidocaine, 0.1% epinephrine, the specified stabilizers, crosslinked water-soluble polymer reservoirs, and ready-to-use packaging would historically have faced a high infringement risk. That risk is no longer based on an enforceable 6,862,473 patent after term expiration.

Scenario 2: Same active ingredients but different reservoir chemistry

A product using lidocaine and epinephrine in a non-crosslinked matrix, an insoluble adhesive, a liquid reservoir, or another delivery architecture would have had stronger historical design-around arguments. Other patents could still have been relevant.

Scenario 3: Different active ingredient or concentration

Removing epinephrine or using a materially different concentration would avoid a literal limitation of claim 1 or the narrower concentration claims. The product would still need to address clinical and regulatory equivalence.

Scenario 4: Reusable electrode with separately supplied drug reservoir

A system that is not prepackaged as a ready-to-use electrode assembly could avoid the packaging limitation of claim 1. The remaining device features would require separate analysis under other patents.

Which companies challenged or licensed this technology?

The patent is associated with the iontophoretic product platform developed by Vyteris, including the LidoSite topical system. Public product information identifies LidoSite as a lidocaine-epinephrine iontophoretic system intended for topical local anesthesia. FDA records treat the product as a device or combination-product technology rather than as an ordinary oral or injectable generic drug. [5]

No current enforceable licensing position can be inferred from the patent alone. Patent ownership, security interests, assignments, bankruptcy-related transfers, and private licenses must be distinguished. A patent assignment does not establish a commercial license, and the absence of a publicly recorded license does not prove that no private agreement existed.

How strong was the patent estate, and how strong is it now?

Historically, the patent had moderate claim specificity and relatively narrow infringement coverage.

Strength factor	Assessment
Technical specificity	High
Breadth of independent claim	Moderate to narrow
Formulation capture	Strong for the claimed lidocaine-epinephrine profile
Design-around flexibility	Significant
Device-architecture coverage	Limited by the listed claims
Current enforceability	None after expiration
Prior-art value	Continuing
Regulatory relevance	Continuing, but separate from patent exclusivity

The strongest historical claims were likely claims 7 and 8 for a commercial-style formulation, provided the accused product also used the required polymer reservoirs and ready-to-use assembly. Claim 1 was broader in formulation detail but still required the full device combination.

What patent litigation affects U.S. Patent 6,862,473?

The patent number alone does not establish a current litigation threat. Any historical infringement dispute would need to be assessed through federal court dockets, USPTO Patent Center records, assignment records, and settlement filings. An expired patent can remain relevant to damages periods before expiration, but it cannot support prospective exclusivity after expiration.

There is no current Paragraph IV litigation pathway that independently preserves exclusivity for the expired device claims. Any settlement involving this patent would need to be interpreted against its expiration date and the scope of any related patents.

Key Takeaways

• U.S. Patent 6,862,473 covers a prepackaged iontophoretic assembly with lidocaine and epinephrine in a working reservoir.
• Both working and return reservoirs must independently contain a crosslinked water-soluble polymer.
• Narrow claims cover approximately 10% lidocaine, 0.1% epinephrine, glycerin, sodium metabisulfite, and EDTA.
• Additional claims cover electrode count, electrode surface area, stabilizers, additives, adhesive function, and specified polymer classes.
• The patent’s ordinary 20-year term expired in 2021, subject to any recorded patent-term adjustment.
• The patent is a device patent, not a conventional Orange Book drug patent.
• Historical infringement risk was highest for a LidoSite-type ready-to-use patch using the claimed formulation and polymeric reservoirs.
• Current market barriers are more likely to involve FDA combination-product requirements, manufacturing controls, clinical performance, and other unexpired patent families.
• No biosimilar pathway applies. A competing product would be evaluated as a device or drug-device combination, not as a biosimilar.
• The patent remains relevant as technical prior art and as evidence of the original product architecture, but it does not provide current patent exclusivity after expiration.

FAQs About U.S. Patent 6,862,473

Does U.S. Patent 6,862,473 cover lidocaine by itself?

No. The claims require an iontophoretic device and additional structural limitations. Lidocaine alone is outside the listed claim scope.

Does the patent cover every lidocaine and epinephrine patch?

No. The claimed device must include the specified electrode assembly, electrolyte return reservoir, crosslinked water-soluble polymer in both reservoirs, and ready-to-use packaging.

Can a competitor use 10% lidocaine and 0.1% epinephrine?

Yes, because the patent term has expired, subject to any separate unexpired patent rights and FDA requirements. During the patent term, the formulation alone would not have determined infringement because the reservoir and device limitations also applied.

Is LidoSite still protected by this patent?

No current exclusivity follows from U.S. Patent 6,862,473 after its expiration. LidoSite or a successor product could still implicate other patents, trademarks, regulatory controls, or proprietary manufacturing information.

Does claim 16 cover all hydrogels?

No. Claim 16 identifies selected crosslinked water-soluble polymers. A hydrogel using a different polymer must be assessed against the broader language of claim 1 and any other relevant patent claims.

References

1. United States Patent and Trademark Office. (2005). U.S. Patent No. 6,862,473, iontophoretic drug delivery device.
2. United States Code. (2023). 35 U.S.C. §§ 154 and 156: Patent term and patent term extension.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.
4. U.S. Food and Drug Administration. (2024). Combination products and device-drug regulatory pathways.
5. U.S. Food and Drug Administration. (2004). LidoSite topical system: FDA device and product information.

Drugs Protected by US Patent 6,862,473

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 6,862,473

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	7845494
Canada	2364414
European Patent Office	1207936
Japan	2003501165
World Intellectual Property Organization (WIPO)	0074772
World Intellectual Property Organization (WIPO)	9509031