US Patent 6,745,071: Claim Scope, Expiration, Iontophoretic Delivery Landscape, and Generic-Entry Risk

US 6,745,071 protects a pre-packaged, wearable iontophoretic delivery system that combines two removable aqueous electrode matrices, a powered anode-cathode device, impermeable release membranes, and a foldable substrate. Independent claim 1 is a narrow combination claim. The strongest commercial limitation is the required folded, self-contained package in which the matrices are brought into conductive contact with shaped electrode recesses before application to skin.

The patent is directed to delivery architecture, not to fentanyl chemistry alone. A fentanyl iontophoretic product avoids claim 1 if it lacks one or more structural limitations, such as the foldable substrate, separately packaged aqueous matrices, shaped electrode recesses, or removable release membranes. A product using the claimed architecture could face infringement exposure even if it uses a different hydrogel, electrode controller, or drug concentration.

Because the supplied material contains the claims but not the patent front page, prosecution history, assignment records, terminal disclaimers, patent-term-adjustment data, or litigation docket, a definitive current legal-status and exact expiration-date determination cannot be made from the claim text alone.

What technology does US 6,745,071 protect?

The patent protects a disposable or semi-disposable iontophoretic patch package with integrated activation and application functions. Its core architecture has five interacting components:

Component	Claim requirement	Commercial function
Substrate	Removable substrate carried by the system	Supports and packages the patch components
Drug reservoirs	Aqueous anode and cathode matrices	Provide conductive contact and, potentially, drug delivery
Packaging	Water-impermeable release membranes	Preserve matrix moisture and shelf stability
Electrical unit	Anode, cathode, and power source	Drives transdermal ion transport
Activation geometry	Fold line and shaped electrode recesses	Brings matrices into contact with the correct electrodes

The invention is therefore more specific than a generic iontophoretic patch. It requires an integrated package that can be folded onto itself so the matrices associate with the electrodes. The claim also requires that the system be self-contained, wearable, and pre-packaged.

Claim 1 does not require fentanyl. Fentanyl appears only in dependent claim 7. The independent claim covers systems containing any “therapeutic ion species” located in the anode matrix, cathode matrix, or iontophoresis device.

What is the scope of independent claim 1?

Claim 1 is a product claim requiring every listed element. The principal limitations are as follows:

A self-contained, wearable system.
A removable substrate.
An aqueous anode matrix on the substrate.
An aqueous cathode matrix on the substrate.
A water-impermeable release membrane isolating each matrix.
An iontophoresis device with an anode, cathode, and power source.
Shaped recesses associated with the electrodes.
Matrices received in the recesses in conductive relation.
At least one fold line allowing the package to fold on itself.
A therapeutic ion species in at least one claimed location.

The requirement for “shaped recesses” is important. A flat patch with hydrogel reservoirs that merely contact planar electrodes may not meet the claim literally if it lacks electrode-associated recesses configured to receive the matrices.

The fold-line limitation is also material. The claim does not cover every preassembled iontophoretic patch. The package must be capable of folding so that the anode and cathode matrices become associated with their corresponding electrodes.

What does “self-contained” require?

The claim places the power source on the substrate and describes a complete pre-packaged system. A product that requires a separate external controller, battery pack, or reservoir assembly may present a noninfringement position, depending on how the components are supplied and interconnected.

The phrase “self-contained” may be disputed if a product is sold as a kit with an external activation accessory. The outcome would depend on the specification, prosecution history, and the way the accused product is supplied and used.

What does “aqueous matrix” require?

The claim requires aqueous anode and cathode matrices. Claims 8, 9, 12, and 13 narrow the matrix to hydrogel or highly viscous materials, including agarose, polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, hydroxypropyl methylcellulose, and carboxymethyl cellulose.

Claim 1 itself is broader than those dependent claims. A matrix can potentially fall within claim 1 without using one of the listed polymers, provided it is aqueous and satisfies the other limitations.

How do claims 2 through 17 narrow the patent?

Claim	Added limitation	Scope effect
2	Adhesive retains both aqueous matrices on the substrate	Covers matrix retention before use
3	Separate membranes with pull-tabs	Requires independently removable membrane structures
4	Removing the substrate exposes both matrices for skin application	Links packaging removal to application
5	Matrices are carried in substrate recesses	Adds substrate-level reservoir geometry
6	Multiple fold lines	Covers multi-fold packaging configurations
7	Fentanyl is the therapeutic ion in the anode matrix	Narrows claim to fentanyl-based delivery
8	Hydrogel or highly viscous matrix	Narrows matrix composition
9	Listed hydrogel polymers	Provides a closed material group
10	Fibrous matrix material	Covers cellulose, polyester, polypropylene, or combinations
11	Specific fibrous materials	Narrows claim 10 to the listed fibers
12	Fibrous and hydrogel/high-viscosity combination	Covers composite matrices
13	Specific hydrogel materials in the fibrous matrix	Narrowest material combination in this group
14	Therapeutic ion is dry in the iontophoresis device before activation	Covers dry-state drug storage in the electrical unit
15	Humectant or antifungal additive	Protects matrix-stability formulations
16	Voltage-control system	Adds electrical regulation
17	Two-position high-low switch	Narrow controller configuration

Claim 7 is commercially significant because it ties the packaging architecture to fentanyl. It does not, however, claim all transdermal fentanyl delivery or all fentanyl iontophoresis. It requires the full apparatus of claim 1.

What formulations are protected by US 6,745,071?

The patent claims multiple formulation categories:

Aqueous matrices.
Hydrogels.
Highly viscous materials.
Fibrous reservoirs.
Fibrous-hydrogel composites.
Matrices containing humectants.
Matrices containing antifungal agents.
Fentanyl-containing anode matrices.
Systems in which the therapeutic ion is stored in a dry state in the iontophoresis device.

The listed polymers create dependent-claim coverage around common hydrogel excipients. They do not necessarily prevent use of all alternative polymers because claim 1 is not limited to the listed materials.

The patent’s formulation coverage is secondary to its device architecture. A competing product may use a listed hydrogel but avoid infringement if it does not use the claimed foldable, pre-packaged electrode-recess system. Conversely, a product using a novel hydrogel may still infringe claim 1 if its physical package satisfies the broader structural limitations.

What is the fentanyl-specific risk?

Claim 7 creates risk for a fentanyl product only when the product also satisfies claim 1. The following fentanyl product categories require careful comparison:

Product configuration	Claim 7 risk
Foldable, pre-packaged patch with aqueous fentanyl anode matrix	High, if all claim 1 elements are present
Fentanyl hydrogel patch with flat electrodes and no shaped recesses	Lower literal risk under claim 1
External-controller fentanyl iontophoresis system	Potentially lower risk if not self-contained
Dry fentanyl reservoir with no aqueous matrix	Lower risk under claim 7, but claim 14 may become relevant
Passive transdermal fentanyl patch	Generally outside the claimed iontophoretic architecture
Fentanyl iontophoretic device with separate, non-folding packaging	Lower literal risk, subject to equivalents analysis

A product that stores fentanyl in a dry electrical device before activation could implicate claim 14, but only if the remaining claim 1 elements are present.

When does US 6,745,071 lose exclusivity?

The applicable U.S. patent term is generally 20 years from the earliest effective nonprovisional filing date for applications governed by the Uruguay Round Agreements Act, subject to patent-term adjustment, terminal disclaimers, and other statutory modifications (35 U.S.C. § 154).

The issue date alone does not establish the expiration date. A precise expiration calculation requires the patent’s:

Earliest effective nonprovisional filing date.
Priority chain.
Patent-term-adjustment amount.
Any terminal disclaimer.
Any applicable patent-term extension.

Because those records are not included in the supplied material, the exact expiration date and present enforceability cannot be stated accurately. A patent issued in 2004 would ordinarily have reached the end of its 20-year term no later than the mid-2020s, absent unusual priority or adjustment facts.

Patent expiration would eliminate ordinary infringement liability for the expired patent, but it would not eliminate risk from continuation patents, divisional patents, foreign counterparts, or separately issued patents claiming the same commercial product.

What is the Orange Book status of US 6,745,071?

US 6,745,071 is a device and drug-delivery-system patent. It is not a composition-of-matter patent for fentanyl. Its Orange Book relevance depends on whether it was submitted for listing against a specific approved drug product and whether FDA accepted the listing under the applicable product-patent rules.

A patent number alone does not establish an Orange Book listing. The relevant analysis must distinguish:

FDA listing status.
NDA or supplement associated with the patent.
Patent-use-code status.
Whether the patent was delisted, expired, or removed.
Whether the NDA remains approved or has been withdrawn.

The patent’s claims are broad enough to relate to a fentanyl iontophoretic product, but the claims do not themselves establish an Orange Book listing.

What Paragraph IV challenges could target this patent?

A generic or 505(b)(2) applicant could challenge a listed patent through a Paragraph IV certification. The strongest invalidity or noninfringement theories would likely focus on the following issues:

Anticipation

A challenger would search for a single reference disclosing all claim 1 elements in combination, especially:

Foldable pre-packaged iontophoresis systems.
Separate aqueous anode and cathode matrices.
Water-impermeable membranes.
Shaped electrode recesses.
An integrated power source.

A reference disclosing iontophoresis and hydrogels but lacking the foldable package would not, by itself, anticipate claim 1.

Obviousness

The combination of known iontophoretic patches, hydrogel reservoirs, peelable membranes, and foldable packaging may support an obviousness challenge. The patentee would likely rely on the claimed integration of these features and any prosecution-history evidence showing that the fold-line or recess geometry distinguished the prior art.

Claims 8 through 17 are more vulnerable if their added features were conventional, including common hydrogel polymers, fibers, humectants, voltage controls, and high-low switches.

Indefiniteness

Potentially contestable terms include:

“Self-contained.”
“Wearable.”
“Shaped recesses.”
“Configured to receive.”
“Conductive relation.”
“Therapeutic ion species.”
“When desired.”
“Highly viscous material.”

These terms may be supported by the specification and ordinary technical meaning. The grammatical defect in claim 13 and the misspelling “antifungel” in claim 15 are unlikely, standing alone, to invalidate the broader patent if the intended meaning is clear.

Which companies and products are most relevant?

The competitive landscape is defined by iontophoretic delivery platforms rather than by conventional passive fentanyl patches.

Technology group	Relevance to US 6,745,071
IONSYS-type fentanyl iontophoresis	Direct commercial relevance because of fentanyl and wearable delivery
Vyteris-style iontophoretic systems	Relevant prior-art and competitive platform
ALZA iontophoretic patch technology	Relevant because of integrated drug-device delivery systems
Passive fentanyl patches	Therapeutic competitors but generally outside the claimed device architecture
Microneedle systems	Competing transdermal technology with different delivery mechanics
Electroporation and sonophoresis	Alternative energy-assisted delivery platforms
Conventional reservoir iontophoresis	Potentially relevant prior art but not necessarily within claim 1

The most important freedom-to-operate distinction is between a product that copies the patented package geometry and a product that merely uses the same general iontophoretic principle.

What manufacturing and intellectual-property barriers remain?

The patent’s manufacturing value lies in the integration of:

Moisture-protected aqueous matrices.
Peelable release membranes.
Electrode-aligned recesses.
Folded packaging.
On-board power.
Controlled activation.
Wearable skin application.

Even after expiration, manufacturing barriers may remain because the system requires stable storage of aqueous materials, electrical safety, dose uniformity, adhesion, moisture retention, and reliable electrode contact.

Separate patent rights may also cover:

Electrode construction.
Hydrogel chemistry.
Fentanyl formulation.
Battery and controller design.
Dose-control algorithms.
Patch manufacturing methods.
Packaging and activation mechanisms.
Clinical methods of use.

The expired or expiring status of one packaging patent would not establish freedom to operate for the entire product.

What litigation and settlement issues matter?

The supplied record contains no litigation docket, settlement agreement, assignment chain, or prosecution history. The claims alone cannot establish whether US 6,745,071 has been asserted, challenged, licensed, disclaimed, or included in a patent settlement.

For a commercial product, litigation exposure should be assessed across four layers:

The patent’s direct apparatus claims.
Related continuation and divisional patents.
Orange Book-listed patents for the relevant NDA.
Separate patents covering fentanyl formulation, control electronics, and manufacturing.

A Paragraph IV case involving this patent could produce a 30-month stay only if the patent were properly listed against an eligible NDA and the statutory conditions were satisfied. The existence of claim 7 would not independently create a regulatory stay.

How strong is the patent estate?

The patent has moderate claim strength as a narrow combination patent and weaker strength as a broad platform patent.

Strength factor	Assessment
Independent claim breadth	Moderate to narrow
Structural specificity	High
Fentanyl coverage	Narrow because claim 7 depends on claim 1
Formulation coverage	Moderate in dependent claims
Design-around potential	Meaningful
Prior-art exposure	Potentially significant for conventional components
Commercial relevance	Highest for foldable pre-packaged iontophoretic systems
Biosimilar relevance	None
Generic relevance	Relevant only to an iontophoretic drug-device product

The principal design-around routes are removing the fold line, using flat electrode geometry, separating the power source from the patch, eliminating aqueous matrices, or packaging the matrices in a configuration that does not place them in claimed electrode recesses.

Key Takeaways

US 6,745,071 is a combination patent for a foldable, self-contained, wearable iontophoretic delivery system.
Claim 1 requires all major structural elements, including aqueous anode and cathode matrices, impermeable release membranes, shaped electrode recesses, an on-substrate power source, and at least one fold line.
Claim 7 specifically covers fentanyl, but only when the complete claim 1 architecture is present.
Claims 8 through 17 add hydrogel, fiber, additive, dry-drug, voltage-control, and high-low-switch limitations.
Passive fentanyl patches and most non-iontophoretic transdermal systems are outside the central claim architecture.
The patent’s exact expiration date cannot be established from the supplied claims alone.
Orange Book listing, Paragraph IV exposure, litigation, licensing, and settlement status cannot be established from the claim text.
The most credible design-around strategies target the foldable package, shaped recesses, aqueous matrix configuration, or self-contained power architecture.
Biosimilar risk is not applicable because the patent concerns a drug-delivery device rather than a biologic.
A complete freedom-to-operate opinion must include related patent-family members, continuations, prosecution history, Orange Book records, and current legal-status data.

FAQs

Does US 6,745,071 cover all fentanyl iontophoresis products?

No. Fentanyl is covered only in dependent claim 7, which incorporates every limitation of claim 1.

Can a product avoid the patent by using a different hydrogel?

Possibly. A different hydrogel may avoid the narrower composition claims, but it may still fall within claim 1 if the complete package and electrode architecture are substantially the same.

Does a flat iontophoretic patch fall within claim 1?

A flat patch may avoid literal infringement if it lacks the claimed shaped recesses or fold line. The final analysis would depend on claim construction and the prosecution history.

Is US 6,745,071 a patent on IONSYS itself?

The claims are directed to an iontophoretic delivery-system architecture with a fentanyl-dependent claim. They do not, on their face, claim every aspect of a commercial fentanyl product or every IONSYS implementation.

Does expiration of this patent clear all barriers to a fentanyl iontophoretic launch?

No. Other patents may cover the drug formulation, electrode system, controller, manufacturing process, packaging, dosing method, or approved product.

References

United States Patent No. 6,745,071, “Iontophoretic drug delivery system,” claims 1–17 (2004). U.S. Patent and Trademark Office, Patent Center, https://patentcenter.uspto.gov/
U.S. Patent and Trademark Office. (2024). Manual of Patent Examining Procedure, § 2710: Term of patent. https://www.uspto.gov/web/offices/pac/mpep/
35 U.S.C. § 154. (2024). Contents and term of patent; provisional rights. https://www.law.cornell.edu/uscode/text/35/154
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-filesablytyped

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	518561	⤷ Start Trial
Australia	2003267229	⤷ Start Trial
Canada	2512368	⤷ Start Trial
China	100486656	⤷ Start Trial
China	1780661	⤷ Start Trial
European Patent Office	1599255	⤷ Start Trial
Spain	2395251	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,745,071

Summary for Patent: 6,745,071