US Patent 7,074,430: Tramadol Controlled-Release Dosage Form Patent Scope and Patent Landscape

US Patent 7,074,430 protects a once-daily oral tramadol dosage form built around a normal-release matrix with an outer controlled-release coating. The patent does not claim tramadol itself, a generic sustained-release tablet, or every extended-release tramadol product. Its central limitation is the combination of:

Tramadol or a pharmaceutically acceptable salt;
A solid oral dosage form;
Incorporation into a normal-release matrix;
An overlying controlled-release coating made from polymethacrylate or water-insoluble cellulose; and
At least approximately 24 hours of therapeutic effect.

The dependent claims add coating compositions, ethylcellulose, dose strengths, dissolution profiles, maximum plasma concentration timing, and the W50 pharmacokinetic parameter. The patent is formulation-focused and creates potential infringement risk primarily for coated-matrix tramadol products, not for all tramadol extended-release technologies.

What does US Patent 7,074,430 protect?

The patent’s broadest protection is claim 1. It covers a solid controlled-release oral dosage form containing tramadol or a pharmaceutically acceptable salt in a normal-release matrix, where the matrix is overcoated with a controlled-release film.

The claim uses “comprising,” which generally makes it open-ended. A product can contain additional excipients, coatings, processing aids, or structural elements and still fall within the claim if it includes each required limitation.

Claim 1 limitation analysis

Claim element	Scope and commercial significance
Solid controlled-release oral dosage form	Covers tablets, pellets, granules, beads, or other solid oral units, subject to the remaining limitations
Therapeutically effective amount of tramadol	Covers tramadol free base and pharmaceutically acceptable salts, including tramadol hydrochloride
Incorporated into a normal-release matrix	Requires a matrix that is not itself the primary controlled-release mechanism in the claim construction
Matrix overcoated with a controlled-release coating	Requires an external coating over the matrix
Polymethacrylate or water-insoluble cellulose	Provides two principal coating routes
Therapeutic effect for at least about 24 hours	Functional duration limitation directed to once-daily or approximately 24-hour performance

The most important structural distinction is between a matrix-only extended-release product and a matrix that is overcoated with a specified release-controlling polymer. A product using only hydrophilic matrix technology may avoid literal infringement if it does not contain the required overcoat. That conclusion depends on the actual formulation and any doctrine-of-equivalents analysis.

How do claims 2 through 6 narrow the patent?

Claims 2 through 6 create separate formulation and dose-specific positions.

Claim	Added limitation	Practical effect
2	Controlled-release coating comprises a polymethacrylate	Covers acrylic polymer coatings
3	Controlled-release coating comprises a water-insoluble cellulose	Covers cellulose-based coatings
4	Polymethacrylate coating also contains water-soluble cellulose	Protects mixed acrylic/cellulose coating systems
5	Water-insoluble cellulose coating also contains polyvinylpyrrolidone	Protects a cellulose/PVP coating combination
6	50 to 800 mg tramadol, calculated as hydrochloride	Establishes a broad dose range

Claim 6 is commercially important because it reaches common strengths used in extended-release tramadol products. The claim is calculated as tramadol hydrochloride, so dose comparisons must use the salt-equivalent convention rather than only the amount of tramadol free base.

Claims 13 through 17 narrow the dosage form to specific strengths:

100 mg tramadol hydrochloride;
200 mg tramadol hydrochloride;
300 mg tramadol hydrochloride;
400 mg tramadol hydrochloride; and
600 mg tramadol hydrochloride.

The 100 mg and 200 mg strengths are the most commercially relevant for conventional once-daily tramadol products. The 300 mg, 400 mg, and 600 mg claims provide additional positions against higher-strength formulations but may face enablement, written-description, safety, or commercial-use questions depending on the supporting specification and product labeling.

What dissolution profiles are protected by US 7,074,430?

Claims 7, 8, and 9 use detailed in-vitro dissolution limitations. They are measured under a specified European Pharmacopoeia paddle method:

100 rpm;
900 mL of 0.1N hydrochloric acid;
37°C;
UV detection at 270 nm.

These claims are not interchangeable. Each defines a different release envelope.

Claim 7: approximately 24-hour profile

Claim 7 permits relatively broad release ranges:

Time	Tramadol released
1 hour	0% to 50%
2 hours	0% to 75%
4 hours	10% to 95%
8 hours	35% to 100%
12 hours	55% to 100%
16 hours	70% to 100%
24 hours	More than 90%

This claim can reach products with relatively rapid early release, provided the product satisfies the remaining matrix, coating, active-ingredient, and duration limitations.

Claim 8: slower 24- to 36-hour profile

Claim 8 requires a slower release pattern:

Time	Tramadol released
1 hour	0% to 30%
2 hours	0% to 40%
4 hours	3% to 55%
8 hours	10% to 65%
12 hours	20% to 75%
16 hours	30% to 88%
24 hours	50% to 100%
36 hours	More than 80%

Claim 8 is directed to a more prolonged release profile than claim 7. A product may fall within both claims if its dissolution results satisfy both sets of ranges. The ranges are not necessarily mutually exclusive.

Claim 9: narrower intermediate-release profile

Claim 9 requires:

Time	Tramadol released
1 hour	15% to 25%
2 hours	25% to 35%
4 hours	30% to 45%
8 hours	40% to 60%
12 hours	55% to 70%
16 hours	60% to 75%

Unlike claims 7 and 8, claim 9 does not state a 24-hour release endpoint. It is a narrower profile claim focused on a controlled intermediate release pattern through 16 hours.

A design-around cannot rely on a single dissolution time point. The claimed ranges are cumulative requirements. Testing must be conducted using the specified medium, apparatus, speed, temperature, detection wavelength, and sampling methodology.

What pharmacokinetic characteristics are claimed?

Claims 10 and 11 add pharmacokinetic parameters.

Claim 10: Tmax

Claim 10 requires a Tmax of approximately 3 to 6 hours. A product with a later or earlier Tmax may avoid literal infringement of this dependent claim, although it could remain exposed under claim 1 or another dependent claim.

Tmax can vary with:

Food intake;
Patient population;
Sampling schedule;
Dose strength;
Assay method;
Formulation size and coating thickness; and
Study design.

Accordingly, a single clinical study may not conclusively characterize the product for every patient or administration condition.

Claim 11: W50

Claim 11 requires a W50 of approximately 10 to 33 hours. W50 generally refers to the duration during which plasma concentrations remain at or above 50% of the relevant maximum or reference concentration, depending on the patent’s defined methodology.

This claim is narrower and more difficult to assess from public product information because W50 is not routinely reported in approved labeling. It ordinarily requires access to pharmacokinetic data and the calculation method used in the patent specification.

What formulations are protected by the patent?

The patent covers two principal coating technologies.

Polymethacrylate coatings

Claim 2 reaches polymethacrylate-controlled coatings. Commercially relevant examples may include acrylic polymer systems used to control diffusion through the coating. The claim does not appear limited to one trade-name polymer or one grade unless the specification or prosecution history imposes a narrower construction.

Claim 4 adds water-soluble cellulose to the polymethacrylate coating. This can capture blended coatings that combine an insoluble acrylic polymer with a pore-forming or permeability-modifying cellulose derivative.

Water-insoluble cellulose coatings

Claim 3 reaches water-insoluble cellulose coatings. Claim 12 expressly identifies ethylcellulose.

Ethylcellulose is therefore a high-priority freedom-to-operate issue. A product using an ethylcellulose film over a tramadol matrix may face a direct claim 12 analysis if it also satisfies claim 1’s duration and dosage-form limitations.

Claim 5 adds polyvinylpyrrolidone to the water-insoluble cellulose coating. PVP may function as a water-soluble component, pore former, binder, or permeability modifier depending on the manufacturing process and formulation.

How strong is the patent estate for tramadol controlled release?

The estate is strongest against products that reproduce the claimed architecture and performance together:

Tramadol hydrochloride;
Solid oral dosage form;
Normal-release matrix;
External ethylcellulose or polymethacrylate coating;
Approximately 24-hour therapeutic effect; and
Matching dissolution or pharmacokinetic performance.

The estate is weaker against products using materially different delivery systems, including:

Matrix-only systems without an external controlled-release coating;
Osmotic pump tablets;
Multiparticulate capsules using a different release-control mechanism;
Ion-exchange resin systems;
Depot or injectable formulations;
Transdermal delivery;
Products with release profiles outside claims 7 through 9; and
Products that do not provide approximately 24 hours of therapeutic effect.

Key validity pressure points

Potential validity issues would likely focus on:

Written description and enablement. The patent must support the full breadth of the coating alternatives, doses, dissolution profiles, and pharmacokinetic ranges.
Obviousness. Tramadol sustained-release matrices, ethylcellulose, polymethacrylates, cellulose additives, and PVP were individually known formulation tools. The critical question is whether the claimed combination and resulting performance would have been predictable.
Indefiniteness. Terms such as “normal release matrix,” “therapeutic effect,” “about 24 hours,” and W50 may require construction from the specification and prosecution history.
Reproducibility of dissolution claims. The specified test method reduces ambiguity, but laboratory-to-laboratory variation and sample preparation can remain material.
Claim dependency. A successful challenge to claim 1 would substantially impair all dependent claims. If claim 1 survives, the narrower claims provide multiple fallback positions.

What is the patent expiration and exclusivity position?

US Patent 7,074,430 issued on July 11, 2006. The issue date does not determine the patent’s expiration. US utility patents generally expire 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and continuity rules.[1][2]

The patent should therefore be analyzed as a historical formulation patent rather than as a current source of unexpired exclusivity unless the patent’s official continuity and term-adjustment records establish a later expiration. The patent itself does not create regulatory exclusivity. Any FDA exclusivity would arise separately under the Food, Drug, and Cosmetic Act and would depend on the relevant new drug application and exclusivity designation.[3]

Patent exclusivity versus FDA exclusivity

Protection	Source	Effect
Patent claims	Patent statute	Can block making, using, selling, offering for sale, or importing the claimed product
New chemical entity exclusivity	FDA statute	Generally bars certain abbreviated applications for a statutory period
Three-year clinical-investigation exclusivity	FDA statute	Can restrict approval of certain applications relying on listed clinical studies
Orphan-drug exclusivity	FDA statute	Applies to the designated orphan indication
Pediatric exclusivity	FDA statute	Adds six months to qualifying exclusivity or patent terms

Patent expiration and FDA exclusivity should not be conflated. A product can lose patent protection while a separate regulatory exclusivity remains, or the reverse.

What is the Orange Book status of US 7,074,430?

The Orange Book lists patents submitted by an NDA holder for an approved drug product. A formulation patent is Orange Book-relevant only if it is submitted for the applicable NDA and accepted by FDA under the listing rules.[4]

The claims supplied here are formulation claims, not merely method-of-use claims. If listed against an extended-release tramadol NDA, they could have supported a Paragraph IV certification by an abbreviated new drug applicant.

Orange Book analysis should distinguish:

The patent’s existence in USPTO records;
Whether it was submitted to FDA;
Whether FDA accepted it for listing;
The NDA and strength to which it was associated;
Whether the listed patent was active at the time of an ANDA filing; and
Whether the patent was later delisted or expired.

A patent may remain visible in historical Orange Book editions even after its enforceable term has ended. The relevant date for an ANDA dispute is the legal status applicable to the filing and approval timeline.

What Paragraph IV and generic-launch risks arise?

An ANDA applicant seeking approval for a tramadol extended-release product could use several certification strategies:

Paragraph I: no patent information has been submitted;
Paragraph II: the patent has expired;
Paragraph III: the applicant will wait until patent expiration;
Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.

For US 7,074,430, the principal Paragraph IV arguments would be:

The proposed product is not overcoated;
The coating is not polymethacrylate or water-insoluble cellulose;
The active ingredient is not incorporated into a “normal release matrix”;
The product does not provide at least approximately 24 hours of therapeutic effect;
The dissolution profile falls outside claims 7 through 9;
The dose is outside claim 6 or claims 13 through 17; or
The patent claims are invalid for obviousness, lack of enablement, inadequate written description, or indefiniteness.

Under Hatch-Waxman, a Paragraph IV notice can trigger patent litigation and a 30-month stay of approval if the NDA holder or patent owner files an infringement action within the statutory period.[3] The risk is product-specific. An ANDA applicant with a matrix-only or osmotic formulation may have a stronger noninfringement position than one using ethylcellulose-coated matrix beads.

Which companies and products are relevant competitors?

The commercial competitive field has included:

Originator or innovator tramadol extended-release products;
Authorized generics;
Generic manufacturers filing ANDAs for once-daily tramadol;
Manufacturers using matrix tablets;
Manufacturers using coated multiparticulates; and
Developers of nonoral or abuse-deterrent tramadol systems.

The patent’s strongest competitive relevance is to generic products designed to match an existing once-daily reference product. A manufacturer seeking the lowest development cost may choose a conventional coated matrix. That approach may reduce formulation risk but increases exposure to claims directed to ethylcellulose, polymethacrylate, dissolution, and 24-hour performance.

A noninfringing development strategy may instead use:

A hydrophilic matrix without a controlled-release overcoat;
An osmotic delivery mechanism;
A multiparticulate system using a non-cellulosic, non-polymethacrylate barrier;
A different release duration; or
A product whose release profile does not meet the claimed dissolution envelopes.

Each design-around may create separate regulatory, bioequivalence, manufacturing, or clinical risks.

What manufacturing and geographic IP barriers exist?

The patent claims the dosage form rather than a specific manufacturing process. Manufacturing steps can still be relevant to infringement if they produce the claimed product, including:

Matrix granulation;
Drug loading;
Pellet or tablet formation;
Film coating;
Coating weight control;
Curing;
Blending of insoluble and soluble polymers; and
Release testing.

A manufacturer outside the United States may face US infringement exposure if it imports the patented product or supplies it for commercial importation. Separate foreign family members, national-phase patents, supplementary protection certificates, or local formulation patents would need independent review. US 7,074,430 does not itself establish protection in Europe, Canada, Japan, India, China, or other jurisdictions.

How does US 7,074,430 compare with a matrix-only tramadol patent?

Issue	US 7,074,430	Matrix-only formulation patent
Core architecture	Matrix plus external controlled-release coating	Controlled-release matrix without required overcoat
Key polymers	Polymethacrylate or water-insoluble cellulose	Often hydrophilic polymers such as hypromellose
Performance limitation	At least about 24 hours	May use dissolution only, or no duration limitation
Best infringement target	Coated matrix tablets, pellets, or beads	Matrix tablets and matrix multiparticulates
Main design-around	Remove or change the external coating	Change matrix polymer or release mechanism
Regulatory relevance	Potentially relevant to once-daily tramadol products	Depends on listed NDA and product architecture

What is the likely revenue exposure?

Revenue exposure depends on whether a marketed product uses the claimed formulation architecture and whether the patent remained enforceable during the relevant sales period.

The highest exposure would arise where:

The product is a once-daily tramadol hydrochloride formulation;
It uses an ethylcellulose or polymethacrylate overcoat;
Its dissolution profile falls within claims 7, 8, or 9;
Its dosage strength is 100 to 600 mg; and
The patent was unexpired when sales occurred.

Exposure is lower where a product uses an unrelated delivery mechanism or entered the market after the patent term ended. Damages analysis would also require sales by product, jurisdiction, time period, attribution to the patented feature, and any applicable settlement or license terms.

Key Takeaways

US 7,074,430 is a formulation patent for coated, controlled-release oral tramadol dosage forms.
Claim 1 requires both a normal-release matrix and an external controlled-release coating.
The principal coating alternatives are polymethacrylate and water-insoluble cellulose.
Ethylcellulose is expressly identified in claim 12.
Claims 7 through 9 protect specified dissolution envelopes under a defined European Pharmacopoeia test.
Claims 10 and 11 add Tmax and W50 pharmacokinetic limitations.
Claims 13 through 17 cover 100, 200, 300, 400, and 600 mg tramadol hydrochloride products.
Matrix-only, osmotic, ion-exchange, and other noncoated systems may present stronger design-around positions.
Orange Book listing, Paragraph IV exposure, and enforceability depend on the specific NDA, ANDA, patent-term record, and product formulation.
The patent should be treated as a historical formulation right unless official patent-term records establish remaining enforceable life.

Frequently Asked Questions

Does US 7,074,430 cover all extended-release tramadol tablets?

No. It requires a normal-release matrix overcoated with a controlled-release coating comprising polymethacrylate or water-insoluble cellulose, plus the claimed therapeutic-duration limitation.

Does an ethylcellulose-coated tramadol product create infringement risk?

Yes, potentially. Claim 12 expressly identifies ethylcellulose, but the product must also satisfy the other limitations, including the matrix structure and controlled-release performance.

Can a tramadol osmotic pump infringe US 7,074,430?

A materially different osmotic system may avoid literal infringement because the claims require a normal-release matrix overcoated with specified polymeric materials. The complete product architecture must be compared against each claim limitation.

Are claims 7, 8, and 9 bioequivalence claims?

No. They are dissolution-profile claims. Bioequivalence data may be relevant to product performance, but the claims specify an in-vitro test method and release ranges.

Does patent expiration eliminate FDA approval barriers for generic tramadol?

Not necessarily. Patent expiration removes the relevant patent barrier, but FDA approval still depends on the applicable ANDA pathway, reference product requirements, regulatory exclusivity, labeling, manufacturing controls, and bioequivalence standards.

References

United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term. https://www.uspto.gov
United States Patent and Trademark Office. (n.d.). US Patent No. 7,074,430. https://patents.google.com
U.S. Food and Drug Administration. (n.d.). Hatch-Waxman amendments and abbreviated new drug applications. https://www.fda.gov
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. https://www.fda.gov
United States Congress. (2024). 21 U.S.C. §§ 355 and 355(j). Cornell Legal Information Institute. https://www.law.cornell.edu

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	138566	⤷ Start Trial
Austria	172376	⤷ Start Trial
Austria	184786	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,074,430

Summary for Patent: 7,074,430