United States Patent 8,303,986: Ropinirole Controlled-Release Tablet Patent Scope and Landscape

US 8,303,986 protects a controlled-release ropinirole tablet built around a hydrophilic-lipophilic matrix. The independent claim requires a 24-hour release profile, dose-independent percentage release, 0.75 mg to 12 mg of ropinirole base, hydrophilic polymers, lipophilic substances, and a specified hydrophilic-to-lipophilic weight ratio of 10:1 to 0.5:1. The patent is formulation-specific rather than a broad composition-of-matter patent covering ropinirole itself.

The principal infringement risk is a once-daily ropinirole tablet using a swelling or eroding polymer matrix with a lipophilic excipient and a release profile that meets the claimed dissolution conditions. A generic developer could reduce risk by changing the matrix architecture, omitting the claimed lipophilic component, moving outside the claimed ratio, or producing a dissolution profile that does not satisfy the claim limitations. Those design changes would not eliminate risks under other ropinirole patents, regulatory requirements, or the doctrine of equivalents.

What does US Patent 8,303,986 protect?

The patent protects a controlled-release tablet containing ropinirole or a pharmaceutically acceptable salt, including ropinirole hydrochloride. Claim 1 combines formulation, dosage, manufacturing, and performance limitations.

Claim element	Required limitation
Dosage form	Controlled-release tablet
Active ingredient	Ropinirole or a pharmaceutically acceptable salt
Dose	0.75 mg to 12.0 mg ropinirole, measured as base
Release duration	Approximately 24 hours in vitro
Dissolution method	USP XXIII apparatus 2, paddle, 100 rpm
Dissolution medium	500 mL citrate buffer at pH 4.0
Temperature	37° C
Matrix components	Hydrophilic polymeric substances, lipophilic substances, and adjuvants
Hydrophilic polymer function	Gels, swells, and/or erodes in aqueous liquid
Matrix ratio	Hydrophilic polymer to lipophilic substance from 10:1 to 0.5:1
Dose proportionality	Percentage release is independent of the amount of ropinirole
Layer structure	One active layer under claim 1

The claim is therefore cumulative. A product must satisfy every limitation of claim 1 to infringe literally. A tablet containing ropinirole in a hydrophilic matrix is not enough. The product also must contain a lipophilic substance within the specified ratio and meet the claimed release behavior.

How should claim 1 be construed?

“Approximately 24 hours”

“Approximately 24 hours” is a functional and potentially fact-sensitive limitation. It does not necessarily require a precise 24-hour release endpoint. The relevant inquiry would consider the patent specification, prosecution history, claimed examples, and the actual dissolution profile.

A product releasing drug over 16 or 18 hours could argue that it does not meet the limitation. A product releasing over 20 to 24 hours presents greater risk, particularly if its release curve resembles the patent examples. The phrase also creates potential indefiniteness and claim-construction issues if the patent does not identify acceptable tolerance around 24 hours.

“Release rate ... independent of the amount of ropinirole”

This limitation requires more than a single dose strength. It implies that different strengths exhibit substantially comparable percentage-based release behavior when tested under the specified method.

A generic manufacturer would likely need comparative dissolution testing across multiple strengths. A formulation in which higher-strength tablets release a materially different percentage of ropinirole could challenge this limitation. The patent owner could argue that ordinary formulation variability does not defeat dose-independent release if the profiles remain within the disclosed performance range.

Hydrophilic polymeric substances

The claim covers polymers that gel, swell, erode, or perform a combination of those functions upon contact with aqueous liquid. The language is broad enough to encompass common hydrophilic matrix polymers, including certain grades of hypromellose, hydroxypropyl cellulose, polyethylene oxide, and related water-responsive excipients, depending on the specification and prosecution history.

The claim does not identify one named polymer. A product could therefore fall within the claim even if it uses a different hydrophilic polymer from the commercial product, provided the polymer performs the claimed function and the remaining limitations are met.

Lipophilic substances

The lipophilic limitation is central to claim scope. The claim does not identify a single required lipophilic excipient. Potentially relevant materials may include hydrophobic waxes, fatty acids, glycerides, hydrogenated oils, or other poorly water-soluble excipients, subject to the patent’s specification and claim construction.

The scope depends on whether the material qualifies as “lipophilic” under the ordinary meaning informed by the patent. A developer could reduce literal infringement risk by using a formulation with no lipophilic substance or by using only soluble, hydrophilic, or amphiphilic excipients. That strategy would require assessment of the doctrine of equivalents.

Hydrophilic-to-lipophilic ratio

The ratio is calculated by weight and ranges from 10:1 to 0.5:1. Expressed differently, the lipophilic component can range from 10% to 200% of the hydrophilic polymer weight, depending on the formulation.

This is a relatively broad ratio limitation. A formulation with a hydrophilic-to-lipophilic ratio of 8:1, 3:1, 1:1, or 0.75:1 would fall within the literal range if the other limitations are satisfied. A formulation at 12:1 or 0.4:1 would be outside the express range, although prosecution history and equivalents would remain relevant.

What do the dependent claims add?

Claim	Added limitation	Commercial relevance
2	Dissolution profile shown in Figure 13	Narrower performance claim tied to a specific profile
3	Tablet is coated	Covers coated versions of the claim 1 tablet
4	Coating is gastroresistant and enterosoluble	Adds an enteric or delayed-release coating limitation
5	Contains ropinirole hydrochloride	Narrows the active ingredient to a commercially practical salt
6	Hydrophilic polymer is 30% to 75% of active-layer weight	Adds a quantitative matrix limitation
7	Tablet is a multi-layer tablet	Covers a multilayer structure despite claim 1’s active-layer requirement

Claim 5 is likely commercially important because ropinirole hydrochloride is the conventional pharmaceutical form. Claim 6 gives the patent owner a more specific fallback position if the broader polymer limitation is challenged.

Claim 7 requires careful structural analysis. Claim 1 requires one active layer, while claim 7 states that the tablet is multilayer. Those limitations can be reconciled if the tablet has one active ropinirole layer plus one or more inactive, barrier, coating, or other non-active layers. A multilayer tablet with two separate ropinirole-containing layers could raise a claim-construction issue.

What formulations are protected by US 8,303,986?

The strongest coverage applies to a once-daily matrix tablet with:

Ropinirole hydrochloride or another ropinirole salt.
A hydrophilic polymer matrix.
A hydrophobic or lipophilic release-modifying excipient.
A hydrophilic-to-lipophilic weight ratio between 10:1 and 0.5:1.
A total ropinirole-base strength of 0.75 mg to 12 mg.
A substantially 24-hour dissolution profile.
Comparable percentage release across strengths.

The patent may reach both single-layer and multilayer commercial tablets, depending on whether the multilayer construction has only one active layer. It also reaches coated tablets and, under claim 4, enteric-coated tablets.

The patent does not expressly require a particular tablet hardness, compression force, particle size, manufacturing process, coating weight, or specific polymer grade. Those omissions increase formulation breadth but also create potential validity and written-description issues if the asserted scope exceeds the examples and disclosure.

How strong is the patent estate for ropinirole extended release?

US 8,303,986 is best characterized as a medium-strength formulation patent with meaningful commercial relevance.

Strengths

It combines structural and functional limitations.
It covers a broad range of hydrophilic polymers.
It does not require a single named lipophilic excipient.
The 0.5:1 to 10:1 ratio covers many conventional matrix formulations.
It covers multiple strengths from 0.75 mg to 12 mg.
The dose-independence limitation can reach a complete strength range rather than one dose.
Dependent claims provide narrower positions for ropinirole hydrochloride and polymer loading.

Weaknesses

The claim depends heavily on a specified in vitro test.
The meaning of “approximately 24 hours” may be contested.
“Independent of the amount” requires an objective comparison framework.
The lipophilic-substance limitation may be vulnerable to disputes over excipient classification.
The claim does not cover every extended-release ropinirole formulation.
A competitor may design around the matrix ratio or use a non-matrix delivery system.
Figure 13 may create a demanding profile-matching burden under claim 2.

The patent is stronger against conventional hydrophilic-lipophilic matrix tablets than against osmotic systems, multiparticulate capsules, coated pellets, reservoir systems, or formulations that use a different release mechanism.

What is the Orange Book and FDA relevance?

Ropinirole extended-release products are regulated as drug products rather than biologics. The relevant FDA pathway for a generic extended-release product is generally an abbreviated new drug application, with bioequivalence and formulation-specific requirements under the ANDA framework.

The FDA Orange Book is the controlling public source for listed patents, expiration dates, pediatric exclusivity, and reference-product information. An issued patent can be relevant to a branded product even when it is not the original composition-of-matter patent. Formulation patents are commonly used to support Paragraph IV litigation after a generic applicant certifies that the listed patent is invalid, unenforceable, or not infringed. FDA, however, does not decide infringement or patent validity through the Orange Book process.[1]

For a ropinirole extended-release reference product, the commercial patent analysis should separate:

patents listed for the reference product;
patents covering the active ingredient;
formulation patents;
method-of-use patents;
manufacturing patents;
patents owned by third parties but not listed in the Orange Book;
regulatory exclusivity that is independent of patent term.

When does US 8,303,986 lose exclusivity?

The issue date, November 6, 2012, does not determine expiration. US utility patents generally expire 20 years from the earliest effective nonprovisional US filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and priority rules.[2]

The expiration analysis should therefore use the patent’s USPTO bibliographic record and maintenance records. For commercial planning, the relevant date is the enforceable expiration date after any patent-term adjustment or terminal disclaimer. FDA listing data may show a different date if the patent has pediatric exclusivity or if the listed patent is subject to a separate regulatory period.

Because the patent is a formulation patent rather than a basic ropinirole compound patent, its commercial value depends on whether the branded product practices the claimed matrix and whether competing generic products need to use the same architecture to obtain approval.

What Paragraph IV challenges and litigation risks exist?

A generic applicant targeting a product covered by US 8,303,986 could use a Paragraph IV certification asserting that the patent is invalid, unenforceable, or not infringed. The principal litigation positions would likely include:

Non-infringement

A generic could argue that:

its formulation has no lipophilic substance;
its hydrophilic-to-lipophilic ratio is outside the claimed range;
its polymer does not gel, swell, or erode as claimed;
its release is not approximately 24 hours;
its percentage release varies by strength;
its active dose falls outside the 0.75 mg to 12 mg range;
its product does not contain one active layer;
its dissolution profile does not satisfy Figure 13.

Invalidity

Potential invalidity theories could include anticipation, obviousness, indefiniteness, lack of written description, lack of enablement, and double patenting. The most fact-intensive issues would be:

whether prior art disclosed a ropinirole hydrophilic matrix with lipophilic excipients;
whether the claimed ratio was an obvious optimization;
whether prior art disclosed dose-independent release;
whether “approximately 24 hours” gives a legally definite boundary;
whether the full claimed range is enabled;
whether the specification supports all covered polymers and lipophilic substances.

Doctrine of equivalents

A formulation outside the numerical ratio or using a chemically different excipient could still create risk if it performs substantially the same function in substantially the same way to obtain substantially the same result. Prosecution history may limit that argument, particularly if the ratio or excipient distinction was added to overcome prior art.

How can a generic manufacturer design around the patent?

The clearest design-around options are:

Design-around strategy	Main patent risk
Use an osmotic delivery system	Reduced literal risk under the matrix limitations; other patents may apply
Use coated multiparticulates or pellets	Avoids a single active-layer matrix; release-profile claims remain relevant
Omit lipophilic substances	Avoids a core structural limitation
Use a hydrophilic-to-lipophilic ratio outside 10:1 to 0.5:1	Creates numerical non-infringement position
Use a non-gelling or non-swelling release polymer	May avoid the hydrophilic-polymer limitation
Use a formulation with materially different strength-dependent release	Challenges dose-independence
Use a non-enteric coating	Avoids claims 3 and 4, but not claim 1
Use a different salt or delivery form	May avoid claim 5, but not necessarily claim 1

The design-around must be tested against the entire claim, not only the most visible ingredient. A formulation outside claim 5 can still infringe claim 1 because claim 1 covers ropinirole and pharmaceutically acceptable salts generally.

How does this patent compare with method-of-use and manufacturing patents?

US 8,303,986 is a product-by-process-adjacent formulation patent, but its claims focus on the finished dosage form and performance rather than a manufacturing sequence. It differs from:

composition-of-matter patents covering ropinirole itself;
method-of-use patents covering Parkinson’s disease, restless legs syndrome, or dose-regimen indications;
manufacturing patents covering granulation, compression, coating, or excipient processing;
polymorph or salt patents covering a particular solid form;
device patents covering delivery hardware.

A generic product can avoid this patent and still face method-of-use exposure if its labeling encourages a patented indication. Conversely, a product that practices the claimed formulation may face infringement even if the generic label omits a patented method of use.

What is the commercial impact of the patent?

The patent has its greatest value where the reference product uses a hydrophilic-lipophilic matrix and where bioequivalence can be demonstrated only through a similar release architecture. Its value is lower if alternative extended-release technologies can meet FDA requirements without using the claimed ratio or matrix structure.

Revenue exposure depends on:

sales of once-daily ropinirole extended-release tablets;
the number of commercially relevant strengths within the 0.75 mg to 12 mg range;
the timing of Paragraph IV filings;
whether litigation triggers a 30-month FDA stay;
the availability of non-infringing generic formulations;
the enforceability and remaining term of the patent;
the presence of other listed patents.

The patent should be valued as one layer in a ropinirole extended-release estate, not as a standalone monopoly over the drug.

Key Takeaways

US 8,303,986 is a controlled-release formulation patent, not a basic ropinirole compound patent.
Claim 1 requires a hydrophilic-lipophilic matrix, a 0.75 mg to 12 mg dose, a specific weight-ratio range, and approximately 24-hour release.
The dose-independent release limitation is central to both infringement and validity analysis.
Ropinirole hydrochloride is expressly covered by claim 5.
The patent reaches coated and certain multilayer tablets through dependent claims.
Osmotic, multiparticulate, non-matrix, lipophilic-free, or ratio-shifted formulations offer the clearest design-around paths.
Paragraph IV risk will turn on dissolution testing, excipient classification, ratio calculations, and the patent’s prosecution history.
Patent expiration cannot be determined from the issue date alone; the USPTO patent-term record and Orange Book listing control the commercial timeline.
The patent should be analyzed alongside other formulation, method-of-use, manufacturing, and listed Orange Book patents.

FAQs

Does a ropinirole extended-release tablet automatically infringe US 8,303,986?

No. It must satisfy every limitation of claim 1, including the hydrophilic-lipophilic matrix, ratio range, dose range, release duration, and dose-independent percentage release.

Is ropinirole hydrochloride specifically covered?

Yes. Claim 5 expressly covers a tablet containing ropinirole hydrochloride. Claim 1 separately covers ropinirole and pharmaceutically acceptable salts.

Can a formulation avoid the patent by changing the polymer?

Potentially. Changing the polymer may avoid infringement only if the replacement does not satisfy the claimed hydrophilic-polymer function or does not meet the other claim limitations. A different polymer name alone is not sufficient.

Does an enteric coating avoid the patent?

No. Claim 4 expressly covers a gastroresistant, enterosoluble coating when the underlying tablet satisfies the incorporated limitations of claim 1 and claim 3.

Are biosimilars relevant to this patent?

No. Ropinirole is a small-molecule drug. The relevant competitors are generic drug applicants under the ANDA pathway, not biosimilar applicants under the Biologics Price Competition and Innovation Act.

References

U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
United States Patent and Trademark Office. (n.d.). Manual of Patent Examining Procedure, Chapter 2700: Patent term. https://www.uspto.gov/web/offices/pac/mpep/mpep-2700.html
United States Patent and Trademark Office. (2012). U.S. Patent No. 8,303,986. Patent Center. https://patentcenter.uspto.gov/
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application process. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda
U.S. Food and Drug Administration. (n.d.). Approved drug product label for ropinirole extended-release tablets. Drugs@FDA. https://www.accessdata.fda.gov/scripts/cder/daf/

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Italy	MI00A0852	Apr 14, 2000
Italy	MI00A1963	Sep 07, 2000

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	030557	⤷ Start Trial
Austria	401867	⤷ Start Trial
Australia	2005201805	⤷ Start Trial
Australia	2009230759	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,303,986

Summary for Patent: 8,303,986