Details for Patent: 8,337,890

Which drugs does patent 8,337,890 protect, and when does it expire?

Patent 8,337,890 protects DYANAVEL XR 10, DYANAVEL XR 15, DYANAVEL XR 20, DYANAVEL XR 5, and NEXICLON XR, and is included in two NDAs.

This patent has twenty-one patent family members in fourteen countries.

Summary for Patent: 8,337,890

Title:	Modified release formulations containing drug-ion exchange resin complexes
Abstract:	A coated drug-ion exchange resin complex comprising a core composed of a drug complexed with a pharmaceutically acceptable ion-exchange resin is provided. The drug-ion exchange resin complex is in admixture with a release retardant. The coating is a polyvinyl acetate polymer and a plasticizer. Methods of making and products containing this coated complex are described.
Inventor(s):	Ketan Mehta, Yu-Hsing Tu
Assignee:	Tris Pharma Inc
Application Number:	US12/722,857
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,337,890
Patent Claim Types: see list of patent claims	Composition; Compound; Process; Dosage form;

United States Patent 8,337,890: Claim Scope, Expiration, Litigation Risk, and Drug-Resin Modified-Release Patent Landscape

U.S. Patent No. 8,337,890 protects a multipart modified-release platform using drug-ion exchange resin complexes, a polymer-containing particulate matrix, and a cured polyvinyl acetate diffusion barrier. The broadest claims require a specific combination of formulation architecture, resin chemistry, particle size, coating composition, plasticizer content, and at least an eight-hour release profile.

The patent is most relevant to oral liquid, powder, capsule, and tablet products containing ionizable drugs such as dextromethorphan, diphenhydramine, opioids, antihistamines, sympathomimetics, and selected analgesics. A product that uses only one element of the platform, such as a drug-resin complex or polyvinyl acetate coating alone, would not necessarily fall within the independent claims.

What does U.S. Patent 8,337,890 cover?

U.S. Patent 8,337,890 covers orally ingestible modified-release compositions in which drug-resin particles are first incorporated into a polymer-containing matrix and then coated with a cured, water-permeable, water-insoluble, nonionic polymeric barrier.

The claimed formulation has these required elements:

Claim element	Required limitation
Dosage form	Oral solid composition or oral powder
Release	At least an eight-hour release profile
Drug carrier	Drug bound to a water-insoluble ion-exchange resin
Resin morphology	Irregularly shaped particles
Resin chemistry	Styrene-divinylbenzene copolymer, including quaternary ammonium-functionalized resin
Particle size	Matrix capable of passing through a No. 40 mesh screen
Matrix polymer	Water-insoluble polymer, copolymer, or hydrophilic polymer
Matrix polymer loading	About 3% to about 30% by weight relative to the drug-resin complex
Barrier coating	Cured, high-tensile-strength, water-permeable, water-insoluble, nonionic polymer
Coating process	Applied as an aqueous dispersion
Coating polymer	About 75% to about 90% polyvinyl acetate
Stabilizer	Required, although claim 1 does not specify a single stabilizer
Plasticizer	About 2.5% to about 20% by weight, effective to enhance tensile strength

The invention is therefore a layered release-control system. Drug release is controlled by the drug-resin bond, the matrix surrounding the resin complex, and the external polymeric coating.

Which claims are independent in U.S. Patent 8,337,890?

Claims 1 and 27 are the principal independent claims.

Claim 1 covers a finished orally ingestible solid composition. Claim 27 covers an orally ingestible modified-release powder composition. The two claims share nearly the same platform limitations, but claim 27 is directed to powder and permits encapsulation through dependent claim 28.

Claim 1: solid composition

Claim 1 is directed to a composition containing coated particulates. It can reach:

• compressed tablets under claim 26;
• powder-filled capsules through the powder claim structure;
• multiparticulate solid dosage forms;
• formulations containing one or more drug-resin complexes.

The claim requires the barrier coating to be applied over the polymer-containing particulate matrix. A coating directly over an unmodified drug-resin complex, without the claimed matrix, may avoid claim 1 if the matrix limitation is absent.

Claim 27: powder composition

Claim 27 covers a powder containing the same core technology. Claim 28 narrows the product to powder loaded into a capsule.

The absence of a maximum plasticizer concentration in claim 27 is significant. Claim 1 requires about 2.5% to about 20% plasticizer, while claim 27 requires at least an amount effective to enhance tensile strength. Claims 29 narrows claim 27 to about 5% to about 10% plasticizer.

How do the dependent claims narrow the patent scope?

The dependent claims add specific resin, polymer, coating, drug, dosage-form, and process limitations.

Claims	Subject matter
2	Matrix polymer at about 5% to about 20% of drug-resin complex weight
3	Coating elongation factor of about 125% to about 400%
4	Sulfonated styrene-divinylbenzene resin
5	Quaternary ammonium-functionalized styrene-divinylbenzene resin
6-7	Addition of an uncoated drug-resin complex, with the same or different drug
8-9	Hydrophilic polymer, including polyvinylpyrrolidone
10	Approximately 30% solids coating dispersion with polyvinyl acetate and polyvinylpyrrolidone at a 10:1 dry-weight ratio
11-13	Polyvinyl acetate matrix and specified manufacturing process
14-15	Acrylate polymer, including ethyl acrylate-methyl methacrylate copolymer
16-17	Plasticizer at about 5% to about 10%, including triacetin
18	Sodium lauryl sulfate in the barrier coating
19-22	Coating weight from about 5% to 200% of matrix weight, with narrower ranges of 30%-45%, 35%-50%, and 50%
23	Defined list of active pharmaceutical ingredients
24-25	Diphenhydramine or dextromethorphan
26	Compressed tablet
28-29	Capsule-filled powder and 5%-10% plasticizer

Claims 13 and 23 are particularly important commercially. Claim 13 captures a practical manufacturing recipe, while claim 23 ties the platform to a long list of drug products.

What drug products and active ingredients are implicated?

Claim 23 identifies the following active ingredients or pharmaceutically acceptable salts:

• morphine;
• oxycodone;
• albuterol;
• dextromethorphan;
• codeine;
• tramadol;
• pseudoephedrine;
• phenylephrine;
• hydrocodone;
• venlafaxine;
• ibuprofen;
• oxybutynin;
• clonidine;
• dexchlorpheniramine;
• fexofenadine;
• diphenhydramine;
• oxymorphone;
• carbinoxamine;
• dicyclomine;
• chlorpheniramine;
• amphetamine;
• naproxen;
• diclofenac;
• paroxetine;
• amoxicillin.

The claim does not protect the active ingredient as such. It protects a specified dosage-form architecture containing the active ingredient in a drug-ion exchange resin complex and coated matrix.

Claims 24 and 25 narrow the invention to diphenhydramine and dextromethorphan. These claims may be commercially significant because both drugs are used in oral cough, cold, allergy, and sleep products. The wording contains internal antecedent and drafting inconsistencies, including references to the drug-resin matrix in “(ii)” where the relevant matrix appears in “(i).” Such errors are evaluated under claim-construction rules and may affect enforceability or scope depending on whether the meaning is reasonably clear from the specification and prosecution history.

What formulation technology is protected?

Drug-ion exchange resin complex

The drug must be bound to a pharmaceutically acceptable, water-insoluble ion-exchange resin. The claim expressly identifies styrene-divinylbenzene copolymers and quaternary ammonium-functionalized versions.

The resin limitation excludes many alternative controlled-release systems, including:

• nonionic adsorption resins;
• soluble polymer-drug conjugates;
• lipid matrices without ion-exchange resin;
• osmotic systems;
• coated crystals without resin binding;
• purely hydrophilic gel matrices.

The claim does not require a particular commercial resin name. A different commercial resin may still fall within the claim if its chemical structure and functional characteristics satisfy the claimed styrene-divinylbenzene or quaternary ammonium limitations.

Particulate matrix

The drug-resin complex is combined with a water-insoluble polymer, copolymer, or hydrophilic polymer. The claimed concentration is about 3% to about 30% relative to the weight of the drug-resin complex.

Examples include:

• polyvinyl acetate;
• polyvinylpyrrolidone;
• acrylate polymers;
• ethyl acrylate-methyl methacrylate copolymers;
• combinations of water-insoluble and hydrophilic polymers.

The matrix must be particulate and capable of passing through a No. 40 mesh screen. This corresponds to a particle-size limitation of approximately 425 micrometers, although the precise analytical result depends on the applicable mesh standard and testing method.

Polyvinyl acetate barrier coating

The external barrier is a cured aqueous-dispersion coating containing approximately 75% to 90% polyvinyl acetate. The coating must remain water permeable and water insoluble after curing.

The coating also requires:

• a stabilizer;
• a plasticizer;
• sufficient tensile strength;
• diffusion-control functionality;
• nonionic polymeric character.

Triacetin is expressly identified as a plasticizer. Polyvinylpyrrolidone and sodium lauryl sulfate are identified in narrower claims.

The coating weight is highly consequential. Claims 19-22 extend from approximately 5% to 200% of the matrix weight, with commercially practical embodiments at 30%-45%, 35%-50%, and 50%.

How strong is the patent estate for U.S. Patent 8,337,890?

The patent has moderate technical breadth but narrow literal claim architecture.

Strengths

1. The independent claims combine several formulation layers, making a direct copy more difficult to design.
2. The claim covers multiple drugs and both tablet and powder formats.
3. The resin chemistry is defined functionally and structurally.
4. The coating system includes commercially practical polyvinyl acetate dispersions.
5. The claims cover both composition and, through claim 13, a specific preparation process.
6. The at-least-eight-hour release requirement is a product-performance limitation that can support infringement testing through dissolution data.

Weaknesses

1. Every limitation in claim 1 must be present for literal infringement.
2. A competitor may attempt to replace polyvinyl acetate with another coating polymer.
3. A competitor may use a non-ion-exchange carrier or a different resin chemistry.
4. The claimed matrix polymer percentage is measured relative to the drug-resin complex, creating potential analytical disputes.
5. “At least an 8 hour release profile” may require construction of the release test, medium, apparatus, sampling schedule, and percentage-release endpoint.
6. The term “high tensile strength” may require specification-based interpretation.
7. Claims 24 and 25 contain drafting defects that could create construction disputes.
8. The claim set does not clearly cover every liquid dosage form, despite the technology’s relevance to oral liquid products.

The most defensible infringement theory would focus on a product that uses the same drug-resin complex, a polyvinyl acetate/polyvinylpyrrolidone matrix, an aqueous polyvinyl acetate coating, triacetin, and an eight-hour dissolution profile.

When does U.S. Patent 8,337,890 lose exclusivity?

The patent issued on December 25, 2012. Its ordinary U.S. patent term is generally measured as 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension under 35 U.S.C. §§ 154 and 156 [2].

Public patent records identify the patent as part of a modified-release formulation family associated with Tris Pharma. The practical expiration date must be confirmed from the USPTO Patent Center term calculation because the effective date can change with:

• the earliest priority filing;
• continuation or divisional relationships;
• patent-term adjustment;
• terminal disclaimer;
• any patent-term extension.

For commercial planning, the patent should be treated as potentially relevant through the late 2020s unless the USPTO record establishes an earlier terminal date. A patent expiration date cannot be inferred solely from the grant date.

What is the Orange Book status of U.S. Patent 8,337,890?

A patent number alone does not establish Orange Book listing status. FDA Orange Book listings are tied to an approved drug application and a specific NDA or supplement, not to the patent in isolation [3].

The patent’s claims are formulation claims and method-adjacent product claims. They could be listed in the Orange Book if an NDA holder submitted them as claiming:

• the drug substance;
• the drug product;
• a method of using the approved product.

The claims provided do not identify an NDA, reference-listed drug, trade name, or approved strength. On the available claim information, Orange Book listing status is not established.

For a listed product, a generic applicant could challenge an applicable listed patent through a Paragraph IV certification under the Hatch-Waxman framework. The patent’s inclusion in the Orange Book, rather than its technical relevance alone, would determine whether a Paragraph IV notice and associated 30-month stay could arise [4].

Which companies are likely to challenge or design around the patent?

Potential challengers would include generic manufacturers and branded companies developing oral modified-release products based on drug-resin technology. The principal competitive groups are:

Competitor type	Likely strategy
Generic drug manufacturers	Paragraph IV certification if the patent is listed for the target NDA
OTC cough and cold companies	Substitute coating polymer, resin, or release mechanism
Specialty pharmaceutical companies	Use alternative multiparticulate technology
Contract manufacturers	Develop non-infringing resin and coating combinations
Branded lifecycle managers	License or acquire drug-resin technology

A Paragraph IV challenge would likely attack claim construction, written description, enablement, obviousness, anticipation, or indefiniteness. The most vulnerable issues would be the combination of known drug-resin complexes with known polyvinyl acetate coatings, the definition of tensile strength and elongation, and the scope of the eight-hour release limitation.

What prior-art technologies compete with this patent?

The relevant patent landscape includes four technology groups.

Drug-resin complexes

Earlier patents broadly disclose binding ionizable drugs to ion-exchange resins to control release, mask taste, or improve formulation handling. These references create prior-art pressure against broad claims directed only to drug-resin complexes.

Polymer-coated resin particles

A second group covers coating drug-resin particles with water-insoluble or semipermeable polymers. These references may be relevant to anticipation or obviousness, depending on whether they disclose the claimed particulate matrix before the external polyvinyl acetate coating.

Polyvinyl acetate aqueous dispersions

A third group covers aqueous polyvinyl acetate dispersions, stabilizers, plasticizers, curing conditions, and film properties. The patent’s strongest distinction is the claimed use of this coating in combination with a drug-resin matrix and a specified release duration.

Multiparticulate tablets and capsules

A fourth group covers compressed multiparticulates, powder-filled capsules, and immediate-release particles combined with modified-release particles. Claims 6 and 7 are directed to this mixed-release architecture.

The patent’s competitive position depends on the combination of these elements, not on any single material.

What generic launch risks exist?

At-risk launch

A generic company could launch at risk if it believes the patent is invalid, not infringed, expired, or not properly listed. The principal exposure would be an injunction, damages, enhanced damages for willful infringement, and disruption of supply or approval strategy.

Paragraph IV litigation

If the patent is listed against an NDA, a Paragraph IV certification could trigger:

1. notice to the patent owner and NDA holder;
2. a 45-day period for filing an infringement action;
3. a potential 30-month FDA approval stay;
4. litigation over validity, enforceability, and infringement [4].

Skinny-label strategy

A skinny-label or section viii strategy is less straightforward for these claims because the claims are directed primarily to composition and dosage-form architecture rather than only to a patented indication. Removing a method-of-use indication would not avoid a formulation claim.

Design-around strategy

A competitor could seek to avoid infringement by using:

• a non-styrene-divinylbenzene resin;
• a cationic or anionic carrier outside the claimed resin categories;
• a coating other than polyvinyl acetate;
• a nonaqueous coating process;
• a matrix polymer concentration outside the claimed range;
• a particle size larger than the claimed No. 40 mesh threshold;
• a release profile shorter than eight hours;
• a nonionic coating with materially different composition;
• a liquid or non-solid dosage form, if the final product falls outside the claim language.

A design-around must account for claim construction and doctrine-of-equivalents risk.

Does the patent cover manufacturing processes?

The patent primarily claims compositions. Claim 13 adds a process limitation involving:

• mixing the drug-resin complex with an aqueous polyvinyl acetate, polyvinylpyrrolidone, and sodium lauryl sulfate dispersion;
• forming a mass;
• drying the mass;
• milling through a No. 40 mesh screen;
• using a specified solids composition.

This process claim creates manufacturing-IP risk for a supplier or contract manufacturer even if the finished product’s composition is disputed. Process evidence may be obtained through batch records, master manufacturing instructions, coating records, raw-material specifications, and dissolution testing.

What litigation and licensing issues should be reviewed?

No litigation, settlement, or license agreement can be attributed solely from the claim text. The relevant diligence sources are USPTO Patent Center, PACER, FDA’s Orange Book, SEC filings, and assignment records.

A transaction involving this patent should examine:

• prosecution-history amendments;
• examiner interviews;
• terminal disclaimers;
• continuity statements;
• reexamination or post-grant proceedings;
• assignment and security-interest records;
• Orange Book submissions;
• NDA-specific patent certifications;
• covenant-not-to-sue provisions;
• field-of-use licenses;
• settlement agreements with generic applicants;
• manufacturing licenses involving resin complexes or polyvinyl acetate coatings.

Patent ownership and licensing should be separated from product-specific rights. A company may own the patent while another company controls the NDA, formulation, manufacturing process, or commercial license.

How does U.S. Patent 8,337,890 compare with alternative controlled-release platforms?

Platform	Core release mechanism	Main difference from U.S. 8,337,890
Ion-exchange resin without polymer matrix	Drug-resin ionic binding	Lacks the claimed matrix/coating combination
Hydrophilic gel matrix	Polymer swelling and diffusion	Does not require an ion-exchange resin
Water-insoluble polymer matrix	Diffusion through polymer	May lack drug-resin complex and external coating
Osmotic tablet	Osmotic pressure and membrane	Different dosage-form architecture
Lipid or wax matrix	Erosion and diffusion	Does not require polyvinyl acetate barrier
Enteric coating	pH-dependent dissolution	Does not necessarily provide an eight-hour neutral diffusion profile
Multiparticulate coating	Polymer membrane diffusion	May be close if combined with the claimed resin and matrix

The closest competing technology is a multiparticulate drug-resin system using a water-insoluble polymer coating. The key differentiation is the required intermediate particulate matrix plus cured polyvinyl acetate barrier.

Key Takeaways

• U.S. Patent 8,337,890 is a formulation-platform patent, not a compound patent.
• Claims 1 and 27 require a drug-ion exchange resin complex, polymer-containing particulate matrix, cured polyvinyl acetate barrier, and at least an eight-hour release profile.
• The patent covers tablets, powders, and capsules through its claim structure.
• Claims 23-25 connect the platform to dextromethorphan, diphenhydramine, opioids, antihistamines, sympathomimetics, antidepressants, and other drugs.
• Claims 13 and 16-22 create substantial process and coating-specific limitations.
• A product using only a drug-resin complex or only a polyvinyl acetate coating may avoid literal infringement.
• Orange Book status cannot be determined from the patent number without an associated NDA and FDA listing.
• Paragraph IV risk depends on Orange Book listing, patent term, claim construction, and the target product’s formulation.
• The primary design-around routes are alternative resin chemistry, alternative coating polymer, nonaqueous processing, different matrix loading, and a different release architecture.
• The patent’s practical exclusivity period should be verified through USPTO Patent Center, with potential relevance extending into the late 2020s.

Frequently Asked Questions

Does U.S. Patent 8,337,890 cover dextromethorphan itself?

No. It covers specified modified-release compositions containing dextromethorphan in a drug-ion exchange resin complex. The active ingredient alone is not protected by these claims.

Can a tablet infringe if it contains uncoated immediate-release drug particles?

Yes. Claims 6, 7, and 26 contemplate a finished tablet containing coated modified-release particles and an uncoated drug-resin complex. The uncoated component may contain the same or a different drug.

Is a polyvinyl acetate coating alone enough to infringe?

No. The independent claims require the polyvinyl acetate coating in combination with the claimed drug-resin complex and particulate matrix architecture.

Does the patent cover an oral liquid formulation?

The claims provided are directed to a solid composition or powder composition. An oral liquid would require separate analysis under the claim language, prosecution history, and any related patent family members.

Can a generic use a different ion-exchange resin?

Potentially. A different resin may avoid literal infringement if it does not satisfy the claimed styrene-divinylbenzene or quaternary ammonium-functionalized resin limitations. Equivalence, however, would depend on the specific formulation and litigation record.

References

1. United States Patent No. 8,337,890, “Modified release compositions.” U.S. Patent and Trademark Office, issued December 25, 2012.

2. United States Code, Title 35, §§ 154 and 156. Patent term and patent-term extension provisions.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

4. U.S. Food and Drug Administration. (2017). Regulatory procedures for drug products submitted under section 505(b)(2) and 505(j) of the Federal Food, Drug, and Cosmetic Act. FDA.

Drugs Protected by US Patent 8,337,890

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Tris Pharma Inc	DYANAVEL XR 10	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-002	Nov 4, 2021		RX	Yes	No	8,337,890		Y
Tris Pharma Inc	DYANAVEL XR 15	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-003	Nov 4, 2021		RX	Yes	No	8,337,890		Y
Tris Pharma Inc	DYANAVEL XR 20	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-004	Nov 4, 2021		RX	Yes	Yes	8,337,890		Y
Tris Pharma Inc	DYANAVEL XR 5	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-001	Nov 4, 2021		RX	Yes	No	8,337,890		Y
Rosemont	NEXICLON XR	clonidine	TABLET, EXTENDED RELEASE;ORAL	022500-001	Dec 3, 2009		RX	No	No	8,337,890		Y
Rosemont	NEXICLON XR	clonidine	TABLET, EXTENDED RELEASE;ORAL	022500-002	Dec 3, 2009		DISCN	No	No	8,337,890		Y

International Family Members for US Patent 8,337,890

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	E536867
Australia	2007227569
Brazil	PI0709606
Canada	2645855
China	101400343
China	102488652
Denmark	2018160