Details for Patent: 11,590,081

Which drugs does patent 11,590,081 protect, and when does it expire?

Patent 11,590,081 protects DYANAVEL XR 10, DYANAVEL XR 15, DYANAVEL XR 20, and DYANAVEL XR 5, and is included in one NDA.

Summary for Patent: 11,590,081

Title:	Extended release amphetamine tablets
Abstract:	An oral amphetamine extended release solid dose is described. The compositions contain a combination of an uncoated amphetamine-cation exchange resin complex, a barrier coated amphetamine—cation exchange resin complex—matrix, and an uncomplexed amphetamine, wherein one or more of these components contains blends of different forms of amphetamines. Either the modified release coated and/or the uncoated amphetamine—cation exchange resin complex may have two forms of amphetamine in a complex with a single cation exchange resin. Following administration of a single dose of the composition, a therapeutically effective amount of amphetamine is reached by about one hour and the composition provides at least a thirteen hour effect post-dose.
Inventor(s):	Ketan Mehta, Kalyan Kathala
Assignee:	PROVIDENT BANK
Application Number:	US16/139,251
Patent Claim Types: see list of patent claims	Use; Composition; Dosage form;

United States Patent 11,590,081: Scope, Claims, Expiration, and Amphetamine Patent Landscape

United States Patent No. 11,590,081 protects specific extended-release amphetamine tablets and compositions that combine immediate-release and modified-release amphetamine fractions. The patent is directed to mixed d-amphetamine/l-amphetamine products using cation-exchange resin complexes, pH-independent barrier coatings, defined release proportions, pharmacokinetic profiles, and, in several claims, chewable or orally disintegrating dosage forms.

The claims are highly formulation-specific. They do not broadly cover amphetamine, mixed amphetamine salts, or extended-release amphetamine products generally. The principal commercial relevance is to products resembling Adzenys XR-ODT and related mixed-amphetamine oral dosage forms developed by Neos Therapeutics.

What drug product does United States Patent 11,590,081 protect?

The patent protects a multipart extended-release amphetamine dosage form with three functional drug populations:

Component	Function	Key claim limitations
Modified-release component	Delivers amphetamine over an extended interval	Barrier-coated amphetamine-cation exchange resin complex; pH-independent coating
First immediate-release component	Provides early systemic exposure	d-amphetamine and l-amphetamine, or corresponding mixtures and salts
Second immediate-release component	Provides additional immediate release from a resin complex	d- and l-amphetamine bound to the same cation-exchange resin

Claim 1 requires the tablet to provide a single plasma concentration peak for both d-amphetamine and l-amphetamine. It also requires the tablet to lack a pH-dependent coating that delays release of an amphetamine component.

The claimed architecture is therefore different from a conventional enteric dosage form. The release profile is generated primarily through the proportion of immediate-release amphetamine, resin-complexed amphetamine, and a pH-independent barrier coating.

How many independent claims are in US 11,590,081?

The patent contains five principal independent claim groups:

Claim	Independent subject matter	Commercial significance
1	Extended-release amphetamine tablet	Broadest tablet formulation claim
27	Extended-release amphetamine solid composition	More specific percentage and coating limitations
32	ADHD treatment method using claim 1 composition	Once-daily therapeutic-use claim
33	ADHD treatment method using claim 27 composition	Once-daily use of the defined solid composition
34	Extended-release amphetamine tablet	Product-specific claim with named salts and a 3.2:1 d/l ratio
35	Once-daily ADHD treatment method	Chewable tablet administered in the morning

Claims 2 through 26 depend directly or indirectly from claim 1. Claims 28 through 31 depend from claim 27. Claims 36 and 37 depend from claim 35.

The patent’s practical protection is concentrated in claims 1, 27, 34, and 35. The dependent claims narrow the formulation by adding release percentages, pharmacokinetic ranges, dosage form, coating chemistry, tablet weight, dose, duration, and administration conditions.

What are the core limitations of claim 1?

Claim 1 requires all of the following:

1. An extended-release amphetamine tablet.
2. A single plasma concentration peak for d-amphetamine.
3. A single plasma concentration peak for l-amphetamine.
4. No pH-dependent coating that delays release of an amphetamine component.
5. A modified-release amphetamine component.
6. At least one barrier-coated amphetamine-cation exchange resin complex.
7. At least two amphetamines bound to the same cation-exchange resin.
8. At least d-amphetamine and l-amphetamine in the modified-release complex.
9. A pH-independent barrier coating.
10. Modified-release amphetamine representing at least 5% of total amphetamines.
11. Immediate-release amphetamine representing more than 70% of total amphetamines.
12. A first immediate-release component containing d- and l-amphetamine.
13. A second immediate-release component containing an amphetamine-cation exchange resin complex.
14. At least 5% of total amphetamine in each immediate-release subcomponent.

A competitor avoiding any required element may avoid literal infringement of claim 1. The most important design-around variables are the immediate-release percentage, resin structure, d/l amphetamine distribution, coating chemistry, and release profile.

What formulations are protected by claims 27 and 34?

Claim 27: defined three-component composition

Claim 27 narrows the formulation in several important respects:

• Modified-release component: approximately 10% to 30% by weight of amphetamine.
• Modified-release complex: d,l-amphetamine and d-amphetamine bound to the same cation-exchange resin.
• Coating: water-insoluble, water-permeable, pH-independent polymer plus plasticizer.
• First immediate-release component: at least 15% of amphetamine.
• Second immediate-release component: at least 15% of amphetamine.
• Total immediate-release fraction: at least 70%.
• Therapeutic effect: approximately 13 hours.
• Single plasma peak for each amphetamine enantiomer.

Claim 27 is narrower than claim 1 because it specifies the approximate proportion of the modified-release fraction and requires the two immediate-release components to meet individual minimum amounts.

Claim 34: commercial mixed-salt formulation

Claim 34 has a different and commercially important profile. It requires:

• At least about 13 hours of therapeutic effect.
• A single peak for d-amphetamine and l-amphetamine.
• A pH-independent water-insoluble, water-permeable barrier coating.
• Polyvinyl acetate and a plasticizer in the coating.
• A d-amphetamine:l-amphetamine ratio of approximately 3.2:1.
• More than 60% immediate-release amphetamine.
• An immediate-release resin complex containing d- and l-amphetamine.
• Amphetamine aspartate.
• Dextroamphetamine sulfate.

The named salts and 3.2:1 enantiomer ratio make claim 34 easier to compare with a product label and formulation record than claim 1. They also make it narrower and potentially more vulnerable to a salt, ratio, or excipient design-around.

What do claims 2 through 26 add?

The principal dependent-claim limitations are:

Claims	Added limitation
2	Approximately 80% of total amphetamine is immediate release
3	Approximately 20% is in the first immediate-release component
4	Approximately 60% is in the second immediate-release component
5-8	Defined d-amphetamine and l-amphetamine PK ranges after chewing or swallowing
9-12	PK relationship to pediatric or adult reference profiles
13	Water-insoluble or hydrophilic polymer matrix
14	Modified-release component includes d,l-amphetamine and d-amphetamine
15	Immediate-release component includes d,l-amphetamine and d-amphetamine
16	Resin-complex coating releases amphetamine in less than 45 minutes
17	Defined d/l amphetamine and salt combinations
18	At least two different amphetamine salt counterions
19	Chewable tablet
20	Orally dissolving, disintegrating, or dispersible chewable tablet
21	Specific pH-independent coating chemistries
22	Tablet weight no greater than 500 mg
23	Therapeutic effect lasting up to approximately 18 hours
24	Separate cation-exchange resins for d,l-amphetamine and d-amphetamine
25	Approximately 70% to 90% polyvinyl acetate and 2% to 10% plasticizer
26	Plasticizer is triacetin

Claims 19 through 26 are especially relevant to an orally disintegrating or chewable commercial product. Claims 21, 25, and 26 target manufacturing and coating choices rather than only pharmacokinetics.

The claim text contains internal nomenclature inconsistencies. For example, claims 15, 16, and 21 refer to immediate-release component “C,” although claim 1 labels the components as B(i) and B(ii). Similar inconsistencies appear in claims 5 through 12, including duplicated units and imprecise references to arithmetic and geometric means. These issues may create claim-construction and definiteness disputes, although they do not automatically invalidate the claims.

What is the scope of the pharmacokinetic claims?

Claims 5 through 12 cover products meeting specified PK parameters for both amphetamine enantiomers under fasted conditions. The parameters include:

• AUC0-inf.
• AUC0-2.
• AUC0-5.
• AUC5-t.
• Cmax.
• Tmax.
• Chewed-dose exposure.
• Whole-swallowed-tablet exposure.
• Pediatric exposure.
• Adult exposure.
• Arithmetic and geometric means.

Representative claim 6 values for a 20 mg equivalent dose include:

Parameter	Chewed dose	Whole swallowed dose
d-amphetamine geometric mean AUC0-inf	About 1,164 ng-h/mL	About 1,185 ng-h/mL
d-amphetamine geometric mean Cmax	About 54 ng/mL	About 53 ng/mL
d-amphetamine Tmax	About 5 hours	About 5 hours
l-amphetamine geometric mean AUC0-inf	About 453 ng-h/mL	About 466 ng-h/mL
l-amphetamine geometric mean Cmax	About 17 ng/mL	About 17 ng/mL
l-amphetamine Tmax	About 5 hours	About 5 hours

PK claims can be difficult to enforce because infringement requires reliable testing of the accused product under the specified dose, fasting condition, administration mode, population, assay, and statistical method. They can still be important in litigation when a generic applicant’s bioequivalence data are available through an ANDA dispute.

Claims 9 through 12 also use 80% to 125% and 90% to 110% relationships to reference PK values. These limitations may create disputes over whether the claimed range applies to an individual parameter, a confidence interval, or the full PK profile.

What patent protects Adzenys XR-ODT and related products?

Adzenys XR-ODT is an extended-release amphetamine orally disintegrating tablet containing mixed amphetamine salts. The FDA-approved product uses a 3:1 d-amphetamine to l-amphetamine ratio and includes amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, and dextroamphetamine sulfate.[1]

The product’s dosage form and formulation characteristics overlap with the subject matter of US 11,590,081:

• Mixed d- and l-amphetamine.
• Extended release.
• Orally disintegrating tablet.
• Immediate-release and modified-release fractions.
• Ion-exchange resin technology.
• pH-independent release technology.
• Approximately 13-hour clinical effect.

The precise relationship between the patent claims and the approved product must be assessed against the approved labeling, FDA reference-listing information, manufacturing records, and the patent’s prosecution history. A product can practice the patent’s technology without infringing every issued claim.

What is the Orange Book status of US 11,590,081?

The FDA Orange Book is the controlling source for patent and exclusivity listings associated with an approved drug product.[2] Patent listing status is product-specific. A patent is not automatically an Orange Book patent merely because it covers a formulation resembling an approved product.

US 11,590,081 should be evaluated in four separate categories:

Issue	Relevance
Listed patent	Determines whether an ANDA applicant must address the patent
Use code	Determines whether the listed method relates to the proposed indication
Patent expiration	Determines the nominal end of the listed patent barrier
Pediatric exclusivity or other extensions	Can add six months to applicable listed protection

The claims include composition, dosage-form, and treatment-method limitations. FDA listing rules generally focus on patents that claim the drug substance, drug product, or an approved method of use. A method claim directed to once-daily ADHD treatment may be listed only if it meets FDA listing requirements and is associated with an approved use code.[3]

Patent No. 11,590,081 issued on February 28, 2023. Its enforceability period depends on the earliest effective nonprovisional filing date, patent-term adjustment, terminal disclaimers, and any applicable regulatory exclusivity. The issue date alone does not establish the expiration date.

When does US 11,590,081 lose exclusivity?

The patent’s statutory term generally runs 20 years from the earliest effective nonprovisional U.S. filing date, subject to patent-term adjustment and terminal disclaimer rules.[4] The provisional priority date does not itself start the 20-year patent term.

For commercial planning, the relevant date is the later of:

1. The patent’s calculated statutory expiration date.
2. Any applicable patent-term adjustment.
3. Any pediatric exclusivity period attached to the relevant product.
4. The end date of other Orange Book-listed patents that may independently block approval or launch.

Patent expiration also does not guarantee immediate generic entry. An ANDA sponsor may face other listed patents, regulatory exclusivity, controlled-substance manufacturing requirements, or a settlement-restricted launch date.

Which companies are challenging the amphetamine patent estate?

The relevant competitive field includes:

• Neos Therapeutics, the original developer of Adzenys XR-ODT.
• Aytu BioPharma, which acquired commercial rights and products from Neos.
• Shire and Takeda, commercial developers of Mydayis and other mixed amphetamine products.
• Teva, Sandoz, Amneal, Mallinckrodt, and other generic manufacturers with amphetamine product capabilities.
• Manufacturers of generic mixed amphetamine salts immediate-release and extended-release capsules.

A Paragraph IV challenge would be expected to target one or more of the following:

• Absence of a pH-dependent delayed-release coating.
• Different d/l amphetamine ratio.
• Different amphetamine salt combination.
• Immediate-release fraction below the claimed threshold.
• Use of separate resins rather than the same resin.
• Different coating polymer or plasticizer.
• Lack of a single plasma peak.
• Failure to meet the claimed 13-hour therapeutic effect.
• Failure to satisfy the PK limitations.

No biosimilar pathway applies. Amphetamine is a chemically synthesized small molecule, so a competitor would use an ANDA, 505(b)(2) application, or NDA pathway rather than a biosimilar application.[5]

How strong is the patent estate for US 11,590,081?

The patent has meaningful commercial value but a narrower infringement perimeter than a drug-substance patent.

Strength factor	Assessment
Formulation detail	Strong; multiple structural limitations identify the product architecture
Product relevance	Strong for mixed-salt chewable and orally disintegrating tablets
Design-around exposure	Moderate to high because release percentages, salts, ratios, resin selection, and coatings can change
PK claim value	Moderate; useful but testing-intensive
Manufacturing protection	Moderate; coating composition claims may capture process-equivalent formulations
Composition breadth	Limited; the patent does not broadly cover all extended-release amphetamine
Invalidity exposure	Moderate; complex claims may face written-description, enablement, definiteness, obviousness, or anticipation attacks
Litigation leverage	Strongest where the accused product uses the same salt set, resin architecture, coating, and d/l ratio

The strongest claims are likely claims 27, 34, and 35 when the commercial product matches their numerical and structural requirements. Claim 1 is broader in some respects but still requires the unusual combination of two immediate-release components, a modified-release resin complex, and a single peak for each enantiomer.

What generic launch risks exist?

A generic launch could proceed through several scenarios:

Launch scenario	Risk profile
Paragraph III certification	Launch deferred until patent expiration
Paragraph IV certification with notice	Patent litigation risk and possible 30-month stay
505(b)(2) route	Potentially different regulatory and patent strategy
Formulation design-around	Lower literal-infringement risk but higher development risk
Authorized or licensed generic	Reduces litigation exposure but requires commercial agreement
Settlement with delayed entry	Entry date depends on negotiated terms and antitrust review

A generic manufacturer must compare its formulation against every limitation, not only the active ingredient and dosage strength. A product containing mixed amphetamine salts but lacking the claimed resin complex or pH-independent coating may avoid infringement. Conversely, changing only the tablet presentation may not avoid claims that cover the underlying composition.

What manufacturing and geographic barriers matter?

The patent is a United States right. It does not establish protection in Europe, Canada, Japan, or other jurisdictions. International protection must be assessed through the related PCT application and national-stage patents.

Manufacturing barriers may remain even after patent expiry. The product requires control of:

• Amphetamine loading onto cation-exchange resin.
• Enantiomer and salt composition.
• Barrier-coating weight gain.
• Polymer permeability.
• Plasticizer content.
• Release uniformity.
• Chewability and oral disintegration.
• Dose proportionality.
• Stability of controlled-substance material.
• Bioequivalence after chewing and swallowing.

The combination of formulation engineering and controlled-substance manufacturing can delay generic commercialization even when a patent challenge succeeds.

What litigation and settlement agreements affect the patent?

The patent document itself does not establish a settlement agreement or a definitive launch date. Settlement terms, if any, would typically appear in Hatch-Waxman litigation dockets, FDA communications, or antitrust filings rather than in the issued patent.

For diligence, the key litigation questions are whether an ANDA applicant has:

• Filed a Paragraph IV certification.
• Received a notice letter.
• Triggered a 45-day infringement period.
• Been sued within that period.
• Obtained a 30-month stay.
• Entered a license or early-entry settlement.
• Agreed to a consent judgment or covenant not to sue.

Patent litigation involving related Adzenys XR-ODT patents may affect commercial risk even if US 11,590,081 is not the only asserted patent.

Key Takeaways

• US 11,590,081 is a formulation and method-of-use patent, not a broad amphetamine composition patent.
• Its central technology combines immediate-release amphetamine with pH-independent modified-release amphetamine-resin complexes.
• The most commercially relevant limitations are the mixed d/l amphetamine composition, cation-exchange resin, pH-independent barrier coating, immediate-release percentage, single plasma peak, and approximately 13-hour effect.
• Claims 34 and 35 are particularly important for products using the named amphetamine salts, a 3.2:1 d/l ratio, chewable administration, and morning once-daily dosing.
• Claims 5 through 12 add PK limitations that may be difficult to establish without controlled testing.
• Generic risk is formulation-specific. A generic sponsor may design around the patent by changing the resin architecture, coating, salt mixture, release proportions, or enantiomer ratio.
• No biosimilar pathway applies because amphetamine is a small-molecule controlled substance.
• Patent expiration must be calculated from the earliest effective nonprovisional filing date and adjusted for patent-term adjustment, terminal disclaimers, and applicable exclusivity.
• The FDA Orange Book, patent prosecution file, related family members, and Hatch-Waxman litigation records control the final launch analysis.

Frequently Asked Questions

Does US 11,590,081 cover all mixed amphetamine salts products?

No. It covers products meeting the claim’s specific release architecture, resin, coating, amphetamine distribution, and pharmacokinetic limitations.

Can a generic avoid the patent by using a different amphetamine salt?

Potentially. Claims requiring amphetamine aspartate and dextroamphetamine sulfate may be avoided by a formulation using different salts, provided the product does not infringe another claim or related patent.

Does the patent cover an amphetamine capsule?

The issued claims are directed primarily to tablets and solid compositions, including chewable, orally dissolving, orally disintegrating, dispersible, and scored tablets. A capsule would require a separate claim analysis.

Is a 13-hour duration alone enough to infringe?

No. The duration limitation is only one element. The accused product must satisfy all limitations of the asserted claim.

Can a Paragraph IV applicant launch before patent expiry?

It can launch only after resolving the patent dispute, obtaining a judgment of noninfringement or invalidity, reaching a settlement permitting launch, or otherwise clearing the applicable patent and regulatory barriers.

References

1. U.S. Food and Drug Administration. (2023). Adzenys XR-ODT prescribing information.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
3. U.S. Food and Drug Administration. (2016). Approved drug product and patent listing requirements and recommendations.
4. United States Patent and Trademark Office. (2024). Patent term and adjustment provisions under 35 U.S.C. §§ 154 and 156.
5. U.S. Food and Drug Administration. (2024). Abbreviated new drug application pathway for generic drugs.
6. U.S. Patent No. 11,590,081. (2023). Extended release amphetamine formulation. United States Patent and Trademark Office.

Drugs Protected by US Patent 11,590,081

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	11,590,081		Y			METHOD OF TREATING ATTENTION DEFICIT HYPERACTIVITY DISORDER
Tris Pharma Inc	DYANAVEL XR 15	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-003	Nov 4, 2021		RX	Yes	No	11,590,081		Y			METHOD OF TREATING ATTENTION DEFICIT HYPERACTIVITY DISORDER
Tris Pharma Inc	DYANAVEL XR 20	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-004	Nov 4, 2021		RX	Yes	Yes	11,590,081		Y			METHOD OF TREATING ATTENTION DEFICIT HYPERACTIVITY DISORDER
Tris Pharma Inc	DYANAVEL XR 5	amphetamine; amphetamine aspartate/dextroamphetamine sulfate	TABLET, EXTENDED RELEASE;ORAL	210526-001	Nov 4, 2021		RX	Yes	No	11,590,081		Y			METHOD OF TREATING ATTENTION DEFICIT HYPERACTIVITY DISORDER