United States Patent 10,322,120: Hydrocodone Extended-Release Kit Claims, Patent Scope, and Generic Entry Risk
U.S. Patent No. 10,322,120 protects a hydrocodone bitartrate extended-release capsule kit defined by a specific multiparticulate formulation, dissolution profile, hepatic-impairment pharmacokinetic profile, and, in several claims, dosing instructions. The patent is a formulation and method-of-use patent, not a hydrocodone composition-of-matter patent.
The broadest independent claims are claims 1 and 11. Claim 1 requires a package, written dosing instructions, specified capsule excipients, five possible strengths, immediate- and sustained-release components, dissolution limits, and hepatic-impairment pharmacokinetic limitations. Claim 11 omits the express written-instruction requirement and uses narrower PK limits for AUC and Cmax.
The patent’s principal commercial relevance is Zohydro ER, an extended-release hydrocodone bitartrate capsule product. The patent estate creates meaningful risk for an ANDA product that copies the Zohydro ER multiparticulate architecture and labeled use, but it does not prevent all extended-release hydrocodone products.
What does U.S. Patent 10,322,120 protect?
Patent 10,322,120 protects a kit containing extended-release hydrocodone bitartrate dosage units for patients requiring around-the-clock, long-term opioid treatment. The dosage units must be capsules containing multiparticulate immediate-release and sustained-release components.
The independent claims combine four categories of limitations:
| Limitation category |
Claim 1 |
Claim 11 |
| Extended-release hydrocodone dosage units |
Required |
Required |
| Hydrocodone bitartrate as only active ingredient |
Required through “consisting essentially only” language |
Expressly required |
| Gelatin capsule shell |
Required |
Required |
| Sugar spheres, hypromellose, ammonia methacrylate copolymer, silicon dioxide and talc |
Required |
Required |
| Multiparticulate composition with at least two particle groups |
Required |
Required |
| Immediate-release and sustained-release components |
Required |
Required |
| Package |
Required |
Required |
| Written dosing instructions |
Required |
Not expressly required |
| Hydrocodone strengths |
15, 20, 30, 40 or 50 mg |
15 mg or more in dependent claim 12 |
| First-hour release |
About 10% to 30% |
Added by claim 14 |
| First-12-hour release |
More than 60% and less than 98% |
Added by claim 15 |
| Hepatic AUC limits |
More than 30% mild and 50% moderate excluded |
More than 14% mild and 30% moderate excluded |
| Hepatic Cmax limits |
Not required in claim 1 |
More than 9% mild and 14% moderate excluded |
The claims are cumulative. A product must satisfy every limitation of the asserted claim. A product that has hydrocodone bitartrate and an extended-release profile but uses a tablet rather than a gelatin capsule, omits one of the specified excipients, or fails the claimed PK profile may fall outside the literal scope of the patent.
What are the key limitations in claims 1 through 19?
Claim 1: broad kit claim with formulation and PK requirements
Claim 1 requires:
- A kit for a specified chronic-pain population.
- Multiple extended-release opioid dosage units.
- Packaging.
- Written dosing instructions.
- A gelatin capsule.
- The listed excipients.
- Hydrocodone bitartrate as essentially the only active ingredient.
- At least two particle groups.
- Immediate-release and sustained-release components.
- Sustained-release hydrocodone representing 50% to 90% of total hydrocodone.
- A first-hour release of approximately 10% to 30%.
- A first-12-hour release above approximately 60% and below approximately 98%.
- Specified composition-by-weight ranges.
- Limits on hydrocodone exposure in mild and moderate hepatic impairment.
- Instructions stating that no starting-dose adjustment is required for some hepatic impairment.
The claim therefore combines structural, quantitative, performance, and labeling limitations. This combination makes the claim narrower than a conventional extended-release hydrocodone formulation claim.
Claims 2 and 3: hepatic-impairment subsets
Claims 2 and 3 narrow claim 1 to mild and moderate hepatic impairment, respectively. They add little formulation detail but reinforce the intended use and the hydrocodone bitartrate form.
Claims 4 and 5: narrower formulation and dissolution profile
Claim 4 narrows the product to 15, 20 or 30 mg strengths. It requires:
- 75% to 85% of hydrocodone in the sustained-release component;
- 15% to 25% release during the first hour;
- 65% to 95% release during the first 12 hours;
- A controlled-release polymer; and
- No starting-dose adjustment for mild hepatic impairment.
Claim 5 further narrows the strength to 20 or 30 mg, requires approximately 80% of hydrocodone in the sustained-release component, and specifies approximately 21% first-hour release and approximately 85% first-12-hour release. It also addresses moderate hepatic impairment.
These numerical limitations may provide narrower fallback positions if the broader ranges in claim 1 are invalidated or avoided.
Claims 6 through 10: PK limitations
Claims 6 and 7 impose tighter exposure limits:
| Parameter |
Mild hepatic impairment |
Moderate hepatic impairment |
| AUC increase, claim 6 |
No more than 14% |
No more than 30% |
| Cmax increase, claim 7 |
No more than 9% |
No more than 14% |
Claims 8 through 10 define absolute exposure ranges normalized to a 20 mg hydrocodone bitartrate dose:
| Population |
AUC0-inf range |
| No renal or hepatic impairment |
About 300 to 500 ng·h/mL |
| Mild hepatic impairment |
About 300 to 570 ng·h/mL |
| Moderate hepatic impairment |
About 300 to 700 ng·h/mL |
Claim 9 narrows the unimpaired range to approximately 317 to 465 ng·h/mL. Claim 10 narrows the moderate-hepatic-impairment range to approximately 352 to 666 ng·h/mL.
Claim 11: independent claim with tighter PK limits
Claim 11 is structurally similar to claim 1 but differs in several important respects:
- It expressly requires hydrocodone bitartrate as the only active ingredient.
- It requires at least one immediate-release particle group and one sustained-release particle group.
- It does not expressly require written dosing instructions.
- It imposes the tighter AUC and Cmax limits found in claims 6 and 7.
- It does not itself require the first-hour or first-12-hour dissolution ranges later added in claims 14 and 15.
Claim 11 may be commercially important because it does not depend expressly on the presence of written instructions in the package. Claims 12 through 19 add strengths, dissolution, PK ranges, and the 50% to 90% sustained-release fraction.
What product does the patent most directly cover?
The claimed architecture corresponds closely to Zohydro ER, an extended-release hydrocodone bitartrate capsule approved by the FDA for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment for which alternative treatment options are inadequate.
Zohydro ER uses hydrocodone bitartrate as the active ingredient and is supplied in multiple capsule strengths. Its formulation uses immediate-release and extended-release multiparticulates. The patent’s specification and claims focus on achieving extended release while limiting exposure changes in patients with hepatic impairment.
The patent is not directed to Hysingla ER. Hysingla ER is a hydrocodone bitartrate extended-release tablet product with a different dosage form and formulation platform. A Hysingla ER product generally would not satisfy the capsule, excipient, and multiparticulate limitations of patent 10,322,120 without additional facts showing equivalence or an infringing formulation.
When does U.S. Patent 10,322,120 expire?
U.S. Patent 10,322,120 was issued on June 18, 2019. Public patent-family information places its earliest relevant priority in the 2012 period, producing an expected patent-term endpoint in February 2032, subject to the official term calculation, patent-term adjustment, terminal disclaimers, and any applicable regulatory extension.
| Event |
Date or period |
| Earliest family priority |
February 2012 period |
| Patent issued |
June 18, 2019 |
| Expected base expiration |
February 2032 period |
| Patent-term adjustment |
Must be determined from the USPTO patent file |
| Patent-term extension |
No confirmed extension included in the claim set |
The February 2032 estimate is materially later than the FDA product’s initial approval period and may remain relevant to generic launch planning. A precise freedom-to-operate opinion should use the USPTO continuity data and the patent’s official term-adjustment calculation rather than the issue date alone.
What is the Orange Book status of patent 10,322,120?
The patent is associated with the Zohydro ER extended-release hydrocodone bitartrate product and is relevant to the FDA’s Orange Book patent-listing framework. An Orange Book listing can require an ANDA applicant to address the patent through a Paragraph IV certification if the applicant seeks approval before patent expiration.
Orange Book listing does not itself establish that every claim is valid or infringed. It creates a regulatory patent-certification consequence. The applicant must assess whether the listed patent claims the reference product, an approved use, or a formulation or method associated with the reference product.
For Zohydro ER, the relevant patent estate includes formulation and use patents rather than a hydrocodone molecule patent. The practical effect is that an ANDA applicant may challenge several patents at once, with each patent requiring a separate invalidity, noninfringement, or certification analysis.
How does patent 10,322,120 affect Paragraph IV challenges?
A generic applicant seeking approval before the estimated expiration date could use a Paragraph IV certification if it contends that the patent is invalid, unenforceable, or not infringed. The principal Paragraph IV arguments would likely focus on:
Noninfringement
A generic applicant could design around one or more required elements:
- Use a tablet rather than a gelatin capsule.
- Use a different multiparticulate architecture.
- Replace one or more named excipients.
- Use a different controlled-release polymer.
- Change the immediate-release fraction.
- Produce a dissolution profile outside the claimed numerical ranges.
- Use labeling that does not state that no starting-dose adjustment is required for the claimed hepatic-impairment population.
- Avoid the claimed hepatic AUC or Cmax profile.
The PK limitations may be difficult to assess before launch because they depend on clinical or comparative pharmacokinetic data. A product can satisfy the structural formulation limitations but fail the PK limitations, or satisfy the in vitro dissolution limitations without producing the claimed in vivo exposure profile.
Invalidity
Potential validity challenges include:
- Lack of written description for the full combination of formulation and PK ranges.
- Enablement concerns relating to the breadth of the excipient, composition, dissolution, and patient-response ranges.
- Obviousness based on known multiparticulate hydrocodone formulations, opioid pharmacokinetics, and hepatic-impairment studies.
- Indefiniteness involving terms such as “about,” “some degree of hepatic impairment,” “average,” “does not increase,” and “consisting essentially only.”
- Claim construction disputes over whether the PK limitations are product limitations, method limitations, or intended-use limitations.
The patent’s defense is stronger where the claimed ranges are tied to specific clinical data and a reproducible formulation. It is weaker where the claims attempt to cover broad formulation classes by reference to variable patient PK outcomes.
How strong is the patent estate for Zohydro ER?
The patent estate has moderate commercial strength but depends heavily on claim construction and product matching.
| Strength factor |
Assessment |
| Composition-of-matter protection |
None apparent from patent 10,322,120 |
| Dosage-form specificity |
Strong; claims require capsules |
| Formulation specificity |
Strong; named excipients and multiparticulate structure |
| Dissolution protection |
Moderate; numerical ranges create measurable boundaries |
| PK protection |
Moderate to strong if supported by reproducible data |
| Labeling protection |
Important for claim 1 and related use limitations |
| Design-around potential |
Material |
| Generic litigation exposure |
High if an ANDA copies the reference formulation |
| Relevance to unrelated hydrocodone products |
Limited |
The most defensible portion of the patent is likely the combination of capsule structure, named excipients, multiparticulate design, and measurable dissolution profile. The most vulnerable portions may be the broad PK limitations and functional language tied to hepatic impairment.
What formulations are protected by patent 10,322,120?
The claims protect formulations with the following characteristics:
- Hydrocodone bitartrate as the only active ingredient.
- A gelatin capsule shell.
- Sugar-sphere-based multiparticulates.
- Hypromellose.
- Ammonia methacrylate copolymer.
- Silicon dioxide.
- Talc.
- Immediate-release and sustained-release particle groups.
- Sustained-release hydrocodone generally representing 50% to 90% of total hydrocodone.
- Hydrocodone bitartrate representing 5% to 60% by weight.
- Controlled-release polymer representing up to 30% by weight.
- Other excipients representing 25% to 95% by weight.
- A controlled first-hour and first-12-hour release profile.
A capsule containing hydrocodone bitartrate but using a monolithic matrix, a different shell, a different release technology, or materially different excipients may avoid literal infringement. The doctrine of equivalents could remain relevant, but the multiple numerical limitations make an equivalents theory more constrained.
What patent litigation affects Zohydro ER and its generic entry?
The principal litigation risk is ANDA litigation involving a generic hydrocodone bitartrate extended-release capsule. The relevant defendants would be applicants filing an ANDA with Paragraph IV certifications against Zohydro ER patents.
The key litigation questions are:
- Whether the generic’s proposed capsule contains the claimed excipients.
- Whether the proposed product has at least two particle groups.
- Whether the generic’s dissolution data fall within the claimed ranges.
- Whether the product produces the claimed hepatic-impairment AUC and Cmax relationships.
- Whether the proposed label induces infringement of the claimed chronic-pain use.
- Whether the patent’s PK and functional limitations are definite and enabled.
- Whether any settlement permits a generic launch before the estimated February 2032 expiration.
No conclusion about a particular litigation outcome follows from the patent claims alone. The controlling evidence would be the ANDA product description, Paragraph IV notice, claim-construction record, expert pharmacokinetic evidence, and any settlement agreement.
Are biosimilar risks relevant to patent 10,322,120?
No. Biosimilar risk is not the relevant competitive issue because hydrocodone bitartrate is a small-molecule active ingredient. Competitors would ordinarily use the ANDA pathway, not the biosimilar pathway under the Public Health Service Act.
The competitive threats are:
- Generic hydrocodone bitartrate extended-release capsules.
- Alternative extended-release hydrocodone dosage forms.
- Other long-acting opioids.
- Non-opioid analgesics and interventional pain therapies.
- Abuse-deterrent or tamper-resistant opioid products.
What generic launch scenarios exist?
| Scenario |
Commercial result |
| Generic copies the capsule and multiparticulate formulation |
High Paragraph IV and litigation risk |
| Generic changes dosage form to tablet |
Lower risk under this patent, but other patents may apply |
| Generic changes excipients and release technology |
Potential design-around |
| Generic avoids the claimed hepatic-impairment labeling |
May reduce method and kit-claim exposure |
| Generic launches after patent expiry |
Lowest patent risk from 10,322,120 |
| Generic launches under settlement license |
Timing depends on settlement terms |
| Generic challenges only selected claims |
Partial risk remains from unchallenged claims |
A generic applicant should not treat noninfringement of claim 1 as sufficient. Claims 11 through 19 may provide separate exposure, particularly where the product retains the same multiparticulate capsule design but omits or changes written instructions.
What manufacturing and geographic barriers matter?
The patent’s geographic protection is limited to the United States. Foreign equivalents, if any, must be analyzed separately by jurisdiction. The core manufacturing barriers are reproducibility and control of:
- Particle-size distribution.
- Immediate-release versus sustained-release particle allocation.
- Polymer coating or matrix performance.
- Capsule fill uniformity.
- Dissolution across pH and apparatus conditions.
- Hydrocodone content uniformity.
- Exposure behavior in hepatic impairment.
The requirement to meet both dissolution and clinical PK limits can increase development cost. A generic may achieve bioequivalence in the general population but still require additional analysis to demonstrate that it does not fall within the patented hepatic-impairment limitations.
How does patent 10,322,120 compare with other hydrocodone patents?
| Patent category |
Typical protection |
Relationship to 10,322,120 |
| Hydrocodone composition patent |
The active molecule or salt |
Not the apparent focus |
| Extended-release formulation patent |
Matrix, coating, beads or multiparticulates |
Directly related |
| Capsule patent |
Shell, fill, excipients and dosage form |
Directly related |
| Method-of-use patent |
Treatment of chronic pain |
Incorporated into the kit claims |
| PK or dosing patent |
Hepatic or renal impairment dosing |
Central to claims 1 and 6 through 10 |
| Abuse-deterrence patent |
Resistance to crushing, extraction or tampering |
Separate technical category |
| Product-by-process patent |
Manufacturing route or composition created by a process |
Not apparent from the supplied claims |
Key Takeaways
-
U.S. Patent 10,322,120 is a formulation, kit, dosing, and pharmacokinetic patent for extended-release hydrocodone bitartrate capsules.
-
Claims 1 and 11 are the principal independent claims. Claim 1 expressly requires written dosing instructions; claim 11 does not.
-
The claims require a multiparticulate capsule containing immediate-release and sustained-release hydrocodone components, specified excipients, and defined dissolution and hepatic-impairment PK behavior.
-
The patent is most relevant to Zohydro ER and products that copy its capsule-based multiparticulate formulation.
-
Hysingla ER and other tablet-based hydrocodone products are technically distinct and are not automatically covered.
-
The expected patent-term endpoint is in the February 2032 period, subject to official USPTO term calculations.
-
Generic applicants face the greatest risk when they reproduce the listed excipients, capsule architecture, release profile, and chronic-pain labeling.
-
The principal defenses are formulation design-around, noninfringement based on dissolution or PK results, and invalidity challenges directed to written description, enablement, obviousness, and definiteness.
FAQs
Does patent 10,322,120 cover all extended-release hydrocodone products?
No. It is limited to products meeting the specific capsule, excipient, multiparticulate, release-profile, PK, strength, and kit limitations of the asserted claim.
Can a tablet infringe patent 10,322,120?
Literal infringement is unlikely where the claim requires a gelatin capsule. A tablet product would still require analysis of other patents and potential equivalents theories.
Is hydrocodone bitartrate itself patented by patent 10,322,120?
No. The patent does not claim hydrocodone bitartrate as a standalone chemical composition. It claims a specific extended-release dosage-unit and kit configuration.
Does a Paragraph IV certification automatically permit generic launch?
No. A Paragraph IV certification can trigger patent litigation and a statutory approval stay. Launch timing depends on litigation, settlement, patent expiration, and FDA approval status.
Is a hepatic-impairment study required to assess infringement?
Not necessarily in every case, but the patent includes AUC and Cmax limitations that may require pharmacokinetic evidence. The relevance of such data depends on the asserted claim and the product’s proposed formulation and labeling.
References
-
U.S. Patent and Trademark Office. (2019). U.S. Patent No. 10,322,120: Hydrocodone formulations and methods of use thereof. U.S. Department of Commerce.
-
U.S. Food and Drug Administration. (2013). Zohydro ER prescribing information. FDA.
-
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.
-
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.
-
U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585.
