Details for Patent: 9,675,611

Summary for Patent: 9,675,611

Title:	Methods of providing analgesia
Abstract:	A solid oral controlled-release oral dosage form of hydrocodone is disclosed. The dosage form comprising an analgesically effective amount of hydrocodone or a pharmaceutically acceptable salt thereof, and a sufficient amount of a controlled release material to render the dosage form suitable for twice-a-day administration to a human patient, the dosage form providing a C12/Cmax ratio of 0.55 to 0.85, said dosage form providing a therapeutic effect for at least about 12 hours.
Inventor(s):	Benjamin Oshlack, Hua-pin Huang, John Masselink, Alfred Tonelli
Assignee:	Purdue Pharma LP
Application Number:	US15/376,851
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 9,675,611
Patent Claim Types: see list of patent claims	Use; Composition; Dosage form;

United States Patent 9,675,611 (Hydrocodone Oral Controlled-Release) Scope, Claim Map, and US Patent Landscape

United States Patent 9,675,611 claims methods of oral analgesia using hydrocodone (or a pharmaceutically acceptable salt) in a tablet or capsule with controlled release for 12 hours or longer, with specific in vivo pharmacokinetic (PK) thresholds (notably ≥8 ng/mL at ~8 hours and ≥3.93 or ≥5 ng/mL at ~12 hours, plus defined C12/Cmax ratios), and constraints that hydrocodone is the only active drug in the dosage form. Dependent claims further narrow to polymer/excipient composition ranges (including hydroxyalkylcellulose such as HPMC or Hysropropylcellulose variants) and excipient melting point ranges, plus PK profile shape requirements (relative flatness of part of the curve, fed vs fasted calculation basis, linear Cmax increase across strengths).

Important scope takeaway: the claim set is PK-engineered and formulation-linked. Design-around risk depends less on general “hydrocodone ER” categorization and more on whether a competitor’s dosage form hits the claimed exposure guardrails and the structural formulation limitations (polymer class, polymer weight fraction, excipient melting point) where those dependent claims are asserted.

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What exactly is the claim scope of US Drug Patent 9,675,611 for hydrocodone controlled-release analgesia?

Core independent claim theme: “orally administering” hydrocodone-only controlled-release dosage forms that produce a hydrocodone plasma exposure profile meeting specific numeric thresholds over at least ~12 hours, with an additional “therapeutic window” framing (maintained within therapeutic range but below toxic concentrations).

What the independent claim requires (Claim 1, and Claim 31 as a variant)

Claim 1 (method of providing analgesia) requires all of the following elements:

1. Administration route: oral administration to a human.
2. Dosage form content:
   • A therapeutically effective amount of hydrocodone or a pharmaceutically acceptable salt.
   • Hydrocodone (or salt) is the only drug in the dosage form.
3. Release duration: dosage form releases hydrocodone at a rate that maintains plasma concentration in the therapeutic range below toxic concentrations for about 12 hours or longer.
4. PK numeric thresholds:
   • ≥ about 8 ng/mL at about 8 hours after administration.
   • ≥ about 5 ng/mL at about 12 hours after administration.
5. Dosage form type: tablet or capsule.

Claim 31 (method of providing analgesia) is similar but with a lower 12-hour floor:

• Same structure (oral, hydrocodone-only, therapeutic-window framing, tablet/capsule).
• PK thresholds:
  • ≥ about 8 ng/mL at about 8 hours.
  • ≥ about 3.93 ng/mL at about 12 hours.
• Adds a specific tablet dosage example in Claim 32 (15 mg hydrocodone bitartrate).

Net effect: the claim family covers multiple hydrocodone ER release profiles with explicit numeric endpoints at ~8 and ~12 hours. A competitor can fall outside scope by missing either the 8-hour floor or the 12-hour floor, even if the product is broadly “extended release.”

How the claims treat salts, dose strengths, and “only drug” constraints

• The claims are written to include hydrocodone salts (no specific salt mandated in Claim 1; Claim 32 narrows to bitartrate).
• The “only drug in the dosage form” language functions as a composition purity limitation. If a competitor’s dosage form combines hydrocodone with another active (including certain opioid combinations or adjunct analgesics), it avoids the literal “only drug” constraint, at least for method claims requiring that limitation.

What the “tablet vs capsule” boundary means

• Claim 1 and Claim 31 include tablet or capsule.
• Several dependent claims narrow to tablet.
• A competitor launching an ER capsule could still face Claim 1/31 exposure if its PK meets thresholds; a competitor could narrow risk by switching to a different dosage form type only if the independent claims are written against that type. Here, independent claims already cover both.

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Which dependent claims narrow the formulation scope: polymers, excipient melting points, and HPMC/hydroxypropyl methylcellulose?

Dependent claims translate PK performance into formulation “handles.” In enforcement, that typically supports arguments that the claimed exposure is not a happenstance formulation outcome but a result of claimed materials and ratios.

Polymer/excipient-dependent narrowing (Claims 5–11)

Claim 5 (tablet + polymer): tablet comprises a pharmaceutically acceptable polymer.
Claim 6 (polymer weight fraction): polymer is 1% to 80% by weight of the tablet.
Claim 7 (excipient melting point): dosage form comprises an excipient having a melting point of 30 to 200°C.
Claim 8 (polymer class): polymer is hydroxyalkylcellulose.
Claim 9 (subclass): hydroxyalkylcellulose is hydroxypropylcellulose or hydroxypropylmethylcellulose.
Claim 10 (specific polymer): polymer is hydroxypropylmethylcellulose.
Claim 11 (excipients): excipient is a polyalkylene glycol.

Practical claim meaning:

• If asserted against a competitor’s product, these limitations can sharply reduce design-around options only if the product uses comparable polymer class and composition.
• If a competitor uses different matrix-formers (e.g., ethylcellulose, methacrylate polymers, waxes, or osmotically active systems without hydroxyalkylcellulose as recited), it may avoid these dependent claims even if it hits PK thresholds.

“Controlled release for 24 hours” escalation (Claim 2)

• Claim 2 requires controlled release for about 24 hours (vs “about 12 hours or longer” in Claim 1).
• A product whose release is closer to 12 hours may fall into Claim 1 but not Claim 2.

PK profile architecture dependent claims (Claims 12–21, 27–29, 18)

The claims don’t just require numeric exposure. They also define internal profile features:

• Linear Cmax increase across strengths (Claim 12): Cmax increases linearly from one dosage strength to another.
• C12/Cmax ratio bands (Claims 13–15, 27):
  • 0.55 to 0.85 (Claim 13)
  • tighter sub-ranges: 0.55 to 0.65 (Claim 14) and 0.65 to 0.85 (Claim 15)
• Fed vs fasted computation basis:
  • Several claims specify C12/Cmax is calculated from plasma concentrations from first administration to fasted (Claims 16–17, 22) or fed populations (Claims 19–21, 23).
• “Relatively flat” portion of plasma concentration profile (Claim 18, Claim 28)

Scope risk for a generic or challenger product: PK program design matters. A competitor that misses the ratio band or the flatness feature for the specified study condition could avoid these dependent claim limitations even if it meets the 8-hour and 12-hour floors.

Dosage range and excipient fraction dependent scope (Claim 24)

Claim 24 is another independent method claim with explicit dosage and excipient fraction constraints:

• Hydrocodone or salt amount about 5 mg to about 1250 mg
• Dosage form has an excipient comprising 1% to 80% by weight
• Only drug in dosage form is hydrocodone or its salt
• Controlled release over about 8 to about 24 hours
• PK floors:
  • ≥ about 8 ng/mL at about 8 hours
  • ≥ about 5 ng/mL at about 12 hours

This claim is broader on dose quantity but similar on PK performance and excipient fraction.

Claim 25 narrows to tablet; Claim 26 adds ≥ about 8 ng/mL at about 2 hours. This is an early exposure constraint that can narrow design space for products that have delayed onset.

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How strong is the patent estate around these claims: what the claim structure implies about enforceability and invalidity vectors?

From claim language alone, the strongest enforcement lever is PK numeric specificity. Courts generally treat quantitative pharmacokinetic limitations as a meaningful boundary for infringement and validity if tied to supported examples.

Likely litigation-relevant claim categories

1. PK guardrails (8-hour floor, 12-hour floor, C12/Cmax bands)

   • Strong for infringement if accused product PK matches.
   • Strong for validity arguments only if prior art discloses the same PK behavior or if it is obvious to hit these targets given common ER design.

2. Composition boundary: hydrocodone-only

   • If competitors use hydrocodone combination products, literal infringement is less likely for this limitation.
   • If competitors use hydrocodone-only, it becomes a standard contention.

3. Formulation dependent constraints (hydroxypropylmethylcellulose, polymer fraction, melting point range, polyalkylene glycol)

   • This creates a second line of defense/attack: literal infringement depends on the specific matrix system.
   • For design-around, choosing different polymers or excipients could avoid dependent claim limitations but still be caught by the independent claims if PK requirements are met.

Built-in strength from multiple “ways in”

The family is structured so a competitor can be captured by:

• Claim 1/31 (PK thresholds + hydrocodone-only + tablet/capsule)
• Claim 24 (dose and excipient fraction band + PK floors)
• Dependent claims (polymer class, excipient melting point, HPMC, C12/Cmax ratio band, fed/fasted first administration, relative flatness, early 2-hour floor)

This increases the probability that at least one claim maps onto an accused product.

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What does a claim chart look like for infringement: which evidence will matter most?

Infringement for method claims typically hinges on demonstrating that the accused dosage form, when administered, produces the claimed PK profile in the relevant patient condition (fasted or fed per the dependent claims).

Evidence most likely to drive infringement analysis

• Bioequivalence or bridging PK data for hydrocodone plasma:
  • 8-hour concentration ≥ 8 ng/mL
  • 12-hour concentration ≥5 ng/mL (Claim 1/24) or ≥3.93 ng/mL (Claim 31)
  • C12/Cmax ratio within specified ranges
  • early 2-hour level (if Claim 26 asserted): ≥8 ng/mL
• Study condition:
  • “first administration” to fasted and fed populations for ratio/condition-dependent claims
• In vitro formulation:
  • polymer identity (hydroxypropylmethylcellulose)
  • polymer weight fraction (1% to 80%)
  • excipient class (polyalkylene glycol)
  • excipient melting point (30 to 200°C)
• Product composition:
  • proof that hydrocodone (salt) is the only drug (helps identify literal infringement exposure boundaries)

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When does hydrocodone controlled-release exclusivity end in the US, and how does this patent timing affect generic entry risk?

This analysis cannot be completed from the claim text alone because exclusivity and relevant statutory dates depend on:

• filing date, priority chain, prosecution history
• Orange Book “listed drug” and listed patents tied to the NDA/ANDA
• FDA reference product, approval dates, and patent listing expirations
• any Hatch-Waxman 180-day exclusivity triggers from ANDA Paragraph IV filings

No complete and accurate US exclusivity or Orange Book timeline can be produced from the provided claim text.

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What generic entry risks exist if a challenger markets a hydrocodone ER tablet or capsule?

Risk is primarily PK-driven for independent claims and material-driven for dependent claims.

“Caught by Claim 1 / 24” risk pattern

A challenger’s hydrocodone ER tablet/capsule is at higher risk if it:

• is hydrocodone-only (no other active ingredient),
• has controlled release ≥ about 12 hours,
• achieves:
  • ≥8 ng/mL at ~8 hours, and
  • ≥5 ng/mL at ~12 hours.

“Caught by Claim 31 but not Claim 1” scenario

If a challenger targets lower 12-hour exposure, it may still be exposed to Claim 31 if it meets:

• ≥8 ng/mL at ~8 hours, and
• ≥3.93 ng/mL at ~12 hours.

“Avoid dependent claims using formulation divergence” scenario

Even if a challenger meets PK thresholds, it can reduce dependent-claim risk by:

• using polymer systems not within hydroxyalkylcellulose, not limited to HPMC,
• changing excipient melting point out of 30 to 200°C, or
• avoiding polyalkylene glycol as a recited excipient.

However, if infringement proceeds under independent claims, dependent-claim avoidance may not be sufficient.

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How do claims map to tablet vs capsule development: where does a capsule escape work?

Claim 1 and Claim 31 cover both tablet and capsule. Switching to a capsule does not, by itself, avoid infringement. Only PK performance and “only drug” constraints change the risk surface.

Dependent claims explicitly narrows to tablet (Claims 3, 25), and add polymer presence constraints through tablet-specific limitations (Claims 5–11). A capsule-only strategy can avoid those dependent claims but not the independent claim scope.

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What patent scope exists beyond PK: does the claim cover only hydrocodone or also salts like bitartrate?

• Claim 1: hydrocodone or pharmaceutically acceptable salt.
• Claim 32: 15 mg hydrocodone bitartrate.

So, if an accused product uses bitartrate at 15 mg, Claim 32 becomes a closer match. If not, it still faces independent PK scope via Claim 1 or Claim 31, depending on its 12-hour profile.

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Key Takeaways

• US Patent 9,675,611 is a PK-defined, hydrocodone-only ER method-of-analgesia patent covering oral tablet or capsule with controlled release for ≥ ~12 hours.
• The independent claims are anchored to specific exposure thresholds: ≥8 ng/mL at ~8 hours plus either ≥5 ng/mL at ~12 hours (Claims 1/24) or ≥3.93 ng/mL at ~12 hours (Claim 31).
• Dependent claims narrow further to hydroxyalkylcellulose polymers, with specific coverage for hydroxypropylmethylcellulose, plus excipient melting point 30–200°C and polyalkylene glycol recitations, and PK architecture features like C12/Cmax bands and “relatively flat” portions of the concentration-time profile.
• Generic entry risk is highest for challengers that match both PK endpoints and “hydrocodone-only” composition; formulation changes can reduce dependent claim exposure but do not automatically remove risk if independent PK thresholds are met.
• A complete Orange Book status, patent expiration, Paragraph IV landscape, and exclusivity timeline cannot be derived from the claim text provided.

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FAQs

1. What plasma concentration values matter most for infringement under these claims?
   The claims emphasize hydrocodone ≥8 ng/mL at ~8 hours and ≥5 ng/mL at ~12 hours (Claims 1/24) or ≥3.93 ng/mL at ~12 hours (Claim 31).

2. Do the claims require hydrocodone to be the only active ingredient?
   Yes. The dosage form must have hydrocodone (or salt) as the only drug in the dosage form.

3. Does using a different ER excipient polymer avoid liability?
   It can avoid dependent claims tied to hydroxyalkylcellulose/HPMC and other formulation features, but independent claims can still apply if the accused product meets the PK thresholds.

4. Are fed and fasted conditions relevant to claim scope?
   Yes. Some dependent claims specify that C12/Cmax ratio calculations are made using fasted or fed population plasma concentrations from first administration.

5. Does switching between tablet and capsule avoid the independent claims?
   No. Independent claims include tablet or capsule; the tablet-only narrowing applies mainly to certain dependent claims.

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References (APA)

1. Provided claim text for United States Patent 9,675,611 (user-provided).

Drugs Protected by US Patent 9,675,611

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 9,675,611

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	526950
Australia	1446501
Australia	2003262463
Australia	764453