United States Patent 9,161,937: What Claims Actually Cover and How the Landscape Closes In

US 9,161,937 is an oral controlled-release (CR) opioid abuse-deterrent composition built around oxycodone plus naloxone with tightly constrained dose ratios and release kinetics. The claims are written to capture formulations that (i) keep naloxone suppressed during normal intact oral dosing while (ii) deliver naloxone rapidly enough when the dosage form is crushed to induce withdrawal and block euphoric effects.

What is the core claim scope?

The independent claim scope is concentrated in Claim 1, with a parallel set in Claims 28 to 30. The key control points are:

Oral CR composition
Oxycodone + naloxone
Oxycodone:naloxone ratio between 5:1 and 1:1
Naloxone release fraction over 4 hours: 65.9% to 95.9% of naloxone is released over 4 hours
Dependent claims then narrow dose ranges, salts, matrix structure, and abuse-deterrent functional outcomes (crushing, separation, withdrawal induction, naloxone not blocking analgesia intact).

Claim 1 (base scope)

Oral CR composition with:
- oxycodone
- naloxone
Ratio: 5:1 to 1:1
Release: 65.9-95.9% of naloxone released over 4 hours

Claim 28 (salt-specific parallel)

Oral CR composition with:
- oxycodone hydrochloride
- 2-40 mg naloxone salt (pharmaceutically acceptable salt)
Ratio: 4:1 to 1:1
Release: 65.9-95.9% of the naloxone salt released over 4 hours

How do the kinetic limits functionally define the product?

The claims use two types of kinetic language:

1) Absolute release over a 4-hour window

Claim 1 and Claim 28 anchor enforcement on a specific fraction:
- 65.9-95.9% naloxone released from the composition over 4 hours

2) Comparative and duration-based kinetics

Claim 15: naloxone release rate is approximately 100% to 25% of oxycodone release rate
Claim 16: naloxone release rate is approximately 100% of oxycodone release rate
Claim 17-18: both actives can be pushed to release over >10 hours (as alternative dependent claim coverage)
Claim 19: both can be released over a period greater than 4 hours
Claim 30 (salt version): naloxone release rate approximately 100% of oxycodone release rate

Taken together, the claim set targets CR systems where naloxone is not merely present but is engineered to reach the same absorption “timing zone” (or a definable fraction of it) that matters for abuse deterrence.

What do the dosage and ratio limitations narrow?

Oxycodone dose ranges

Claims 2 to 8 provide layered oxycodone dose limits, all within the Claim 1 framework:

Claim 2: oxycodone 10-160 mg
Claim 3: oxycodone 10-80 mg
Claim 4: oxycodone 10-40 mg
Claim 5: oxycodone 10 mg, naloxone 2-10 mg
Claim 6: oxycodone 20 mg, naloxone 5-20 mg
Claim 7: oxycodone 40 mg, naloxone 8-40 mg
Claim 8: oxycodone 80 mg, naloxone 16-80 mg

These dependent claims strongly suggest the patentee expected commercially relevant strengths in the 10/20/40/80 mg band, with corresponding naloxone mg ranges that maintain the ratio envelope.

Naloxone dose ranges

Claims 9 to 11 specify naloxone ranges independent of oxycodone strength:

Claim 9: naloxone 2-160 mg
Claim 10: naloxone 2-40 mg
Claim 11: naloxone 5-20 mg

In practice, this gives flexibility for different oxycodone strengths while keeping naloxone within a defensible operational range that still respects the ratio and release fraction limits.

Ratio ranges

Claim 1: oxycodone:naloxone 5:1 to 1:1
Claim 12: ratio also narrowed to 4:1 to 1:1

This means an accused product with a ratio below 1:1 (naloxone higher than oxycodone) is outside claim coverage. A product at ratio between 1:1 and 4:1 may fall under the narrower dependent claim 12, while a product between 4:1 and 5:1 can still land in Claim 1.

What “abuse-deterrent” functional language is actually claimed?

The claims do not rely only on chemical release parameters. They also claim behavior when the dosage form is abused.

Crushing and naloxone “not readily separable”

Claim 22: naloxone is not readily separable from the oxycodone
Claim 23: “sufficient naloxone is released to block the opioid euphoric effect when the pharmaceutical composition is crushed”
Claim 24: naloxone is released as immediate release capable of inducing withdrawal in dependent individuals if the composition is crushed and controlled release properties broken
Claim 25: naloxone released at a rate ineffective for inducing withdrawal when taken orally in intact form
Claim 26: release of naloxone does not block action of oxycodone when controlled release properties intact

This language maps to the abuse-deterrent feature set that regulators and litigation commonly scrutinize: whether naloxone delivery is sufficiently “switched on” by crushing, yet “switched off” during normal use.

Release profile versus analgesia retention

Claims 25 and 26 are particularly important for enforcement posture because they separate two states:

intact oral ingestion: naloxone should not drive withdrawal
intact-release integrity: naloxone should not block oxycodone
crushed state: naloxone should be immediate-release capable and induce withdrawal

That structure gives the patent two different infringement hooks:

physical-kinetic evidence (release fractions and rates)
functional abuse outcome evidence (withdrawal induction and euphoric effect blocking)

What formulation features are claimed beyond ratios and release?

Controlled release matrix

Claim 20: composition further comprises a controlled release matrix containing oxycodone and naloxone

Dosage form

Claim 21: composition is in the form of a tablet

Salt forms

Claim 13: oxycodone is oxycodone hydrochloride
Claim 14: naloxone is a pharmaceutically acceptable salt
Claim 28: oxycodone hydrochloride + naloxone salt in 2-40 mg; ratio 4:1 to 1:1; release fraction 65.9-95.9% over 4 hours

These salt/form claims matter because many generic or authorized-combination attempts will use different salt forms, different matrix chemistries, or different unit dose formats.

How the dependent claim matrix broadens or narrows litigation positioning

Coverage ladder

The claim structure creates a coverage ladder where an accused formulation can be found infringing if it matches: 1) the base CR composition and release fraction over 4 hours (Claim 1 / Claim 28), and then 2) additional dependent constraints like dose strength, salt identity, matrix, tablet form, or abuse-deterrent functional outcomes.

Duration alternatives

Claims 17 and 18 introduce a second time horizon:

Claim 17: >90% oxycodone released over 10 hours
Claim 18: >90% naloxone released over 10 hours

This creates potential overlap for formulations engineered with longer CR behavior, even though Claim 1 already forces naloxone to be substantially released within 4 hours.

Parallel claim set: Claim 28 and Claim 30

Claims 28 and 30 repeat key constraints but in salt-specific terms:

Claim 28:
- oxycodone hydrochloride
- naloxone salt, 2-40 mg
- ratio 4:1 to 1:1
- 65.9-95.9% naloxone salt released over 4 hours
Claim 30:
- naloxone release rate approx 100% of oxycodone release rate

This redundancy suggests the patent was drafted to preserve enforcement even if the oxycodone is only on an HCl basis and the naloxone is in a salt form, not free base.

Patent landscape and competitive implications (US drug patent context)

Your request asks for “scope and claims and patent landscape” for US 9,161,937. Based strictly on the information provided, the landscape analysis below is limited to what can be inferred from the claim architecture itself (release engineering, abuse-deterrent trigger, and dose-ratio control). A full landscape requires bibliographic retrieval (related patents, continuations, prosecution history, cited prior art, and legal status), which is not present in the input and therefore cannot be completed without adding non-provided facts.

What the claim architecture does show, at a business level, is the likely competitive design space being targeted:

What product attributes competitors must engineer to avoid capture

An alternative product seeking to stay outside Claim 1 or Claim 28 likely needs to move at least one of these levers:

Naloxone release fraction over 4 hours: avoid the 65.9-95.9% window
Naloxone/oxycodone ratio: move outside 1:1 to 5:1 (or outside 4:1 to 1:1 for the salt version dependent claim 12/28 structure)
Salt selection and dose form: use different oxycodone/naloxone salt forms or a non-tablet dosage format (Claim 21 is tablet-specific)
Matrix containment and separability: make naloxone “readily separable” in a way that defeats Claim 22 and undermines Claims 23-26 functional hooks
Functional “crush trigger” behavior: prevent naloxone from reaching immediate-release capable delivery on crushing that induces withdrawal

Where the claim likely bites hardest in ANDA or authorized generic design

Claims with explicit release fractions and ratio bounds tend to be hardest to “design around” without extensive dissolution/CR profiling. In practical terms, the highest infringement risk is in products that:

match the same oxycodone strength set (10/20/40/80 mg)
maintain naloxone doses in the corresponding mg ranges
achieve a similar “naloxone burst” within 4 hours

Litigation evidence focus

If a dispute turns on Claim 1, the evidentiary center of gravity is likely:

dissolution testing aligned to the “over 4 hours” naloxone fraction
comparative release rate tests (Claims 15, 16, 30)
crush studies that connect release behavior to withdrawal induction and euphoric effect blocking (Claims 23-26)
formulation characterization supporting “controlled release matrix” and “not readily separable”

Claim-by-claim scope map (what each claim adds)

Claim	What it covers	Main restriction type
1	Oral CR oxycodone + naloxone; ratio 5:1 to 1:1; 65.9-95.9% naloxone released over 4 hours	Composition + ratio + release fraction
2-4	Oxycodone strength bands: 10-160, 10-80, 10-40 mg	Strength limits
5-8	Specific strength pairings with naloxone ranges for 10/20/40/80 mg	Strength + ratio-in-mg
9-11	Naloxone strength bands: 2-160, 2-40, 5-20 mg	Strength limits
12	Ratio 4:1 to 1:1	Ratio narrowing
13-14	Oxycodone HCl; naloxone pharmaceutically acceptable salt	Salt form
15-16	Naloxone release rate approx 100% to 25% of oxycodone; or approx 100%	Relative release kinetics
17-19	Release over >10 hours, and both release over >4 hours	Duration kinetics
20	Controlled release matrix containing both actives	Formulation architecture
21	Tablet	Dosage form
22	Naloxone not readily separable from oxycodone	Abuse deterrence mechanism
23-26	Crush triggers euphoric blocking and withdrawal; naloxone ineffective in intact use; does not block oxycodone intact	Functional abuse-deterrent outcomes
27	Method of treating pain by administering Claim 1 composition	Method claim
28	Oral CR oxycodone HCl + naloxone salt 2-40 mg; ratio 4:1 to 1:1; 65.9-95.9% naloxone released over 4 hours	Salt-specific base
29	Oxycodone in 10/20/40/80 mg amounts	Strength limits
30	Naloxone release rate approx 100% of oxycodone	Relative release kinetics

Key Takeaways

US 9,161,937 claims are engineered around quantifiable release engineering: specifically 65.9-95.9% naloxone released over 4 hours, plus oxycodone:naloxone ratio 5:1 to 1:1 (or 4:1 to 1:1 in the salt-specific coverage).
The patent’s abuse-deterrent scope is not purely physical. It ties formulation behavior under crushing to withdrawal induction and blocking euphoric effect, while also requiring naloxone to be ineffective in intact oral use and not block oxycodone.
Salt and dosage form narrowing matters: oxycodone HCl, naloxone pharmaceutically acceptable salt, and tablet are explicitly claimed.
The enforcement posture likely hinges on dissolution/release testing matched to the 4-hour naloxone fraction window, plus crush studies aligned to functional outcomes.

FAQs

Does US 9,161,937 require naloxone and oxycodone to release at the same rate?
Not exactly. Claim 1 sets a naloxone release fraction over 4 hours; dependent claims include relative release rate limits, including an “approx 100%” relationship (Claims 16 and 30) and a broader band (Claim 15).
What is the most infringement-critical quantitative parameter?
The claim’s naloxone release fraction over 4 hours: 65.9-95.9% (Claim 1 and Claim 28).
Are oxycodone and naloxone ratio limits flexible?
Yes, but only within defined bounds: 5:1 to 1:1 in Claim 1 and 4:1 to 1:1 in Claim 12 and in the salt-specific Claim 28 framing.
Does the patent cover both composition and method claims?
Yes. Claim 27 is a method of treating pain by administering the Claim 1 composition.
What abuse-deterrent behavior is explicitly claimed?
When crushed, the formulation releases naloxone as immediate-release capable of inducing withdrawal (Claim 24), with naloxone not readily separable from oxycodone (Claim 22), and naloxone ineffective for withdrawal in intact oral use (Claim 25).

References

[1] US 9,161,937 claims text provided in the prompt (Claims 1-30).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	493130	⤷ Start Trial
Australia	2002305559	⤷ Start Trial
Australia	2008202967	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,161,937

Summary for Patent: 9,161,937