US Patent 11,433,066: Scope, claim-by-claim coverage, and US opioid-dependence buprenorphine/naloxone tablet patent landscape
Executive summary: US Patent 11,433,066 claims a specific sublingual buprenorphine/naloxone fixed-dose tablet for opioid dependence with defined dose ratios (buprenorphine 11.4/8.6/5.7/2.9/1.4 mg ±2% and naloxone about one-quarter of buprenorphine) plus citric acid and an associative admixing process that forms an associative admixture of buprenorphine microparticles with citric-acid particles (simple mixing and/or granulation), followed by mixing with naloxone particles and compression. Dependent claims narrow to specific disintegrants and additional excipients such as sodium citrate and cellulose-gum/microcrystalline-cellulose binders, and to process modes (simple mixing vs granulation; granulation subtypes). The enforceable scope is therefore concentrated on (i) dose-range and ratio, (ii) sublingual tablet architecture and excipient selection, and (iii) a particular “associative admixture” preparation sequence before compression.
What does US Patent 11,433,066 claim for buprenorphine/naloxone opioid dependence tablets?
Featured-snippet answer: The independent claim is a method-of-treatment that requires preparing and administering a sublingual tablet containing buprenorphine (specified dose range), naloxone (about 1/4 of buprenorphine dose), citric acid, and a disintegrant, where the tablet is made by associatively admixing buprenorphine microparticles with citric-acid particles, then mixing that admixture with naloxone particles and compressing.
Core elements required by claim 1 (element-by-element scope)
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Indication / method-of-treatment
- Treating opioid dependence in a subject.
- Requires sublingual administration of the tablet (not oral swallowing).
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Drug substance dose amounts and ratio
- Buprenorphine free base (or salt calculated as free base): 11.4 mg (±2%), 8.6 mg (±2%), 5.7 mg (±2%), 2.9 mg (±2%), or 1.4 mg (±2%).
- Naloxone free base (or salt calculated as free base): about 1/4 of the above buprenorphine doses.
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Excipients required
- Citric acid is mandatory.
- A disintegrant is mandatory (the claim’s dependent claims specify exemplary disintegrants).
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Manufacturing process required
- Step (a): Associatively admixing buprenorphine microparticles (or salt) with particles comprising citric acid by simple mixing and/or granulation, forming an associative admixture between buprenorphine microparticles and citric-acid particles.
- Step (b): mixing the associative admixture with naloxone particles.
- Step (c): compressing to form the tablet.
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Delivery form
- Explicitly a tablet for sublingual administration.
How claim 1 drives infringement risk for competing products
To infringe claim 1, an accused product must satisfy all of: (a) the formulation/excipient package (buprenorphine/naloxone/citric acid/disintegrant), (b) the dosing ratio and absolute dose ranges, and (c) a preparation method that includes an associative admixture of buprenorphine microparticles with citric acid particles, followed by naloxone mixing and compression.
This combination is stricter than claims that only cover “buprenorphine/naloxone sublingual tablets” generally. It is also stricter than process-by-mixing claims that do not require formation of an associative admixture between drug microparticles and an acid component.
How do dependent claims narrow US 11,433,066 (disintegrants, binders, sodium citrate, carriers)?
Claim 2: Which disintegrants are covered?
- Disintegrant is selected from:
- croscarmellose sodium
- sodium starch glycolate
- crosslinked polyvinylpyrrolidone
- mixtures thereof
Scope impact: If an accused product uses a different disintegrant (or no disintegrant), it may avoid dependent-claim coverage even if claim 1’s generic “disintegrant” is met. However, if claim 1 requires a disintegrant without specifying type, then the product can still potentially map to claim 1.
Claim 3: What about sodium citrate?
- Tablet further comprises sodium citrate.
Scope impact: This is an added limitation. A product containing only citric acid and no sodium citrate may remain outside claim 3, while still potentially within claim 1.
Claim 4-5: Binders and carrier particles
- Claim 4: tablet further comprises a binder, carrier particles, or both.
- Claim 5: binder is:
- cellulose gum or
- microcrystalline cellulose
Scope impact: These are further narrowing limitations. If the binder is different (e.g., povidone alone, HPMC, PVP K-series as binder, etc.), dependent-claim coverage decreases.
Claims 6-8: “Associative admixture” by simple mixing vs granulation; granulation types
- Claim 6: associative admixture step (a) carried out by simple mixing.
- Claim 7: associative admixture step (a) carried out by granulation.
- Claim 8: granulation includes types such as:
- dry granulation
- wet granulation
- melt granulation
- thermoplastic pelletising
- spray granulation
- extrusion/spheronisation
Scope impact: Claim 1 already allows simple mixing and/or granulation. Dependent claims carve out specific process modes for step (a), creating multiple infringement angles. A manufacturer using any of those granulation modalities for step (a) aligns more readily with claim 7/8.
Claim 9: Associative admixture of binder/carrier in step (a)
- If binder/carrier are present, they are associatively admixed in step (a).
Scope impact: If the binder/carrier is introduced only after step (a) (or elsewhere), it may avoid claim 9.
Claims 10-11: Sodium citrate and carrier particles as associatively admixed materials
- Claim 10: sodium citrate is present as particles and is associatively admixed in step (a).
- Claim 11: carrier particles are present and associatively admixed in step (a).
Scope impact: These limit the timing/location of how sodium citrate/carriers are combined with buprenorphine microparticles and citric-acid particles.
What is the practical claim scope: formulation vs method-of-manufacture vs method-of-treatment?
US 11,433,066 is drafted as a method of treatment claim, but it imports product preparation steps as structural constraints on the tablet that must be administered. That drafting pattern creates a hybrid infringement theory:
- Commercial/prescription-side conduct: prescribing/dispensing/administering can be framed as the treatment step.
- Manufacturing-side constraints: infringement depends on whether the administered tablet is made using the claimed associative admixture process (and contains the claimed composition and dose ratio).
In practice, proving the manufacturing process often turns on:
- maker disclosures (regulatory CMC dossiers),
- patents referenced in filings,
- discovery in litigation,
- supplier process evidence,
- and particulate-level characterization that corroborates “associative admixture” formation.
How does the dose and ratio limitation affect design-around strategies for buprenorphine/naloxone?
Claim 1 locks in both:
- absolute buprenorphine dose levels (with ±2% windows), and
- a naloxone-to-buprenorphine ratio: “about ¼”.
Potential design-around axes (conceptual, not advisory):
- Use a different naloxone ratio outside “about ¼” or different buprenorphine strength outside the enumerated windows.
- Remove citric acid or replace it with a different acid system.
- Use a disintegrant that is absent (not feasible given the claim) or not compatible with avoiding claim 1’s “disintegrant” element.
- Change the manufacturing process so it does not create the claimed associative admixture of buprenorphine microparticles with citric-acid particles.
The strength enumeration plus ratio makes the claim more attackable than broader “any dose” compositions, but also more valuable if competitors rely on similar strength sets and ratio structures.
How does “associatively admixing microparticles” limit the patent beyond standard blending?
The novelty hinge is the requirement for:
- buprenorphine microparticles (drug in microparticle form),
- citric-acid particles, and
- an associative admixture between them achieved via simple mixing and/or granulation.
This is narrower than:
- simply mixing finished buprenorphine and citric acid powders;
- granulating without any claimed drug–acid “associative admixture” relationship; or
- using citric acid incorporated later, blended with other components after drug granulation.
In infringement terms, the accused product must reflect:
- use of buprenorphine microparticles,
- particle-level co-association with citric acid, and
- formation during step (a), not only in later blending.
US patent landscape: how do other buprenorphine/naloxone sublingual formulations typically cluster around this design space?
Without additional document metadata (publication family, assignee, continuation claims, and prosecution history), only high-confidence qualitative mapping is possible:
Likely neighboring patent categories that this claim intersects
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Buprenorphine/naloxone sublingual tablet formulation patents
- Strength sets and naloxone ratios
- Sublingual wetting/disintegration performance packages
- Acid systems (citric acid, sodium citrate, alternative acids)
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Manufacturing process patents
- Wet vs dry granulation routes
- Drug microparticle granulation strategies
- Associative granulation or layered/co-processed excipient–drug approaches
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Excipients and excipient functionality
- Disintegrant selection (croscarmellose sodium, SSG, crosslinked PVP)
- Binder/cellulose gum and microcrystalline cellulose choices
- Carrier particles roles
What 11,433,066 adds relative to typical clusters
Most buprenorphine/naloxone sublingual IP focuses on:
- composition (actives, excipients),
- disintegration/wetting mechanics,
- and standard granulation/compression methods.
US 11,433,066 ties composition to a specific two-step particle association:
- step (a): buprenorphine microparticles + citric-acid particles form an associative admixture;
- step (b): add naloxone;
- step (c): compress.
That explicit associative-particle step is the strongest discriminator in designing around.
What patents are likely implicated in US litigation or Orange Book challenges for buprenorphine/naloxone sublingual products?
This question requires:
- the Orange Book listing(s) for the relevant US product(s),
- the Orange Book “listed drug” and product strength mapping,
- and the actual US 11,433,066 bibliographic assignee and family relations.
Those data are not provided in the prompt, so a complete landscape cannot be produced without risking fabrication.
Per your constraints, no incomplete or speculative landscape is provided.
Claim-strength assessment: how enforceable is US 11,433,066 given the limitations?
Answer: The claim is enforceable but narrower than broad formulation patents because it combines multiple specific limitations:
- enumerated buprenorphine strengths,
- ratio-constrained naloxone,
- mandatory citric acid and disintegrant,
- and a manufacturing process requiring associative admixture of buprenorphine microparticles with citric-acid particles followed by naloxone mixing and compression.
Net effect: Competitors that can shift (i) strength/ratio, (ii) acid system, or (iii) drug–acid associative step likely reduce infringement exposure. Competitors that use closely similar microparticle + citric-acid association during granulation and match strength and ratio are at heightened risk.
Key Takeaways
- US 11,433,066 claims a sublingual tablet method-of-treatment for opioid dependence that is limited to tablets made with a specific dose set of buprenorphine and a naloxone dose about one-quarter of buprenorphine.
- The formulation is constrained to citric acid and a disintegrant; dependent claims specify disintegrants (croscarmellose sodium, SSG, crosslinked PVP).
- The process limitation is central: the tablet must be made by associatively admixing buprenorphine microparticles with citric-acid particles in step (a), then mixing with naloxone and compressing.
- Dependent claims further narrow with sodium citrate, cellulose gum or microcrystalline cellulose binders, and specific granulation variants.
FAQs
- Can a buprenorphine/naloxone sublingual tablet infringe claim 1 if it uses a different acid than citric acid?
- How does changing from buprenorphine microparticles to non-microparticle drug powder affect potential infringement of US 11,433,066?
- Does using granulation in step (a) automatically satisfy the “associative admixture” limitation, or must the drug–citric acid association be demonstrably created?
- If a product matches buprenorphine/naloxone dose strengths but alters the naloxone ratio slightly, where does the claim’s “about ¼” boundary typically matter?
- Do dependent claims materially increase risk if a competitor includes sodium citrate and a cellulose gum binder?
References
- United States Patent 11,433,066 (claims as provided).
