Details for Patent: 10,592,168

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Which drugs does patent 10,592,168 protect, and when does it expire?

Patent 10,592,168 protects SUBLOCADE and is included in one NDA.

This patent has forty-four patent family members in thirty-one countries.

Summary for Patent: 10,592,168

Title:	Injectable flowable composition comprising buprenorphine
Abstract:	The present invention is directed to a buprenorphine sustained release delivery system capable of delivering buprenorphine, a metabolite, or a prodrug thereof for a duration of about 14 days to about 3 months. The buprenorphine sustained release delivery system includes a flowable composition and a solid implant for the sustained release of buprenorphine, a metabolite, or a prodrug thereof. The implant is produced from the flowable composition. The buprenorphine sustained release delivery system provides in situ 1-month and 3-month release profiles characterized by an exceptionally high bioavailability and minimal risk of permanent tissue damage and typically no risk of muscle necrosis.
Inventor(s):	Richard L. Norton, Andrew Watkins, Mingxing Zhou
Assignee:	Indivior UK Ltd
Application Number:	US16/693,726
Patent Claim Types: see list of patent claims	Use; Composition; Formulation; Device;

US Patent 10,592,168: Buprenorphine Depot Injection Claims, Exclusivity, and Patent Landscape

US Patent No. 10,592,168 protects a method of treating opioid dependence with a monthly subcutaneous buprenorphine depot formed from buprenorphine, poly(lactide-co-glycolide) or PLGA, and N-methyl-2-pyrrolidone. The patent is directed primarily to clinical administration and pharmacokinetic performance, not merely to the composition itself.

The commercial embodiment most closely associated with the claims is Sublocade, Indivior’s extended-release buprenorphine injection. The central claim covers a formulation containing approximately 18 wt% buprenorphine free base, 32 wt% PLGA, and 50 wt% N-methyl-2-pyrrolidone, administered subcutaneously at approximately 28-day intervals.

What does US Patent 10,592,168 protect?

The independent claim requires every element below:

Required element	Scope of claim 1
Therapeutic use	Treatment of opioid dependence
Patient	Subject in need of treatment
Administration route	Subcutaneous injection
Dosage form	Injectable, flowable pharmaceutical composition
Active ingredient	10 wt% to about 50 wt% buprenorphine, as free base or pharmaceutically acceptable salt
Polymer	About 5 wt% to about 70 wt% PLGA
Solvent	N-methyl-2-pyrrolidone, or NMP
Pharmacokinetic result	Specified buprenorphine plasma concentration and/or burst-release profile

The claim is a method-of-use claim with formulation limitations. A competing product would generally need to satisfy both the formulation requirements and the claimed treatment-performance limitations to present a direct literal infringement risk.

The claim does not require a particular brand, syringe, needle gauge, injection site, polymer supplier, or manufacturing process. It does require subcutaneous administration and the specified therapeutic use.

What is the commercial formulation covered by the patent?

Claim 22 identifies the most commercially relevant formulation:

Component	Claimed amount
Buprenorphine free base	About 18 wt%
PLGA	About 32 wt%
NMP	About 50 wt%

A 300 mg dose of buprenorphine free base is separately covered by claim 12. The claims also cover formulations containing 3 mg to 900 mg of buprenorphine free base.

The composition is designed to be injected as a flowable solution. After injection, contact with water or bodily fluid causes the formulation to form an in-situ depot or implant. NMP functions as the water-miscible organic solvent, while PLGA forms the biodegradable polymer matrix.

How do the claims operate as a patent protection strategy?

The patent uses overlapping claim layers rather than relying on one broad composition claim.

Broad treatment claim

Claim 1 covers treatment with a broad composition range:

• Buprenorphine: 10 wt% to about 50 wt%
• PLGA: about 5 wt% to about 70 wt%
• Subcutaneous injection
• NMP
• Defined concentration or burst-release outcome

The use of alternative pharmacokinetic limitations gives the claim several infringement pathways. The method may satisfy the claim through the 28-day concentration range, the narrower day-three-to-day-24 concentration range, or the less-than-10% 24-hour burst-release limitation.

Pharmacokinetic dependent claims

Claims 2 and 3 narrow the method by requiring specified plasma concentrations:

• About 1.82 ng/mL to about 12.1 ng/mL for approximately 28 days
• About 2.18 ng/mL to about 3.26 ng/mL from day three through day 24

These limitations are important because they connect patent scope to clinical and pharmacokinetic data. They also create evidentiary issues. An accused product may require clinical studies, pharmacokinetic modeling, product testing, or regulatory disclosures to determine whether the claimed concentration ranges are met.

Burst-release claim

Claim 4 covers a 24-hour buprenorphine burst release of less than 10%. This limitation targets early drug dumping after injection. A formulation that uses the same ingredients but produces a higher initial release could have a stronger noninfringement position against this dependent claim, although it could still implicate other claims.

Dosing-interval claims

Claims 5 and 6 cover administration once every 28 days or once per month. These claims align closely with monthly depot treatment and materially increase risk for products using the same formulation architecture and dosing schedule.

What formulations are protected by US 10,592,168?

The formulation claims cover a wide technical range beyond the 18/32/50 formulation in claim 22.

Formulation variable	Claimed range
Buprenorphine	10 wt% to about 50 wt%
Narrower buprenorphine range	10 wt% to about 30 wt%
Preferred buprenorphine range	About 15 wt% to about 20 wt%
PLGA	About 5 wt% to about 70 wt%
Narrower PLGA range	About 15 wt% to about 70 wt%
Injection volume	About 0.10 mL to about 2.0 mL
Organic liquid phase	About 30 wt% to about 70 wt%
Polymer composition	PLGA ratios from 50/50 through 95/5
Polymer molecular weight	About 5,000 to 20,000 Daltons
Polymer terminal group	Carboxy-terminal PLGA

Claim 14 covers multiple lactide:glycolide ratios, including 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/15, 90/10, and 95/5. Claim 15 narrows the protection to 50/50 PLGA.

Claim 21 expands the solvent system to NMP combined with glycerin, propylene glycol, polyethylene glycol, or combinations of those excipients. A competitor therefore cannot necessarily avoid the patent by adding a second organic liquid to NMP.

What are the principal infringement issues?

The patent’s highest-risk combination is:

1. Buprenorphine free base;
2. Approximately 18 wt% active ingredient;
3. Approximately 32 wt% PLGA;
4. Approximately 50 wt% NMP;
5. Subcutaneous injection;
6. Monthly or 28-day dosing;
7. Opioid-dependence treatment; and
8. Pharmacokinetic behavior within the claimed ranges.

The claim is narrower than a pure composition claim because the accused product must be administered for the claimed indication. It is broader than a product-specific claim because it does not require the Sublocade trademark, a particular device, or a particular manufacturing process.

A design-around based only on a different dose may not be sufficient. The claims cover a large dose range, from 3 mg to 900 mg, and a broad buprenorphine concentration range. A change in polymer ratio, molecular weight, terminal group, solvent system, or dosing interval could be more relevant, but those changes must be assessed against the full claim set and related patent families.

What is the Orange Book status of US 10,592,168?

Sublocade is an FDA-approved extended-release buprenorphine injection for subcutaneous use in the treatment of moderate-to-severe opioid use disorder in patients who have initiated treatment with a transmucosal buprenorphine-containing product.[2]

US Patent 10,592,168 is associated with the Sublocade patent estate and should be reviewed against the current FDA Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book, for the applicable listing status and patent-use-code information.[3]

The Orange Book analysis must distinguish among:

• Listed patents covering the drug substance;
• Formulation patents;
• Method-of-use patents;
• Device or delivery-system patents;
• Patent-use codes;
• Listing removals or corrections; and
• Any pediatric exclusivity or patent-term-extension adjustments.

The patent number alone does not establish the current regulatory listing, because Orange Book records can change through certifications, corrections, delistings, or FDA administrative updates.

When does US 10,592,168 lose exclusivity?

The patent’s expiration date cannot be calculated reliably from the March 17, 2020 issue date alone. US patent term generally runs 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other prosecution factors.[4]

For commercial diligence, the relevant date should be taken from:

• The issued patent’s USPTO term data;
• The earliest effective nonprovisional filing date;
• Any terminal disclaimer;
• Patent-term adjustment;
• Any patent-term extension under 35 U.S.C. § 156; and
• Related continuation or divisional prosecution.

The patent’s practical exclusivity also depends on other Sublocade patents. Expiration of US 10,592,168 would not necessarily create immediate unrestricted generic entry if additional formulation, dosing, manufacturing, device, or method-of-use patents remain enforceable.

Which companies are challenging the Sublocade patent estate?

The principal competitive risks come from two groups:

Competitor	Product or approach	Competitive significance
Generic manufacturers	Long-acting injectable buprenorphine or alternative depot formulations	Potential Paragraph IV and ANDA-based challenge
Braeburn	Brixadi weekly and monthly extended-release buprenorphine	FDA-approved branded alternative using a different delivery platform
Other developers	Depot, implant, injectable, or long-acting buprenorphine systems	Potential design-around or new-product competition

Brixadi received FDA approval in 2023 for subcutaneous administration in weekly and monthly presentations.[5] Its presence reduces Sublocade’s commercial exclusivity even if no generic version directly practices the claims of US 10,592,168.

Publicly available information should be reviewed for any Paragraph IV certification, ANDA litigation, inter partes review, or district-court action specifically naming US 10,592,168. A Paragraph IV challenge would typically target patent validity, noninfringement, unenforceability, or the scope of the listed method-of-use claims. Without a confirmed litigation docket, no specific challenger should be treated as having filed against this patent.

What is the biosimilar risk?

There is no conventional biosimilar pathway for Sublocade because buprenorphine is a small-molecule active pharmaceutical ingredient. Competitive products would generally proceed through an abbreviated new drug application, a 505(b)(2) application, or a full NDA, depending on the degree of formulation and clinical differentiation.[6]

The main regulatory distinction is:

• A generic injectable with the same active ingredient, route, dosage form, and reference-product characteristics may pursue an ANDA.
• A materially different depot system, excipient platform, dosing regimen, or clinical profile may require a 505(b)(2) application or NDA.
• A branded competing product such as Brixadi does not depend on biosimilar interchangeability.

How strong is the patent estate for Sublocade compared with Brixadi?

Sublocade has the stronger first-mover position in the US monthly injectable buprenorphine market, with FDA approval preceding Brixadi by several years. Its protection is distributed across formulation, depot formation, dosing, pharmacokinetics, and product-specific commercial rights.

Brixadi creates a competitive alternative but does not automatically invalidate or avoid Sublocade patents. The relevant technical distinction is the delivery platform. A competing product with a different polymer-solvent system, release mechanism, or formulation composition may reduce direct infringement exposure while still competing clinically.

Issue	Sublocade	Brixadi
Sponsor	Indivior	Braeburn
Active ingredient	Buprenorphine	Buprenorphine
Administration	Subcutaneous	Subcutaneous
Dosing	Monthly	Weekly and monthly
Market entry	2017 FDA approval	2023 FDA approval
Principal IP concern	PLGA/NMP in-situ depot and associated methods	Distinct long-acting delivery platform and related patents
Biosimilar classification	Not applicable	Not applicable

What generic launch scenarios exist?

Scenario 1: Formulation-equivalent ANDA

A generic uses buprenorphine, PLGA, NMP, subcutaneous administration, and a monthly regimen. This scenario has the highest exposure to US 10,592,168 and related Sublocade patents. A Paragraph IV certification and patent litigation would be likely if the patents remain listed and enforceable.

Scenario 2: Different depot chemistry

A competitor uses a different polymer, solvent, implant technology, or release mechanism. This may reduce literal infringement risk but could require a 505(b)(2) or NDA and additional clinical evidence.

Scenario 3: Different dosing interval

A weekly or biweekly product may avoid the monthly dosing claims in claims 5 and 6. It could still implicate claim 1 if the formulation and claimed pharmacokinetic results are satisfied.

Scenario 4: Alternative indication or labeling

A product labeled for a different use may reduce method-of-use exposure, but off-label use, induced infringement, and the scope of any broader product or formulation patents remain relevant.

What manufacturing and geographic barriers apply?

The claims do not require a particular manufacturing process, but the formulation presents technical barriers:

• Uniform dispersion of buprenorphine in a high-solids polymer system;
• Control of PLGA molecular weight and terminal chemistry;
• Control of injection force and flowability;
• Prevention of premature phase inversion;
• Reproducible depot formation after subcutaneous injection;
• Control of initial burst release;
• Sterility and particulate limits for injectable products; and
• Consistent 28-day pharmacokinetics.

US 10,592,168 is a United States patent. Parallel rights must be assessed separately in Europe, Canada, Japan, Australia, and other markets. A US noninfringement position does not establish freedom to operate outside the United States. International patent families may contain different claim scope, prosecution amendments, expiration dates, and opposition histories.

What is the commercial exposure?

Sublocade is Indivior’s principal long-acting injectable opioid-dependence product. Revenue exposure is material because a formulation-equivalent generic could compete directly on monthly dosing, procurement price, and payer coverage.

Commercial erosion would depend on:

• The number of enforceable Orange Book patents;
• The earliest legally permissible generic launch date;
• Whether a generic is substitutable at the pharmacy level;
• Manufacturing capacity for long-acting sterile injections;
• Payer adoption;
• Distribution restrictions;
• Physician preference for monthly treatment; and
• The continued presence of Brixadi as a branded alternative.

Key Takeaways

• US 10,592,168 is primarily a method-of-treatment patent with formulation and pharmacokinetic limitations.
• The commercial core is a monthly subcutaneous buprenorphine depot using approximately 18 wt% buprenorphine free base, 32 wt% PLGA, and 50 wt% NMP.
• Claims 5 and 6 directly target 28-day and monthly administration.
• The patent covers broad ranges of buprenorphine concentration, PLGA content, polymer ratio, molecular weight, dose, volume, and solvent composition.
• A generic using the same PLGA/NMP depot architecture faces substantial infringement risk.
• Brixadi is a branded competitive product, not a biosimilar, and may compete without practicing the same formulation claims.
• The expiration date must be determined from the full USPTO prosecution and patent-term record, not the issue date alone.
• Generic entry risk depends on the entire Sublocade patent estate, Orange Book listings, any Paragraph IV certifications, and related litigation.

FAQs

Is US 10,592,168 a composition patent or a method patent?

It is principally a method patent. The claims require treating opioid dependence by subcutaneous administration of a defined buprenorphine-PLGA-NMP composition with specified pharmacokinetic or burst-release characteristics.

Does changing the buprenorphine salt avoid the patent?

Not necessarily. Claim 1 covers buprenorphine in the form of the free base or a pharmaceutically acceptable salt. A salt substitution alone may remain within the claim.

Does a weekly buprenorphine injection avoid the patent?

It may avoid the specific monthly dosing claims, but it could still raise issues under claim 1 if the composition, route, indication, and pharmacokinetic limitations are satisfied.

Is NMP required in every claim?

NMP is expressly required by claim 1. Claim 21 permits NMP in combination with glycerin, propylene glycol, polyethylene glycol, or combinations of those liquids.

Can a different PLGA ratio avoid infringement?

A different ratio may avoid the narrower 50/50 claim, but claim 14 covers a broad list of PLGA ratios, and claim 1 does not specify one particular lactide:glycolide ratio. The complete claim set and related patents must be analyzed together.

References

1. United States Patent and Trademark Office. (2020). U.S. Patent No. 10,592,168, injectable compositions and methods of use thereof.
2. U.S. Food and Drug Administration. (2017). Sublocade prescribing information. Indivior Inc.
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations.
4. United States Code. (2024). 35 U.S.C. §§ 154, 156.
5. U.S. Food and Drug Administration. (2023). Brixadi prescribing information. Braeburn Inc.
6. U.S. Food and Drug Administration. (2024). ANDA, 505(b)(2), and new drug application regulatory pathways.

Drugs Protected by US Patent 10,592,168

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Indivior	SUBLOCADE	buprenorphine	SOLUTION, EXTENDED RELEASE;SUBCUTANEOUS	209819-001	Nov 30, 2017		RX	Yes	No	10,592,168					TREATMENT OF MODERATE TO SEVERE OPIOID USE DISORDER
Indivior	SUBLOCADE	buprenorphine	SOLUTION, EXTENDED RELEASE;SUBCUTANEOUS	209819-002	Nov 30, 2017		RX	Yes	Yes	10,592,168					TREATMENT OF MODERATE TO SEVERE OPIOID USE DISORDER

International Family Members for US Patent 10,592,168

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2011263478
Brazil	112012031290
Canada	2801676