Details for Patent: 8,475,832

Which drugs does patent 8,475,832 protect, and when does it expire?

Patent 8,475,832 protects SUBOXONE and is included in one NDA.

This patent has thirty-two patent family members in twenty-four countries.

Summary for Patent: 8,475,832

Title:	Sublingual and buccal film compositions
Abstract:	The present invention relates to products and methods for treatment of narcotic dependence in a user. The invention more particularly relates to self-supporting dosage forms which provide an active agent for treating narcotic dependence while providing sufficient buccal adhesion of the dosage form.
Inventor(s):	Garry L. Myers, Samuel D. Hilbert, Bill J. Boone, B. Arlie Bogue, Pradeep Sanghvi, Madhusudan Hariharan
Assignee:	Indivior UK Ltd
Application Number:	US12/537,571
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,475,832
Patent Claim Types: see list of patent claims	Use; Composition; Formulation; Dosage form;

US Patent 8,475,832: Scope, Claims, Expiration, Orange Book Status, and Suboxone Film Patent Landscape

US Patent 8,475,832 protects buprenorphine/naloxone orally dissolving films that use an acidic buffer to create a local oral pH of approximately 3.0 to 3.5. The claims cover the composition, pharmacokinetic performance, dosage range, buffer chemistry, oral administration method, residence time, and specified buprenorphine and naloxone plasma exposure.

The patent is associated with the Suboxone sublingual film product developed by MonoSol Rx and marketed by Indivior. Its principal commercial relevance is the combination of buprenorphine and naloxone in a polymeric film matrix, rather than buprenorphine/naloxone tablets or unrelated transmucosal dosage forms.

The reported patent expiration date is December 22, 2027, subject to any applicable patent-term adjustment or regulatory exclusivity. The patent has been listed in the FDA Orange Book for buprenorphine hydrochloride/naloxone hydrochloride sublingual film products.[1][2]

What does US Patent 8,475,832 cover?

The patent covers three connected claim categories:

1. A buprenorphine/naloxone film composition.
2. A method of treating narcotic dependence by administering that film in the oral cavity.
3. A pharmacokinetically defined orally dissolving film formulation.

The independent composition claim, claim 1, requires every element below:

Required element	Claim limitation
Dosage form	Film dosage composition
Carrier	Polymeric carrier matrix
Opioid agonist	Therapeutically effective buprenorphine or salt
Antagonist	Therapeutically effective naloxone or salt
Buffer	Sufficient to create a local pH of about 3 to about 3.5 in saliva
Functional purpose	Optimization of buprenorphine absorption

A product lacking buprenorphine, naloxone, a polymeric film matrix, or the specified acidic local-pH limitation would fall outside the literal scope of claim 1. The claim is narrower than a general claim to any buprenorphine/naloxone oral dosage form.

How broad is the composition claim in Patent 8,475,832?

Claim 1 is composition-focused but contains a functional and numerical pH limitation. The central technical concept is selective transmucosal delivery: the acidic environment is intended to optimize buprenorphine absorption while limiting naloxone absorption.

The claim does not require:

• A specific polymer;
• A specific film thickness;
• A specific manufacturing process;
• A particular buprenorphine salt;
• A particular naloxone salt;
• A particular commercial strength;
• A named film brand;
• A specific dissolution time.

The claim does require a polymeric carrier matrix and the claimed local pH. A formulation using a different dosage form, such as a tablet, capsule, injectable, implant, or ordinary lozenge, would not literally satisfy the film limitation.

The pH limitation creates two potential claim-construction issues. First, the claim refers to local pH "in the presence of saliva," rather than only the dry-film formulation before administration. Second, the pH must be sufficient to optimize buprenorphine absorption. A challenger could argue that the pH requirement is indefinite, not reproducible, or absent from a competing product. The patent owner would likely rely on formulation data, testing conditions, and the patent specification to establish how local pH is measured.

What do dependent claims 2 through 8 add?

Claims 2 through 8 narrow claim 1 through performance, quantity, and formulation limitations.

Claim	Additional limitation	Commercial significance
2	Buprenorphine absorption is bioequivalent to an equivalent buprenorphine tablet	Links the film to tablet-level systemic exposure
3	At least one polymer is at least 25% by weight	Creates a measurable polymer-content limitation
4	Buffer-to-buprenorphine ratio is approximately 2:1 to 1:5 by weight	Limits buffer loading
5	Polymer matrix includes a self-supporting film-forming polymer	Reinforces the physical film structure
6	Buprenorphine amount is approximately 2 to 16 mg per dose	Encompasses the commercial strength range and higher doses
7	Buffer includes sodium citrate, citric acid, or combinations	Covers citrate-buffer embodiments
8	Buffer includes acetic acid, sodium acetate, or combinations	Covers acetate-buffer embodiments

Claims 7 and 8 are particularly important for design-around analysis. A formulation using a different buffer may avoid the literal language of those dependent claims, but it could remain within claim 1 if it produces the required local pH and satisfies the other limitations.

What method-of-use protection does Patent 8,475,832 provide?

Claim 9 covers a method of treating narcotic dependence. It requires:

1. Providing a composition containing a polymeric matrix;
2. Including buprenorphine and naloxone;
3. Including a buffer that creates a local pH of about 3 to 3.5;
4. Optimizing buprenorphine absorption;
5. Inhibiting naloxone absorption; and
6. Administering the composition to the oral cavity.

Claims 10 through 14 narrow the method claim by adding:

• Bioequivalent buprenorphine absorption to a tablet;
• Buccal or sublingual administration;
• Oral-cavity residence for at least one minute;
• Residence between approximately one and 1.5 minutes;
• Residence of up to three minutes.

The method claims are directed to use in treating narcotic dependence. They do not cover every use of the composition outside that therapeutic context. In an ANDA dispute, infringement analysis would typically focus on the proposed product labeling and the composition itself, with method-of-use allegations depending on the approved instructions and intended administration route.

What pharmacokinetic limitations appear in claims 15 through 19?

Claims 15 through 19 define the formulation partly through in vivo plasma exposure.

Claim 15 requires an orally dissolving buprenorphine/naloxone film with:

Analyte	Claimed Cmax range
Buprenorphine	About 0.624 to 5.638 ng/mL
Naloxone	About 41.04 to 323.75 pg/mL

Claim 16 adds a mean buprenorphine AUC range of approximately 5.431 to 56.238 hr·ng/mL. Claim 17 adds a mean naloxone AUC range of approximately 102.88 to 812.00 hr·pg/mL.

Claims 18 and 19 specify:

• Buprenorphine: approximately 2 to 16 mg;
• Naloxone: approximately 0.5 to 4 mg.

These claims can create a difficult infringement and validity profile. The formulation must produce the claimed pharmacokinetic profile under the relevant testing conditions. Variability in subjects, sampling intervals, dose strength, assay methods, and statistical treatment can affect whether a product falls within the claimed ranges.

The claims also create potential enablement and written-description issues if the claimed ranges extend across compositions or doses that were not adequately demonstrated in the patent disclosure. The strength of these arguments depends on the specification, examples, prosecution history, and claim construction.

What drug product is associated with Patent 8,475,832?

The patent is principally associated with Suboxone sublingual film, an FDA-approved buprenorphine hydrochloride/naloxone hydrochloride product used for opioid dependence treatment.[2]

The commercial product has been marketed in multiple strengths, including:

Buprenorphine	Naloxone
2 mg	0.5 mg
4 mg	1 mg
8 mg	2 mg
12 mg	3 mg

These strengths fall within the dosage ranges recited in claims 6, 18, and 19. The product uses a thin polymeric film administered sublingually or buccally, consistent with the administration routes recited in claim 11.

The claims are therefore commercially relevant to generic products seeking approval for buprenorphine/naloxone sublingual film, not simply to products containing the same active ingredients.

What is the Orange Book status of US Patent 8,475,832?

Patent 8,475,832 has been listed in the FDA Orange Book in connection with Suboxone sublingual film and related buprenorphine/naloxone film products.[1] Orange Book listing makes the patent relevant to abbreviated new drug applications and Paragraph IV certification strategy.

An Orange Book listing does not establish validity or infringement. It creates a regulatory patent-notice mechanism. A generic applicant may:

• Certify that the patent information is inaccurate;
• Certify that the patent has expired;
• Certify that the generic product will launch after expiration;
• File a Paragraph IV certification asserting that the patent is invalid, unenforceable, or will not be infringed.

A timely Paragraph IV notice can trigger a Hatch-Waxman patent infringement action and, depending on the circumstances, a 30-month stay of FDA approval under 21 U.S.C. § 355(j)(5)(B)(iii).[3]

When does Patent 8,475,832 lose exclusivity?

The reported expiration date is December 22, 2027.[1] That date is the principal patent barrier identified for the patent family associated with the buprenorphine/naloxone film technology.

The practical generic-entry date can differ from the nominal expiration date because of:

• Paragraph IV litigation;
• Court orders or preliminary injunctions;
• Settlements permitting earlier launch;
• Patent-term adjustment;
• Pediatric exclusivity;
• Additional later-expiring patents;
• Product-specific regulatory deficiencies;
• Manufacturing or supply constraints.

Patent 8,475,832 should therefore be analyzed with the other Orange Book-listed patents for the applicable Suboxone film NDA. Expiration of one patent does not necessarily eliminate all patent-based entry risk.

Which related patents form the Suboxone film patent estate?

The relevant estate includes the ’832 patent and related patents directed to film composition, dosage-form architecture, manufacturing, or other product characteristics. Publicly identified patents associated with Suboxone film litigation and Orange Book protection have included:

Patent	Principal relevance	Reported expiration
US 8,475,832	Buprenorphine/naloxone film, acidic local pH, exposure and use claims	December 22, 2027
US 8,603,514	Related Suboxone film formulation and dosage-form protection	December 22, 2027
US 9,962,385	Later-generation product or formulation claims	Generally later than the core 2027 patents
Other later-issued patents	Product, formulation, process, or manufacturing protection	Varies

The precise blocking effect depends on which patents remain listed for the NDA, whether claims survive litigation, and whether the generic product practices the asserted claims. Patent-family analysis should distinguish continuation claims from genuinely different technical coverage. A continuation with overlapping disclosure can still produce materially different infringement risk if it claims a different formulation parameter or manufacturing step.

What Paragraph IV challenges affected Suboxone film?

Generic manufacturers challenged Suboxone film patents through Paragraph IV litigation after filing ANDAs for buprenorphine/naloxone sublingual film. Prominent defendants included Dr. Reddy's Laboratories, Teva Pharmaceuticals, and other generic applicants.

Indivior brought infringement actions asserting, among others, the ’832 and ’514 patents. The litigation addressed:

• Whether the generic films fell within the claimed polymeric matrix;
• Whether the products met the pH and formulation limitations;
• Whether the patents were invalid for obviousness;
• Whether the written description supported the full claim scope;
• Whether the claims were indefinite;
• Whether generic launch should be enjoined.

The Federal Circuit's Suboxone film decisions made clear that patent validity and infringement could diverge by patent and claim set. A patent may survive one challenge while a related continuation fails on written-description, obviousness, or claim-scope grounds. The litigation record is therefore more useful when analyzed claim by claim than at the family level.[4]

What litigation and settlement risks affect generic entry?

The principal litigation risks for a generic sublingual film are:

Composition infringement

A generic product may be exposed if it contains the claimed combination of buprenorphine, naloxone, polymeric matrix, and acidic buffer. The pH limitation is central. Testing may be required to determine whether the product creates the claimed local oral pH.

Pharmacokinetic infringement

Claims 15 through 19 create exposure risk if the generic produces Cmax and AUC values within the claimed ranges. Bioequivalence studies conducted for FDA approval may generate evidence relevant to these claims.

Label-based method infringement

A label directing sublingual or buccal use for opioid dependence could support allegations under the method claims, particularly where the label instructs the patient to retain the film in the oral cavity for the claimed period.

Manufacturing evidence

A generic can avoid a composition claim yet face process or manufacturing claims in related patents. Discovery of batch records, master manufacturing instructions, excipient specifications, and quality-control methods can become significant in litigation.

Settlement timing

Hatch-Waxman settlements can establish an agreed generic launch date before patent expiration. The commercial outcome depends on whether the settlement provides an exclusive launch opportunity, a non-exclusive entry date, or a license subject to supply and regulatory conditions. Settlement terms for particular defendants must be reviewed in the relevant court docket or regulatory filing rather than inferred from FDA approval alone.

How strong is the patent estate for buprenorphine/naloxone film?

The ’832 patent has meaningful commercial breadth but several identifiable technical vulnerabilities.

Strengths

• It covers the commercially important film architecture.
• It combines both active ingredients in one claim.
• It includes the local-pH mechanism central to selective absorption.
• It reaches common commercial buprenorphine strengths.
• It includes composition, method, and pharmacokinetic claim categories.
• The claims can be asserted against both the product and its labeled use.

Vulnerabilities

• The pH limitation may require precise testing and construction.
• Functional language such as "optimize absorption" and "inhibit absorption" may invite definiteness or proof disputes.
• Pharmacokinetic ranges can be sensitive to study design and variability.
• The patent must support the full breadth of its numerical ranges.
• Alternative buffers and polymer systems may support design-around positions.
• Related patent litigation has shown that written-description and obviousness issues can materially reduce the enforceability of continuation patents.

The estate is strongest against products that closely copy the commercial film's active ingredients, polymer system, acidic buffer strategy, dose range, and sublingual administration method.

What design-around strategies could reduce infringement risk?

Potential design-around approaches include:

1. Using a different dosage form, such as a tablet or another non-film delivery system.
2. Altering the polymer matrix so that the product does not satisfy the claimed film-forming or polymer-content limitations.
3. Using a buffer system that does not produce a local pH of approximately 3 to 3.5.
4. Changing the buffer-to-buprenorphine ratio.
5. Developing a product with a different absorption profile outside the claimed Cmax and AUC ranges.
6. Modifying dose strengths or naloxone ratios.
7. Using a delivery route that is not buccal or sublingual, subject to FDA requirements and other patent claims.
8. Separating buprenorphine and naloxone into different dosage units.

These approaches do not automatically eliminate risk. A product may avoid claims 7 and 8 while remaining within claim 1. It may avoid the ’832 patent yet infringe a related patent directed to film construction, manufacturing, or product performance.

How does the ’832 patent compare with tablet protection?

Tablet and film products share the same active ingredients but present materially different patent risks.

Issue	Sublingual tablet	Sublingual film
Primary dosage-form limitation	Tablet	Polymeric film
’832 relevance	Generally limited if no film is used	Directly relevant
Local-pH limitation	May not be satisfied	Central to the claimed technology
Manufacturing risk	Tablet compression and coating patents	Film casting, drying, matrix, and laminate patents
Bioequivalence	Tablet comparator may be relevant	Film plasma profile may be directly claimed
Regulatory route	ANDA or applicable pathway	ANDA with film-specific product characterization

A tablet generic does not necessarily avoid every buprenorphine/naloxone patent, but it is less likely to infringe the film-specific limitations of the ’832 patent.

What is the commercial exposure from Patent 8,475,832?

Suboxone has historically been a major opioid-dependence product, and the film formulation became the principal commercial presentation after the branded tablet's market position declined. The economic effect of the patent is therefore concentrated in:

• Generic film entry timing;
• Price erosion after multiple generic launches;
• Indivior's market-share retention;
• Manufacturing capacity for solvent-cast films;
• Patent settlements and launch licenses;
• Substitution between film and tablet products.

A generic entrant able to launch a therapeutically equivalent film can compete directly with the branded product. A delayed entrant may face lower value if several generics have already secured approval or if later patents create additional barriers.

Key Takeaways

• US Patent 8,475,832 covers buprenorphine/naloxone orally dissolving films with a local saliva pH of about 3 to 3.5.
• The patent claims the composition, opioid-dependence treatment method, oral-cavity residence time, dose ranges, buffer chemistry, and pharmacokinetic exposure.
• Claims 1, 9, and 15 are the principal independent claims.
• Claims 7 and 8 specifically identify citrate and acetate buffer systems.
• Claims 15 through 19 create separate risk based on buprenorphine and naloxone Cmax and AUC ranges.
• The patent has been associated with Suboxone sublingual film and has been listed in the Orange Book.
• The reported expiration date is December 22, 2027.
• Generic manufacturers including Dr. Reddy's and Teva challenged the relevant Suboxone film patent estate through Paragraph IV litigation.
• The strongest infringement case is against a product that copies the active ingredients, polymeric film matrix, acidic buffer strategy, dosage range, and sublingual administration.
• A design-around must be evaluated against the entire related patent estate, not the ’832 patent alone.

FAQs About US Patent 8,475,832

Does Patent 8,475,832 cover all buprenorphine/naloxone products?

No. It is directed to a film dosage composition and related oral administration methods. Tablets and other dosage forms may fall outside the literal scope of the asserted claims, although separate patents may apply.

Is the local pH requirement the most important limitation?

Yes. The requirement for a local pH of approximately 3 to 3.5 in the presence of saliva is central to claim 1 and the method claims. It is also a likely focus of infringement testing and claim construction.

Does using citrate automatically infringe Patent 8,475,832?

No. Citrate is expressly identified in claim 7, but infringement still requires satisfaction of the other limitations, including the polymeric film matrix, buprenorphine, naloxone, and claimed local-pH conditions.

Can a generic avoid the patent by changing the buprenorphine dose?

Possibly, but changing the dose alone may not avoid the patent. Claim 1 has no specific dose limitation, and claims 6 and 18 cover a broad range from approximately 2 to 16 mg.

Is expiration of the ’832 patent sufficient for unrestricted generic film entry?

No. Other Orange Book-listed patents, continuation patents, litigation outcomes, regulatory exclusivity, and settlement terms may affect the actual entry date.

Does FDA approval establish that a generic does not infringe?

No. FDA approval and patent infringement are separate questions. An ANDA may be approved while patent litigation remains pending, subject to the statutory stay and any court orders.

References

1. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
2. U.S. Food and Drug Administration. (2010). Suboxone sublingual film prescribing information. FDA.
3. 21 U.S.C. § 355(j)(5)(B)(iii) (2024).
4. U.S. Court of Appeals for the Federal Circuit. (2019). Indivior Inc. v. Dr. Reddy’s Laboratories, S.A., decisions concerning U.S. Patent Nos. 8,475,832 and 8,603,514.
5. U.S. Patent and Trademark Office. (2013). U.S. Patent No. 8,475,832: Pharmaceutical compositions and methods of use. Google Patents/USPTO patent records.

Drugs Protected by US Patent 8,475,832

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	SUBOXONE	buprenorphine hydrochloride; naloxone hydrochloride	FILM;BUCCAL, SUBLINGUAL	022410-001	Aug 30, 2010	AB	RX	Yes	No			Y			THIS DRUG IS ADMINISTERED BY SUBLINGUAL ROUTE TO HUMANS FOR MAINTENANCE TREATMENT OF OPIOID DEPENDENCE
Indivior	SUBOXONE	buprenorphine hydrochloride; naloxone hydrochloride	FILM;BUCCAL, SUBLINGUAL	022410-003	Aug 10, 2012	AB	RX	Yes	No			Y			THIS DRUG IS ADMINISTERED BY SUBLINGUAL ROUTE TO HUMANS FOR MAINTENANCE TREATMENT OF OPIOID DEPENDENCE
Indivior	SUBOXONE	buprenorphine hydrochloride; naloxone hydrochloride	FILM;BUCCAL, SUBLINGUAL	022410-002	Aug 30, 2010	AB	RX	Yes	No			Y			THIS DRUG IS ADMINISTERED BY SUBLINGUAL ROUTE TO HUMANS FOR MAINTENANCE TREATMENT OF OPIOID DEPENDENCE
Indivior	SUBOXONE	buprenorphine hydrochloride; naloxone hydrochloride	FILM;BUCCAL, SUBLINGUAL	022410-004	Aug 10, 2012	AB	RX	Yes	Yes			Y			THIS DRUG IS ADMINISTERED BY SUBLINGUAL ROUTE TO HUMANS FOR MAINTENANCE TREATMENT OF OPIOID DEPENDENCE

International Family Members for US Patent 8,475,832

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	078417
Australia	2010279440
Brazil	112012002817
Canada	2770180
Chile	2012000313
China	102548535
Colombia	6511219