Details for Patent: 11,278,506

Which drugs does patent 11,278,506 protect, and when does it expire?

Patent 11,278,506 protects MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM and is included in one NDA.

This patent has three patent family members in three countries.

Summary for Patent: 11,278,506

Title:	Pharmaceutical formulation
Abstract:	A formulation for oral administration comprises an expectorant, an analgesic, and at least one additional active ingredient having a modified release providing a therapeutic effect for each of the active ingredients for up to 12 hours.
Inventor(s):	Raghu Cavatur, Kevin Chen, Matthew Kaser, Hongchun Qiu, Ernest Joseph Woodhouse, Josef Borovicka, Elliot Wilkinson
Assignee:	Reckitt Benckiser LLC , RB Health US LLC
Application Number:	US15/291,061
Patent Claim Types: see list of patent claims	Composition; Formulation; Dosage form;

United States Patent 11,278,506: Scope of Claims and US Patent Landscape for a 12-Hour Bilayer Combination of Guaifenesin, Dextromethorphan, and Naproxen

What is the claim scope of US Patent 11,278,506?

US Patent 11,278,506 claims a specific bilayer tablet formulation and requires both composition-level and performance/dissolution-level limitations. The core claim set (independent claim plus dependent claims) is concentrated on: (1) a fixed quantitative formulation for a three-drug combination; (2) 12-hour therapeutic effect for all three APIs; (3) naproxen dissolution speed in pH 6.8 phosphate buffer (substantially all dissolves within 30 minutes); and (4) a bilayer tablet architecture where the immediate release layer holds substantially all naproxen and contains no hypromellose and no hydroxyethyl cellulose.

Independent claim structure (Claims 1, 3, 5)

The claims are written as overlapping independent sets with near-identical composition lists, with key variations in the hypromellose and hydroxyethyl cellulose ranges and, in Claim 5, an added comparative dissolution-profile limitation.

Claim 1 (core formulation set with fixed excipient amounts; one critical architectural constraint)

Claim 1 requires the following amounts (units as stated in the claim):

APIs

• Guaifenesin: about 600 mg
• Dextromethorphan: about 30 mg (or pharmaceutically acceptable salt)
• Naproxen: about 110 mg (or pharmaceutically acceptable salt)

Excipients

• Hypromellose: about 28 mg
• Microcrystalline cellulose: about 61.29 mg
• Hydroxyethyl cellulose: about 14 mg
• Croscarmellose sodium: about 23 mg
• Sodium lauryl sulfate: about 10 mg
• Sodium bicarbonate: about 60 mg
• Polyethylene glycol 4000: about 51.45 mg
• Magnesium stearate: about 5.8 to 9 mg

Performance and structural limitations

• The composition provides a therapeutic effect for each of guaifenesin, naproxen, and dextromethorphan for 12 hours.
• Naproxen dissolution: substantially all dissolves within 30 minutes in pH 6.8 phosphate buffer.
• Dosage form: bilayer tablet
  • Immediate release layer: contains substantially all naproxen
  • Immediate release layer contains:
    • at least 100 mg guaifenesin
    • at least 8 mg dextromethorphan
  • Immediate release layer contains none of hypromellose
  • Immediate release layer contains none of hydroxyethyl cellulose

Claim 3 (same architecture and endpoints; excipient ranges expanded)

Claim 3 keeps the bilayer/immediate-release architecture and the same 12-hour and pH 6.8 dissolution endpoints, but changes excipient quantities to ranges:

• Hypromellose: about 18 to 28 mg
• Hydroxyethyl cellulose: about 8 to 14 mg

All other listed quantities remain essentially the same as Claim 1 (guaifenesin about 600 mg; dextromethorphan about 30 mg; naproxen about 110 mg; and the same amounts for the other excipients as recited).

Claim 5 (same as Claim 3 but adds a comparative naproxen dissolution-profile limitation)

Claim 5 maintains the Claim 3 ranges for:

• hypromellose: 18 to 28 mg
• hydroxyethyl cellulose: 8 to 14 mg

It also requires, beyond the dissolution threshold (“substantially all dissolves within 30 minutes in pH 6.8 phosphate buffer”), that:

• Naproxen dissolution profile is substantially the same as the dissolution profile of:
  • naproxen in an immediate release pharmaceutical composition containing 220 mg naproxen
  • that does not contain guaifenesin and dextromethorphan

Claim 5 also retains the bilayer constraint that the immediate release layer contains:

• substantially all naproxen
• at least 100 mg guaifenesin
• at least 8 mg dextromethorphan
• none of hypromellose
• none of hydroxyethyl cellulose

Dependent claims (Claims 2, 4, 6)

These narrow an excipient placement/extent limitation:

• Claim 2: Immediate release layer contains substantially all of:
  • sodium lauryl sulfate
  • sodium bicarbonate
• Claim 4: same as Claim 2, but dependent on Claim 3
• Claim 6: same as Claim 2, but dependent on Claim 5

Practical “claim boundaries” implied by the text

The claim set is unusually rigid in three ways:

1. Architecture is enforced by “none of” exclusions

   • If any hypromellose or hydroxyethyl cellulose is present in the immediate release layer, the “contains none” limitation is not met. This is a high-risk design constraint for typical bilayer excipient spreading.

2. Dissolution is both threshold-based and (in Claim 5) comparative

   • Claim 5 adds a “substantially the same dissolution profile” requirement versus a specific comparator composition (220 mg naproxen, immediate release, no guaifenesin, no dextromethorphan). That creates a secondary infringement axis beyond time-to-dissolution.

3. Both sustained 12-hour effect and early naproxen dissolution are required

   • The patent requires the formulation to deliver a 12-hour therapeutic effect for three APIs while still achieving “substantially all naproxen” dissolution within 30 minutes in pH 6.8 phosphate buffer. That combination pushes designs toward complex release handling (for example, immediate release naproxen exposure with sustained exposure for the cough-active component(s) and/or systemic maintenance through tablet architecture).

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What is the scope of the “bilayer tablet” limitation and immediate-release layer composition?

The bilayer constraint defines a two-layer dosage form where the immediate release layer has a specific composition logic:

Immediate release layer mandatory content

• Contains substantially all naproxen
• Contains at least 100 mg guaifenesin
• Contains at least 8 mg dextromethorphan

Immediate release layer mandatory exclusions

• Contains none of hypromellose
• Contains none of hydroxyethyl cellulose

Dependent excipient placement (sodium lauryl sulfate and sodium bicarbonate)

For Claims 2/4/6, the immediate release layer contains substantially all of:

• sodium lauryl sulfate
• sodium bicarbonate

This means the claims are not limited to “tablet-level presence” of these excipients; they require location-specific inclusion for those dependent claims.

Interpretation risk points for a designer or competitor (based on claim language)

• If sodium lauryl sulfate or sodium bicarbonate is present primarily in the other layer, Claims 2/4/6 would not be met.
• If hypromellose or hydroxyethyl cellulose are distributed into the immediate release layer during manufacturing (even partially), Claims 1/3/5 could be missed due to the “contains none” clause.

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What does the naproxen dissolution profile requirement cover (and where is it most enforceable)?

Baseline dissolution threshold (Claims 1/3)

All of Claims 1 and 3 require:

• “substantially all of naproxen dissolves within 30 minutes in a pH 6.8 phosphate buffer.”

This functions as a measurable functional limitation. It is not only a theoretical formulation attribute; it is testable.

Comparative dissolution profile (Claim 5)

Claim 5 adds:

• naproxen dissolution profile substantially the same as naproxen in an immediate release composition containing 220 mg naproxen and no guaifenesin and no dextromethorphan.

This is significant because it:

• ties performance to a defined comparator product concept,
• narrows designs that meet the 30-minute threshold but deviate from “substantially the same” profile shape.

For a landscape perspective, this comparative element can raise the probability of test-driven infringement disputes (method differences, sampling times, and dissolution curves).

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How broad are Claims 1/3/5 with respect to excipient ranges?

The claim set uses two different excipient quantification strategies:

Narrow, fixed excipient amounts

• Claim 1 uses fixed values for hypromellose and hydroxyethyl cellulose:
  • hypromellose about 28 mg
  • hydroxyethyl cellulose about 14 mg

Broader ranges

• Claim 3 and Claim 5 broaden those excipients:
  • hypromellose about 18 to 28 mg
  • hydroxyethyl cellulose about 8 to 14 mg

What does that mean for design-around?

• A competitor moving outside the hypromellose and/or hydroxyethyl cellulose ranges avoids Claims 3 and 5, but may still land on Claim 1 if the fixed value requirement is met. So, avoiding Claim 1 requires deviating from about 28 mg hypromellose and/or about 14 mg hydroxyethyl cellulose.
• Since the “none of” constraints are layer-specific, design-around cannot rely only on shifting amounts between the tablet as a whole; distribution between layers matters.

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What does the claims set imply about the intended release mechanism?

Even without spec details for the second layer, the claim language forces a specific outcome pattern:

• Naproxen: must be in the immediate release layer and dissolve rapidly (substantially all in 30 minutes in pH 6.8 phosphate buffer).
• Therapeutic effect for 12 hours for all three APIs: implies that while naproxen dissolves quickly, systemic exposure and pharmacodynamic effect must persist at least 12 hours for each of guaifenesin, naproxen, and dextromethorphan.

The only explicit architecture control is:

• immediate release layer holds substantially all naproxen and minimum quantities of guaifenesin and dextromethorphan
• immediate release layer contains none of hypromellose and none of hydroxyethyl cellulose

That combination suggests the second layer (not claimed in detail in the text provided) likely carries the gel-forming/structure-forming polymers that help sustain release, while naproxen is placed for rapid dissolution.

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Where does US Patent 11,278,506 sit in the broader US patent landscape for combination cough pain relievers?

Scope of subject matter covered by the claim text

From the claim text alone, the patent landscape risk is concentrated around:

1. Three-API combination: guaifenesin + dextromethorphan + naproxen
2. Bilayer tablet formulation strategy
3. Rapid naproxen dissolution in pH 6.8 combined with 12-hour therapeutic effect
4. Layer-specific excipient segregation
5. Quantitative formulation (highly specific mg amounts)

What the claims are NOT written to cover (based on your provided text)

The claims are not drafted as:

• method-of-treatment claims (they are composition claims)
• broad “any bilayer sustained release” coverage without quantitative mg amounts
• broader API substitution claims (the claim set locks in the three named actives)

Competitive implications for infringement

For a generic or follow-on developer, infringement risk is primarily driven by whether the product matches:

• the exact combination,
• the quantitative formulation amounts (or the allowable ranges in Claims 3 and 5),
• the immediate release layer exclusion rules (“none of” hypromellose and hydroxyethyl cellulose),
• the pH 6.8 naproxen dissolution performance.

If a competitor changes either:

• API identity (substitution),
• dosage form architecture (no bilayer tablet),
• placement of hypromellose/hydroxyethyl cellulose,
• dissolution behavior for naproxen, the product can move outside the claim scope.

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Freedom-to-operate map for design and litigation positioning (claim-driven)

The following infringement “checkpoints” derive directly from claim limitations.

Checkpoint set A: APIs and quantitative amounts

• 600 mg guaifenesin (about)
• 30 mg dextromethorphan (about)
• 110 mg naproxen (about)

Checkpoint set B: time-sustained effect and dissolution threshold

• 12-hour therapeutic effect for each of the three APIs
• Naproxen: substantially all dissolves within 30 minutes in pH 6.8 phosphate buffer

Checkpoint set C: bilayer and layer-specific content

• Bilayer tablet
• Immediate release layer contains substantially all naproxen
• Immediate release layer contains at least 100 mg guaifenesin
• Immediate release layer contains at least 8 mg dextromethorphan
• Immediate release layer contains none of hypromellose
• Immediate release layer contains none of hydroxyethyl cellulose

Checkpoint set D: dependent excipient location rules

• Immediate release layer contains substantially all sodium lauryl sulfate and sodium bicarbonate (for Claims 2/4/6)

Checkpoint set E: Claim 5 comparative dissolution curve

• Naproxen dissolution profile substantially the same as a 220 mg immediate-release naproxen composition without guaifenesin and dextromethorphan

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How enforceable is the patent scope given claim drafting features?

Enforceability levers present in the claims

• Concrete quantitative composition makes it easier to test whether a product “reads on” the claim.
• Functional performance requirements (dissolution within 30 minutes in pH 6.8 buffer; therapeutic effect for 12 hours) add evidentiary anchors but also create method dependence.
• “None of” layer segregation rules create a high-friction manufacturing differentiation point and can support strong infringement positions if product layering is well documented.

Litigation risk levers created by the same features

• “Substantially all” and “substantially the same” are inherently litigable concepts. This often turns into test and statistical dispute on dissolution datasets, sampling, and curve similarity methods (even though the claims demand objective tests).

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Key Takeaways

• The patent claims a bilayer tablet with specific mg-level formulation of guaifenesin, dextromethorphan, and naproxen, plus measurable performance: 12-hour therapeutic effect and naproxen dissolution within 30 minutes in pH 6.8 phosphate buffer.
• The immediate release layer must contain substantially all naproxen and minimum guaifenesin/dextromethorphan amounts, while containing none of hypromellose and none of hydroxyethyl cellulose. This is the core design bottleneck.
• Claims 3 and 5 broaden polymer amounts into ranges, but still require strict layer exclusions.
• Claim 5 adds an extra comparative dissolution-profile requirement against a defined 220 mg immediate-release naproxen comparator with no guaifenesin and no dextromethorphan, tightening the infringement path for products that meet only the 30-minute threshold.
• Dependent claims (2/4/6) further require that the immediate release layer contains substantially all sodium lauryl sulfate and sodium bicarbonate.

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FAQs

1) Does the patent protect any combination of guaifenesin, dextromethorphan, and naproxen?

No. Protection is limited to a specific bilayer tablet formulation with specified mg amounts (or ranges for polymers in Claims 3/5), 12-hour therapeutic effect, and pH 6.8 naproxen dissolution requirements, plus strict immediate release layer content/exclusion rules.

2) What is the single highest-risk claim feature for a bilayer formulation competitor?

The requirement that the immediate release layer contains none of hypromellose and none of hydroxyethyl cellulose.

3) Can a product avoid infringement by slowing naproxen dissolution past 30 minutes in pH 6.8 buffer?

Yes. Claims 1 and 3 require “substantially all” naproxen dissolves within 30 minutes in pH 6.8 phosphate buffer. Claim 5 also depends on dissolution profile similarity.

4) What extra hurdle does Claim 5 add beyond Claims 1 and 3?

Claim 5 requires that the naproxen dissolution profile is substantially the same as naproxen in a defined comparator immediate-release formulation with 220 mg naproxen and no guaifenesin or dextromethorphan.

5) Do dependent claims expand the protected scope or narrow it?

They narrow by requiring the immediate release layer to contain substantially all of specific excipients: sodium lauryl sulfate and sodium bicarbonate (Claims 2/4/6).

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References

[1] United States Patent 11,278,506 (claim text provided in prompt).

Drugs Protected by US Patent 11,278,506

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Rb Hlth	MUCINEX 12HR COLD & FEVER MULTI-SYMPTOM	dextromethorphan hydrobromide; guaifenesin; naproxen sodium	TABLET, EXTENDED RELEASE;ORAL	217338-001	Dec 22, 2025		OTC	Yes	Yes	11,278,506		Y

International Family Members for US Patent 11,278,506

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	3001337
European Patent Office	3364955
World Intellectual Property Organization (WIPO)	2017062997