United States Patent 8,318,202 Scope and Claims for Ibuprofen-Famotidine Immediate-Release Bilayer and Tablet-in-Tablet Compositions
Executive summary: U.S. Patent 8,318,202 claims an immediate-release, direct-contact ibuprofen (750–850 mg) plus famotidine (24–28 mg) combination tablet in which the layers are engineered to release both actives at about the same time, with no enteric coating and no barrier-coated famotidine multiparticulates dispersed in an ibuprofen matrix. The claims are tightly constrained by layer geometry (including tablet-in-tablet where the ibuprofen layer completely surrounds the famotidine layer), direct physical contact parameters (surface area cap tied to claim 27), and stability/impurity controls around sulfamide formation at defined storage conditions. Claim 2/11/28 define a specific dose pair (800 mg ibuprofen + 26.6 mg famotidine). The patent’s protection is largely composition- and structure-defined, with expiration and enforcement strength depending on how the claims align to product-specific tablet construction, coating, and impurity specifications in FDA-approved labeling and CMC.
What patents protect an immediate-release ibuprofen plus famotidine bilayer or tablet-in-tablet tablet like US 8,318,202?
Core answer: The patent protects specific tablet constructions for an immediate-release ibuprofen/famotidine combination where the actives are in direct contact and the release profiles are engineered to begin at about the same time, with strict exclusions of enteric coating and certain famotidine particulate architectures.
Claim 1: What is actually protected
Claim 1 is the broad independent claim and defines a composition with these required elements:
- Tablet dosage form (immediate release).
- Two layers:
- First layer: 750–850 mg ibuprofen + excipients
- Second layer: 24–28 mg famotidine + excipients
- Direct contact of the active ingredients (ibuprofen and famotidine are in direct contact).
- Immediate release:
- No enteric coating
- No sustained or delayed release formulation
- Release of both actives begins at about the same time.
- No enteric or altered-release architecture:
- “None of the pharmaceutical composition, the first layer, the second layer, the famotidine, or the ibuprofen is enterically coated”
- “or formulated for sustained or delayed release”
- Specific exclusion of a known architecture:
- Famotidine is not present as barrier coated famotidine multiparticulates dispersed in an ibuprofen matrix.
- Stability/impurity limitation:
- No more than ~1% sulfamide after storage at 40°C/75% RH for one month.
Claim set: How the dependent claims narrow the protected embodiments
Claims 2–7 and 11–17 and 18–24 repeat a pattern:
- Lock the active dose (claim 2 and 11) to 800 mg ibuprofen + 26.6 mg famotidine.
- Add time-and-temperature dependent sulfamide limits:
- ~1% threshold for longer storage windows (e.g., 3, 6 months; room temperature windows up to 36 months).
- ~0.6% threshold for corresponding windows (again up to 36 months).
Claim 8–9 and 25–26 and 42–43 constrain the tablet geometry:
- Tablet-in-tablet where the first layer completely surrounds the second layer.
- Bilayer tablet.
Claim 27: What additional structural constraint appears
Claim 27 introduces a new quantified parameter beyond claim 1:
- It keeps the same general architecture (ibuprofen + famotidine, immediate release, no enteric coating, direct contact, same-time release, and the exclusion regarding barrier coated famotidine multiparticulates).
- It adds a surface area limit:
- “famotidine active pharmaceutical ingredient and ibuprofen active pharmaceutical ingredient have a surface area of direct physical contact that does not exceed 130 mm².”
So claim 27 is effectively a direct-contact geometry cap claim, narrowing the scope from “direct contact” (claim 1) to “direct contact with limited interfacial area” (claim 27).
How many claims in US 8,318,202 are dose-locked or impurity-limited?
Executive answer: In the claim text provided, the patent uses two main narrowing levers: (1) dose lock at a single pair of amounts and (2) sulfamide impurity limits at multiple storage regimes. The dependent claims are largely structured as repeated stability windows.
Dose-locked claims
- Claim 2: 800 mg ibuprofen + 26.6 mg famotidine (within the claim 1 framework)
- Claim 11: same dose pair (within claim 10 framework)
- Claim 28: same dose pair (within claim 27 framework)
Sulfamide impurity-limited claims (all depend on the core structure)
Across the provided text, sulfamide limits appear with these quantitative tripwires:
- ~1% sulfamide:
- Claim 3: ≤1% at 40°C/75% RH for 3 months
- Claim 4: ≤1% at 40°C/75% RH for 6 months
- Claim 12–17: ≤1% sulfamide at room temperature for 6 to 36 months (with 1% thresholds through 36 months)
- Claim 29–34: ≤1% at room temperature for 6 to 24 months
- ~0.6% sulfamide:
- Claim 5–7: ≤0.6% at 40°C/75% RH for 1, 3, 6 months
- Claim 18–24: ≤0.6% at room temperature for 3 to 36 months
- Claim 35–41: ≤0.6% at room temperature for 3 to 36 months
Interpretation for scope: these are not broad “stability broadly” statements. They are numerical acceptance thresholds that can become decisive in infringement analysis if a commercial product’s internal impurity profile differs by even small amounts or storage condition interpretation.
When does US 8,318,202 lose exclusivity, and what does that mean for enforcement?
Executive answer: No expiration, priority date, or patent-term-adjustment/extension data is provided in the input. Without that data, it is not possible to compute or state the exclusivity end date for U.S. Patent 8,318,202, or to map it to Hatch-Waxman periods and generic launch windows.
Enforcement relevance (from claim structure alone):
- The claims appear to be directed to formulation structure and impurity outcomes rather than methods, which usually means infringement pivots on product-by-product tablet construction and specification compliance.
What is the Orange Book status of U.S. Patent 8,318,202 for ibuprofen-famotidine?
Executive answer: Orange Book listing status cannot be determined from the provided claim text alone because no drug product name, NDA/ANDA number, listed active ingredient pair, or patent listing data is supplied.
How strong is the patent estate for an ibuprofen-famotidine direct-contact tablet?
Executive answer: Within the provided claim set, strength is highest where competitors must adopt the same structural constraints:
- Immediate release with no enteric coating on the whole tablet and on both layers and actives.
- Direct physical contact between ibuprofen and famotidine actives.
- Same-time release onset for both actives.
- Exclusion of a specific famotidine architecture: “barrier coated famotidine multiparticulates dispersed in an ibuprofen matrix.”
- Tablet geometry:
- bilayer tablet, or
- tablet-in-tablet with complete surrounding.
- Quantified impurity limits for “sulfamide” at specified storage conditions.
- In claim 27, an interfacial surface area limit (≤130 mm²).
Where strength can be tested in practice:
- If a competing product is engineered to avoid one of the excluded constructions (especially the barrier-coated multiparticulate dispersion architecture), or if its direct-contact surface area exceeds the claim-27 cap (when asserting claim 27), it may reduce literal overlap.
- If a competitor’s manufacturing and stability profiles result in a different sulfamide spec after defined conditioning, the impurity-driven limitations become a factual battleground.
What formulations are protected by US 8,318,202: bilayer vs tablet-in-tablet?
Executive answer: The patent protects both bilayer tablets and tablet-in-tablet embodiments, but both require the same functional and structural anchors: direct contact, immediate release, no enteric or sustained/delayed release, same-time release onset, and no barrier-coated famotidine multiparticulates dispersed in ibuprofen.
Bilayer tablet embodiments
- Explicitly covered by claims stating the composition “is a bilayer tablet” (e.g., claim 9 and 26).
Tablet-in-tablet embodiments
- Explicitly covered by claims requiring the first layer completely surrounds the second layer (e.g., claim 8 and 25 and 42).
Direct contact as a functional constraint
The claims repeatedly require:
- Actives are “in direct contact.”
- For claim 27, the direct-contact interfacial surface area does not exceed 130 mm².
Which claim limitations create the highest design-around risk for generic or follow-on products?
Executive answer: The most design-sensitive elements in the provided claim text are:
-
Immediate-release and no enteric coating
- “None … is enterically coated”
- No sustained/delayed release formulation for composition or layers.
-
Same-time release onset
- “release … begins to occur at about the same time.”
-
Exclusion of barrier coated famotidine multiparticulates dispersed in an ibuprofen matrix
- A competitor can design around by changing famotidine form/dispersion system to avoid that specific multiparticulate architecture.
-
Direct physical contact and, for claim 27, the ≤130 mm² surface area cap
- This targets microstructural contact area created during tableting, granulation, layer thickness, and interface design.
-
Sulfamide acceptance limits under defined conditioning
- Multiple thresholds at multiple times and temperatures.
- If competitors set their process and formulation to manage sulfamide differently, they may fall outside literal limits or force noninfringement arguments based on measured impurity results.
What generic entry risks exist for an ibuprofen-famotidine combination tablet under these claims?
Executive answer: High-risk exposure arises when a generic product:
- Uses a structurally similar direct-contact bilayer or tablet-in-tablet approach,
- Achieves “about the same time” release initiation for both actives,
- Uses no enteric coating and avoids delayed-release/sustained-release architectures, and
- Meets similar or worse sulfamide behavior such that its measured sulfamide after specified storage is within the claimed thresholds.
What reduces generic risk based on claim text:
- Using an enteric or delayed-release architecture (the claims exclude it).
- Using famotidine multiparticulates that are barrier-coated and dispersed in an ibuprofen matrix (the claims exclude that architecture).
- Producing a tablet where direct-contact interfacial surface area exceeds 130 mm² (claim 27-specific narrowing).
- Having sulfamide impurity outcomes above the claimed thresholds under the specified storage conditions.
How does this patent compare with typical enteric-prodrug or delayed-acid-suppressing strategies?
Executive answer: US 8,318,202 is positioned against common acid-control design choices that rely on:
- enteric coatings, or
- delayed/sustained-release profiles,
- or multiparticulate barrier strategies in which the barrier-coated component is dispersed in a matrix.
Its claims instead require:
- immediate release
- no enteric coating
- direct contact and engineered release synchrony.
This makes the patent most relevant to products that intentionally co-formulate ibuprofen and famotidine for early co-release while controlling unwanted impurity formation (sulfamide).
What patent litigation affects US 8,318,202?
Executive answer: Litigation status cannot be determined from the provided claim text because no parties, case captions, forum, settlement terms, or docket references are supplied.
What regulatory pathway facts matter for infringement in practice (ANDA vs 505(b)(2))?
Executive answer: The claim text is formulation-focused and does not depend on the FDA regulatory pathway. Practical infringement evidence typically comes from:
- NDA/ANDA-embedded CMC describing tablet architecture,
- batch records for layer geometry and actives contact,
- stability/impurity datasets addressing “sulfamide,”
- dissolution profiles supporting “about the same time” release onset.
Key Takeaways
- U.S. Patent 8,318,202 claims an immediate-release ibuprofen (750–850 mg) plus famotidine (24–28 mg) tablet with direct contact between actives and release onset at about the same time.
- The patent excludes enteric coating and excludes formulations where famotidine appears as barrier coated multiparticulates dispersed in an ibuprofen matrix.
- Scope is constrained by tablet construction (bilayer; tablet-in-tablet with complete surrounding) and, in claim 27, by an interfacial direct-contact surface area limit of ≤130 mm².
- Multiple dependent claims add numerical sulfamide impurity limits (≤1% or ≤0.6%) across defined storage conditions and timepoints, making impurity/stability evidence central to enforcement and design-around.
- Specific dosage embodiments are locked at 800 mg ibuprofen + 26.6 mg famotidine in multiple claims.
FAQs
- Does “direct contact” require physical contact of pure API particles or can it be contact through excipients at the layer interface?
- How does the “about the same time” dissolution onset language typically get tested in infringement arguments?
- What is the design-around impact of exceeding the 130 mm² direct-contact surface area limit in claim 27?
- If a competitor uses enteric coating on only one layer or only on one API, is it automatically outside claim scope?
- How do sulfamide limits under specific storage conditions affect both literal infringement and expert-based noninfringement?
References
- Provided claim text for U.S. Patent 8,318,202 (claims 1–43) in the prompt.
