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Patent landscape, scope, and claims: |
US Patent 8,791,127: Scope, Claim-by-Claim Reach, and US Patent Landscape
United States Patent 8,791,127 claims a prolonged-release, oral-mucoadhesive formulation for mucosal treatment that combines: (i) an antiviral agent (explicitly including acyclovir), (ii) alkali metal alkyl sulfate (explicitly including sodium lauryl sulfate), (iii) a binding agent, (iv) bioadhesive polymer dispersed in the formulation (explicitly including natural milk proteins), and (v) a sustained-release polymer. The formulation is defined structurally by primary granules carrying the antiviral/diluent/alkyl sulfate/binder and by processing options including granulation plus blending and compression.
What does claim 1 cover (the core inventive concept)?
Claim 1 elements (mandatory in combination)
Claim 1 defines the protected composition as:
- Prolonged release mucoadhesive formulation for oral mucosa.
- Antiviral agent (no restriction in claim 1; later dependent claims specify acyclovir).
- Diluent.
- Alkali metal alkyl sulfate.
- Binding agent.
- At least one bioadhesive polymer that allows adherence to oral mucosa after administration.
- At least one sustained release polymer.
- Granular architecture:
- Primary granules comprise: antiviral agent + diluent + alkali metal alkyl sulfate + binding agent.
- Bioadhesive polymer is dispersed in the formulation (not limited to being inside the primary granules in claim 1).
Key scope characteristics
- Combination requirement: all listed functional components must be present together.
- Oral mucosa mucoadhesion is a structural/functional requirement: the formulation must adhere post-administration.
- Two-phase material placement: claim 1 fixes that primary granules contain the antiviral/diluent/alkyl sulfate/binder, while the bioadhesive polymer is dispersed at the formulation level.
- Prolonged release is tied to the presence of sustained release polymer.
What narrowing occurs in dependent claims 2-30?
Positioning of the bioadhesive polymer
- Claim 2: limits polyvinylpyrrolidone (PVP) as a component of the formulation to no more than 5% by weight.
- Claim 3: states bioadhesive polymer is not in the primary granules.
- This matters because claim 1 allows dispersion broadly; claim 3 explicitly forces external placement relative to primary granules.
- Claims 9-10: constrain bioadhesive polymer to natural proteins, specifically natural milk proteins.
Quantitative ranges that operationalize the claim
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Claim 4: alkali metal alkyl sulfate is 2% to 6% by weight.
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Claim 5: bioadhesive polymer is 10% to 40%.
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Claim 6: sustained release polymer is 10% to 40%.
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Claim 7: binding agent is 0.5% to 5%.
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Claim 8: binding agent can be PVP.
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Claim 12: antiviral agent is acyclovir in 10 mg to 200 mg.
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Claim 13: acyclovir in 50 mg to 100 mg.
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Claim 14: compositional macro-range:
- Antiviral: 10 mg to 200 mg
- Diluent: 1% to 75%
- Alkali metal alkyl sulfate: 1% to 10%
- Bioadhesive polymer: 5% to 80%
- Sustained release polymer: 5% to 80%
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Claim 15: tightened subset:
- Alkali metal alkyl sulfate: 2% to 6%
- Bioadhesive polymer: 10% to 40%
- Sustained release polymer: 10% to 40%
Hard identity constraints (composition “species” claims)
-
Claim 16 specifies:
- alkali metal alkyl sulfate = sodium lauryl sulfate
- bioadhesive polymer = natural milk proteins (or mixtures)
- sustained release polymer = hypromellose
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Claim 17: antiviral = acyclovir.
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Claim 18: binding agent = PVP.
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Claim 19 adds a numeric embodiment:
- acyclovir = 50 mg or 100 mg
- sodium lauryl sulfate = 2% to 10%
- bioadhesive polymer = 10% to 40% (natural milk proteins)
- hypromellose = 10% to 40%
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Claim 20: binding agent = PVP.
Exclusion / formulation hygiene
- Claim 21: formulation is devoid of starch.
Granule physical characteristic
- Claim 22: predominant fraction of primary granules has diameter < 125 μm.
Manufacturing format constraints
- Claim 23: formulation is formed by compressing a mixture of:
- primary granules,
- bioadhesive polymer,
- sustained release polymer.
- Claim 24: method of preparing claim 1:
- a) granulating antiviral + diluent + alkyl sulfate + binding agent,
- b) blending granules with bioadhesive polymer and sustained release polymer,
- c) compressing blended mixture to prepare the formulation.
- Claims 25-27 mirror dependent composition constraints by specifying natural milk proteins and acyclovir in the method.
Therapeutic method claims
- Claim 28: method of treating mucosal disease by administering formulation of claim 1 to oral mucosa.
- Claim 29: method using formulation of claim 15.
- Claim 30: method using formulation of claim 19.
How broad is the protection in practice? (Claim strategy map)
Breadth ladder
- Claim 1 (broadest composition): any antiviral, any diluent, any binding agent, any bioadhesive polymer, any sustained-release polymer, as long as:
- primary granules contain antiviral/diluent/alkyl sulfate/binder, and
- bioadhesive polymer is dispersed and enables oral mucoadhesion,
- sustained release polymer provides prolonged release.
- Claims 4-7 and 14-15 (range locks): define numeric ceilings/floors, reducing design-around flexibility.
- Claims 9-10 and 16-20 (material identity locks): narrow to specific polymers and excipients.
- Claim 21 (starch exclusion): imposes compositional exclusion.
- Claims 22-23 and 24 (process/structure locks): narrower on how the formulation is formed and on granule size distribution.
What a competitor must match to infringe
To capture composition-level infringement, an accused product must satisfy claim 1’s combination structure. The most frequent design-around points are:
- swapping alkali metal alkyl sulfate for a non-alkyl-sulfate surfactant system,
- replacing the bioadhesive polymer with a non-“natural proteins” system (if only narrower dependent claims are asserted),
- ensuring the bioadhesive polymer placement avoids “dispersed in formulation” or, if claim 3 is asserted, ensuring bioadhesive polymer is actually within primary granules (or eliminating the functional mucoadhesion polymer requirement),
- removing starch is easy but not a viable design-around if the competitor already uses no starch.
For method claims (28-30), infringement depends on the accused product being administered to oral mucosa for mucosal disease using the claimed formulation.
Claim-by-claim “scope impact” table
| Claim |
What it adds or limits |
Practical infringement effect |
| 1 |
Core: prolonged release + oral mucoadhesion; antiviral + diluent + alkali metal alkyl sulfate + binding agent; primary granules contain antiviral/diluent/alkyl sulfate/binder; bioadhesive polymer dispersed |
Baseline composition coverage |
| 2 |
PVP limited to ≤5 wt% |
Narrows embodiments that use PVP beyond this limit |
| 3 |
Bioadhesive polymer not in primary granules |
Forces placement constraint; helps distinguish formulations |
| 4 |
Alkyl sulfate: 2% to 6% |
Tight excipient window |
| 5 |
Bioadhesive polymer: 10% to 40% |
Tight polymer window |
| 6 |
Sustained release polymer: 10% to 40% |
Tight polymer window |
| 7 |
Binding agent: 0.5% to 5% |
Tight binder window |
| 8 |
Binding agent = PVP |
Identifies binder identity |
| 9 |
Bioadhesive polymer = natural proteins |
Narrows polymer class |
| 10 |
Bioadhesive polymer = natural milk proteins |
Narrows to milk proteins |
| 11 |
Antiviral agent = acyclovir |
Antiviral identity |
| 12 |
Acyclovir: 10-200 mg |
Strength window |
| 13 |
Acyclovir: 50-100 mg |
Strength narrow |
| 14 |
Broad composition numeric ranges across all components |
Establishes macro-range embodiment |
| 15 |
Tight subset ranges for alkyl sulfate and polymers |
Strengthens enforceability against close variants |
| 16 |
Sodium lauryl sulfate + milk proteins + hypromellose |
Identifies 3 critical excipient/polymers |
| 17 |
Acyclovir |
Locks antiviral species |
| 18 |
Binder = PVP |
Locks binder identity |
| 19 |
Embodiment: acyclovir 50/100 mg; SLS 2-10 wt%; milk proteins 10-40 wt%; hypromellose 10-40 wt% |
Enables direct claim matching for specific dosage strengths |
| 20 |
Binder = PVP |
Reinforces binder identity |
| 21 |
Starch-free |
Excludes starch formulations |
| 22 |
Primary granule size predominant fraction <125 μm |
Limits granular physical distribution |
| 23 |
Compression of primary granules + bioadhesive polymer + sustained release polymer |
Mechanistic/form-factor constraint |
| 24 |
Manufacturing steps: granulate antiviral/diluent/alkyl sulfate/binder; blend with polymers; compress |
Method claim enforceability tied to this process |
| 25-27 |
Natural milk proteins and acyclovir within method |
Narrows method species |
| 28-30 |
Oral mucosa administration using formulations of claims 1/15/19 |
Provides therapeutic enforcement lane |
What is the likely patent “center of gravity” of this family?
Even without the spec text, the claim set shows a consistent architecture:
- Primary granules carry the antiviral + excipient package (diluent, alkyl sulfate, binder).
- Bioadhesive polymer controls mucoadhesion but is (at least for some claims) not in primary granules.
- Sustained-release polymer controls drug release kinetics.
- The formulation is compressed into a final solid dosage form (tablet or similar compressed unit).
This “segregated placement” approach (granules vs dispersed polymer phase) is the main technical narrative that the claims operationalize via claim 1 and claim 3, then reinforce via claim 23 and claim 24.
US patent landscape (relevant around this composition theme)
Landscape dimensions that matter for infringement and freedom-to-operate
The claim set implicates at least four patentable technology clusters in the US:
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Oral mucosal mucoadhesive antiviral dosage forms
- Typical prior art themes: mucoadhesive polymers, sustained release matrices, and oral mucosal delivery of antivirals.
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Acyclovir oral mucosal delivery
- Prior art themes: acyclovir in mucoadhesive systems to extend residence time and improve local exposure.
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Sodium lauryl sulfate (or alkyl sulfates) in drug delivery matrices
- Typical prior art themes: surfactant roles in wetting, penetration enhancement, and formulation stabilization.
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Natural milk proteins as bioadhesive polymers
- Prior art themes: milk-derived proteins (casein/whey fractions) used for mucoadhesion and binding properties.
How to read “landscape risk” based on these clusters
- If a generic formulation uses acyclovir + mucoadhesive polymer + sustained-release polymer, it can still be outside the claim if it does not contain alkali metal alkyl sulfate in the claimed role/range or if it does not use natural milk proteins (when dependent claims are asserted).
- If a product uses milk proteins but replaces sodium lauryl sulfate with a different surfactant, it may still avoid claim 1 (depending on how broadly the alkyl sulfate concept is interpreted).
- If a product contains sodium lauryl sulfate and a mucoadhesive polymer but does not have the primary granule architecture (antiviral/diluent/alkyl sulfate/binder in primary granules, with the bioadhesive polymer dispersed), it can avoid claim 1 structure.
What is missing to produce a complete landscape
A complete US landscape requires:
- the patent family members of US 8,791,127 (application publication numbers, continuation history, claim amendments),
- prosecution history and cited references,
- live patent status for each potential competitor patent and any terminal disclaimers.
No such metadata is included in the prompt, and producing it without direct source verification would be noncompliant with high-stakes patent analysis.
Key takeaways
- US 8,791,127 protects a specific architecture: primary granules containing the antiviral + diluent + alkali metal alkyl sulfate + binder, with bioadhesive polymer dispersed to adhere to oral mucosa, combined with a sustained-release polymer for prolonged release.
- The claims include tight numeric windows (notably alkyl sulfate 2-6 wt%, bioadhesive polymer 10-40 wt%, sustained release polymer 10-40 wt%) plus species limits that identify acyclovir, sodium lauryl sulfate, natural milk proteins, and hypromellose, with PVP as a recurring binding agent.
- Design-around leverage is concentrated in four variables: (i) presence and amount of alkali metal alkyl sulfate, (ii) bioadhesive polymer identity/class (natural milk proteins), (iii) placement relative to primary granules (claim 3), and (iv) granule/process constraints if narrower claims are asserted.
- The therapeutic method claims extend coverage through administration to the oral mucosa using the claimed formulations.
FAQs
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Is the strongest infringement position at claim 1 or at claims 16/19?
Claim 1 is the broadest because it is not limited to acyclovir, sodium lauryl sulfate, milk proteins, or hypromellose. Claims 16 and 19 tighten identity and are easier to map to specific formulations.
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What is the most meaningful structural limitation in claim 1?
The requirement that primary granules comprise the antiviral agent, diluent, alkali metal alkyl sulfate, and binding agent, with the bioadhesive polymer dispersed in the overall formulation.
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How does claim 3 change scope versus claim 1?
Claim 3 constrains placement: the bioadhesive polymer is not in the primary granules, which can be decisive if an accused product places mucoadhesive polymer inside granules.
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Does claim 21 (starch-free) materially affect design-around?
Only for formulations that use starch. If starch is absent, claim 21 provides no differentiation; if starch is used, claim 21 can block close variants.
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Are the therapeutic claims enforceable without proving dosing intent?
Therapeutic method claims hinge on administering the claimed formulation to oral mucosa for a mucosal disease. If the product matches the formulation claims, actual administration for the claimed indication is the enforcement trigger.
References
[1] US Patent 8,791,127 (claim text provided in prompt).
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