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Patent landscape, scope, and claims: |
Scope & Claims for U.S. Patent 6,733,780 (Tablets with Poly(allylamine)/Poly(diallylamine) Cores and Water-Based HPMC Coatings) + US Patent Landscape
U.S. Patent 6,733,780 centers on tablets where an aliphatic amine polymer (dominantly poly(allylamine), poly(diallylamine), and related N-substituted variants or salts) makes up at least 95% of a tablet core, including hydrated and cross-linked forms, plus optional water-based coatings, and in a dependent claim a specific “core + coating” composition using hydrated cross-linked poly(allylamine hydrochloride and an HPMC/diacetylated monoglyceride coating system. The claim set is tightly claim-limited on (i) polymer identity and dominance in the core (≥95 wt%), (ii) hydration/moisture range and cross-linking in specific embodiments, and (iii) the coating being water-based and, in narrower claims, HPMC viscosity grades with diacetylated monoglyceride.
What does U.S. Patent 6,733,780 claim protection cover for tablets?
Core claim coverage (independent claims are not provided verbatim beyond claim 1 and claim 6/11/18/19 text supplied):
- A tablet with:
- a core and a coating;
- ≥ about 95% by weight of the core is an aliphatic amine polymer selected from:
- unsubstituted and N-substituted poly(allylamine)
- poly(diallylamine)
- poly(vinylamine)
- Dependent limitations narrow to:
- N-substituents (C1–C24 alkyl groups, including trialkylammonioalkyl groups) (claims 2–3).
- cross-linked polymers (claim 4).
- presence of excipients (claim 5).
- Parallel narrower independent-format coverage is also present through additional claim text you provided (claim 6 and onward), focusing on:
- poly(allylamine) (linear or cross-linked) and its pharmaceutically acceptable salts (claim 6);
- hydrated poly(allylamine with defined water content (claims 7–10);
- hydrated cross-linked poly(allylamine hydrochloride with additional dominance language (claim 11);
- water-based coating (claims 12–13);
- a specific HPMC low-viscosity + HPMC high-viscosity + diacetylated monoglyceride coating system (claims 14–15);
- specific moisture/hardness/friability targets (claim 18);
- a fully specified embodiment using a sevelamer hydrochloride core with 6% moisture and specific excipients, coated with a defined HPMC/diacetylated monoglyceride ratio (claim 19).
H3: Key claim-protectable elements (high signal for infringement/clearance)
- Core composition dominance rule: at least 95 wt% of the core must be the specified aliphatic amine polymer family (claim 1). This is a hard claim boundary.
- Polymer identity rule: poly(allylamine), poly(diallylamine), poly(vinylamine), with allowance for N-substitution and salts (claims 1–3, 6, 11).
- Hydration and cross-linking are claim-critical only in specific dependent claim paths: moisture content ranges and cross-link % appear in claims 7–10 and operationally in claim 18.
- Coating system is claim-critical only in specific dependent claim paths: water-based coating language is broad (claims 12–13), while the HPMC viscosity grades + diacetylated monoglyceride system is narrow (claims 14–15).
- Performance limitations (hardness ≥150 N; friability ≤0.8%) appear in a narrow claim (claim 18), functioning as additional constraints tied to the claimed material system.
How broad is the independent claim scope for the core polymer composition (≥95 wt%)?
Breadth drivers
- Claim 1 is broad on polymer variants: it covers unsubstituted and N-substituted poly(allylamine), plus poly(diallylamine) and poly(vinylamine).
- It does not, in claim 1, force hydration parameters, specific hardness/friability thresholds, or the specific HPMC coating recipe.
Breadth limit
- The ≥95 wt% core rule likely prevents coverage of formulations where the aliphatic amine polymer is present as a minor excipient, binder, or disintegrant.
- In product development terms, this means the claim is geared toward tablets where this polymer forms the substantive core matrix, not a coating or small additive.
H3: What design-around approaches are suggested by the claim language
- Reduce the polymer below the 95 wt% threshold (for claim 1 coverage).
- Use an active/matrix system where the core is dominated by a different polymer class or different binder system (outside the specified aliphatic amine polymer list).
- If targeting water-based HPMC coating claim paths (claims 12–15), change the coating system away from the specified HPMC viscosity grades and/or diacetylated monoglyceride composition.
What do the N-substitution limitations add to coverage (C1–C24 alkyl; trialkylammonioalkyl)?
Claim 2 narrows N-substituted poly(allylamine) to C1–C24 alkyl substituents.
Claim 3 further narrows to trialkylammonioalkyl groups.
Practical scope effect
- If a competing formulation uses N-substitution outside C1–C24 alkyl, or uses different substitution patterns (e.g., aryl, heteroaryl, or non-alkyl substituents), it is outside those dependent claim paths.
- If the polymer is unsubstituted poly(allylamine) or poly(diallylamine) or poly(vinylamine), claims 2–3 dependent coverage may not apply, but claim 1 can still cover the overall tablet if the polymer dominance requirement holds.
When does cross-linking matter for patent coverage?
Claim 4 explicitly covers tablets where the aliphatic amine polymer is cross-linked.
Claim 10 and claim 11 then layer additional constraints:
- Claim 10: cross-linking level is specified as about 1% to about 10% cross-linked (in the context of hydrated poly(allylamine) with prior moisture constraints).
- Claim 11: hydrated cross-linked poly(allylamine hydrochloride** is the ≥95 wt% core polymer.
Scope implication
- For cross-linked versions, the claim set becomes narrower but more “performance-controlled.” If the formulation is linear (non-cross-linked), claim 4’s dependent coverage is avoided, while claim 1 still may capture non-cross-linked embodiments if the polymer identity and dominance rule are met.
What do hydration and water content requirements mean for infringement risk?
Claims 7–10 specify hydration and water content ranges:
- Claim 7: hydrated poly(allylamine)
- Claim 8: 3% to 10% water
- Claim 9: 5% to 8% water
- Claim 10: poly(allylamine) is 1% to 10% cross-linked (within the hydrated context described by claims 7–9)
Operational effect
- Moisture content can be variable by manufacturing and storage conditions. These claims likely aim to lock in a specific manufacturing target window for a stable tablet core matrix.
- From an infringement lens, these dependent claim paths are most relevant if a competitor’s product matches the same moisture and cross-linking window.
Which water-based coatings are protected (and how narrow is the HPMC system)?
Broad coating coverage
- Claim 12: coating is water-based
- Claim 13: in the poly(allylamine)-dominant embodiments, coating is water-based
Narrow coating coverage
- Claim 14: water-based coating comprises:
- hydroxypropylmethylcellulose (HPMC) and a plasticizer
- Claim 15: water-based coating comprises:
- HPMC low viscosity
- HPMC high viscosity
- diacetylated monoglyceride
H3: Scope boundary for coating claims
- If a competitor uses a non-water-based coating (e.g., solvent-based systems) or uses a plasticizer other than diacetylated monoglyceride in combination with the specific dual-viscosity HPMC grades, they can avoid the narrow dependent claims 14–15.
- Claim 12–13 alone is broader and could still be asserted if the competitor uses a water-based coating regardless of the exact HPMC/plasticizer composition, assuming core dominance and polymer identity are met.
How do the hardness and friability limitations affect enforceable scope (claim 18)?
Claim 18 adds a product-parameter package:
- moisture content of the poly(allylamine): about 5% to about 9% by weight
- tablet hardness: ≥ about 150 N
- tablet friability: ≤ about 0.8%
Scope effect
- This is narrower than composition-only claims. A product with compliant polymer identity and dominance but different mechanical properties may avoid claim 18 while still potentially falling into earlier composition/coating claims.
- In portfolio terms, claim 18 can be a valuable hook if competitors adopt similar composition/hydration but do not optimize mechanical properties in the claimed window.
What is the fully specified composition embodiment in claim 19 (sevelamer hydrochloride core)?
Claim 19 is a specific “core + coating” recipe:
- Core:
- 98% by weight sevelamer hydrochloride
- moisture content 6% by weight
- 1% colloidal silicon dioxide
- 1% stearic acid
- Coating mixture:
- 38.5% low viscosity HPMC
- 38.5% high viscosity HPMC
- 23% diacetylated monoglyceride
H3: Why claim 19 is structurally important for landscape mapping
Claim 19’s core is sevelamer hydrochloride, not poly(allylamine) as the dominant polymer. That creates two key analytical implications:
- Either claim 19 is an independent claim with a different core identity (as drafted in your excerpt), in which case it creates a separate protection lane for sevelamer tablet architecture with a defined HPMC/diacetylated monoglyceride coating and moisture/excipient profile.
- Or claim 19 is dependent in an earlier chain that still ties back to the poly(allylamine) concepts (not fully visible in your excerpt).
Either way, for freedom-to-operate, claim 19 is a high-value target because it locks down an exact recipe for a sevelamer hydrochloride tablet core and an HPMC viscosity blend coating system.
How many separate claim “lanes” exist for U.S. Patent 6,733,780?
Based on the claim text you provided, the estate divides into at least four enforceable lanes:
- Poly(allylamine)/poly(diallylamine)/poly(vinylamine) core dominance tablets (claim 1 plus dependent claim variants for N-substitution and cross-linking).
- Hydrated poly(allylamine) and hydrated cross-linked poly(allylamine hydrochloride) with defined water and cross-link windows (claims 7–11).
- Water-based coatings, escalating to a specific HPMC low/high viscosity plus diacetylated monoglyceride coating formulation (claims 12–15).
- Performance-qualified tablets using specific moisture/hardness/friability targets (claim 18).
- Recipe-specific sevelamer hydrochloride tablet with exact moisture, excipients, and coating blend ratios (claim 19).
This structure matters because a competitor can avoid one lane while still triggering another depending on what is actually manufactured and how it is tested.
What does this imply for generic entry risk scenarios in the US?
H3: Scenario 1: Competitor makes tablets with ≥95 wt% aliphatic amine polymer core
- Generic risk is elevated if the competitor’s core polymer identity overlaps with poly(allylamine), poly(diallylamine), or poly(vinylamine) and the core is dominated (≥95 wt%).
- If the competitor also uses water-based coatings, there is additional exposure to coating-dependent claims.
- If hydration/cross-linking are tuned into the claimed windows, dependent claims 7–11 and 18 can become relevant.
H3: Scenario 2: Competitor uses sevelamer hydrochloride cores with the claimed coating
- Even if the core is not poly(allylamine), claim 19 creates a direct recipe-driven exposure lane for sevelamer tablets that match:
- 98 wt% sevelamer hydrochloride
- 6 wt% moisture
- 1 wt% colloidal silicon dioxide
- 1 wt% stearic acid
- and the 38.5/38.5/23 coating composition (HPMC low, HPMC high, diacetylated monoglyceride)
H3: Scenario 3: Competitor changes only one parameter
- If a generic changes only one excipient or slightly shifts moisture, they may avoid specific dependent claims but still face broader claim paths (especially claim 1, claim 12–13).
- If a generic changes the coating away from HPMC low/high + diacetylated monoglyceride, it can target avoidance of claims 14–15 and possibly claim 19’s coating portion.
Patent landscape: what this patent is likely doing in the broader US framework
You provided only the claim text, not:
- the patent’s publication history,
- its application family,
- related continuations,
- assignees,
- or citations.
Because of that, an accurate mapping of “competing patents,” “family members,” and “Orange Book listings” cannot be produced from the information provided.
What can be stated from claim scope alone
- The claim focus on tablet core matrix composition dominated by aliphatic amine polymers and water-based HPMC-based coatings suggests a patent positioned against:
- replication of a particular polymer-based tablet technology; and/or
- replication of a coating recipe and its mechanical outcomes; and/or
- replication of a sevelamer hydrochloride tablet architecture and coating system.
Without the patent number-to-database link and without assignee/applicant and file history, any enumeration of US continuation filings, competitor patents, or Paragraph IV litigation outcomes would be speculative.
Key Takeaways
- U.S. Patent 6,733,780 is claim-structured around tablet cores where aliphatic amine polymers are ≥95 wt% (poly(allylamine)/poly(diallylamine)/poly(vinylamine)) plus optional dependent controls on N-substitution, cross-linking, and hydration.
- Coating protection is water-based broadly (claims 12–13), with a narrow and commercially actionable coating recipe using HPMC low + HPMC high + diacetylated monoglyceride (claims 14–15).
- Enforceability increases in narrower lanes via moisture + hardness + friability constraints (claim 18).
- Claim 19 is a highly specific sevelamer hydrochloride tablet recipe with defined moisture/excipients and an exact HPMC viscosity blend + diacetylated monoglyceride coating composition, creating a direct product-configuration risk lane.
FAQs
- Can a tablet avoid claim coverage by reducing the aliphatic amine polymer below 95 wt% of the core?
- Does the HPMC coating claim require diacetylated monoglyceride, or is any water-based coating enough?
- How do the moisture ranges (3–10%, 5–8%, 5–9% in claim 18) interact with storage-induced moisture changes?
- If a competitor uses linear poly(allylamine) instead of cross-linked poly(allylamine), which dependent claims are most likely avoidable?
- What level of formulation detail matters most for claim 19 (sevelamer hydrochloride core and specific coating ratios)?
References
- User-provided claim text for U.S. Patent 6,733,780 (claims 1–19 excerpt).
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