United States Patent 11,234,938: Scope, Claims, and US Landscape for Chewable Sucrroferric Oxyhydroxide Tablets
What does US 11,234,938 claim, in operational terms?
US 11,234,938 covers oral pharmaceutical compositions where sucroferric oxyhydroxide is formulated specifically as a chewable tablet with tightly controlled mechanical integrity (hardness and friability), oral disintegration (time window), dose range/weight, and sucroferric oxyhydroxide particle size distribution. The claim set is built to protect multiple “manufacturing and product” levers: tablet format (chewable, compressed, direct compression) and powder/PSD (volume percent ranges and D50 range).
Core claim architecture
Across independent claim 1 and composition claim 6 and broader composition claim 11, the protected subject matter is anchored by the same technical constraints:
- Drug substance: sucroferric oxyhydroxide
- Dosage form: chewable tablet (with dependent claim options for compressed tablet and direct compression)
- Tablet performance targets:
- Disintegration time: 5 to 18 minutes (European Pharmacopoeia 04/2011:20901)
- Hardness: 100 N to 200 N (European Pharmacopoeia 01/2008:20908)
- Friability: 0% to 7% (European Pharmacopoeia 01/2010:20907) (dependent)
- Dose/format weight:
- Tablet weight: 2000 mg to 3000 mg (dependent/independent set)
- Drug loading by dry basis:
- More than 65% by weight sucroferric oxyhydroxide (claim 1)
- About 2500 mg sucroferric oxyhydroxide (claim 6)
- More than 80% by weight sucroferric oxyhydroxide (claim 11)
- Particle size and distribution:
- At least 80% by volume of sucroferric oxyhydroxide particles in 4 μm to 200 μm
- D50 (by volume distribution): 40 μm to 80 μm
- Dependent variants tighten the particle size cutoffs (see below)
These constraints are specific enough that infringement analysis typically turns on (1) whether the tablet disintegrates within 5 to 18 minutes under EP method, (2) whether hardness/friability fall within the claimed windows, and (3) whether the PSD of the sucroferric oxyhydroxide raw material (as used in the tablet) satisfies the volume-percent and D50 ranges.
What are the exact claim elements and what do the dependent claims narrow?
Independent claim 1 (broadest format + drug loading baseline)
Claim 1 defines a chewable tablet composition with:
- Sucroferric oxyhydroxide
- Chewable tablet
- Disintegration time: 5-18 min (EP 04/2011:20901)
- Hardness: 100-200 N (EP 01/2008:20908)
- Tablet weight: 2000-3000 mg
- Drug loading: >65% by weight on dry basis
- PSD requirements:
- ≥80% by volume particles 4-200 μm
- D50: 40-80 μm (by volume distribution)
- Prepared using sucroferric oxyhydroxide particles meeting those PSD requirements
Dependent claims to claim 1:
- Claim 2: ≥80% by volume particles 5-160 μm
- Claim 3: ≥90% by volume particles 4-200 μm
- Claim 4: Friability 0%-7% (EP 01/2010:20907)
- Claim 5: tablet is formed by direct compression
Claim 6 (dose-specific anchor)
Claim 6 is similar to claim 1 but with an explicit drug load target:
- ~2500 mg sucroferric oxyhydroxide in the chewable tablet
- Chewable tablet
- Disintegration: 5-18 min (EP 04/2011:20901)
- Hardness: 100-200 N (EP 01/2008:20908)
- Drug loading: >65% by weight on dry basis
- PSD requirements:
- ≥80% by volume particles 4-200 μm
- D50 40-80 μm
- (Tablet weight window appears as fixed by the earlier structure of the claim set; the claim as provided does not restate the 2000-3000 mg weight element.)
Dependent claims to claim 6:
- Claim 7: ≥80% by volume particles 5-160 μm
- Claim 8: chewable tablet is a compressed tablet
- Claim 9: chewable tablet formed by direct compression
- Claim 10: Friability 0%-7% (EP 01/2010:20907)
Claim 11 (higher drug loading threshold)
Claim 11 keeps the tablet/performance/PSD structure but changes drug loading:
- Sucroferric oxyhydroxide
- Chewable tablet
- Tablet weight: 2000-3000 mg
- Disintegration: 5-18 min (EP 04/2011:20901)
- Hardness: 100-200 N (EP 01/2008:20908)
- Drug loading: >80% by weight on dry basis
- PSD requirements:
- ≥80% by volume particles 4-200 μm
- D50 40-80 μm
Dependent claims to claim 11:
- Claim 12: ≥80% by volume particles 5-160 μm
- Claim 13: ≥90% by volume particles 5-160 μm (as written, claim 13 is inconsistent with the original style but still restricts particle size coverage)
- Claim 14: chewable tablet is a compressed tablet
- Claim 15: chewable tablet formed by direct compression
- Claim 16: Friability 0%-7% (EP 01/2010:20907)
Where is the claim “pressure point” for infringement risk?
The claim set creates three practical bottlenecks that often decide freedom-to-operate and design-around feasibility:
1) Particle size distribution (PSD) is claim-critical
The independent claims require both:
- Volume fraction in size window:
- At least 80% by volume in 4-200 μm (claims 1 and 11; claim 6 also)
- D50 window:
- 40-80 μm D50 (by volume distribution)
This means that even if tablet disintegration and hardness are matched, using sucroferric oxyhydroxide sourced/processed to shift D50 outside 40-80 μm or shift volume fraction outside 4-200 μm is likely to move the product outside at least the independent claims.
2) Oral performance windows are narrow and method-defined
- Disintegration time: 5-18 minutes using EP 04/2011:20901
- Hardness: 100-200 N using EP 01/2008:20908
- Friability: 0-7% using EP 01/2010:20907 (dependent)
Method references reduce room for argument over which test governs, making batch testing and comparability to EP methods decisive.
3) Drug load thresholds create multiple “escape hatches,” but not many
Independent claims split on drug loading:
- >65% by weight (claim 1 and claim 6)
- >80% by weight (claim 11)
A formulation that changes drug loading meaningfully could avoid one branch, but it may still land in the other if it stays above both thresholds.
What is the scope of coverage across formulation variations?
The claims do not explicitly restrict excipients by type, except by requiring:
- A chewable tablet with the performance metrics; and
- A sucroferric oxyhydroxide PSD that meets the specified volume percent and D50.
Therefore, coverage plausibly extends across different filler/binder systems as long as the tablet still hits:
- disintegration 5-18 min,
- hardness 100-200 N,
- friability 0-7% (if the dependent claim is asserted),
- and the sucroferric oxyhydroxide PSD constraints.
Manufacturing method coverage
Dependent claims include:
- direct compression (claims 5, 9, 15)
- “compressed tablet” variants (claims 8, 14)
If a product uses alternative tableting (e.g., wet granulation), it may still infringe the independent claims if disintegration/hardness/PSD/loading requirements are met, because the independent claims do not mandate direct compression.
How strong is the position of each claim within the set?
Claim 1
- Most general across weight range and >65% drug loading
- Requires PSD baseline plus tablet performance metrics
- Does not explicitly lock excipient identity
Claim 6
- Adds dose anchoring: about 2500 mg sucroferric oxyhydroxide
- Often narrower in product match due to the “about” qualifier but still tied to the same PSD and performance windows
Claim 11
- Raises drug loading to >80% by weight
- May be easier to design around on drug loading than claim 1, but harder if a formulation is already highly drug-loaded
Dependent claims (2-5; 7-10; 12-16)
These create layered fallbacks:
- PSD tightening (2, 3, 7, 12, 13)
- tablet friability tightening (4, 10, 16)
- manufacturing method narrowing (5, 9, 14, 15)
What does the patent landscape likely look like in the US around this claim theme?
The claim strategy indicates a landscape where competitors are likely to pursue one or more design-around levers:
- PSD redesign of sucroferric oxyhydroxide to move D50 and/or volume percent outside the claimed windows.
- Mechanical performance manipulation (hardness/disintegration) using different compression forces, lubrication, or tablet geometry to land outside EP-defined windows.
- Drug loading management to move below >65% or >80% thresholds.
- Manufacturing method changes to avoid direct compression-dependent claims, though that does not avoid independent claim coverage.
Given the specificity to EP test methods and granulometry ranges, the most credible competitive threats typically come from:
- alternate particle engineering routes that still keep D50 in-window, or
- formulations that can reproduce disintegration/hardness outcomes under EP tests.
Competitive risk map: product changes that likely avoid vs. risk infringement
Likely to avoid independent claims (if achieved consistently under EP testing)
- Shift sucroferric oxyhydroxide D50 outside 40-80 μm (volume basis)
- Ensure less than 80% by volume of particles fall within 4-200 μm
- Fail the disintegration window (EP 04/2011:20901): outside 5-18 minutes
- Fail hardness window (EP 01/2008:20908): outside 100-200 N
- Reduce drug loading below the relevant threshold:
- ≤65% by weight (to avoid claim 1/6) or
- ≤80% by weight (to avoid claim 11)
Likely to reduce risk only against dependent claims (not enough alone)
- Changing from direct compression to another method may avoid dependent direct compression claims (5, 9, 15) but not necessarily independent claims.
- Adjusting friability outside 0-7% may avoid dependent claims (4, 10, 16) but independent claims still require disintegration and hardness.
What practical “claim parsing” matters in enforcement or challenges?
If litigated, the claim is likely to be assessed in the order a technical lab would test:
- Confirm dosage form (chewable tablet).
- Test disintegration time by EP method referenced in the claims.
- Measure hardness by EP method referenced.
- Determine tablet weight and drug loading on dry basis.
- Characterize sucroferric oxyhydroxide particle size distribution:
- volume percent in the specified ranges,
- and D50.
- For dependent claims, assess friability and manufacturing method.
Because the claim ties PSD and EP test methods, parties typically need comparability of sampling, equipment, and procedure to establish whether a product matches “as used” conditions.
Key Takeaways
- US 11,234,938 protects chewable tablets of sucroferric oxyhydroxide with EP-defined disintegration (5-18 min), hardness (100-200 N), and strict sucroferric oxyhydroxide PSD (≥80% by volume in 4-200 μm and D50 40-80 μm).
- The claim set is layered by drug loading: >65% (claims 1 and 6) and >80% (claim 11), plus a dose-specific anchor (~2500 mg) in claim 6.
- Dependent claims add narrower guardrails on PSD cutoffs (5-160 μm, ≥80% or ≥90% variants), friability (0-7%), and manufacturing by direct compression.
- For design-around, PSD and EP performance windows are the highest-leverage variables; direct compression mainly affects dependent claim exposure.
FAQs
1) Does US 11,234,938 require direct compression to infringe?
No. Direct compression appears only in dependent claims (5, 9, 15). Independent claims cover the chewable tablet with the performance metrics and PSD/loading requirements.
2) If a tablet meets disintegration and hardness but the PSD shifts, can it avoid the patent?
Yes. Independent claims require both volume percent particle size coverage and D50 within specified ranges.
3) Which test methods govern the key performance metrics?
Disintegration uses European Pharmacopoeia 04/2011:20901; hardness uses European Pharmacopoeia 01/2008:20908; friability uses European Pharmacopoeia 01/2010:20907 (dependent).
4) What changes are most likely to move a product outside independent claims?
Shifting D50 outside 40-80 μm, reducing volume percent in 4-200 μm below the stated threshold, moving disintegration or hardness outside the claimed windows, or reducing drug loading below the independent claim thresholds.
5) Are there multiple independent “branches” within the claim set?
Yes. Claim 1 and claim 6 share the >65% loading structure with PSD and performance metrics, while claim 11 uses >80% by weight and shares the same PSD/performance framework.
References
[1] US Patent 11,234,938. Claims 1-16 (as provided).
