US Patent 5,753,265: Scope, Claim Structure, and US Patent Landscape
US Drug Patent 5,753,265 protects an oral multiple-unit tablet built from individually enteric-coated core units containing an acid-labile H+/K+-ATPase (PPI-class) inhibitor in a neutral or salt form, with explicit constraints on enteric mechanical integrity under compression. The independent claim is claim 1; all other claims narrow the active-ingredient scope, the enteric coating performance under compression, and the dosage/package forms, and add formulation and method claims.
What is the core claim scope in US 5,753,265?
Claim 1 (independent): Multiple-unit tablet with individually enteric-coated acid-labile PPI units
Claim 1 requires every element below:
- Dosage form
- Oral pharmaceutical composition in the form of a multiple unit tablet.
- Architecture
- The tablet contains:
- a tablet excipient, and
- a multiple of a core unit.
- Active ingredient requirement
- The core unit has as active ingredient an acid-labile H+/K+-ATPase inhibitor compound in:
- a neutral form or a salt form, and
- either a single enantiomer or an alkaline salt of a single enantiomer.
- Key protection hook: mechanical properties of enteric coating under compression
- Each core unit is covered with at least one enteric coating layer whose mechanical properties are such that it does not significantly affect acid resistance of the enteric-coated core unit by compression during tableting.
Put plainly: it is not just “enteric coated particles inside a tablet.” The novelty line is protection of acid resistance after compression via mechanical properties of the enteric layer.
Claim 1 dependent constraints (how the protection narrows)
Claims 4 and 5 define acid resistance performance benchmarks; claims 6 to 10 define enteric material, thickness, and dosage unit behavior.
How do the claims define the active ingredient and chemical boundaries?
Claim 2: Formula I family + exclusions
Claim 2 limits the active ingredient to a compound of general formula I (or alkaline salts or single enantiomers), with the detailed substitution pattern provided in the claim text.
It also includes explicit exclusions: it states “except the compounds”:
- 5-methoxy-2 (4-methoxy-3,5-dimethyl-2-pyridinyl)methyl!sulfinyl!-1H-benzimidazole
- 5-fluoro-2 (4-cyclopropylmethoxy-2-pyridinyl)methyl!sulfinyl!-1H-benzimidazole
- 5-carbomethoxy-6-methyl-2 (3,4-dimethoxy-2-pyridinyl)methyl!sulfinyl!-1H-benzimidazole
…and the claim includes their single enantiomers or alkaline salts.
Impact on scope: claim 2 is a “formula with carve-outs” structure. Competitors must check whether their specific PPI exists inside formula I parameters and whether it falls into the listed exceptions.
Claim 3: Enumerated compounds
Claim 3 narrows further by listing additional compound structures (“following compounds” in the claim text), again limited to alkaline salts or single enantiomers.
Impact on scope: claim 3 increases enforceability by anchoring to specific actives, not only broad formula coverage.
What does the patent require about enteric coating acid resistance during tableting?
Claim 4: Acid resistance in USP-defined enteric coated article requirements
Claim 4 requires that the acid resistance of the individually enteric coated layered units complies with United States Pharmacopeia (USP) requirements for enteric coated articles.
Claim 5: Compression integrity benchmark (quantified)
Claim 5 specifies:
- the acid resistance does not decrease more than 10% during compression of the individually enteric-coated units into the multiple-unit tablet.
This is the strongest, most litigable formulation limitation because it is quantitative and directly tied to the asserted mechanical properties concept.
How does the patent characterize the enteric coating materials and unit size behavior?
Enteric coating material and thickness
- Claim 6: enteric layer material is plasticized enteric coating layer material.
- Claim 7: enteric coating layer thickness is at least 10 μm.
Over-coating and dispersibility
- Claim 8: individually enteric-coated units can have an over-coating layer comprising pharmaceutically acceptable excipients.
- Claim 10: dosage form is dispersible to a suspension of the individually enteric-coated units in aqueous liquid.
- Claim 9: dosage form is divisible.
Separating layer
- Claim 11: includes a separating layer soluble or disintegrating in water.
Impact on infringement analysis: if a competitor uses individually enteric-coated units but uses a different mechanical strategy, different enteric thickness, or a coating process that causes more than a 10% acid-resistance drop after compression, claim 1 and/or claim 5 can be designed around.
How are the core units defined and manufactured?
Core unit formation
- Claim 12: core unit is a seed layered with the active ingredient.
- Claim 13: seeds size is 0.1–2 mm.
Process claim 14: method of manufacture
Claim 14 protects a manufacturing sequence:
- (a) shaping a core unit comprising the active ingredient as defined,
- (b) covering core with at least one enteric coating layer,
- (c) mixing a multiple of the enteric-coated core unit with tablet excipients,
- (d) compressing into tablet form,
- with the condition that the enteric coating layer has mechanical properties so it does not affect acid resistance of enteric-coated units.
Process-dependent narrowings
- Claim 15: over-coating layer applied before compression.
- Claim 18: core unit further comprises an alkaline compound.
- Claim 19: core unit is covered with a separating layer under the enteric coating.
- Claim 17: separating layer comprises an alkaline excipient.
Impact: the process claims can block method-by-method manufacturing even where end-product appearances match.
What packaging and use claims extend the scope beyond the formulation?
Press-through blister package
- Claim 20: press-through blister package containing the composition of claims 1–16 or 17.
- Claim 23: press-through blister package with at least one press-through blister containing a tableted dosage form per claims 1–16 or 17.
These claims expand enforcement to packaging systems containing the covered dosage form.
Methods of treatment
- Claim 21: method for inhibiting gastric acid secretion in mammals and man by administering a therapeutically effective dose.
- Claim 22: method for treatment of gastrointestinal inflammatory disease in mammals and man by administering a therapeutically effective dose.
Impact: use claims may support enforcement when the formulation is used in covered indications and administered as claimed.
What is the enforceable claim perimeter (practical infringement checklist)?
A product is at high risk of falling within the perimeter if it matches all of the following:
- Oral multiple-unit tablet containing a multiple of enteric-coated core units.
- Active ingredient is an acid-labile H+/K+-ATPase inhibitor.
- Active is present as neutral or salt and is either a single enantiomer or alkaline salt of a single enantiomer.
- Core units have at least one enteric coating layer with mechanical properties so compression does not significantly reduce acid resistance.
- Acid resistance meets USP enteric coated article requirements and shows ≤10% decrease in acid resistance after compression.
- Enteric coating is plasticized and thickness is ≥10 μm (where claim 6 and claim 7 are asserted).
- Optional but commonly relevant additions: over-coat, separating layer, seed layered core, and seed size 0.1–2 mm.
US patent landscape: how to map likely competitive coverage
Because the user-provided text includes only the claim set and not the patent’s bibliographic identifiers (application number, filing date, priority date, assignee, or related family members), the landscape below is limited to what the claim scope implies for surrounding prior art and subsequent design-around space. No external database cross-links are included here.
1) Prior art categories that the claim design targets
The claimed architecture suggests the applicant built around prior art that used:
- simple enteric-coated beads/tablets that fractured during compression,
- formulations using acid-labile PPI without specifying compression robustness,
- enteric coatings without plasticization or with insufficient thickness,
- multi-part tablets without individually enteric-coated units that remain acid-protective after compression.
The explicit ≤10% acid resistance drop and mechanical property language is typical of a patent that distinguishes over “enteric coated units that lose integrity during tableting.”
2) Likely direct competitors (design-around axes)
Competitors can reduce risk by changing one or more of:
- Coating strategy: eliminate individually enteric-coated units and use an alternative gastroprotection mechanism.
- Unit architecture: avoid compression of enteric-coated subunits (for example, use separate dosing forms, coated granules that are not compressed as a unit, or different consolidation methods).
- Enteric performance: allow greater acid resistance loss during compression (though that can harm efficacy and invites regulatory failure).
- Active chemistry: use a different acid-labile H+/K+-ATPase inhibitor not covered by the formula/enantiomer/salt constraints.
- Salt/enantiomer form: avoid “alkaline salt of a single enantiomer” if that is a strict required element for the claims asserted.
- Packaging: in some enforcement strategies, avoid press-through blister arrangements covered by claims 20 and 23.
3) Follow-on improvement opportunities consistent with the claims
Later patents often tighten:
- specific coating polymers/plasticizers,
- coating thickness ranges and process parameters linked to measured acid-resistance retention,
- the separation layer composition,
- specific seed size distributions,
- dispersible/divisible tablet variants that maintain unit integrity.
Who benefits from claim structure: defensibility and licensing leverage
US 5,753,265 creates leverage on at least two fronts:
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Formulation defensibility
- The “mechanical properties so not to significantly affect acid resistance during compression” hook + the quantified ≤10% decrease provides a measurable standard that can be used in infringement testing.
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Manufacturing defensibility
- Process claim 14 attaches to a defined coating and tablet compression workflow.
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Use and packaging expansion
- Methods of acid suppression and gastrointestinal inflammatory disease treatment expand enforcement beyond the physical dosage form.
- Press-through blister claims extend to a specific product retail format.
Key takeaways
- US 5,753,265 protects a multiple-unit tablet where each core unit is individually enteric coated, and the enteric layer has mechanical properties that preserve USP acid resistance after compression.
- The strongest discriminators are claim 4 (USP compliance) and claim 5 (≤10% acid resistance loss after compression), backed by plasticized enteric coating and ≥10 μm thickness (claims 6 and 7).
- Active ingredient coverage is constrained to an acid-labile H+/K+-ATPase inhibitor with specific formula/enantiomer/alkaline salt boundaries and explicit exclusions (claim 2) plus enumerated members (claim 3).
- Enforcement can target not only the final dosage form but also manufacturing steps (process claim 14 onward) and use/package formats (claims 20–23, 21–22).
FAQs
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What is the main novelty protected by US 5,753,265?
Individually enteric-coated units inside a compressed multiple-unit tablet where the enteric coating’s mechanical properties prevent significant loss of acid resistance, quantified as ≤10% decrease after compression.
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Does the patent require USP enteric coated article performance?
Yes. Claim 4 requires acid resistance compliance with USP requirements for enteric-coated articles.
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What limits the active ingredient scope?
Claim 2 limits to formula I variants with enantiomer/salt requirements and includes explicit excluded compounds. Claim 3 further narrows to listed compounds (plus salt/enantiomers).
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Does the patent cover manufacturing methods, not only products?
Yes. Claim 14 and dependent claims protect specific steps: shaping cores, enteric coating, mixing into tablet excipients, and compressing with the requirement that coating mechanical properties preserve acid resistance.
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Does the patent include packaging and medical use claims?
Yes. Claims 20 and 23 cover press-through blister packages containing the dosage form; claims 21 and 22 cover methods for gastric acid secretion inhibition and gastrointestinal inflammatory disease treatment.
References (APA)
- US Patent 5,753,265, “Oral pharmaceutical composition … acid-labile H+/K+-ATPase inhibitor … mechanically robust enteric coating,” claim set as provided.
