US Patent 6,749,864: What Is Claimed, Where It Lands, and How the Landscape Breaks
US 6,749,864 is directed to a stabilized pharmaceutical composition for inhibiting gastric acid secretion, built around a benzimidazole compound of formula (I) plus a basic inorganic salt stabilizing agent that is homogeneously admixed in an effective amount. Claim scope is anchored on (1) the allowed substituent set for the benzimidazole core, (2) the requirement that the stabilizer is limited to specific basic inorganic salts, and (3) the formulation/process constraint that the stabilizing agent is homogeneously admixed to stabilize the compound.
What does claim scope cover? (core technical subject matter)
1) Therapeutic purpose: gastric acid secretion inhibition
All independent claim coverage is tied to use for inhibition of gastric acid secretion. The claims do not restrict route of administration, dosage form, or specific drug product format beyond “pharmaceutical composition,” and they do not require a particular in vitro/in vivo potency threshold.
2) Active ingredient: benzimidazole formula (I)
Claim 1 requires an effective amount of a benzimidazole compound “of the formula (I)” where substituents satisfy the enumerated constraints:
- R1 (broadly permissive): hydrogen; alkyl; halogen; cyano; carboxy; carboalkoxy; carboalkoxyalkyl; carbamoyl; carbamoylalkyl; hydroxy; alkoxy hydroxyalkyl; trifluoromethyl; acyl carbamoyloxy; nitro; acyloxy; aryl; aryloxy; alkylthio; alkylsulfinyl
- R2: hydrogen; alkyl; acyl; carboalkoxy; carbamoyl; alkylcarbamoyl; dialkylcarbamoyl; alkylcarbonylmethyl; alkoxycarbonylmethyl; alkylsulfonyl
- R3 and R5: each is hydrogen, alkyl, alkoxy, or alkoxyalkoxy
- R4: hydrogen; alkyl; alkoxy optionally fluorinated; or alkoxyalkoxy
- m: integer 0 to 4
The claim also covers:
- “a derivative thereof or salt thereof having a gastric acid secretion inhibitory property.”
This language expands capture to prodrugs/analogs/derivatives and salts, as long as they retain gastric acid secretion inhibitory activity.
3) Stabilization strategy: specific basic inorganic salts
Claim 1 additionally requires:
- “a basic inorganic salt stabilizing agent”
- The stabilizer is “at least one selected from magnesium, calcium, potassium, and sodium.”
- The stabilizer is homogeneously admixed with the compound of formula (I) in an effective amount “to provide stability to the compound of formula (I).”
Dependent claims narrow stabilizer identity to single cations:
- Claim 2: magnesium or calcium
- Claim 3: sodium
- Claim 4: potassium
Key legal effect: Claim scope is formulation-defined. A benzimidazole active that is otherwise identical can fall outside infringement if the stabilizer system is not one of these specific basic inorganic salts or is not homogeneously admixed as required.
What does “homogeneously admixed” do to infringement risk?
Claim 1 imposes a formulation/process-type limitation: the basic inorganic salt stabilizer must be homogeneously admixed in an effective amount.
From a claim construction standpoint, this likely forces proof about:
- whether the salt is uniformly distributed (not merely co-formulated or present as a bulk separate phase),
- whether the admixture is performed such that the salt and active are mixed to achieve the claimed stability effect.
Practical consequence for development and freedom-to-operate: even if a product uses an eligible cation (Na, K, Mg, Ca), infringement risk rises if the stabilizer is not present in a uniform dispersion or if the product argues the salt is not functioning as a “stabilizing agent” for the benzimidazole compound. The claim does not specify particle size, mixing method, or analytical assay, but it does require “homogeneously admixed” and an “effective amount” to “provide stability.”
How broad is the chemical substituent coverage around formula (I)?
The substituent list in R1 and R2 is expansive. Two features expand coverage:
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R1 is very permissive across typical benzimidazole substitution space, including electron-withdrawing groups (cyano, trifluoromethyl, nitro), electron-donating/heteroatom-containing groups (hydroxy, alkoxy hydroxyalkyl, aryloxy), and thioether/sulfinyl options (alkylthio, alkylsulfinyl).
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R2 allows carbonyl and sulfone motifs (acyl, carboalkoxy, alkylcarbonylmethyl, alkoxycarbonylmethyl, alkylsulfonyl), which often map onto medicinal chemistry strategies for potency, binding affinity, and prodrug-like tuning.
The claim also includes m = 0–4, giving multiple ring/bonding or substituent position possibilities inside the formula (I) scaffold (without the exact structural depiction, the scope is constrained only by the formula definition in the specification, but the integer range is explicit).
Legal outcome: the active ingredient claim element is not limited to a single compound. It covers a family defined by the enumerated substitution allowances plus derivatives/salts with gastric acid secretion inhibitory activity.
What does claim scope exclude? (design-around pressure points)
Even without reading the full specification, the claim language creates clear exclusion zones:
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Stabilizer cation restriction
- Excludes stabilizing agents that are basic inorganic salts of other cations (for example, ammonium-based basic salts, or basic salts of metals not listed).
- Excludes stabilization approaches that use non-inorganic bases (organic bases), unless they also qualify as “basic inorganic salt.”
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Stabilizer identity must be “basic inorganic salt”
- If the product uses an inorganic salt that is not “basic” (neutral or acidic), it is outside the claim. The claim does not include inorganic salts like sodium chloride, phosphate monobasic/dibasic would need to be “basic” by claim construction.
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Homogeneous admixture requirement
- Coating a tablet with a separate layer containing stabilizer, or using stabilizer in a way that is not “homogeneously admixed” with the active may avoid the limitation, depending on claim construction.
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“To provide stability to the compound”
- The stabilizer must be in an effective amount to provide stability. If a formulation uses eligible salts but the commercial rationale is not stabilization or evidence shows no stability benefit for the benzimidazole compound, infringement can be contested on the fact pattern.
How does this patent fit into the gastric-acid inhibitor ecosystem?
US 6,749,864 sits in a formulation-stabilization layer around a benzimidazole acid suppression scaffold. The claim structure indicates a typical follow-on strategy: keep the pharmacophore within a broad formula envelope while capturing a specific product-level stabilization method using selected basic inorganic salts.
Likely competitive nodes (based on claim logic)
- Direct competitors in acid suppression often fall into different chemical classes (various proton pump inhibitors, H2 blockers, etc.), which are not captured unless they fit the benzimidazole formula (I) plus stabilizer constraints.
- Products in this space that use benzimidazole acid suppressors could face overlap if they employ Mg/Ca/Na/K basic inorganic salt stabilizer systems.
Claim-by-claim map: exact capture points
| Claim |
Core active requirement |
Stabilizer requirement |
Narrowing effect |
Practical infringement trigger |
| 1 |
Benzimidazole of formula (I), with defined R1/R2/R3/R4/R5/m, including derivatives/salts with gastric acid inhibition |
Basic inorganic salt of at least one of Mg, Ca, K, Na; homogeneously admixed in effective amount providing stability |
Broadest capture |
Any formulation matching active formula envelope + eligible salt + homogeneous admixing + stability function |
| 2 |
Same as claim 1 |
Stabilizer limited to Mg or Ca |
Narrows cation list |
Use of Na or K would avoid this dependent claim (but not necessarily claim 1) |
| 3 |
Same as claim 1 |
Stabilizer limited to Na |
Narrows cation list |
Use of K, Mg, Ca would avoid this dependent claim |
| 4 |
Same as claim 1 |
Stabilizer limited to K |
Narrows cation list |
Use of Na, Mg, Ca would avoid this dependent claim |
What does the patent landscape likely look like around this claim?
Without the full prosecution history and the family listing, the landscape analysis must be tied to what the claims themselves indicate: a stabilization formulation claim that would often be challenged via:
-
Earlier benzimidazole compound disclosures
- Prior art that discloses benzimidazole derivatives matching formula (I) substitutions and gastric acid secretion inhibition could affect novelty for the active compound set.
- The claim’s novelty hinge then becomes the stabilization system and the homogeneous admixture limitation.
-
Earlier formulation approaches using basic inorganic salts
- Prior patents or publications may disclose using Mg/Ca/Na/K salts in formulations for stability of related actives.
- If such prior art already teaches homogeneously admixing basic inorganic salts for stabilization of benzimidazole acid inhibitors, it can erode inventive step.
-
Later generic or “at-risk” launch strategies
- If the active ingredient is stable and doesn’t require the claimed stabilization approach, later manufacturers may avoid the claim by:
- using alternate stabilizers (non-basic inorganic or different cations),
- changing how stabilizer is integrated (not homogeneous admixing),
- formulating as salts/derivatives outside the claimed umbrella.
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Patent thickets around salt forms and derivatives
- The claim itself includes “derivatives” and “salts” with gastric acid secretion inhibition.
- This can broaden the set of forms captured, but it also increases the relevance of competing patents that carve out specific salts/derivatives and their formulation conditions.
Actionable bottom line: the competitive battleground is less about the benzimidazole scaffold and more about stabilizer selection and formulation integration.
Where are the highest-value monitoring targets?
For business and R&D teams, the monitoring set should focus on patents and applications that address one of these three elements:
- benzimidazole compound families with gastric acid secretion inhibition mapped to the formula (I) space (substitution patterns, m range, derivatives/salts).
- formulation stabilization using basic inorganic salts specifically selected from Mg, Ca, Na, K.
- mixing/integration language corresponding to “homogeneously admixed” or equivalent uniform distribution requirements, including process steps that would argue for uniform admixture vs. separate-phase incorporation.
Key Takeaways
- US 6,749,864 claims a formulation: a benzimidazole acid secretion inhibitor defined by formula (I) plus basic inorganic salt stabilizers from Mg, Ca, Na, K.
- The claim’s most meaningful infringement constraints are: (i) the stabilizer must be one (or more) of the specified cations, (ii) it must be homogeneously admixed in an effective amount, and (iii) it must provide stability to the benzimidazole compound.
- Dependent claims narrow to specific cations: Mg/Ca, Na, or K, but all sit under claim 1’s broader formulation frame.
- Landscape pressure is expected around alternative stabilizer systems, different inorganic/basic selection, and formulation integration that avoids “homogeneous admixture.”
FAQs
1. What is the single most important claim element for infringement analysis?
The stabilizing agent must be a basic inorganic salt selected from Mg, Ca, Na, K and it must be homogeneously admixed with the benzimidazole compound.
2. Does the patent cover any gastric acid secretion inhibitor?
No. Coverage is limited to benzimidazole compounds matching formula (I) (plus derivatives/salts with the same gastric acid secretion inhibitory property).
3. If a product uses sodium as an ingredient but not as a stabilizer, is it covered?
Not necessarily. Claim 1 requires the sodium (or other eligible cation) to function as a basic inorganic salt stabilizing agent that is admixed to provide stability.
4. Do dependent claims add meaningful narrowing?
Yes. Claim 2 restricts the stabilizer to Mg/Ca; claim 3 restricts to Na; claim 4 restricts to K.
5. What is the most direct design-around path?
Use a stabilizer system that is not a basic inorganic salt of Mg/Ca/Na/K, or implement stabilization in a way that avoids the claim’s homogeneously admixed limitation and stability function.
References
[1] United States Patent 6,749,864. “Stabilized pharmaceutical compositions for the inhibition of gastric acid secretion.” Claims 1-4.
