US Patent 8,871,273: Scope, Claims, and US Landscape for pH-Controlled Coated Granules of Benzimidazole PPIs
US Patent 8,871,273 claims a coated granule engineered for pH-dependent dissolution/elution and pH-dependent release control of a benzimidazole proton pump inhibitor (PPI) using a specific two-stage coating system and a defined heating regime involving low substituted hydroxypropyl cellulose. The claims are method-linked to product-by-process features and constrain polymer selection, coating architecture (intermediate vs controlled-release film), and a heating step with a time/temperature window.
What does US 8,871,273 claim, in plain technical scope?
Core claim subject matter (Claim 1)
Claim 1 defines:
- A coated granule comprising:
- A biologically active substance that is a benzimidazole proton pump inhibitor
- A granule matrix including low substituted hydroxypropyl cellulose
- A manufacturing method that yields a granule with a two-stage coating architecture:
- Intermediate coating layer applied to the granule:
- Coating polymer base is selected from:
- Low substituted hydroxypropyl cellulose
- Hydroxypropyl cellulose
- Hydroxypropylmethyl cellulose
- Polyvinyl pyrrolidone
- Polyvinyl alcohol
- Methyl cellulose
- Hydroxyethylmethyl cellulose
- Controlled release coating film applied next:
- Coating contains a mixture of two or more polymers
- Polymer mix is selected from:
- Methyl methacrylate methacrylic acid copolymers
- A defined heating step during or around specific process steps:
- Granules are heated to about 50°C or higher
- Held at that temperature for about 1 minute to about 1 hour
- The heating can occur:
- During step (a), or
- During/before/after step (b), or
- During/before/after step (c)
Functional product limitations (release and dissolution)
Claim 1 includes performance limitations:
- The coated granule:
- Dissolves or elutes the benzimidazole PPI pH-dependently
- Controls release depending on the pH exposure
This ties the physical structure and method parameters to a pH-responsive release profile as an enforceable feature of the coated granule.
Heat parameter fallbacks (Claims 2–7)
Claims 2–4 refine temperature and hold time:
- Claim 2: heating temperature about 60°C or higher
- Claim 3: heating temperature about 65°C or higher
- Claim 4: maintained heated for about 3 minutes to about 1 hour
Claims 5–7 allocate when heating is performed:
- Claim 5: heating/maintaining is performed before step (b)
- Claim 6: performed during either step (b) or (c)
- Claim 7: performed after either step (b) or (c)
Where is the real claim leverage? (Structure vs polymer identity vs heat timing)
1) Polymer identity is tightly cabined
The claim is not just “controlled release coating”; it requires:
- Intermediate polymer base chosen from a closed list (HPC/HPCH/HPMC/PVP/PVA/MC/HEMC; with the first granule already containing low substituted HPC)
- Controlled release film polymer mix limited to methyl methacrylate methacrylic acid copolymers, and specifically requires a mixture of two or more kinds of these copolymers.
That combination limits design-around options to:
- Switching the controlled release polymer family (not permitted by Claim 1) or
- Avoiding the “mixture of two or more kinds” requirement (also not permitted by Claim 1).
2) “Heating during/around coating” is a constraint, not a vague process step
Claim 1 sets a numeric heating window and allows flexibility in timing, but does not waive the numeric window. A design-around must avoid:
- ≥ about 50°C during the specified heating event, or
- Holding ≥ about 1 minute and ≤ about 1 hour at that temperature, or
- The required product-by-process linkage in a way that breaks claim correspondence between the coated granule and the method-defined structure.
Claims 2–4 and 5–7 create layered scopes that track practical process variations.
3) Functional “pH-dependent elution/release” may be both strength and vulnerability
The claim requires pH-dependent dissolution and pH-dependent release. In enforcement, that can support arguments that the method/polymers/architecture are chosen to achieve pH control.
In validity challenges, functional limitations sometimes face interpretation disputes (what test method, what pH range, what release profile threshold). However, Claim 1 does not provide numeric release curves in the text provided, so the functional limitation likely relies on intrinsic behavior of the claimed formulation system.
What is the claim architecture (claim chart logic for infringement assessment)?
The simplest way to test Claim 1 coverage is to map each limitation:
| Claim 1 element |
Infringement requirement in substance |
Easy to verify |
Likely high-friction for design-around |
| Benzimidazole PPI as biologically active substance |
Active must be a benzimidazole PPI |
Yes (drug identity) |
Medium |
| Granule includes low substituted hydroxypropyl cellulose |
Matrix includes low substituted HPC |
Yes (formulation) |
High |
| Step (b) intermediate coating |
Intermediate layer applied using one polymer base from closed list |
Yes (excipient ID + coating) |
High |
| Step (c) controlled release film composition |
Mixture of two or more methyl methacrylate/methacrylic acid copolymers |
Yes (polymer ID + multiplicity) |
Very high |
| Heating regime |
About 50°C+; hold about 1 min to 1 hr |
Yes (process record) |
Very high |
| Heating timing flexibility |
During (a), before/during/after (b)/(c) |
Yes (batch records) |
Medium |
| Functional pH-dependent dissolution/release |
Must behave pH-dependently and control release with pH |
Product testing |
Medium to high |
What does the dependent-claim set add (scope narrowing vs process flexibility)?
Claims 2–4 narrow by adding tighter numeric heating thresholds:
- Temperature thresholds (≥60°C, ≥65°C)
- Hold time floor/ceiling (3 min to 1 hour)
Claims 5–7 are procedural permutations that can be used to capture multiple manufacturing strategies:
- Heating before intermediate coating (before (b))
- During either intermediate or controlled-release coating (during (b) or (c))
- After either coating step (after (b) or (c))
Net effect: the dependent claims are not large conceptual changes; they close gaps across realistic process scheduling.
How does this relate to the typical PPI formulation landscape?
PPI formulations commonly address:
- Acid stability (protecting or releasing active based on gastric/intestinal pH)
- Controlled release profiles
- Avoiding premature release in stomach conditions
- Taste/mucoadhesion and granule processing
Claim 1’s approach is recognizable as a controlled-release coating architecture using:
- Cellulose derivatives / PVP / PVA as an intermediate coating base
- Methyl methacrylate/methacrylic acid copolymers for pH-dependent solubility
- A heating step at moderate temperatures that can affect film formation, solvation state, or coating adherence for granule processing
What are the claim boundaries that create enforceable design constraints?
1) The controlled release polymer is locked to methacrylate/methacrylic acid copolymers
Claim 1 does not allow other enteric polymers (e.g., Eudragit-like alternatives outside the specified family) in the controlled release layer.
2) The controlled release layer requires a polymer mixture of “two or more kinds”
Even within the allowed family, a single polymer grade may be outside Claim 1 if it is not a mixture of two or more kinds.
3) The granule and intermediate layer tie back to low substituted hydroxypropyl cellulose
Low substituted hydroxypropyl cellulose is required as part of:
- The base granule (step (a) granule composition)
- Optionally also the intermediate coating base (step (b) polymer base list includes low substituted hydroxypropyl cellulose)
A design-around could:
- Change the base granule excipient identity (not allowed by Claim 1)
- Use a different intermediate base outside the listed cellulose/PVP/PVA set (not allowed)
- Use a controlled release polymer outside the specified copolymer family (not allowed)
- Use the correct polymer family but avoid the “mixture of two or more kinds” requirement (not allowed)
- Avoid the heating window (not allowed)
US patent landscape: what matters for freedom-to-operate around 8,871,273?
Based on the claim text provided, the landscape dimensions that determine overlap and enforceability are:
- Enteric or pH-dependent controlled-release coating systems for PPIs
- Methacrylate/methacrylic acid copolymer film formers and whether they are used as a single polymer vs a mixture of grades/types
- Use of cellulose derivatives or PVP/PVA as an intermediate coating base
- Manufacturing thermal steps (≥50°C, hold 1 min to 1 hr) applied during or around coating deposition
- Product-by-process correspondence: whether an accused product can be argued to be “obtained by” the claimed method steps in a way that yields the same coated granule architecture and pH-dependent behavior
What would constitute likely infringement vs likely non-infringement (category view)?
Likely infringement triggers
- A generic or branded PPI product that is a coated granule with:
- Low substituted hydroxypropyl cellulose in the granule
- Intermediate coating layer using one of the listed polymer bases
- Controlled-release film using a blend of two or more methyl methacrylate/methacrylic acid copolymer types
- Manufacturing includes a heating step at ~50°C+ held 1 min to 1 hr, with timing in the permitted scope
- Demonstrated pH-dependent release/elution
Likely non-infringement triggers
- Using a controlled-release coating polymer system not limited to the specified methyl methacrylate/methacrylic acid copolymer mixture
- Using only a single kind of the specified copolymer rather than “two or more kinds”
- Eliminating low substituted hydroxypropyl cellulose from the granule base
- Manufacturing with no heating step in the specified window, or showing the coated granule is not “obtained by” the claimed method steps (depending on the exact fact pattern)
Key Takeaways
- US 8,871,273 Claim 1 is a tightly constrained formulation and process patent: it requires a benzimidazole PPI in a granule containing low substituted hydroxypropyl cellulose, an intermediate coating using a closed list of polymer bases, and a controlled release film made from a mixture of two or more methyl methacrylate/methacrylic acid copolymer types.
- The patent adds a numeric heating regime (~50°C+, ~1 minute to ~1 hour) that can occur during or around the coating steps, plus pH-dependent dissolution and release behavior as functional limitations.
- Dependent claims mainly narrow the heating temperature/time window and allocate heating timing relative to the intermediate and controlled-release coatings.
- For freedom-to-operate, the highest-risk overlap areas are: (i) the specific methacrylate/methacrylic acid copolymer mixture requirement, (ii) the presence of low substituted hydroxypropyl cellulose in the granule, and (iii) the presence of a qualifying heating step in batch processing.
FAQs
1) Does Claim 1 require the heating step to occur during coating?
No. Claim 1 allows heating during step (a), or during/before/after step (b) or step (c), as long as it meets the numeric heating temperature and hold-time ranges.
2) Can a single methyl methacrylate/methacrylic acid copolymer grade satisfy the controlled-release layer?
Claim 1 requires a coating material comprising a mixture of two or more kinds of these copolymers, so a single kind would not meet the “two or more” limitation.
3) Is the intermediate coating polymer restricted to a single family?
Yes. Step (b) restricts the intermediate polymer base to a closed list: low substituted hydroxypropyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol, methyl cellulose, and hydroxyethylmethyl cellulose.
4) Are pH-dependent release and dissolution just descriptive, or part of the claim?
They are functional limitations of Claim 1: the coated granule dissolves or elutes pH-dependently and controls release depending on pH.
5) What do Claims 2–4 add relative to Claim 1?
They narrow the heating temperature to ≥60°C (Claim 2) or ≥65°C (Claim 3) and narrow the hold time to 3 minutes to 1 hour (Claim 4).
References
[1] United States Patent 8,871,273.
