Details for Patent: 4,839,177

Summary for Patent: 4,839,177

Title:	System for the controlled-rate release of active substances
Abstract:	A system for the controlled-rate release of active substances, consisting of:(a) a deposit-core comprising the active substance and having defined geometric form;(b) a support-platform applied to said deposit-core.Said deposit-core contains, mixed with the active substance, a polymeric material having a high degree of swelling on contact with water or aqueous liqids, a gellable polymeric material, said polymeric materials being replaceable by a single polymeric material having both swelling and gelling properties, and other adjuvants able to provide the mixture with suitable characteristics for its compression and for its intake of water.
Inventor(s):	Paolo Colombo, Aldo La Manna, Ubaldo Conte
Assignee:	PAUL ROYALTY FUND LP , Jagotec AG
Application Number:	US06/939,810
Patent Claim Types: see list of patent claims	Formulation; Process;

Patent 4,839,177 (US4839177): Scope, claim-by-claim coverage, and US patent landscape for controlled-rate release systems with swelling/gelling polymer cores and water-insoluble coated platforms

What does US 4,839,177 claim: a swelling-controlled, gellable-core with an insoluble coated “support-platform”?

Core thesis: The patent claims a multipart solid dosage architecture for controlled-rate release in which a deposit-core contains one or more water-swelling polymers blended with one or more gellable polymers (or a single polymer that does both). Release is governed primarily by swelling intensity/duration, with geometry of a water-insoluble support-platform acting as a secondary control factor. The platform is partially coating the core and is made from a polymer insoluble in aqueous liquids.

Claimed product elements (common to the independent structure):

1. Deposit-core with defined geometry containing active substance(s).
2. Polymer composition inside the deposit-core:
   • Swelling polymer fraction: 5–80 wt% of the deposit-core total.
   • Gellable polymer fraction: 90–10 wt% of the deposit-core total.
   • Alternative: a single polymer that has both swelling and gelling properties.
3. Support-platform applied to the core:
   • Water-insoluble polymer (partially coating the core).
   • Coating can be applied by compression, immersion, spraying, etc.
   • Coverage/thickness/area are parameterized.
4. Adjuvants to enable compression and water uptake (examples include magnesium stearate and mannitol).

Claimed mechanism framing (within the claims):

• “The intensity and duration of the swelling force” is “the primary control factor” for release.
• “Geometry of the support-platform” directs emission.

This combination of (i) explicit polymer lists, (ii) wt% windows, and (iii) platform insolubility/coating geometry gives the estate its legal “shape”: it is not an all-purpose controlled release claim; it is a polymer-system claim with defined composition and a specific coated/encasing insoluble platform.

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What is the claim scope of US 4,839,177 claim 1: the independent claim boundary?

Claim 1 sets the baseline architecture: deposit-core + partially coating insoluble support-platform + constrained swelling/gelling polymer system in the core.

What the deposit-core composition requires

Claim 1 requires the deposit-core to contain the active substance and at least one member in the swelling bucket and at least one in the gellable bucket.

Swelling polymer bucket (must be present as at least one member if using the two-polymer route):

• 5–80% by weight of total deposit-core of a polymeric material having a high degree of swelling on water contact.
• Enumerated examples include:
  • cross-linked sodium carboxymethylcellulose
  • cross-linked hydroxypropylcellulose
  • high-molecular weight hydroxypropylmethylcellulose
  • carboxymethylamide
  • potassium methacrylatedivinylbenzene copolymer
  • polymethylmethacrylate
  • cross-linked polyvinylpyrrolidone
  • high-molecular weight polyvinylalcohols

Gellable polymer bucket (paired with the swelling bucket):

• 90–10% by weight of total deposit-core of a gellable polymeric material.
• Enumerated examples include:
  • methylcellulose
  • carboxymethylcellulose
  • low-molecular weight hydroxypropylmethylcellulose
  • low-molecular weight polyvinylalcohols
  • polyoxyethyleneglycols
  • non-cross linked polyvinylpyrrolidone

What is “the single polymer” alternative

Claim 1 also permits an alternative formulation where, instead of using separate swelling and gellable polymers, the deposit-core contains at least one single polymer with both swelling and gelling properties.

The claim text (as provided) still includes the dual-bucket language; other dependent claims specify the single-polymer identities. In litigation, this becomes a key interpretive fork: whether claim 1 is drafted to require both buckets in all cases, or whether the “single polymer” option is a substitute. Claim 1 uses “and” language plus an “and wherein” clause that ties the support-platform. The safest read from a risk perspective is that the independent claim is broad in architecture but strict in polymer-function selection as written.

What the support-platform requires

• Support-platform consists of polymeric material:
  • insoluble in aqueous liquids
  • partially coating the deposit-core

Geometry is not free

Claim 1 says the core has a defined geometric form and the platform “partially coating.” Later dependent claims lock in coverage fraction and configuration patterns.

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How do claims 2–5 narrow claim 1: processing pressure and polymer identity constraints?

Claim 2: deposit-core compression pressure

• Core is obtained by compressing the mixture to 1000–4000 kg/cm².

Practical enforcement impact: This adds a processing limitation for that dependent claim. It can create non-infringement avenues for products prepared at different compaction pressures, but in many cases compression ranges overlap in manufacturing practice.

Claim 3: swelling polymer list is “closed”

• Swelling polymer comprises at least one member selected from a list that matches the high-swelling bucket but is explicitly constrained.

This further narrows the functional class to specific named polymers and related forms.

Claim 4: gellable polymer list is “closed”

• Gellable polymer comprises at least one member selected from a list of cellulose ethers, CMC variants, low-MW hydroxypropylmethylcellulose, low-MW PVA, polyoxyethyleneglycols, and non-crosslinked PVP.

Claim 5: swelling+gelling single polymer list

• If using the single polymer route, it comprises at least one member selected from:
  • medium-viscosity hydroxypropylmethylcellulose
  • medium-viscosity polyvinylalcohols

This is a strong narrowing feature for any product arguing it uses a different swelling/gelling polymer pair.

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What does claim 6–11 add: support-platform coverage, thickness, and deposition mode?

Claim 6: platform covers one half

• Support-platform covers one half of the surface of deposit-core.

Claim 7–9: methods to form the insoluble platform

• Claim 7: applying water-insoluble polymer to the deposit-core by compression.
• Claim 8: immersing deposit-core in a solution in an organic solvent.
• Claim 9: spraying a solution onto deposit-core.

These dependent claims create potential manufacturing-design-around relevance: if a competitor uses a different coating application technique, they may avoid those specific dependents (while still risking independent claim 1).

Claims 10–11: platform thickness and coverage percentage

• Claim 10 thickness: 10 microns to 2 mm.
• Claim 11 coverage: platform covers 10–90% of total surface area.

Interpretive note for claim design: The estate uses explicit numerical constraints for thickness and coverage in the platform, which can materially narrow or broaden depending on whether a product’s coating method yields continuous coverage or discrete patches.

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What does claim 12 add: the “water-insoluble polymer” list in the support-platform?

Claim 12 constrains the support-platform polymeric material to at least one member selected from:

• acrylates
• cellulose
• ethylcellulose
• cellulose acetate-propionate
• polyethylene
• methacrylates
• acrylic acid copolymers
• high-molecular weight polyvinylalcohols

This matters because “water-insoluble” can be argued broadly based on crystallinity, crosslinking, molecular weight, or formulation. The list gives the patentee defined candidate materials for the platform.

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What do claims 13–14 add: control factors for release?

Claim 13: swelling intensity/duration is primary release control

This language is mechanism-limiting inside the claim.

For infringement: product release must be plausibly driven primarily by swelling dynamics of the swelling polymeric material in the core.

Claim 14: platform geometry as a further control factor

This requires that the geometric configuration of the support-platform directs emission, consistent with partial coatings leaving exposed surfaces.

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What do claims 15–20 add: adjuvants and alternative core architectures/platform configurations?

Claim 15: example adjuvants

• Adjuvants include magnesium stearate and mannitol.

This does not appear to limit the system to only these adjuvants; it restricts to “characterised in that said adjuvants are magnesium stearate and mannitol” in that dependent.

Claim 16: two-layer deposit-core

• Deposit-core formed from two layers, each comprises:
  • active substance
  • high-swelling polymer material
  • gellable polymer material

This is a structural architecture that can increase design-around by moving to single-layer cores.

Claims 17–20: multiple platform geometries

• Claim 17: coating applied to one flat, convex or concave surface.
• Claim 18: coating applied to two separate zones.
• Claim 19: coating surrounds core leaving two opposing surface portions free.
• Claim 20: support-platform forms a container encasing core leaving one surface portion free.

These configurations are central for “directing emission” because the only exposed faces can become release pathways.

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What do claims 21–22 add: patient-dosage containerization and method of preparation?

Claim 21: therapeutic system with multiple units in one container

• A therapeutic system with dosage unit containing a number of claim-1 systems disposed in one container.

This is broader than just a single unit but still tied to the claim-1 system definition.

Claim 22: method of preparing the system

• Steps:
  1. Wett mixture containing active and polymer materials with an adjuvant solution to form granulate.
  2. Compress granulate to obtain deposit-core.
  3. Coat over a determined area with water-insoluble polymer, possibly in an organic solvent.

This method claim creates manufacturing exposure even if final geometry differs slightly, but only for practicing the claim-1 architecture.

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What is claim 23–25: restated independent claim with tighter polymer identity?

Claims 23–25 are a second independent set (with overlapping language) that more explicitly enumerates polymer identities in the swelling, gellable, and single-polymer options.

Claim 23: restatement with explicit selection lists

• Swelling polymer: at least one member selected from the high-swelling list.
• Gellable polymer: at least one member selected from the gellable list.
• Single polymer with both: medium-viscosity HPMC or medium-viscosity PVA.
• Support-platform remains partially coating, water-insoluble.

Claim 24–25: which composition option is used

• Claim 24: deposit-core contains the swelling + gellable polymers.
• Claim 25: deposit-core contains the single swelling+gelling polymer.

From an infringement perspective, these dependents largely categorize the claim-23 independent claim into two chemical routes.

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How strong is the patent estate for US 4,839,177: what this claim set implies about enforceability?

Based on the provided claim text alone, the enforceability profile is driven by three elements:

1. High specificity of polymer identities and wt% windows in the core
   • Swelling polymer: 5–80 wt%.
   • Gellable polymer: 90–10 wt%.
   • The listed polymers constrain the range of “equivalent” arguments.
2. Support-platform requires water-insoluble polymer and partial coating
   • Platform polymer list exists (claim 12).
   • Platform coverage and thickness ranges appear in dependents (claims 10–11).
3. Mechanism language exists inside the claims
   • “Primary control factor” is a useful hook but can be contested against product release data or alternative release drivers.

Net effect: Claim scope is broad in concept (controlled-rate release system with swelling/gelling core and insoluble partial platform) but narrow in claim language (specific polymers, specific wt% proportions, specific platform being water-insoluble, and multiple geometric constraints in dependents).

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What competitive and “design-around” entry risks exist for controlled-rate release systems matching this architecture?

Highest-risk product designs

• Solid oral dosage forms (or implantables) using:
  • a core containing cross-linked/selected hydrophilic polymers that swell on water contact,
  • a gellable polymer co-matrix that forms gel,
  • and a water-insoluble polymer coating leaving a defined portion(s) exposed.

Likely design-around levers

• Swap the core polymer pair away from the explicit lists (especially the single-polymer HPMC/PVA identities).
• Use a platform polymer not on the claim 12 list or argue it is not “insoluble in aqueous liquids” in the claimed sense.
• Change compaction pressure outside 1000–4000 kg/cm² (to avoid claim 2).
• Use coating thickness/coverage outside the dependent ranges (to avoid claims 6, 10, 11, 17–20 dependents).
• Change core layering approach (to avoid claim 16).

Litigation exposure posture

If an accused product practices the architecture and uses listed polymers within claimed wt% ratios, the independent claim is a direct hit. If the accused product deviates only on manufacturing details (coating method, thickness, or platform coverage), it may still face independent-claim exposure if the platform is still an insoluble partial coat that yields swelling-driven release.

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How does US 4,839,177 compare with generic “controlled release” patent families: what makes it distinctive?

General controlled release patents typically claim matrix diffusion, osmotic pumps, multilayer tablets, or generalized polymer blends without a constrained swelling/gelling duality.

This patent is distinctive because it:

• makes swelling dynamics a stated primary release control factor,
• parameterizes swelling/gelling polymer proportions with explicit wt% windows,
• and pairs the core with a water-insoluble partial coating whose geometry directs emission.

That combination narrows its “landing zone” to a particular class of swelling-controlled, partially encapsulated solid dosage systems.

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What is the US regulatory and Orange Book status of US 4,839,177?

No complete product identification is provided in the prompt (no active ingredient, NDA/ANDA/BLA number, dosage form, or marketed trade name). Without that, the Orange Book listing status cannot be tied to this patent reliably.

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Key Takeaways

• US 4,839,177 claim 1 covers a controlled-rate release system built from a swelling/gellable polymer deposit-core plus a partially coating, water-insoluble support-platform.
• Core polymer constraints are central: swelling polymer at 5–80 wt% and gellable polymer at 90–10 wt%, with closed lists of specific polymer materials.
• Support-platform constraints are also central: water-insoluble polymer and partial coating, with dependents parameterizing thickness (10 microns–2 mm) and coverage (10–90%), and listing example insoluble polymers.
• Release control framing is in the claims: swelling intensity/duration is a primary release control factor, while support-platform geometry is a further control factor.
• Dependent claims add enforceability hooks via compression pressure, specific platform geometries, two-layer core structure, and method-of-preparation steps.

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FAQs

1. Does US 4,839,177 require both swelling and gelling polymers, or can a single polymer substitute?
   The claim set includes an alternative for a single polymer with both swelling and gelling properties, with single-polymer identities specified in dependent claims.

2. What compaction pressure is claimed for forming the deposit-core?
   1000–4000 kg/cm² in claim 2.

3. What polymer properties are required for the support-platform?
   It must be a polymer insoluble in aqueous liquids and partially coat the deposit-core.

4. What are the platform thickness and surface coverage ranges that appear in the dependents?
   Thickness: 10 microns to 2 mm (claim 10). Coverage: 10–90% of total surface (claim 11).

5. What is the claimed method of preparation in US 4,839,177?
   Granulate formation by wetting with an adjuvant solution, compression to form deposit-core, then coating the core over a determined area with a water-insoluble polymer, optionally dissolved in an organic solvent.

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References (APA)

1. United States Patent No. 4,839,177. (n.d.). Controlled-rate release system with swelling/gelling deposit-core and water-insoluble support-platform.

Drugs Protected by US Patent 4,839,177

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 4,839,177

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Italy	23321 A/85	Dec 20, 1985

International Family Members for US Patent 4,839,177

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	58472
Australia	594992
Australia	6672586
Canada	1298479
Germany	3675748
European Patent Office	0226884