Details for Patent: 6,183,778

Summary for Patent: 6,183,778

Title:	Pharmaceutical tablet capable of liberating one or more drugs at different release rates
Abstract:	Pharmaceutical tablet consisting of a first layer containing one or more drugs with immediate or controlled release formulation, a second layer containing one or more drugs, either equal to or different from the first layer, with slow release formulation, and a low-permeability barrier-type layer coating said second layer or, alternatively, placed between the first and second layer and, if necessary, containing a drug.
Inventor(s):	Ubaldo Conte, Aldo LaManna, Lauretta Maggi
Assignee:	PAUL ROYALTY FUND LP , Jagotec AG
Application Number:	US09/009,672
Patent Claim Types: see list of patent claims	Dosage form;

United States Patent 6,183,778 Landscape: Multi-Layer Tablet With Swell/Erode/Gellable Barriers and Two-Stage Release Claims

US Drug Patent 6,183,778 claims a specific multi-layer oral tablet architecture that uses aqueous-responsive swell/solubilize and swell/erode/gellable excipients to run two or more releases (including immediate/controlled release in at least one layer), with a third layer that coats free surfaces of the second layer and can act as a barrier for ~3 to 4 hour control. The strongest protection is for the layer-by-layer functional material choices (swelling/solubilizing vs swelling/eroding/gelling) tied to geometric layer shapes and a manufacturing constraint (at least two layers formed by compression of granular mixtures).

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What does US 6,183,778 claim in plain terms (scope and claim construction)?

Core claim theme: a compressed, geometrically shaped, at least three-layer tablet where:

• Layer 1 provides first release that is immediate or controlled, using excipients that swell or solubilize upon contact with aqueous fluids.
• Layer 2 provides second release that is controlled, using excipients that swell, erode, or are gellable.
• Layer 3 at least partially coats free surfaces of Layer 2 and includes excipients that swell, erode, or are gellable (a release-controlling barrier positioned on free surfaces, not only interfaces).
• At least two layers are formed by compression of a granular component mixture.

Claim 1: key limitations that define infringement boundaries

1. Dosage form: “oral dosage form in the form of a tablet” with two or more different releases of pharmaceutically active substances.
2. At least three layers with “specific geometric shape.”
3. Layer 1:
   • First release is immediate or controlled
   • Layer 1 contains substances that swell or solubilize with aqueous liquid contact.
4. Layer 2:
   • Second release is controlled
   • Layer 2 contains substances that swell, erode, or are gellable with aqueous liquid contact.
   • Actives released from Layer 2 can be the same as or different from Layer 1 actives.
5. Layer 3:
   • Coats “one or more free surfaces” of Layer 2
   • Layer 3 contains substances that swell, erode, or are gellable
6. Manufacturing:
   • “At least two layers” are formed by compression of a mixture of granular components.

Practical claim construction: the patent is not a generic “multi-layer tablet.” It requires the combination of:

• Aqueous-responsive excipient function (swelling/solubilizing in Layer 1; swelling/eroding/gelling in Layers 2 and 3),
• Controlled release in Layer 2,
• A third-layer barrier coating free surfaces of Layer 2, and
• Compressed granular formation for at least two layers,
• plus geometric shape specificity.

Claim 2: adds a time-based barrier function

Claim 2 depends on Claim 1 and requires:

• Layer 3 functions as a barrier to release of at least one active from the layer adjacent to Layer 3.
• Layer 3 controls release for at least about three to four hours.

Infringement leverage: this time criterion can become an issue of proof. It typically maps to dissolution testing, in vitro release profiles, and potentially in vivo correlations depending on the litigation record.

Claim 3: intermediate layer option and its release characterization

Claim 3 allows additional intermediate layers between any adjacent layers:

• intermediate layer may contain active or not;
• if it contains active, release from intermediate layer is immediate or controlled.

This expands the claim to tablets with more than three layers, while keeping the Claim 1 structure intact (Layer 1, Layer 2, Layer 3 relationships remain required).

Claim 4-6: film coating layer with pH and sugar solubility limits

Claim 4 depends on Claim 1 and adds:

• an outer film coating layer that at least partially covers the dosage form.

Claim 5 narrows:

• coating dissolves in aqueous fluids with pH > ~5.

Claim 6 narrows further:

• coating comprises a sugar.

Scope impact: these coating limitations reduce coverage to coated embodiments with the specified dissolution behavior and sugar content, but also provide additional fallback positions.

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How broad are the excipient and release definitions (swelling, solubilize, erode, gellable)?

Functional language drives broader coverage but can narrow in practice

The patent uses functional excipient descriptors:

• Layer 1: substances that swell or solubilize.
• Layers 2 and 3: substances that swell, erode, or are gellable.

These are not limited to specific named polymers or excipients. That broad functional framing can capture many formulation choices, but it also creates claim interpretation fights about whether a substitute excipient truly “solubilizes,” “erodes,” or “gellables” in the relevant aqueous conditions.

Controlled release linkage

Claim 1 requires:

• Layer 2 release is controlled release. Layer 1 release can be immediate or controlled. This is important for design-arounds: if Layer 2 is not “controlled release” in the claimed sense, Claim 1 may be avoided, but proving non-equivalence can be difficult without a strong factual record.

“Coats free surfaces” is a structural limitation with manufacturing relevance

The third layer must at least partially coat “free surfaces” of Layer 2. A design where Layer 3 is only an interface layer between Layer 2 and Layer 1 (without coating free outer surfaces of Layer 2) risks falling outside Claim 1.

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How does US 6,183,778 handle multi-active tablets and different release profiles?

Claim 1 expressly allows:

• Layer 1 and Layer 2 to release the same or different active substances.

Scope therefore includes:

• single API with two-stage release,
• combination APIs where each stage targets different pharmacokinetic behavior.

However, the architecture still must satisfy:

• Layer 2 must be controlled release,
• Layer 3 must function as an aqueous-responsive barrier on Layer 2 free surfaces,
• and Layer 1 must have swelling/solubilizing excipients.

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What patentable subject matter is captured: manufacturing by compression of granular mixtures?

Claim 1 contains a concrete manufacturing limitation:

• “At least two layers … formed by compression of a mixture of granular components.”

This matters for potential design-arounds:

• If a tablet architecture is formed via alternative manufacturing (for example, extrusion-based multi-layer compression equivalents, overmolding, casting, lamination, or other processes that do not involve compression of granular mixtures for the required layers), infringement may be harder to establish.

But if the accused tablet uses granulation + compression for Layer 1 and/or Layer 2 and Layer 3 consistent with the claim, the manufacturing limitation is more easily met.

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What is the likely independent claim strength (patent estate quality) based on the limitations?

Strength indicators

• Multiple tight limitations combine structure + excipient function + release behavior + manufacturing.
• “Coats free surfaces” and the time constraint in Claim 2 create potential enforceability anchors.
• The three-layer requirement and layer-specific excipient functions reduce the number of prior-art structures that hit all elements simultaneously.

Vulnerability indicators

• Functional excipient descriptors (“swells,” “solubilizes,” “gellable,” “erodes”) can be attacked in claim construction by disputing whether the accused formulation exhibits the claimed aqueous behavior.
• “Controlled release” and “three to four hours” invite performance-based disputes.

Overall profile

The claim set appears designed to cover a narrow but defensible formulation class: compressed multi-layer tablets using aqueous-responsive barrier layers and layered release timing.

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What formulations are protected by US 6,183,778 (design space and likely covered excipient classes)?

Without relying on a particular list of excipients, the claim points to excipient categories by function:

Layer 1 excipient function: swell/solubilize

Likely functional candidates in practice include:

• swellable polymers,
• solubilizing excipient systems,
• hydrophilic matrices that increase wetting and aqueous penetration.

The key is that Layer 1 must contain “substances which swell or solubilize” when contacted with aqueous liquids.

Layer 2 excipient function: swell/erode/gellable + controlled release

Likely candidates align with:

• gel-forming hydrophilic polymers,
• erodible matrix formers,
• swellable controlled-release polymers.

Layer 2 must provide controlled release with this functional behavior.

Layer 3 excipient function: swell/erode/gellable barrier on free surfaces

Layer 3 must at least partially coat free surfaces of Layer 2 and use swell/erode/gellable excipients. Claim 2 then demands barrier effectiveness for about 3-4 hours.

Optional coating layer: film coating dissolving at pH > 5, sugar-based

For Claim 5-6 embodiments:

• The coating must dissolve at pH greater than about 5,
• and comprises a sugar (e.g., sugar-based film formers).

This suggests the patent anticipates enteric-avoiding or regionally dissolving behavior, but the claim text is the dispositive part: pH > 5 dissolution and sugar composition.

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How can competitors design around US 6,183,778 (infringement risk map)?

High-risk design paths (more likely to be within claim scope)

• Three-layer (or more) compressed tablets where:
  • Layer 1 uses swell/solubilize excipients for immediate/controlled release,
  • Layer 2 uses swell/erode/gellable excipients for controlled release,
  • Layer 3 coats free surfaces of Layer 2 with swell/erode/gellable excipients,
  • and the barrier controls release for ~3-4 hours.

Lower-risk approaches (typical avenues to avoid key limitations)

• Remove the “coats free surfaces” geometry: use a layer stack where Layer 3 is not a coating of Layer 2 free surfaces.
• Change excipient function categories: use excipients that do not qualify as swelling/solubilizing (Layer 1) or swelling/eroding/gelling (Layers 2 and 3) under aqueous contact conditions.
• Eliminate controlled release in Layer 2: shift Layer 2 to a clearly immediate-release profile, while keeping other release stages.
• Alter manufacturing: avoid forming required layers by compression of granular mixtures (for at least two layers).
• Avoid the ~3-4 hour barrier performance: for Claim 2 exposure, reduce barrier effect or shorten release control below the claimed duration (Claim 2 is dependent; Claim 1 remains independent).

Coating-based design around

• If targeting to avoid Claim 4-6, omit film coating, or use non-sugar coating materials, or use coatings that do not dissolve as specified at pH > ~5.

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What litigation-relevant evidence usually matters for this patent?

In disputes over similar tablet architecture patents, the practical focal points are typically:

• Layer mapping: whether the accused product has at least three layers with the required geometric relationships and whether Layer 3 coats “free surfaces” of Layer 2.
• Excipients and mechanisms: whether Layer-specific excipients actually swell/solubilize vs swell/erode/gell.
• Release behavior:
  • whether Layer 2 is controlled release,
  • whether Layer 3 acts as a barrier,
  • and whether release control lasts at least about 3-4 hours (for Claim 2).
• Manufacturing process: whether layers are formed via compression of granular mixtures for at least two layers.

These become the factual pillars for claim element satisfaction.

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What is the likely competitive scope: does US 6,183,778 cover once-daily vs twice-daily?

Claim 2 fixes at least about 3-4 hours for barrier control, but Claim 1 does not set a full dosing-duration requirement. Therefore, the protected universe includes:

• products where the Layer 3 barrier controls a segment of the release curve for roughly that time window,
• including longer total duration regimens if subsequent release mechanics extend beyond 3-4 hours, so long as Layer 3 meets the barrier functionality required by dependent Claim 2 where asserted.

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What is the Orange Book status of US 6,183,778 and which products list it?

No mapping to FDA Orange Book entries can be produced from the information provided. Only the claim text is supplied, not the patent’s Orange Book listings, reference product, NDA/BLA, or listed expiration data. Without those specifics, a product-by-product status matrix cannot be completed.

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Key Takeaways

• US 6,183,778 is a multi-layer tablet architecture patent with tight, element-by-element limitations: three layers minimum, Layer 1 swell/solubilize, Layer 2 controlled release with swell/erode/gell, and Layer 3 coating Layer 2 free surfaces using swell/erode/gell excipients.
• The patent’s enforceable scope is strongest where products use compressed granular formation for at least two layers and where Layer 3 operates as a barrier (Claim 2) for at least about 3-4 hours.
• Design-around efforts most often target the claim’s structural geometry (“coats free surfaces”), the excipient functional behavior (swell/solubilize vs swell/erode/gell), and the manufacturing constraint (compression of granular mixtures), with additional avoidance for dependent coating limitations (sugar and dissolution at pH > ~5).

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FAQs

1) What does “coats free surfaces of the second layer” imply for tablet sectioning evidence?
It implies Layer 3 must cover exposed outer surfaces of Layer 2 in the assembled tablet, not just form an interface between Layer 1 and Layer 2.

2) Can Layer 1 be controlled release and still infringe Claim 1?
Yes. Claim 1 allows Layer 1 release to be immediate or controlled.

3) Does Claim 1 require the same active drug in Layer 1 and Layer 2?
No. Claim 1 allows Layer 2 to release the same or different active substances compared with Layer 1.

4) What is the highest-risk limitation for a formulation using gel-formers only?
If the gel-formers do not meet the required functional categorization for each layer (solubilize/swell for Layer 1; swell/erode/gell for Layers 2 and 3) or if Layer 3 does not coat Layer 2 free surfaces, infringement risk drops.

5) How do Claim 4-6 coating limitations affect freedom to operate?
They narrow coverage to embodiments with a film coating layer that dissolves at pH > ~5 and includes sugar. Non-sugar or non-matching pH dissolution coatings can avoid those dependent claims.

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References

1. US Patent 6,183,778 (claim text provided in prompt).

Drugs Protected by US Patent 6,183,778

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

International Family Members for US Patent 6,183,778

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	165734
Australia	4818293
Australia	675663
Canada	2145513
Germany	69318415
Denmark	0663820