United States Patent 7,927,624: Scope, Claims, and US Patent Landscape for Ropinirole Multi-Layer Controlled-Release Tablets

What does US 7,927,624 claim coverage cover?

US 7,927,624 claims a multi-layer controlled-release tablet for ropinirole that is built around four structural constraints: (1) a ropinirole-containing active layer, (2) an active-layer polymer-lipid ratio window defined by swelling/gelling/eroding hydrophilic polymers vs lipophilic excipients, (3) barrier layers that limit the release surface and contain overlapping excipient families, and (4) optional features that narrow or broaden infringement depending on product formulation and manufacturing.

The claims also include a use claim for treating Parkinson’s Disease via administration of the tablet, including once-daily dosing.

Independent claim 1: What is the core product definition?

Claim 1 defines a tablet with:

(a) One active layer comprising:
- (i) 0.05% to 20% by weight ropinirole (including salts)
- (ii) hydrophilic polymeric substances that swell and gel and/or erode on contact with aqueous liquids
- (iii) lipophilic substances
- (iv) 5% to 50% by weight adjuvant substances
- Active-layer hydrophilic polymer : lipophilic weight ratio: 7:1 to 1:1
- Hydrophilic polymer fraction of active layer: 30% to 75% by weight
(b) One or more barrier layers that:
- limit the release surface of the active layer
- contain one or more of:
- hydrophilic swelling/gelling/eroding polymers
- lipophilic substances
- adjuvant substances
Tablet is optionally coated.

Claim 1 is the broadest formulation-and-structure anchor. It does not require specific polymer identities in the barrier layer (only that barrier layers contain some combination of the listed excipient families), and it does not require the barrier layers to be applied to specific tablet faces in claim 1 (that specificity appears in dependent claims).

How narrow is claim 1 by numeric windows?

The product is constrained by three numeric “gates” that affect likely infringement outcomes:

Active layer gates (Claim 1)

Parameter	Range / requirement
Ropinirole content (by weight of active layer)	0.05% to 20%
Hydrophilic polymer content (by weight of active layer)	30% to 75%
Adjuvant content (by weight of active layer)	5% to 50%
Hydrophilic polymer : lipophilic weight ratio (active layer)	7:1 to 1:1
Release control mechanism	barrier layers limit release surface (and optionally coating)

If a competitor deviates on hydrophilic fraction or on the polymer-lipid ratio, it may fall outside the independent claim. If a competitor uses barrier concepts but does not include barrier layer excipient families as required, it may also fall outside.

Dependent claims: what additional boundaries are introduced?

Claim 2: Active ingredient specificity

Ropinirole hydrochloride is explicitly recited.

Claims 3-4: Tighten lipophilic/adjuvant percentages

Lipophilic substances in active layer: 5% to 55% (Claim 3)
Adjuvant substances in active layer: 10% to 40% (Claim 4)

These do not override claim 1 but restrict within dependent pathways.

Claim 5: Enumerated polymer universe

Claim 5 provides a long list of candidate hydrophilic polymeric substances, including:

non-cross-linked polyvinylpyrrolidone
HPC / HPMC family: hydroxypropylcellulose, hydroxypropylmethylcellulose with MW windows
Na CMC / CMC variants and related carboxymethyl polymers
various copolymers and natural gums (carrageenans, xanthan, alginic acid)
cyclodextrins (alpha, beta, gamma)
additional polymeric swellable/erodible excipients including gellans, scleroglucan, etc.

In infringement terms, claim 5 expands the set of “acceptable” polymer types while staying inside the independent claim’s functional definition (swell/gel/erode).

Claim 6-10: Specific polymer combos and molecular/viscosity windows

Claim 6 narrows hydrophilic polymers to a set that includes:
- hydroxypropylmethylcellulose and sodium carboxymethylcellulose and/or calcium carboxymethylcellulose and other listed polymers
- it still includes the broader polymers by reference to the list
Claim 7 requires inclusion of hydroxypropylmethylcellulose and sodium carboxymethylcellulose
Claim 8 adds a molecular weight/viscosity selection for HPMC:
- HPMC MW: 20,000 to 500,000 OR 2% viscosity 80,000 to 120,000 mPa.sec
Claim 9 fixes HPMC to about 250,000 MW
Claim 10 requires gellable HPMC

This cluster is a high-value navigational subset: a product using HPMC/CMS with specified viscosity or gellability is positioned for stronger fit to dependent claims.

Claim 11-12: Lipophilic excipient list

Claim 11 enumerates lipophilic substances, including:

hydrogenated castor oil, beeswax, glyceryl behenate/palmitostearate, cetyl alcohol, stearic acid, fatty acids
hydrogenated castor oil is among the listed candidates.

Claim 12 narrows the lipophilic substance to hydrogenated castor oil and/or glyceryl behenate.

Claim 13: Specific preferred matrix composition (high evidentiary weight)

Claim 13 ties together:

ropinirole content 0.05% to 20% by weight
hydrophilic polymer includes HPMC or sodium carboxymethylcellulose or calcium carboxymethylcellulose
lipophilic includes hydrogenated castor oil or glyceryl behenate
adjuvants 5% to 50% by weight
polymer-lipid ratio 7:1 to 1:1

Claim 13 reads like a “representative” embodiment inside the claim family. It is the most directly formulation-matching dependent claim.

Claim 14: Barrier-layer ratio constraint

Claim 14 sets:

hydrophilic swelling/gelling/erodable polymers to lipophilic substances in the barrier layer:
- 1:1 to 7.5:1

This matters because claim 1 does not require a barrier-layer numeric ratio. Claim 14 does. Products that satisfy claim 1 structurally but do not satisfy barrier-layer balance may still avoid claim 1 unless claim 14 is asserted as part of the independent proof strategy.

Claims 15-16: Dosage amount windows

Claim 15: ropinirole amount up to 12.0 mg (measured as ropinirole base)
Claim 16: ropinirole amount 0.75 mg to 12 mg (base equivalent)

These constrain dose strengths that a generic or competitor can choose without risking misalignment.

Claims 17-19: Barrier geometry and first-hour release limitation

Claim 17: barrier layers are applied to one or both surfaces of the active layer
Claim 18: barrier is applied to both surfaces
Claim 19: during the first hour after oral administration or immersion, release occurs only from the surface not covered by the one or more barrier layers

Claim 19 adds a performance/functional release-surface constraint that may be tested experimentally against a candidate product.

Claims 20-30: A detailed two-barrier exemplar with fixed weights

Claims 20-30 provide a concrete tablet design with mass breakdowns:

Claim 20: Example tablet with two barrier layers

Total: active layer about 150 mg
Active layer components (essentially):
- up to 12 mg ropinirole HCl (ropinirole base equivalent)
- 41% HPMC type 2208 (100,000 cps)
- 10% sodium carboxymethylcellulose
- 5% maltodextrin
- 10% hydrogenated castor oil
- 1% magnesium stearate
- 0.6% colloidal silicon dioxide
- lactose monohydrate quantum sufficit
Barrier layers: 120-170 mg each set
Barrier layers components (essentially):
- 23.6% mannitol
- 25% glyceryl behenate
- 5% polyvinylpyrrolidone
- 1% magnesium stearate
- 0.4% colloidal silicon dioxide
- HPMC type 2208 (100,000 cps)
- optionally coloring agent
Optional film coat: about 13.80 mg coating agent

Claims 21-24: Mirror and coating specification

Claim 21 recites the same ranges and locks the film coat to 13.80 mg
Claim 24 ties film coating to 13.80 mg

Claims 22-23, 25-27: Barrier weights

One barrier 170 mg, the other 140 mg (Claims 22-23)
One barrier 130 mg, the other 120 mg (Claims 25-26)
Claim 27: tablet is uncoated

Claims 28-29: Coloring

barrier layers contain coloring agent, specifically yellow ferric oxide

These dependent claims are very “product-specific.” They often become the basis for enforcement against close designer-copy tablets, while claim 1 remains the broader legal hook.

Claims 31-32: Exclusions and manufacturing parameter

Claim 31: tablet is not coated by a gastroresistant and enterosoluble polymeric film
Claim 32: preparation by compression at 1000 to 5000 Kg/cm²

The exclusion can be important in design-around: an enteric/gastroresistant coating choice may deliberately avoid claim 31 but still potentially infringe claim 1 depending on how “optionally coated” is interpreted in the overall claim set.

Claims 33-35: Use and dosing regimen

Claim 33: method treating Parkinson’s Disease by administering the tablet
Claim 34: once per day
Claim 35: single tablet once per day

This makes the patent enforceable not only on product form but also on prescribing/using once-daily dosing for Parkinson’s treatment.

Claim construction map: scope by “what must be present”

What a practicing product must have to risk infringement of claim 1

A candidate must satisfy all of the following:

Ropinirole in an active layer at 0.05-20% by weight
Hydrophilic swelling/gelling/eroding polymeric substances present in active layer
Lipophilic substances present in active layer
Adjuvant substances in active layer at 5-50%
Hydrophilic polymer fraction 30-75% of active layer
Hydrophilic polymer : lipophilic ratio 7:1 to 1:1
One or more barrier layers that limit release surface and contain at least one of the polymer/lipid/adjuvant families
Tablet may be optionally coated (no enteric restriction in claim 1; that appears in claim 31)

US patent landscape: where this technology sits and how competitors typically position

What patent strategy does this claim set reflect?

The claim set follows a common controlled-release strategy for oral CNS drugs:

It defines a core sustained-release matrix (active layer) with polymer-lipid balance and polymer functionality (swelling/gel/erode).
It adds surface-limiting barrier layers to control early release and control release area.
It uses composition dependent claims to capture “preferred embodiment” formulations.
It uses a use claim (Parkinson’s disease, once daily).

This combination typically targets both:

close copies that match the example composition, and
broader matrix/barrier designs that stay inside the numeric windows.

What likely matters in US freedom-to-operate (FTO) assessments

In US practice, risk usually clusters around three check points:

Is the product a multi-layer tablet with a barrier limiting release surface?
Do the active layer excipient ratios fall into the 7:1 to 1:1 polymer:lipid band and hydrophilic at 30-75%?
Does the product’s dose strength fall in the up-to 12 mg / 0.75-12 mg windows if those dependent claims are asserted?

Separately, if the accused product uses gastroresistant/enterosoluble enteric film, it may still face claim 1 if the “optionally coated” term covers it, while claim 31 would not map.

Key infringement pressure points (technical)

The highest-leverage technical constraints in this patent for comparative product screening are:

Polymer type + functionality: must swell/gel and/or erode in aqueous liquids.
Polymer fraction and ratio window: hydrophilic polymers 30-75% and hydrophilic:lipophilic 7:1 to 1:1.
Barrier layers: must limit release surface and include at least one of hydrophilic polymers, lipophilic substances, or adjuvants.
Early release behavior: claim 19 requires first-hour release only from uncovered surface.

Practical scope statements tied to specific claim subsets

Broadest scope (Claim 1)

Covers a wide range of polymer identities, lipids, and adjuvants so long as the functional and ratio constraints are met.

Mid-range scope (Claims 2-14 and 16-19)

Covers more likely marketed formulations:

ropinirole hydrochloride
HPMC/CMS or similar gellable polymer stacks
hydrogenated castor oil / glyceryl behenate lipids
barrier layer ratio and early-release restriction

Most specific scope (Claims 20-30)

Captures a highly specific mass and excipient design:

active layer about 150 mg with 41% HPMC type 2208 (100,000 cps)
barrier layers with mannitol and glyceryl behenate and PVP and HPMC type 2208
optional film coat about 13.80 mg
optional yellow ferric oxide coloring
specific barrier layer masses (170/140 mg or 130/120 mg sets)
coating optional vs uncoated

Key Takeaways

US 7,927,624 is anchored by Claim 1, which requires a ropinirole multi-layer controlled-release tablet with an active-layer hydrophilic polymer 30-75%, an active-layer polymer:lipid ratio 7:1 to 1:1, and barrier layers that limit release surface and contain polymer/lipid/adjuvant families.
Dependent claims narrow by specific polymers (HPMC viscosity/MW and CMC variants), specific lipids (hydrogenated castor oil, glyceryl behenate), numeric dose windows (0.75-12 mg), barrier-layer ratio (1:1 to 7.5:1), and first-hour release from only the uncovered surface.
The claim set includes a detailed two-barrier exemplar (active layer about 150 mg; specific excipient percentages and masses; barrier masses including 170/140 mg and 130/120 mg; optional 13.80 mg coating; optional yellow ferric oxide).
Enforcement risk in US typically comes from matching either the broad ratio-and-barrier structure (Claim 1) or the close-formulation embodiment (Claims 20-30), plus potential exposure to the Parkinson’s once-daily use claim.

FAQs

1) Does claim 1 require enteric (gastroresistant) coating?

No. Claim 1 says the tablet is optionally coated. The explicit limitation against gastroresistant and enterosoluble coating appears in Claim 31.

2) What is the defining numeric ratio in the active layer?

The active-layer hydrophilic polymeric substances to lipophilic substances weight ratio must be 7:1 to 1:1 (Claim 1).

3) How is the barrier layer defined?

Barrier layers must limit the release surface of the active layer and contain one or more of: hydrophilic swellable/gellable/erodable polymers, lipophilic substances, and/or adjuvant substances (Claim 1).

4) Is early release constrained in the claims?

Yes. Claim 19 requires that during the first hour after oral administration or immersion, release occurs only from the surface not covered by the barrier layers.

5) What disease and dosing regimen are claimed?

The use is Parkinson’s Disease (Claim 33), with once per day dosing (Claims 34-35).

References

[1] United States Patent No. 7,927,624. Claims provided in user prompt (verbatim claim text).

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Italy	MI2000A0852	Apr 14, 2000
Italy	MI2000A1963	Sep 07, 2000

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	030557	⤷ Start Trial
Austria	401867	⤷ Start Trial
Australia	2005201805	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 7,927,624