US Drug Patent 7,820,203: Scope, Claim-by-Claim Breakdown, and US Landscape for Cyclobenzaprine Extended-Release Multi-Particulates

US Patent 7,820,203 claims multi-particulate extended-release beads for cyclobenzaprine hydrochloride with defined polymer membrane compositions and quantitative in vitro and in vivo performance targets. The core inventive boundary is a water-insoluble polymer membrane around an active-containing core particle, using a specified polymer families list, and delivering USP Apparatus 2 (paddle, 50 rpm) dissolution in 0.1N HCl at 37°C plus single-dose PK ranges (Cmax and AUC0-168) scaled for two dosage strengths (30 mg and 15 mg).

What matters commercially is that the claims tie structure to performance metrics, which raises enforcement leverage against products that match the polymer membrane class and the measured dissolution and PK windows.

What is the claim architecture and what is the protected product boundary?

Independent claims (1 and 2) lock the main structure + performance

Both independent claims are built on the same scaffold:

Dosage form: “a population of extended release beads” in a multi-particulate dosage form
Core: “active-containing core particle comprising cyclobenzaprine hydrochloride”
Membrane: “extended release coating comprising a water insoluble polymer membrane surrounding said core”
Polymer membrane selection: one polymer from a defined group (or mixtures)
Dose strength:
- Claim 1: 30 mg cyclobenzaprine HCl total in dosage form
- Claim 2: 15 mg cyclobenzaprine HCl total in dosage form
Dissolution performance in vivo-relevant test condition:
- USP Apparatus 2 (paddles @ 50 rpm)
- 900 mL of 0.1N HCl
- 37°C
- Release pattern limits:
- 2 hours: no more than ~40% released
- 4 hours: ~40-65% released
- 8 hours: ~60-85% released
Single-dose PK performance (cyclobenzaprine plasma):
- Claim 1 (30 mg):
- Cmax in range 80% to 125% of 20 ng/mL
- AUC0-168 in range 80% to 125% of 740 ng·hr/mL
- Claim 2 (15 mg):
- Cmax in range 80% to 125% of 8 ng/mL
- AUC0-168 in range 80% to 125% of 320 ng·hr/mL

Dependent claims add formulation knobs while staying inside the same membrane concept

Dependent claims expand scope through:

Coating weight fractions (claims 3, 9)
Add-on water-soluble polymer in the coating system (claim 4)
Extended dissolution window up to 12 hours (claim 5)
Plasticizer selection and loading in the membrane system (claims 6, 7)
Dosage format (capsule) (claim 8)
Seal coating layer composition (claim 10)
“Consisting essentially of” limitation (claims 11 and 12) narrowing allowable components beyond the bead population.

What polymers define the water-insoluble membrane, and why does that matter for infringement?

The independent claims restrict membrane composition to a closed list of polymer families:

Cellulose ethers (examples include ethyl cellulose and similar ethers listed explicitly)
Cellulose esters
Cellulose acetate
Ethyl cellulose
Polyvinyl acetate
Neutral copolymers based on ethyl acrylate and methyl methacrylate
Copolymers of acrylic and methacrylic acid esters with quaternary ammonium groups
pH-insensitive ammonio methacrylic acid copolymers
Mixtures of the above

Enforcement implication: a product that uses a membrane polymer outside the list avoids literal coverage on the membrane composition element, even if it matches dissolution and PK.

Claim-by-claim scope map (literal elements and practical reach)

Claim 1: 30 mg cyclobenzaprine HCl bead system with defined polymer membrane + dissolution + PK

Key literal elements:

Multi-particulate dosage form containing a “population of extended release beads”
Each bead has:
- Core with cyclobenzaprine hydrochloride
- Water-insoluble polymer membrane surrounding the core
Membrane polymer is in the defined list
Total cyclobenzaprine HCl in the dosage form: 30 mg
Dissolution pattern (USP App. 2, 0.1N HCl, 900 mL, 37°C, 50 rpm):
- 2 hours: ≤ 40%
- 4 hours: 40-65%
- 8 hours: 60-85%
Single oral administration PK:
- Cmax: 80% to 125% of 20 ng/mL
- AUC0-168: 80% to 125% of 740 ng·hr/mL

Numeric boundaries for PK (as expressed by the claim):

Cmax: 16 to 25 ng/mL
AUC0-168: 592 to 925 ng·hr/mL

Claim 2: 15 mg cyclobenzaprine HCl bead system with same membrane class + dissolution + PK scaled to lower dose

All structural/performance elements track claim 1 except dose and PK targets:

Total cyclobenzaprine HCl: 15 mg
Dissolution pattern: same three time points (2h, 4h, 8h)
Single-dose PK targets:
- Cmax: 80% to 125% of 8 ng/mL (range 6.4 to 10 ng/mL)
- AUC0-168: 80% to 125% of 320 ng·hr/mL (range 256 to 400 ng·hr/mL)

Claim 3: membrane coating weight fraction (7% to 12%)

Extends claim 1 or 2 by requiring:
- “extended release coating comprises about 7% to 12% by weight of the extended release beads”

Practical scope: this narrows to products with that coating mass fraction.

Claim 4: water-soluble polymer additive

Adds requirement:
- Membrane system includes a water soluble polymer selected from:
- methylcellulose
- hydroxypropylcellulose
- hydroxypropyl methylcellulose
- polyethylene glycol
- polyvinylpyrrolidone
- mixtures

Claim 5: extended dissolution to 12 hours

Extends claims 1 or 2 by adding:
- After 12 hours: ~75-85% released

This creates a second performance checkpoint that is absent from independent claims.

Claim 6: plasticizer selection in the membrane

Requires plasticizer selected from:
- triacetin
- tributyl citrate
- triethyl citrate
- acetyl tri-n-butyl citrate
- diethyl phthalate
- dibutyl sebacate
- polyethylene glycol
- polypropylene glycol
- castor oil
- acetylated mono- and di-glycerides
- mixtures

Claim 7: plasticizer loading (10% to 25% by weight)

Membrane includes plasticizer at:
- about 10% to 25% by weight of said plasticizer

Claim 8: capsule dosage form

Extends to “in the form of a capsule”

Claim 9: extended release coating loading (1% to 15% by weight)

Requires:
- extended release coating comprises about 1% to about 15% by weight of the extended release beads

Note on claim interaction: claim 3 (7% to 12%) and claim 9 (1% to 15%) overlap. Products meeting claim 3 automatically meet claim 9, but not vice versa.

Claim 10: seal coating layer

Adds:
- further comprises a seal coating layer comprising hydroxypropyl methylcellulose or hydroxypropylcellulose

Claim 11 and 12: “consisting essentially of” bead population limitation

Claim 11 (dependent on claim 1):
- “pharmaceutical dosage form of claim 1, consisting essentially of a population of the extended release beads”
Claim 12 (dependent on claim 2):
- same but based on claim 2

Scope effect: this narrows allowable additional components in the dosage form beyond the bead population, depending on how “consisting essentially of” is construed in the relevant jurisdiction.

Side-by-side: dosage strength scaling and performance checkpoints

Element	Claim 1	Claim 2
Total cyclobenzaprine HCl	30 mg	15 mg
Dissolution test condition	USP App. 2, paddles 50 rpm, 900 mL 0.1N HCl, 37°C	Same
Dissolution time points	2h, 4h, 8h	Same
Dissolution constraints	2h ≤40%; 4h 40-65%; 8h 60-85%	Same
PK Cmax target	80%-125% of 20 ng/mL	80%-125% of 8 ng/mL
PK AUC0-168 target	80%-125% of 740 ng·hr/mL	80%-125% of 320 ng·hr/mL
PK numeric ranges	Cmax 16-25 ng/mL; AUC 592-925	Cmax 6.4-10 ng/mL; AUC 256-400

What is the competitive read-through: how tightly does this constrain alternatives?

High literal specificity

The combination of:

membrane polymer list (closed set),
defined dissolution in specific medium and apparatus,
defined single-dose PK windows,

makes it harder to design around with small formulation changes. A generic or authorized alternative must typically match at least:

the selected polymer family,
the coating architecture and mass fractions (if dependent claims asserted),
and measurable dissolution and PK endpoints.

Design-around pathways (within the claim language)

The most direct literal design-around is to change at least one of:

membrane polymer type (outside the listed polymers),
dissolution profile at the specified time points and constraints,
PK outcomes relative to the defined reference values,
total dosage strength matching claim scope,
or, where asserted, coat loading/plasticizer/seal layer and “consisting essentially of” constraints.

US patent landscape: scope relationships and how this patent is positioned in enforcement

Where this patent sits in the broader landscape

US 7,820,203 is not framed as a new active ingredient or new route. It is framed as a specific formulation technology:

multi-particulate extended release,
membrane polymer selection limited to specific classes,
coupled with measured dissolution and plasma PK performance.

That places it in the typical “product-by-process / formulation-by-performance” enforcement band, where competitors often litigate over:

whether the competitor uses a polymer membrane within the enumerated list,
whether dissolution testing under the claimed method matches release windows,
and whether single-dose PK fits the numeric ranges.

Interplay with other cyclobenzaprine ER approaches (high-level)

Within US cyclobenzaprine ER portfolios, patents typically cluster around:

modified release matrix systems,
bead/coated particle systems,
and coating polymer plasticizer and porosity modifiers.

US 7,820,203 is specifically anchored to:

water-insoluble polymer membrane selection from the listed set,
and performance patterns tied to USP App. 2 in 0.1N HCl.

That is a materially enforceable posture compared with broad “extended release” claims that do not tether polymer identity to specific dissolution and PK ranges.

Actionable freedom-to-operate framing for R&D and generic strategy

If you are reformulating or designing an “authorized alternative”

For a literal match to independent claims, product development must support:

membrane polymer selection within the enumerated list,
dissolution pattern compliance at 2h, 4h, 8h in the claimed test setup,
and single-dose PK windows within 80% to 125% of the stated reference values.

If you are assessing risk for a competitor product

The decisive evidence set is:

What polymer membrane family is used (and whether it falls within the claimed list)
USP App. 2 dissolution release profile in 0.1N HCl, 37°C, 50 rpm, 900 mL
Single-dose PK (Cmax and AUC0-168) in humans at the matching dose strength

Dependent-claim risk increases if you see:

coating weight fractions in the claimed windows,
a plasticizer consistent with the enumerated set and loading,
a seal coating layer with hydroxypropyl methylcellulose or hydroxypropylcellulose,
and bead-only formulation presence compatible with “consisting essentially of.”

Key Takeaways

US 7,820,203 is an extended-release cyclobenzaprine formulation patent targeting multi-particulate extended release beads with a water-insoluble polymer membrane around drug cores.
Independent claims 1 and 2 fix: (1) membrane polymer in a closed list, (2) USP App. 2 dissolution release windows in 0.1N HCl at 37°C, and (3) single-dose PK ranges for Cmax and AUC0-168, scaled to 30 mg and 15 mg strengths.
Dependent claims further narrow scope via coat loading, optional water-soluble polymer, optional plasticizer type and level, optional extended (12h) dissolution target, capsule format, and a seal coating layer; “consisting essentially of” limits additional components.
The most direct literal design-around is to alter at least one protected axis: membrane polymer class, dissolution release profile under the claimed test, or single-dose PK endpoints, with additional leverage if dependent-claim specifics are avoided.

FAQs

1) Does US 7,820,203 cover any cyclobenzaprine ER product made with beads?

No. Coverage requires extended release beads with a water-insoluble polymer membrane using a specific polymer list, plus matching dissolution release windows and single-dose PK ranges for the relevant dose strength.

2) What dissolution method is locked into the independent claims?

USP Apparatus 2 (paddles @ 50 rpm), 900 mL of 0.1N HCl, 37°C, with release measured at 2, 4, and 8 hours against the stated percentage windows.

3) Are the PK targets absolute or relative?

They are relative ranges: Cmax and AUC0-168 must fall within 80% to 125% of the stated reference values (20 ng/mL and 740 ng·hr/mL for 30 mg; 8 ng/mL and 320 ng·hr/mL for 15 mg).

4) Which claim adds the 12-hour dissolution window?

Claim 5 adds the requirement that after 12 hours the release is about 75-85%.

5) Can a competitor avoid dependent claim risk by changing seal coating or plasticizer?

Yes. Dependent claims 6 to 7 (plasticizer type/loading) and claim 10 (seal coating composition) add additional limitations. If a product does not meet those specific constraints, dependent-claim coverage is reduced even if the independent claim elements are met.

References

[1] U.S. Patent No. 7,820,203.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
World Intellectual Property Organization (WIPO)	2005048996	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,820,203

Summary for Patent: 7,820,203