United States Patent 9,474,722 (Amphetamine Transdermal Flexible Finite System): Scope, Claim Mapping, and US Patent Landscape
US Drug Patent 9,474,722 claims a finite-size, flexible transdermal system for topical amphetamine delivery with a specific polymer matrix and a specific multilayer flexible backing architecture: a polyurethane film layer plus a polyester film layer bonded via a polyurethane adhesive. The independent claim is composition-focused, with dependent claims tightening polymer chemistry, loading ranges, coat weight, film thicknesses, physical dimensions, and pharmacokinetic performance metrics (onset, duration, depletion). The patent also includes a corresponding method claim for topical application.
Claim 1 is the core scope driver and is written broadly enough to cover amphetamines as free base, salts, or prodrugs, but narrowly enough on the backing-layer construction and the finite flexible system concept.
What does US Patent 9,474,722 claim for amphetamine transdermal finite flexible systems (claim 1 scope)?
Claim 1 elements (decomposed into infringement touchpoints)
Claim 1 requires all of the following, as a conjunctive set:
- A composition for transdermal delivery of amphetamine
- Amphetamine is in the form of: amphetamines as free base or pharmaceutically acceptable salt or prodrug
- The composition is in the form of a “flexible finite system for topical application”
- Includes:
- (i) a polymer matrix comprising amphetamine (or salt/prodrug)
- (ii) a backing layer comprising:
- (a) a polyurethane film layer
- (b) a polyester film layer
- a polyurethane adhesive disposed between the polyurethane film layer and polyester film layer
- the polyurethane film layer is adjacent to the polymer matrix
- The backing-layer adjacency is positional: polyurethane film layer is the layer contacting the polymer matrix (not merely present in the laminate).
Scope implication for design-around: A competitor can avoid claim 1 by changing any required structural attribute, especially:
- removing the polyurethane adhesive between the polyurethane film and polyester film, or
- reversing layer adjacency (polyester adjacent to polymer matrix), or
- using a backing without both specific film types in the required laminate relationship, or
- making the system non-finite in the claimed sense (e.g., a different architecture that is not a “flexible finite system” as construed in the patent).
How broad is “amphetamine” in Claim 1?
Claim 1 uses:
- amphetamines in general (not limited to a particular salt, although dependent claims pick out D-amphetamine free base), and
- salt or prodrug language expands coverage beyond the exact free base.
This is important because many transdermal products change the API form to tune permeability. Claim 1 is written to catch those alternatives, so long as they fall under the “amphetically acceptable salt or prodrug” umbrella.
How broad is the polymer matrix in Claim 1?
Claim 1 does not specify polymer chemistries beyond “polymer matrix comprising amphetamine or salt/prodrug.” The polymer specifics appear in dependent claims (claims 6-12).
How broad is the backing layer in Claim 1?
Claim 1 is narrower than the polymer matrix. It locks the backing to:
- polyurethane film layer + polyester film layer
- polyurethane adhesive between them
- polyurethane film adjacent to the polymer matrix
Finite system term
“Flexible finite system” is a claim constraint. Even though Claim 1 itself does not state dimensions, dependent Claim 15 sets a size range. In US practice, “finite system” often aligns with a pre-sized patch rather than a “reservoir” style with selectable extent or other continuous formats. That matters for infringement theories and claim construction.
What additional constraints do dependent claims add to Claim 1 (polymer chemistry, film thickness, loading, and performance)?
Dependent claims on backing-layer material and thickness
- Claim 2: polyurethane film layer is comprised of a polyether aromatic polyurethane polymer.
- Tightens polyurethane chemistry subset.
- Claim 3: polyurethane film layer thickness ~1.5 mils.
- A literal infringement risk for designs outside the thickness value depending on claim construction of “about.”
- Claims 4: polyester film layer thickness ~0.4 to 0.6 mils.
- Another numeric lock on backing construction.
Dependent claims on amphetamine form
- Claim 5: amphetamine is D-amphetamine free base.
- Restricts to one stereochemical and salt state subset.
Dependent claims on polymer matrix composition chemistry
- Claim 6: polymer matrix comprises at least one acrylic polymer.
- Claim 7: polymer matrix comprises at least one non acid-functional acrylic polymer.
- Claim 8: non acid-functional acrylic polymer includes:
- methacrylate monomers
- 2-ethylhexyl acrylate
- optionally methyl methacrylate
- Claim 9: non acid-functional acrylic polymer includes:
- methacrylate monomers
- 2-ethylhexyl acrylate
- amide group-containing monomers
- optionally methyl methacrylate
Dependent claims on drug loading
- Claim 10: polymer matrix has ~10–20% by weight amphetamine (or salt/prodrug).
- Claim 11: polymer matrix includes:
- first acrylic polymer: 50% methacrylate / 50% 2-ethylhexyl acrylate (by weight of that polymer)
- second acrylic polymer: methacrylate + 2-ethylhexyl acrylate + amide monomers (optionally methyl methacrylate)
- drug load ~10–20% by weight.
- Claim 12: polymer matrix consists of:
- 67.5% first acrylic polymer
- 17.5% second acrylic polymer
- 15% amphetamine
- based on total dry weight of polymer matrix.
This set of claims creates a two-tier strategy for coverage:
- Claim 1 can be infringed by a variety of polymer matrix chemistries if they still meet claim 1’s structural backing requirements.
- Claims 6-12 create narrower but higher-confidence coverage where the formulation matches the acrylic chemistries and exact drug load.
Dependent claims on coat weight / dose density
- Claim 13: coat weight ~6–8 mg/cm² (active surface area).
- Claim 14: amphetamine about 1 mg/cm².
These help plaintiffs argue infringement even if some polymer details are contested, provided the coat weight and dose density match and the other required features are met.
Dependent claims on patch size and additional layers
- Claim 15: flexible finite system size ~2 to 60 cm².
- Claim 16: composition further comprises a release liner.
Release liner presence can matter for infringement if the independent claim does not require it. It is a dependent feature, so a product without a release liner would not fall into claims 16 onward, but could still fall under Claim 1.
Dependent claims on pharmacokinetic / performance metrics
- Claim 17: delivers amphetamine over ~8–10 hours.
- Claim 18: onset period ~30 to 90 minutes.
- Claim 19: duration of therapeutic effect at least ~12 hours, when removed at about 9 hours after application.
- Claim 20: drug depletion at least ~85% to ~93% at about 8–10 hours.
- Claim 25: system exhibits one or more of onset/duration/depletion metrics.
Performance claims are often litigated as factual issues. They can also introduce a design-around route: altering flux to change onset/depletion/time profile, assuming the resulting product avoids the other structural limitations and still functions as intended.
What does the method claim cover (Claim 21 and performance refinements in Claims 22–24)?
Claim 21
A method for transdermal delivery by topically applying a composition as claimed in Claim 1 to skin or mucosa.
Key legal implication: method infringement depends on users or entities performing the act of application with a product that meets Claim 1 composition.
Claims 22–24 (method performance metrics)
- Claim 22: onset period ~30–90 minutes
- Claim 23: duration of therapeutic effect at least ~12 hours when removed at ~9 hours
- Claim 24: about 85–93% depletion at ~8–10 hours
These add performance specificity to the method. They can create a higher evidentiary burden for a patentee, but also create additional hooks for litigation if testing data exists for the accused product.
How is the claim scope likely to be enforced in US litigation (what must be shown for infringement)?
Most important literal infringement gates
- Backings laminate architecture: polyurethane film + polyester film + polyurethane adhesive between them, with polyurethane film adjacent to the polymer matrix.
- Use of a flexible finite system.
- Presence of amphetamine in the polymer matrix as free base/salt/prodrug.
- If asserted through dependent claims: polymer chemistry (acrylic, non acid-functional, 2-ethylhexyl acrylate, amide-containing monomers), loading %, coat weight, patch area, and/or performance outcomes.
Infringement evidence that matters
- Backlayer construction documents: BOMs, lamination process descriptions, adhesive identification, and thickness specs.
- Material characterization: polymer film identification, thickness measurements, adhesive layer verification.
- Formulation test reports: drug loading, coat weight, and patch size.
- Pharmacokinetic studies: onset timing, depletion profiles, and duration-on-removal windows.
Non-infringement strategies that align with the claim structure
- Replace polyurethane/polyester laminate with another backing system that lacks the exact two-layer + polyurethane-adhesive configuration.
- Change adjacency so that polyurethane is not adjacent to the polymer matrix.
- Use a different adhesive layer family instead of polyurethane adhesive between the polyurethane film and polyester film.
- Change matrix polymer chemistry away from acrylic non-acid-functional systems if the case is pleaded on dependent claims.
- Alter release kinetics to fall outside the claimed performance metrics if performance claims are asserted.
What US patent landscape typically surrounds amphetamine transdermal systems with acrylic matrices and polyurethane backs (estate mapping framework)?
Because only the claim text and claim numbers are provided, this section maps the landscape using the claim architecture as the organizing principle. For investors and litigators, the most probative nearby patents are those that cover:
- Transdermal amphetamine compositions in polymer matrices (particularly acrylic, pressure-sensitive, or adhesive-free matrix formats).
- Backing laminates for transdermal systems (PU/PE film laminates, adhesive coupling layers, barrier properties, thickness ranges).
- Finite patch architectures and liners for controlled drug depletion.
- Performance targets like onset time, depletion percentage over time, and time-on-skin removal windows.
- Drug form (D-amphetamine free base versus salts/prodrugs) and how that affects flux.
In enforcement terms, Claim 1 is a “materials architecture” claim on the backing. In parallel, dependent claims are “formulation chemistry and process-like performance” claims. That combination usually means an estate has multiple layers: broad composition claims plus tighter dependents plus additional continuation claims focused on alternative polymer chemistries or patch geometries.
What is the practical scope risk for generic or alternative manufacturers (design-around vs. copy)?
If a product uses a different backing laminate
A different backing can avoid Claim 1 even if the drug loading and acrylic matrix resemble the claimed formulation. The backing requirements are the strongest structural constraints in the independent claim.
If a product copies the backing but changes formulation
If the backing laminate matches Claim 1, the polymer matrix can still be a design-around risk depending on whether the plaintiff asserts:
- only Claim 1 (polymer chemistry not limited), or
- dependents 6-12 (acrylic non-acid-functional monomer patterns, drug loading %, coat weight).
If a product copies formulation but changes kinetics
A competitor can attempt to avoid dependents 17-20 and 22-24 by altering release kinetics. That does not avoid Claim 1 unless performance metrics are required by the pleaded claim. But because performance dependents exist, litigation often uses performance to strengthen infringement narratives.
What are the key “claim-to-product” comparison points for an infringement or freedom-to-operate review?
| Category |
Claim feature |
How to compare an accused or target product |
| API form |
amphetamine free base vs salt/prodrug |
Identify API identity and salt/prodrug status |
| Matrix polymer family |
acrylic polymer, non acid-functional |
Characterize polymers via supplier specs and lab analysis |
| Acrylic monomers |
methacrylate + 2-ethylhexyl acrylate; amide monomers |
Confirm monomer composition with polymer supplier documentation |
| Drug load |
~10–20% (or 15% in Claim 12) |
Confirm dry weight loading % and batch specs |
| Coat weight |
~6–8 mg/cm² |
Measure coat weight and active area |
| Backing architecture |
PU film + polyester film |
Confirm laminate layers and materials |
| Adhesive layer |
polyurethane adhesive between PU and polyester |
Confirm adhesive identity and placement |
| Adjacency |
PU film adjacent to polymer matrix |
Verify layer order in stack |
| Film thickness |
PU ~1.5 mil; polyester ~0.4–0.6 mil |
Measure film thickness and tolerances |
| Patch geometry |
flexible finite size ~2–60 cm² |
Measure active area per patch |
| Performance |
onset, duration, depletion |
Run or review TK/flux studies, including depletion at 8–10h |
Key Takeaways
- Claim 1 is the anchor: infringement requires a polymer matrix with amphetamine plus a backing laminate with polyurethane film, polyester film, and a polyurethane adhesive between them, with the polyurethane film adjacent to the polymer matrix.
- Dependent claims narrow scope into specific acrylic, non acid-functional polymer chemistries (including 2-ethylhexyl acrylate and optional amide monomers), drug loading ranges, and numeric thickness/coat-weight/patch size parameters.
- The estate also includes pharmacokinetic/performance constraints (onset, duration, depletion), giving the patentee multiple evidentiary pathways depending on what product characteristics are easiest to prove.
- For design-around, the highest-leverage change is usually the backing laminate/adhesive architecture required by Claim 1; second is polymer chemistry and drug load if dependents are asserted; third is tuning release kinetics to avoid performance dependents.
FAQs
1. Does Claim 1 require D-amphetamine free base?
No. Claim 1 covers amphetamine as free base, pharmaceutically acceptable salt, or prodrug; D-amphetamine free base is specified in dependent claim 5.
2. Can a product avoid infringement by removing the release liner?
A missing release liner affects only dependent Claim 16. A product without a liner could still potentially fall under Claim 1.
3. Which claim elements are most difficult to change without redesign?
Backbone adjacency and the PU adhesive interface between polyurethane film and polyester film are structural and typically hard to alter without re-specifying the laminate.
4. If a product matches the backing but has different onset/duration, does it avoid all claims?
It could avoid dependent performance claims (17-20, 22-24, 25), but it may still infringe Claim 1 if the structural features are met.
5. What is the highest-probability assertion strategy in litigation based on these claims?
A patentee typically pleads Claim 1 for structural laminate infringement and layers dependent claims for tighter formulation and performance hooks where product data is available.
References
No external sources were provided or cited beyond the claim text supplied by the user.
