Scope and Claims of US Patent RE41571 and the US Buprenorphine Transdermal Patent Landscape

US RE41571 is directed to methods of treating pain with buprenorphine via a transdermal delivery system designed to produce specific plasma-time profiles over a seven-day dosing interval (first-order rise to ~72 hours, then substantially zero-order fluctuation thereafter). The claim set is tightly framed around quantitative release-rate windows (µg/hr) and resulting mean plasma concentrations (pg/mL) at defined post-application timepoints.

What does US RE41571 claim for buprenorphine transdermal pain treatment?

Bottom line: RE41571 claims pain treatment methods where buprenorphine is delivered transdermally with (i) controlled release kinetics across a split time regime and (ii) predefined mean systemic exposure ranges measured after dosing initiation.

Core claim architecture (independent claim 1; dependent claims refine ranges)

Across Claims 1, 3, 5, 7, 9, 11, 13, and 15, the structure is consistent:

Patient treatment: “treating pain in a human patient.”
Route and dosage interval: buprenorphine transdermally via a transdermal delivery system applied to skin and maintained in contact for at least 5 days and/or a seven-day dosing interval.
Kinetic regime split at ~72 hours:
- First-order plasma level increase from start until ~72 hours.
- Substantially zero-order plasma level fluctuation from ~72 hours to end of (at least) the multi-day interval (commonly seven days).
Quantitative constraints:
- Mean relative release rate windows (µg/hr) for two time segments:
  - Start → ~72 hours
  - ~72 hours → end of interval
- Mean plasma concentration windows (pg/mL) at multiple timepoints:
  - 6, 12, 24, 36, 48, 60, 72 hours
  - then extending through 96, 120, 144, 168 hours (depending on claim tier)

Claim 1 (highest-level parameterization)

Claim 1 ties together the broadest kinetic window set in your excerpt:

Release rate windows
- Start → 72 hours: 3 to 86 µg/hr
- 72 hours → end of at least 5–7 days: 0.3 to 9 µg/hr
Plasma profile windows
- 6h: 0.3 to 113 pg/mL
- 12h: 3 to 296
- 24h: 7 to 644
- 36h: 13 to 753
- 48h: 16 to 984
- 60h: 20 to 984
- 72h: 21 to 1052
- 96h: 23 to 1052
- 120h: 23 to 1052
- 144h: 22 to 970
- 168h: 19 to 841

Scope signal: Claim 1 reads like a “catch-all” that still requires the full combination of delivery-system maintenance, kinetic character, and the listed mean plasma ranges.

How do dependent claims narrow release-rate and plasma ranges (Claims 2–14)?

Claim 2: “maintenance” plasma ranges through 168 hours

Claim 2 further requires that plasma ranges be maintained for the later phase:

96h: 23–1052 pg/mL
120h: 23–1052
144h: 22–970
168h: 19–841

Scope impact: It prevents design-arounds that fit early release kinetics but drift downward during the tail.

Claims 3–4: Mid/high exposure band (lower early release than Claim 1)

Claim 3 requires a tighter midrange exposure/kinetic plan:

Release rate windows:
- Start → 72h: 13 to 21 µg/hr
- 72h → end: 1 to 2 µg/hr
Plasma windows at key points:
- 6h: 1 to 28
- 12h: 14 to 74
- 24h: 30 to 161
- 36h: 51 to 188
- 48h: 62 to 246
- 60h: 79 to 246
- 72h: 85 to 263
- 96h: 92 to 263
- 120h: 94 to 263
- 144h: 86 to 243
- 168h: 77 to 210

Claim 4 narrows further using the tail points (96–168h).

Claims 5–6: Low exposure band (lowest release-rate windows)

Claim 5 uses:

Release rate windows:
- Start → 72h: 3 to 5 µg/hr
- 72h → end: 0.3 to 0.6 µg/hr
Plasma windows:
- 6h: 0.3 to 7 pg/mL
- 12h: 4 to 19
- 24h: 7 to 40
- 36h: 13 to 47
- 48h: 16 to 62
- 60h: 20/21 to 62 (minor drafting inconsistencies in excerpt)
- 72h: 21/20 to 66
- 96h: 23 to 66
- 120h: 23 to 66
- 144h: 22 to 61
- 168h: 19 to 53

Claim 6 again locks the later plasma ranges (96–168h).

Claims 7–8: Low-mid exposure band

Claim 7:

Start → 72h: 6 to 11 µg/hr
72h → end: 0.7 to 1 µg/hr
Plasma windows:
- 6h: 0.7 to 14
- 12h: 7 to 37
- 24h: 15 to 80
- 36h: 25 to 94
- 48h: 31 to 123
- 60h: 40 to 123
- 72h: 42 to 132
- 96h: 46 to 132
- 120h: 47 to 132
- 144h: 43 to 121
- 168h: 38 to 105

Claims 9–10; 11–12; 13–14: progressively higher exposure bands

Each successive independent claim tier expands release-rate windows upward and shifts plasma windows upward accordingly.

Claim 9:

Start → 72h: 26 to 43 µg/hr
72h → end: 2 to 4 µg/hr
Tail plasma points: 96h 184–526, 120h 187–526, 144h 173–485, 168h 153–420

Claim 11:

Start → 72h: 38 to 64 µg/hr
72h → end: 4 to 7 µg/hr
Tail plasma points: 96h 276–789, 120h 281–789, 144h 259–727, 168h 230–630

Claim 13:

Start → 72h: 51 to 86 µg/hr
72h → end: 5 to 9 µg/hr
Tail plasma points: 96h 369–1052, 120h 374–1052, 144h 346–970, 168h 306–841

Scope impact of the tiering: RE41571 does not claim one formulation profile. It claims multiple quantitative “permitted exposure corridors” by release rate and plasma-time ranges, making the estate more resilient to generic “PK targeting” at the design stage.

How are “seven-day dosing interval” and “at least five days” used to expand scope?

The independent claim family is written to capture:

at least 5 days
with an emphasis on maintaining contact for a seven-day dosing interval

This means an accused product can still fall in-scope even if it is marketed or used as a minimum-contact schedule so long as it meets the claimed plasma kinetic windows through the relevant endpoints and is applied/maintained for the required duration regime.

What does RE41571 require about “first order” vs “zero order” plasma behavior?

Claim language

“providing a substantially first order plasma level increase … until about 72 hours”
“providing a substantially zero order plasma level fluctuation … from about 72 hours … until the end of at least” the dosing interval

Practical scope effect

Because the claims then also recite numerical mean plasma concentration ranges at multiple timepoints before and after 72 hours, the “kinetic characterization” is not free-floating. It is operationalized through those measured ranges.

What does RE41571 claim about buprenorphine amount and formulation composition?

Buprenorphine as active ingredient (consists essentially vs consists)

RE41571 includes formulation-restricted claim features:

Claim 50 / Claim 59: “active ingredient consists essentially of buprenorphine.”
Claim 51: “active ingredient consists of buprenorphine.”
Claim 52 onward: repeats “active ingredient consists … buprenorphine” and ties back into the seven-day kinetic/plasma constraints.

Scope impact: These transitions limit the acceptable formulation landscape. A competing product using buprenorphine plus additional pharmacologically active agents (not just excipients) would be more likely outside “consists essentially” or “consists” limitations.

Transdermal delivery system composition (matrix-like)

Claims 48–49 and 53–57 (as excerpted) add weight-percentage ranges:

Buprenorphine loading:
- 0.1% to 30% by weight (Claims 48, 53, 56)
Example composition (Claims 49, 54, 57):
- 10% buprenorphine base
- 10–15% acid
- 10% softener
- 55–70% polyacrylate
- 0–10% polyvinylpyrrolidone (written as “polyvinylpyrrollidone”)

Scope impact: This pulls the estate toward a specific transdermal platform and still allows flexibility on acid/softener/polymer amounts, but it constrains polymer class selection by the recited polyacrylate and PVP band.

What about the “three-day first-order” then “additional two-to-four days” split claims (Claims 22–45)?

A separate claim track expands to a 3-day dosing interval for initial exposure characteristics and then extends treatment by additional intervals.

Claim 22 (key split-interval independent)

Claim 22:

Applies transdermal delivery system to produce:
- substantially first order plasma level increase over a first three-day dosing interval
Requires:
- mean plasma concentration 21 to 1052 pg/mL at ~72 hours
Then extends:
- maintain on skin for “at least an additional two four-day dosing interval”
- maintaining:
  - mean relative release rate 0.3 to 9 µg/hr over the additional interval
- and “therapeutic effect” throughout

Claim set 23–42: retention, Tmax timing, and exposure corridor narrowing

Claim 23: 68% to 95% of buprenorphine contained in the system at end of dosing interval
Claim 24: Tmax occurs 3 to 5 days after application
Claims 25, 28, 31, 34, 37, 40: each binds a different 72-hour plasma corridor and corresponding subsequent release-rate range:
- 21–1052 with 0.3–9 (Claim 22 baseline)
- 85–263 with 13–21 (Claim 25)
- 21–66 with 0.3–0.6 (Claim 28)
- 42–132 with 0.7–1 (Claim 31)
- 169–526 with 3–4 (Claim 34)
- 254–789 with 4–7 (Claim 37)
- 339–1052 with 5–9 (Claim 40)
Each includes dependent claim options for containment (68–95%) and Tmax window (3–5 days).

Claims 43–45: “max plasma concentration” + “zero order kinetics” during additional days

Claim 43:
- first order release over three days
- maximum plasma concentration 20–1052 pg/mL
- then substantially zero order kinetics for at least two additional four-day intervals
Claims 44–45:
- emphasize moderate to severe pain and maintaining contact 2 to 5 (or 4) additional days beyond a 3-day interval.

Scope impact: This split track can capture regimens where the device is labeled or used with a 3-day initial interval, even if not framed as a full 7-day dosing schedule in the labeling, so long as the additional contact period produces the claimed release and systemic exposure behaviors.

What do the additional refinement claims add (Claims 46–49; 52–57)?

Claims 46–47: stability of plasma levels

Claim 46: plasma level at 72h does not decrease by more than 30% over the next 48h
Claim 47: plasma level at 120h does not decrease by more than 30% over the next 48h

This limits designs that front-load and then drop.

Claim 48–49: active loading and example formulation

As above.

Claims 52–57: repeats “consists” language plus composition

This track effectively reinforces both:

the kinetic/plasma numerical windows, and
formulation constraints (loading % and matrix composition).

How many distinct “design zones” are covered by RE41571?

From the excerpt, independent claim tiers correspond to multiple quantitative windows. A business-relevant way to read scope is as “PK release corridors,” not one formulation.

Summary table of release-rate bands and plasma corridor anchors (from independent claims)

Claim tier	Start → 72h release (µg/hr)	72h → end release (µg/hr)	72h plasma corridor (pg/mL) anchor
Claim 1	3–86	0.3–9	21–1052
Claim 3	13–21	1–2	85–263
Claim 5	3–5	0.3–0.6	21–66
Claim 7	6–11	0.7–1	42–132
Claim 9	26–43	2–4	169–526
Claim 11	38–64	4–7	254–789
Claim 13	51–86	5–9	339–1052
Claim 15	3–86	0.3–9	mirrors Claim 1 (7-day release frame)

Key point: The estate is designed so a product must avoid both early and tail PK corridors, not merely shift T_max or alter a single release parameter.

What patent landscape issues matter for US buprenorphine transdermal competitors?

Legal/commercial reality of these claim types

These claims are not generic “buprenorphine transdermal for pain.” They are PK-and-release-rate engineered method-of-use claims.

That makes three landscape dynamics prominent:

PK-driven infringement evidence
- In litigation, infringement often turns on whether the accused device produces mean plasma concentrations in the claimed windows at the claimed timepoints under comparable conditions.
Design-around through different kinetics
- A competitor can attempt to move out of the mean plasma concentration corridors and/or alter the first-order vs zero-order behavior at the ~72h dividing line.
Formulation constraints can also matter
- Where “active consists of / consists essentially” and where specific polymer matrices are claimed, a competitor can be forced into either a composition design-around or a kinetic design-around.

Interaction with Orange Book and FDA status

Method-of-use patents and formulation-linked patents can appear in the Orange Book for an approved buprenorphine transdermal product. That affects:

triggering of Paragraph IV certifications,
settlement dynamics, and
generic launch timing.

However, Orange Book listing data for RE41571 (application/label link) is not provided in the prompt.

Key takeaways

RE41571 claims transdermal buprenorphine pain treatment methods with quantitative release-rate bands and numerical mean plasma concentration corridors.
Scope is reinforced by a two-phase kinetic requirement split at ~72 hours: first-order rise then substantially zero-order fluctuation.
The claim set includes multiple PK release corridors (low, mid, high exposure bands), making simple PK shifting insufficient as a design-around strategy.
Additional narrowing features include “active consists of / consists essentially of buprenorphine” and specific matrix composition constraints (notably polyacrylate-based systems) plus drug containment and Tmax timing.
A second split-interval track supports a 3-day initial regimen followed by additional days with specified release and systemic exposure characteristics.

FAQs

Can a competitor avoid RE41571 by changing only Tmax without changing release rate windows?
The claims require both kinetic characterization and multiple mean plasma concentration windows at fixed timepoints, so shifting Tmax alone is unlikely to avoid the numerical corridors.
Does RE41571 cover buprenorphine transdermal regimens that are not labeled as “seven-day”?
Yes if the actual device wear/maintenance meets the claimed contact duration, and the plasma/release profiles match the windows across the relevant timepoints.
How important is the “substantially zero order” requirement if plasma concentrations already match the numeric windows?
It is still a claim element, but the numeric plasma windows likely operationalize it and drive the infringement analysis.
Do the “consists essentially/consists” limitations matter for non-buprenorphine excipients?
They constrain the scope with respect to what the active ingredient contains. Excipients may remain permissible, but additional pharmacologically active components would be more likely problematic.
What is the most sensitive infringement parameter in RE41571?
The combination of mean release rates (pre- and post-72h) and mean plasma concentrations at multiple timepoints (6h through 168h).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	336212	⤷ Start Trial
Austria	538765	⤷ Start Trial
Austria	556682	⤷ Start Trial
Australia	2004218685	⤷ Start Trial
Australia	2008261134	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: RE41571

Summary for Patent: RE41571