United States Patent 8,221,785 (Transdermal Contraceptive Patch): Scope, Claim Map, and Landscape
What does US Patent 8,221,785 claim in scope?
US 8,221,785 claims a transdermal contraceptive delivery system (patch) built from:
- a backing layer, and
- an adhesive polymer matrix affixed to the backing layer,
with the adhesive polymer matrix defined by a specific formulation stack that combines:
- Adhesive polymer chemistry (polyacrylate copolymer; and in dependent claims, 2-ethylhexyl acrylate and vinyl acetate content)
- Humectant system (polyvinylpyrrolidone or PVP/vinyl acetate)
- Skin permeation enhancer package (DMSO + fatty lactic acid ester + lower lactic acid ester + capric acid, each with tight wt% bands)
- Actives: levonorgestrel plus ethinyl estradiol or 17β-estradiol
- In one dependent branch, a delivery-rate regime for both hormones and a patch size embodiment
The claims are formulation-and-structure driven, with the highest enforceability weight concentrated in the “consisting essentially of” enhancer compositions and adhesive/humectant definitions.
What are the independent claim boundaries (Claim 1)
Claim 1 recites the baseline system and the core formulation limits.
System structure
- “A transdermal contraceptive delivery system comprising a backing layer and an adhesive polymer matrix affixed to the backing layer.”
Adhesive polymer matrix components
- (a) Adhesive polymer: “polyacrylate copolymer”
- (b) Humectant: “polyvinylpyrrolidone”
- (c) Skin permeation enhancing agents “consisting essentially of” the following wt% ranges on a final percentage by weight of the adhesive polymer matrix after fabrication:
- Dimethyl sulfoxide (DMSO): 4% to 12%
- Fatty (C8-C20) alcohol ester of lactic acid: 4.2% to 12.6%
- Lower (C1-C4) alkyl ester of lactic acid: 0.7% to 2.3%
- Capric acid: 3% to 9%
- (d) Levnonorgestrel
- (e) Ethinyl estradiol or 17β-estradiol
Claim 1 scope takeaways
- The independent claim does not require a particular adhesive monomer (beyond “polyacrylate copolymer”) in Claim 1.
- The independent claim does require the enhancer package to be “consisting essentially of” the four listed enhancer materials in the specified wt% windows.
- The independent claim is not restricted to a patch size or a specific dosing rate of hormones.
How dependent claims tighten scope (key claim variants)
The dependent claims implement layered constraints that narrow the product boundary.
Monomer-specific adhesive polymer (Claims 2-3)
- Claim 2: adhesive copolymer comprises a 2-ethylhexyl acrylate monomer.
- Claim 3: polyacrylate adhesive copolymer further comprises 3% to 60% w/w vinyl acetate.
These dependents matter for design-around: a generic “polyacrylate” is enough for Claim 1, but Claim 2 and Claim 3 require the specific monomer and vinyl acetate fraction.
Adhesive matrix thickness (Claim 4)
- Claim 4: adhesive polymer matrix has a cross-sectional dimension of 10 to 300 microns.
This introduces a manufacturing/geometry constraint that can be a meaningful non-infringement lever if measured in the accused product.
Specific enhancer ester choices (Claims 5-6)
- Claim 5: fatty alcohol ester of lactic acid is lauryl lactate.
- Claim 6: lower alkyl ester of lactic acid is ethyl lactate.
These are not required by Claim 1, but they are required by the dependent branches, and they affect literal infringement for products that use different lactic esters.
Actives delivery rates and regimen timing (Claim 7)
- Claim 7 requires ethinyl estradiol and specifies transdermal delivery:
- Ethinyl estradiol: at least 10 mcg/day but no more than 50 mcg/day, for more than one day to about one week
- Levonorgestrel: about 30 mcg/day for more than one day to about one week
This is a strong regimen-dependent limitation that can narrow enforcement if an accused system differs in delivery rates or patch wear schedule.
Humectant chemistry upgrade to PVP/vinyl acetate (Claims 8-9)
- Claim 8: humectant is polyvinylpyrrolidone/vinyl acetate.
- Claim 9: PVP and vinyl acetate in the humectant mixture are about equal weight percent.
This shifts from the Claim 1 humectant requirement (PVP only) to a copolymer humectant architecture.
Patch diameter embodiments (Claim 10)
- Claim 10: patch diameter 7.5 cm², 10 cm², or 12.5 cm².
This affects literal match for consumer-facing product formats.
A parallel independent branch with tighter enhancer envelope (Claims 11-15)
Claim 11 restates an independently framed system with more specific formulation constraints:
- (a) adhesive polymer: polyacrylate adhesive copolymer with 2-ethylhexyl acrylate and 3% to 60% w/w vinyl acetate
- (b) humectant: polyvinylpyrrolidone/vinyl acetate copolymer
- (c) enhancer combination: between 12% and 36% by weight of adhesive polymer matrix, “consisting essentially of”:
- DMSO 4% to 12%
- lauryl lactate 4.2% to 12.6%
- ethyl lactate 0.7% to 2.3%
- capric acid 3% to 9%
- (d) levonorgestrel
- (e) ethinyl estradiol
Claims 12-13 narrow the enhancer composition total and each component band.
-
Claim 12: enhancer total 18% to 30%, “consisting essentially of”:
- DMSO 5% to 11%
- lauryl lactate 5.2% to 11.6%
- ethyl lactate 1% to 2%
- capric acid 4% to 8%
-
Claim 13: enhancer total 21% to 27%, “consisting essentially of”:
- DMSO 6% to 10%
- lauryl lactate 6.2% to 10.6%
- ethyl lactate 1.2% to 1.8%
- capric acid 5% to 7%
Claim 14 adds humectant MW and ratio constraints:
- humectant is PVP/vinyl acetate copolymer:
- molecular weight at least 50,000
- comprises about equal weight percents of PVP and vinyl acetate
- adhesive polymer and enhancer composition aligned with Claim 13 bands (as restated in Claim 14)
Claim 15 sets “most specific” exemplar composition:
- enhancer package equals, by wt% on final adhesive matrix:
- 8% DMSO
- 8.4% lauryl lactate
- 1.5% ethyl lactate
- 6% capric acid
This is the strongest literal hook. A product that matches Claim 15 composition lands in a very narrow infringement space.
Where is the infringement risk highest? (practical claim mapping)
Risk concentrates where an accused transdermal contraceptive patch matches all of:
- the adhesive system class (polyacrylate copolymer),
- the humectant family (PVP or PVP/vinyl acetate),
- the specific enhancer package and “consisting essentially of” constraint, and
- levonorgestrel + ethinyl estradiol (or 17β-estradiol).
Within that set, enforcement is strongest for combinations that also match:
- 2-ethylhexyl acrylate (Claim 2/11/14),
- vinyl acetate fraction (Claim 3/11/14),
- specific ester identities (lauryl lactate and ethyl lactate),
- enhancer wt% band (Claim 12/13) or exemplar exact wt% (Claim 15),
- dose delivery rates and wear duration window (Claim 7),
- adhesive thickness (Claim 4),
- and patch area (Claim 10).
What does “consisting essentially of” operationally do here?
The enhancer package is framed as “consisting essentially of” four items, which constrains the permissibility of other permeation-enhancing agents in the enhancer portion. In practice for freedom-to-operate analysis, this means:
- literal infringement is favored if the system uses the same four enhancer components,
- and literal infringement is endangered if the accused formulation includes additional enhancers that are not “essentially” encompassed by the claim language and are outside the stated four-part set.
The “final percentage by weight after fabrication” also ties the infringement analysis to post-manufacturing formulation, not just ingredient charge.
What is the “patent landscape” positioning for this family?
A full landscape requires the specific bibliographic record (application number, priority chain, publication numbers, assignee, and prosecution history) for US 8,221,785, plus citation trees and related continuation or divisional filings. That bibliographic record is not included in the provided input, and the claim text alone is insufficient to correctly identify:
- family members,
- related continuations,
- examiner cited references,
- and co-pending competitor patents.
Because accurate landscape mapping depends on those identifiers, no reliable claim-to-family or prior-art correlation can be produced from the claim set alone without introducing unsupported assertions.
Key Takeaways
- Core claim center: A transdermal contraceptive patch with polyacrylate adhesive matrix + PVP/PVP-vinyl acetate humectant + a four-component permeation enhancer package (DMSO + lauryl lactate + ethyl lactate + capric acid) defined by tight wt% ranges and “consisting essentially of” language.
- Highest enforcement hook: Dependent refinements culminate in Claim 15, which locks a specific enhancer composition: 8% DMSO / 8.4% lauryl lactate / 1.5% ethyl lactate / 6% capric acid.
- Most significant variability levers for design-around: change the humectant architecture (PVP vs PVP/vinyl acetate), alter adhesive monomer system (2-ethylhexyl acrylate and vinyl acetate content), shift enhancer wt% outside the claimed bands, or change dose delivery rates/wear time (Claim 7).
- Landscape limits: A defensible US patent landscape cannot be completed from claim text alone because it requires the official bibliographic record and citation/prosecution dataset for US 8,221,785.
FAQs
1) Does Claim 1 require lauryl lactate and ethyl lactate specifically?
No. Claim 1 requires “fatty (C8-C20) alcohol ester of lactic acid” and “lower (C1-C4) alkyl ester of lactic acid” within wt% ranges. Specific species (lauryl lactate, ethyl lactate) appear in dependent claims (Claims 5 and 6).
2) What is the limiting enhancer language that most constrains formulations?
The enhancer components are defined as a “combination … consisting essentially of” four materials (DMSO, lactic acid fatty ester, lactic acid lower alkyl ester, capric acid) with specific wt% ranges on a post-fabrication basis.
3) Which claim is the tightest on exact enhancer percentages?
Claim 15, which recites an exemplar exact enhancer composition: 8% DMSO, 8.4% lauryl lactate, 1.5% ethyl lactate, 6% capric acid.
4) Can a product avoid infringement by changing the estradiol form?
Claim 1 covers ethinyl estradiol or 17β-estradiol. Dependent Claim 7 is specific to ethinyl estradiol with delivery-rate bounds. Avoiding Claim 1 via estradiol substitution is not straightforward because Claim 1 explicitly includes 17β-estradiol.
5) Does patch size matter for infringement?
Patch size appears as a limitation in dependent Claim 10 (7.5 cm², 10 cm², 12.5 cm²). It is not required by Claim 1, so it only constrains infringement for the dependent-claim coverage.
References
[1] Claim text for US Patent 8,221,785 as provided in the prompt.
