Last Updated: July 10, 2026

Patent: 10,046,081


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Summary for Patent: 10,046,081
Title:Electrospun dextran fibers and devices formed therefrom
Abstract: The invention generally relates to dextran fibers which are preferably electrospun and devices formed from such fibers. In particular, such devices may include substances of interest (such as therapeutic substances) associated with the electrospun fibers. Upon exposure to a liquid the electrospun fibers dissolve immediately and the substances of interest are released into the liquid. Exemplary devices include bandages formed from electrospun dextran fibers and associated agents that promote hemostasis, such as thrombin and fibrinogen.
Inventor(s): Bowlin; Gary (Mechanicsville, VA), Simpson; David (Mechanicsville, VA), Bowman; James (Richmond, VA), Rothwell; Stephen (Richmond, VA)
Assignee: The Henry M Jackson Foundation for the Advancement of Military Medicine, Inc. (Rockville, MD) Virginia Commonwealth University (Richmond, VA)
Application Number:14/445,566
Patent Claims:see list of patent claims
Patent landscape, scope, and claims summary:

Executive summary
US 10,046,081 centers on a layered hemostatic matrix built from electrospun dextran fibers, with thrombin in a first dextran layer and fibrinogen in a physically separated second dextran layer, stacked so the enzymes remain separated until use. Claims also narrow to (i) optional top dextran coverage, (ii) multilayer counts (about 5 to 10), (iii) moisture-limited first-layer dextran to retain thrombin, (iv) adjacency of a selected backing/support material, and (v) human thrombin/human fibrinogen. The patent’s enforceability in the US turns on whether an accused product maintains thrombin and fibrinogen separation by structure (layering) and whether it uses electrospun dextran fibers (or functional substitutes that could still be argued as “consisting of” dextran fibers).

Below is a critical, claim-by-claim landscape and infringement-risk analysis for US 10,046,081, with practical generic entry risks and workaround paths.


US 10,046,081 claim scope: what patents protect a dextran electrospun thrombin–fibrinogen separated-layer hemostatic product?

What is the core inventive concept in US 10,046,081?

The independent claim 1 is structured around five limiting elements that jointly define infringement:

  1. Hemostatic product with two hemostatic layers.
  2. Each layer’s scaffold is a “dextran support consisting of electrospun dextran fibers.”
  3. Layer 1 contains thrombin placed on the first electrospun-dextran scaffold.
  4. Layer 2 contains fibrinogen placed on the second electrospun-dextran scaffold.
  5. Stacked configuration where thrombin is separate from fibrinogen.

That separation is not described as “functional” separation. It is asserted as a physical arrangement: two layers placed in a stacked configuration such that the thrombin is separate from the fibrinogen. In litigation, that typically pushes construction toward: (a) no direct contact between thrombin-containing and fibrinogen-containing regions in the finished product, and (b) separation achieved by the layered assembly rather than only by “slow mixing” or formulation kinetics.

How do dependent claims narrow the protection?

Claims 2–6 add composition and architecture limitations; claims 3–5 add quantitative and materials constraints; claims 6 adds biologic sourcing; claims 2 and 5 add additional layers/backing adjacency.

  • Claim 2 adds a top dextran support covering the second hemostatic layer.
  • Claim 3 limits to about 5 to 10 hemostatic layers (which implies a specific “repeat-stack” architecture, not just a single thrombin layer and a single fibrinogen layer).
  • Claim 4 limits the moisture content of the first dextran support to up to 5% by weight, and ties that to thrombin retention due to moisture-thrombin interaction.
  • Claim 5 introduces a support material selected from a closed list (gauze, electrospun dextran, polyglycolic acid polymers, polylactic acid polymers, caprolactone polymers, charged nylon), with the first hemostatic layer adjacent the support material.
  • Claim 6 requires human thrombin and human fibrinogen.

Method claims are “process-mirror” and inherit the same structure

Claim 7 mirrors claim 1 with a fabrication sequence: prepare a first layer with thrombin on electrospun dextran fibers; prepare a second layer with fibrinogen on electrospun dextran fibers; stack so thrombin is separate from fibrinogen. Claims 8–10 add the same incremental limitations (top dextran cover; 5–10 layers; and adjacency of a specific support material to the first layer).

In practice, this matters because process claims can be easier to prove via manufacturing records, incoming raw-material specs, and validated assembly procedures than finished-product internal structure. But they still require the same “consisting of electrospun dextran fibers” and “separate” arrangement.


Claim-by-claim: what each limitation means for infringement risk and design-around

Claim 1: “two electrospun dextran layers with separated thrombin and fibrinogen”

Key infringement hinges

  • Electrospun dextran fibers are required by “consisting of.” This is a strong narrowing phrase. Many competitors in the space use blended polysaccharide matrices, nonwoven meshes, or electrospun fibers of other polymers (or dextran mixed into another polymer). If the accused product’s fiber scaffold is not “dextran fibers” that constitute the support, that is a primary path to avoid literal infringement.
  • Physical separation: layered stacking that keeps thrombin separate from fibrinogen in the finished hemostatic product. A product that is fully pre-mixed (thrombin and fibrinogen together, then activated by blood contact) would not meet “separate,” but typical flowable sealants often mix in the package or upon contact. A layered dry patch can qualify if structurally separated.

Nontrivial doctrine-of-equivalents pressure Even with “consisting of,” plaintiffs can argue equivalents if the accused scaffold uses electrospun dextran-like fibers that perform the same support role. Defense counsel will counter that “consisting of” limits what can be present in the support material itself.

Claim 2: top dextran support covering the second layer

This is a structural add-on. If an accused product has only a bottom backing and a thrombin/fibrinogen sandwich without a top dextran cover, claim 2 likely fails. But claim 1 could still be asserted if the top dextran cover is not required.

Claim 3: 5–10 total hemostatic layers

This adds a numeric architecture limit. Many commercial products are 2-layer (one thrombin, one fibrinogen) or even single-layer. A layered “repeat” stack with 5–10 layers increases surface area and could map more closely to patch manufacturing approaches.

For infringement, a patentee will likely argue: “count hemostatic layers” means each thrombin or fibrinogen layer segment in the stacked assembly. A defendant can avoid by using fewer than 5 or more than 10.

Claim 4: moisture content ≤5% in first dextran support

This is a manufacturing-spec claim with a tether to function (moisture-retained thrombin). For infringement, the practical question becomes whether the accused product’s first dextran support has moisture content at or below 5% by weight at relevant times (often at packaging or during shelf life).

A design-around is to formulate with higher moisture content (outside the limitation) or to control retention via other mechanisms (e.g., crosslinking, binding agents, enzyme stabilization chemistries). The limitation is not “any stabilizer,” it is specifically moisture content plus claimed retention behavior.

Claim 5: adjacency to a support material from a closed list

This claim narrows by the backing/adjacent support. It also uses a closed “selected from” group. If an accused product’s backing is outside that list (e.g., different nonwoven polymer, metallic reinforcement, collagen sponge, or a hybrid not captured), claim 5 likely fails, while claim 1 may still hold if claim 1 does not require a listed backing.

Claim 6: human thrombin and human fibrinogen

This narrows source. If the accused product uses recombinant human thrombin/fibrinogen sourced as “human,” it stays within. If it uses bovine or animal-sourced materials, claim 6 can be avoided, though claim 1 may still be asserted unless claim 1 already requires human proteins (it does not).

Claim 7: method of preparing with layered separation

This method claim is tightly aligned to the product structure. It requires:

  • thrombin placed on a first electrospun dextran support
  • fibrinogen placed on a second electrospun dextran support
  • stacked so thrombin is separate from fibrinogen

Claim 8–10: dependent method constraints

  • Claim 8 adds top dextran cover.
  • Claim 9 adds 5–10 hemostatic layers.
  • Claim 10 adds specific backing material adjacent to the first hemostatic layer.

What is the US patent estate around electrospun dextran and separated thrombin/fibrinogen layers?

Adjacent technology cluster

US 10,046,081 sits in a dense intersection of:

  • hemostatic patch concepts using thrombin–fibrinogen clotting systems
  • barrier/compartmentalized delivery to avoid premature clotting
  • electrospun scaffold materials (dextran or other polymers)
  • enzyme stabilization (moisture control, drying, storage stability)

The risk to competitors is that even if they avoid the exact material system (dextran electrospinning), they can still collide with broader hemostatic compartmentalization patents. Conversely, if competitors use electrospun dextran scaffolds, the “separate thrombin and fibrinogen in stacked layers” requirement makes physical assembly design critical.

How this patent likely interfaces with earlier and later US filings

In enforcement, the typical landscape expectation is:

  • earlier patents on dry hemostatic patches with separated clotting components
  • separate families on electrospun dextran as a tissue engineering/hemostatic scaffold
  • later improvements on moisture control, multilayer repeats, and backing materials

US 10,046,081’s differentiator is the combination: electrospun dextran fibers as both enzyme-scaffold supports plus stacked separation.


Orange Book status and FDA pathway: what does US 10,046,081 likely attach to?

No in-scope data is provided here for:

  • a specific marketed product name
  • NDA/BLA/ANDA number
  • Orange Book listing entry number
  • FDA approval date
  • listed patents for that specific product

Without those, no accurate Orange Book mapping can be produced to link US 10,046,081 to a particular FDA approval, formulation, or clinical indication.


Patent strength assessment: how strong is enforcement likely to be for US 10,046,081?

Strength factors

  • Clear, structural limitations (two layers, electrospun dextran, thrombin on one, fibrinogen on the other, stacked separation) reduce ambiguity in claim construction.
  • “Consisting of electrospun dextran fibers” adds material boundary leverage.
  • Method claims track product structure, supporting proof of infringement through manufacturing.

Strength vulnerabilities

  • “Separate” can be litigated: how much separation is required? A defense may argue that minor bleed-through or diffusion could still meet “separate” depending on the patentee’s stated functional aim and claim construction standard.
  • Moisture content (≤5%) is a measurable parameter but also a timing-based one. Storage and testing conditions can be a focal point.
  • Layer counting (5–10) is a numeric limit that may narrow coverage materially. If competitors keep designs at 2 layers, claim 3 becomes non-assertable for those products.
  • Human protein sourcing (claim 6) can create partial avoidance if animal thrombin/fibrinogen is used.

Overall practical enforceability

  • For products that use electrospun dextran scaffolds and preclude thrombin-fibrinogen contact through layered assembly, US 10,046,081 provides credible infringement hooks.
  • For products using different fibrous supports (non-dextran, blended matrices, or non-electrospun scaffolds), “consisting of electrospun dextran fibers” is the fastest escape route.

How many patents cover this approach and who are the likely competitors?

No claim-coverage count or competitor list can be generated from the information provided. A comprehensive cross-patent count requires the full US family listing (application numbers, publication numbers, continuations) and third-party patent search results tied to the same active hemostatic mechanism and delivery architecture.

Given only the claim text for US 10,046,081, the only defensible statement is that the estate around this area is crowded and typically includes multiple overlapping “component separation” and “hemostatic scaffold” families, but those cannot be enumerated accurately here.


Generic and biosimilar entry risks: can competitors launch around US 10,046,081?

If a competitor wants to replicate the hemostatic function

Key design-around levers (mapped to the claims):

  1. Replace electrospun dextran fibers
    • If the support is not “electrospun dextran fibers consisting of dextran fibers,” literal claim 1 fails.
  2. Allow mixing or pre-contact of thrombin and fibrinogen within the same layer
    • If finished product does not satisfy “thrombin separate from fibrinogen,” claim 1 fails.
  3. Alter layer architecture count
    • Stay outside “about 5 to 10” if claiming claim 3/9 coverage.
  4. Control moisture outside ≤5% for first layer
    • Avoid claim 4 by stabilizing thrombin through chemistry or formulation, or by operating with higher moisture content.
  5. Use a different backing material
    • Avoid claim 5/10 by selecting a support not within the closed list.

Timing for entry

No FDA approval or patent expiration schedule is provided. A precise exclusivity timeline or Paragraph IV strategy cannot be produced without:

  • the Orange Book listing for the associated product
  • listed patent numbers and their expiration dates
  • any FDA exclusivity periods (e.g., orphan, pediatric, 505(b)(2) exclusivity) tied to the same product

What patent litigation affects US 10,046,081?

No litigation docket, district court case number, PTAB history, IPR/PGR, or settlement is provided. A “patent litigation affects” section cannot be completed accurately for US 10,046,081 from the provided inputs.


Key Takeaways

  • US 10,046,081’s enforceability is structurally anchored: electrospun dextran fiber supports with thrombin in one layer and fibrinogen in a physically separated stacked layer.
  • Dependent claims narrow coverage through top dextran coverage, multilayer count (about 5–10), first-layer moisture content (≤5% by weight), adjacency to a closed list of backing materials, and human protein sourcing.
  • Most viable design-arounds are: swap out the electrospun dextran scaffold, change the separation architecture so thrombin and fibrinogen are not “separate” in the finished product, move away from the 5–10 layer structure, or avoid the moisture and backing limitations.
  • Process claims track the product and can support enforcement if manufacturing records confirm the same layered separation and scaffold composition.

FAQs

  1. What does “dextran support consisting of electrospun dextran fibers” exclude in an accused hemostatic patch?
  2. How would courts likely interpret “thrombin is separate from fibrinogen” in a stacked multi-layer assembly?
  3. What evidence is most persuasive to prove a first-layer dextran moisture content “up to 5% by weight”?
  4. Can a competitor infringe claim 1 while avoiding claim 3 by using only 2 layers?
  5. How do backing materials outside the “selected from” list affect infringement of claim 5 and claim 10?

References (APA)

  1. Claims of US Patent 10,046,081 as provided in the prompt.

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Details for Patent 10,046,081

Applicant Tradename Biologic Ingredient Dosage Form BLA Approval Date Patent No. Expiredate
Omrix Biopharmaceuticals Ltd EVITHROM thrombin, topical (human) Solution 125247 August 27, 2007 10,046,081 2034-07-29
Omrix Biopharmaceuticals Ltd EVITHROM thrombin, topical (human) For Injection 125247 September 17, 2009 10,046,081 2034-07-29
Csl Behring Gmbh RIASTAP fibrinogen concentrate (human) For Injection 125317 January 16, 2009 10,046,081 2034-07-29
Octapharma Pharmazeutika Produktionsges.m.b.h. FIBRYGA fibrinogen (human) For Injection 125612 June 07, 2017 10,046,081 2034-07-29
>Applicant >Tradename >Biologic Ingredient >Dosage Form >BLA >Approval Date >Patent No. >Expiredate

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