Scope and Claiming Power of US Drug Patent 4,563,184 (Wound Dressings Using Poly(2-hydroxyethylmethacrylate) + PEG + Hydrogen-Bonding Plasticizers Like DMSO)
US Patent 4,563,184 claims a wound dressing composition and related treatment method built around a specific polymer/solvent matrix and a “hydrogen bonding plasticizer” (with dimethylsulfoxide (DMSO) as a core embodiment), with quantitative weight ranges and downstream coverage for film/bandage formats, adherent substrates, and optional medicaments (including silver sulfadiazine, nitrofurazone, silver nitrate, and mafenide acetate). The patent’s enforceable center of gravity is a composition claim family (claims 1–3, 6–18, 26, 28, 29 and dependent process claims) that is broad on plasticizer identity but narrow on the polymer class, polymer:solvent ratios, and PEG identity/constraints. The method-of-use claims are structurally broad (apply the film/bandage made from the claimed components) but are likely limited by proof that an accused dressing is made using the claimed matrix and weight ranges, and by the fact that several dependent claims lock key parameters (PEG MW, polymer identity, set-up-time behavior).

What is US Patent 4,563,184 and what does it claim?

US 4,563,184 is directed to synthetic resin wound dressings (including preformed film/bandage types) made from:

a particulate, hydrophilic, water-swellable polymer of an acrylate or acrylamide,
an inert, non-toxic, water-miscible organic solvent of polyethylene glycol (PEG), and
a hydrogen bonding plasticizer that is mixed with the polymer/PEG system (DMSO is the primary recited exemplar).

Core inventive concept (as framed by the claims)

The improvement is the use of a hydrogen bonding plasticizer mixed into the polymer/PEG dressing such that the system forms a flexible, elastic, adherent, film/bandage with controlled occlusivity and practical set-up/cure behavior.

What are the key composition claim ranges and what do they capture?

Quantitative backbone that drives infringement risk

Across claims 1–3 and 6, the composition is limited to:

Polymer (acrylate/acrylamide; water-swellable): 30% to 55% by weight of the dressing
PEG solvent: 20% to 60% by weight of the dressing
Hydrogen bonding plasticizer: up to ~20% by weight of the dressing

This triangle (polymer 30–55 / PEG 20–60 / plasticizer ≤20) is the main structural limitation that differentiates this patent from generic hydrogel/PEG based film dressings.

Claim 1 and 2: what’s broad vs specific?

Claim 1: combination in a “synthetic resin wound dressing of the bonding type,” where plasticizer is hydrogen bonding plasticizer of dimethylsulfoxide and weight fractions match the backbone ranges.
Claim 2: same structural dressing, but plasticizer is selected from an enumerated group including DMSO and additional hydrogen-bonding candidates (dimethylphthalate, 2,3-butylene carbonate, dimethylformamide, dimethyltetramethylene sulfone, diethylsulfone, methylene glycolate, methylpropyl sulfone, butyrolactone).

Enforcement takeaway: claim 2 is broader than claim 1 on plasticizer identity but still constrained by the PEG/polymer ratio and PEG class requirement.

Which polymers and PEG specifications are actually required?

Polymer identity constraints that narrow the “acrylate/acrylamide” umbrella

The independent claims use broad language (acrylate or acrylamide; hydrophilic; water swellable) but several dependent claims meaningfully narrow polymer identity:

Claim 6: explicitly requires poly(2-hydroxyethylmethacrylate)
Claims 7–8: specify polymer = poly(2-hydroxyethylmethacrylate; PEG molecular weight ~200–2000
Claim 11–12: provides an expanded but still bounded list of polymer backbones (hydroxyalkyl methacrylates/acrylates, alkoxy variants, N-alkyl acrylamides, crosslinkable/vicinal-epoxy variants) and requires, in claim 12, that polymer is “at least slightly crosslinked” and has MW ≥ 50,000 (only in the dependent layer)

Enforcement takeaway: the “acrylate/acrylamide” language gives claim 1–3 conceptual breadth, but practical claim strength and proof will hinge on whether an accused product uses a polymer captured by the recited polymer class and, in many likely infringement scenarios, the specific PH... HEMA-type matrices described in the dependent claims.

PEG constraints

PEG is the solvent and is required as “water miscible organic solvent of polyethylene glycol” in the independent claims. Dependent claims add:

Claim 14–16: PEG formula H(OCH2CH2)nOH with n ≥ 4; PEG MW ~200–2000; and a narrower range ~200–800 (claim 16)

Enforcement takeaway: products that substitute different solvents (non-PEG plasticizers, co-solvents not falling within “solvent of polyethylene glycol,” or different diols) may fall outside, depending on how strictly courts construe “solvent of polyethylene glycol” in the accused dressing.

What plasticizers are claimed besides DMSO, and how is the claim scope affected?

Enumerated plasticizer list (Claim 2)

Claim 2 expands beyond DMSO to a defined group:

dimethylsulfoxide
dimethylphthalate
2,3-butylene carbonate
dimethylformamide
dimethyltetramethylene sulfone
diethylsulfone
methylene glycolate
methylpropyl sulfone
butyrolactone

Solubility parameter limitation (Claim 13)

Claim 13 adds a physico-chemical constraint: plasticizer has solubility parameter ~10.7 to 12.6.

Enforcement takeaway: claim 2 is identity-based (enumeration) while claim 13 is property-based. If an accused plasticizer is not one of the nine listed, it cannot satisfy claim 2 as written. If it is listed, solubility parameter constraints likely matter only for narrower dependent claim coverage.

Are film/bandage formats covered, and what structural elements matter?

Yes. The patent spans both bonding and preformed film/bandage architectures.

Bonding type (Claim 1)

Claim 1 ties to “bonding type” dressings where polymer/PEG forms a paste and DMSO plasticizes the matrix.

Preformed film/bandage type (Claim 3)

Claim 3 is directed to “preformed film type bandage” bandages:

the polymer/solvent/plasticizer are mixed and cured to form a bandage with controlled flexibility and elasticity
with an adherent surface
and includes optional rigid format constraints (set-up and storage in bandage form)

Substrate layer and stretchability (Claims 9–10)

Claim 9: dressing comprises a substrate with a layer of the paste applied to one face
Claim 10: substrate is biaxially stretchable

Enforcement takeaway: competitors that apply the claimed matrix directly to skin without a substrate layer may still meet claim 3, but substrate-specific dependent coverage (claims 9–10) would be harder for them.

How are medicated wound dressings covered?

Medicaments are expressly optional but claim-scaffolded

Claim 4 adds medicaments as a further ingredient in the dressing, selecting from a broad therapeutic list:

germicide, fungicide, antimicrobial, antibiotic, analgesic, hormone, anti-inflammatory, cardiovascular, anticonvulsant, pulmonary, muscle relaxant

Dependent medicament-specific claims lock in famous burn/wound actives:

Antimicrobials

Silver sulfadiazine (claims 17–18): 0.5% to 7% by weight
Nitrofurazone (claims 21–22): 0.5% to 10%
Silver nitrate (claims 23–24): 0.5% to 10%
Mafenide acetate (claims 26–27): 0.5% to 10%

“Consists essentially of” scope (Claim 25)

Claim 25 limits antimicrobial species to silver sulfadiazine, nitrofurazone, or silver nitrate with 0.5% to 10% by weight.

Enforcement takeaway: the “consists essentially of” language can be favorable to enforceability against formulations that include the specified actives plus additional components deemed more than incidental. It can also complicate infringement if accused products use different antimicrobial combinations.

System-level preformed film with specific medicaments (Claim 28)

Claim 28 is a composite “all-in-one” claim:

preformed polymer film = poly(hydroxyethylmethacrylate)
PEG solvent
DMSO plasticizer
medicament = silver sulfadiazine, nitrofurazone, silver nitrate, or mafenide acetate (or combinations)
weight ranges for polymer/PEG/plasticizer and medicament 0.5–10%

Enforcement takeaway: claim 28 provides a high-proof pathway where the accused product looks like a classic PH...HEMA/PEG/DMSO medicated film.

What process and method-of-use claims exist, and what must an accused party prove?

The patent includes a method of treating a wound site by applying a dressing made from the claimed composition.

Treatment process (independent Claim 29)

Claim 29 requires:

applying a “synthetic resin film type bandage wound dressing” to the wound site
dressing consists essentially of:
- particulate hydrophilic water swellable polymer (acrylate/acrylamide)
- inert non-toxic water miscible PEG solvent
- hydrogen bonding plasticizer selected from the enumerated group (same as claim 2)
plus weight ranges for polymer/PEG/plasticizer
film provides “flexible adherent film dressing”

Additional steps (dependent Claims 30–33)

mixing forms a “settable paste”
applying to adherent substrate and curing (claim 31)
applying to non-adherent surface and curing (claim 32)
optional adding medicaments (claim 33)

Wound type and antimicrobial examples (Claims 38–39)

claim 38: dressing applied to a burn wound site
claim 39: antimicrobial such as silver sulfadiazine / silver nitrate / nitrofurazone / mafenide acetate; antimicrobial up to ~10%

Enforcement takeaway: method-of-use infringement is conditioned on (i) the accused dressing being the claimed “consists essentially of” matrix and (ii) use in the claimed treatment context. “Consists essentially of” can narrow what other excipients are allowed in the dressing.

How strong is the patent estate conceptually, based on claim structure?

Strength drivers

Clear quantitative ratios (polymer 30–55; PEG 20–60; plasticizer up to 20%) create a measurable infringement test.
Plasticizer identity is either fixed (DMSO in claim 1) or enumerated (claim 2), limiting design-around by substituting an unlisted hydrogen-bonding compound.
Material-specific dependent claims (PH...HEMA, PEG MW, DMSO set-up-time effect) create escalation paths for proving infringement once a product aligns with the exemplified formulation.
Medicinal actives are named with explicit concentration ranges, which matters in enforcement because composition matching is the easiest discovery target.

Vulnerability drivers

If accused products:
- use non-PEG solvents,
- use polymer outside the acrylate/acrylamide hydrophilic water-swellable class,
- or use plasticizers outside the enumerated set, then claim 1–3 and claim 29 may be avoided, at least for composition-based infringement.
For “preformed bandage cured” formats, an accused product must show a controlled cured film/bandage architecture rather than a different manufacturing route, to cleanly fit claim 3 and related dependent structure.

How do the claims partition into practical infringement “buckets”?

Bucket A: Pure composition claims (non-medicated)

Primary: claims 1–3
Supporting dependent: claims 6–16 (PH...HEMA + PEG MW; set-up-time relationship; polymer lists; solubility parameter)

Bucket B: Medicament-loaded dressings

Primary: claim 4 plus medicament-specific dependent claims 17–27
High-fit composite: claim 28

Bucket C: Methods of using the dressing

Primary: claim 29
Narrowing: claims 30–39 for paste formation, substrate deposition, burn site, and antimicrobial exemplars

What does the claim wording imply about “set-up time” and occlusive film formation?

Claim 6 states DMSO amount “directly controlling”:

set-up of the composition into a “substantially occlusive film”
set-up time decreasing with increased DMSO, from < 30 seconds at maximum to ~45 minutes at minimum

This is a dependent functional relationship. It can be used to align proof with a DMSO-containing product. It also gives a design-around cue: change formulation behavior by reducing DMSO concentration or altering the matrix.

Key tables: claim elements mapped to enforceability tests

Table 1. Claim 1–3 composition core elements

Claim	Dressing type	Plasticizer requirement	Polymer range	PEG range	Plasticizer cap
1	Bonding type	DMSO	30–55 wt%	20–60 wt%	up to 20 wt%
2	Bonding type	Enumerated hydrogen-bonding plasticizers	30–55 wt%	20–60 wt%	up to 20 wt%
3	Preformed film/bandage	DMSO	30–55 wt%	20–60 wt%	up to 20 wt%

Table 2. Medicament and concentration coverage

Medicament	Claim(s)	Concentration range
Silver sulfadiazine	17–18	0.5–7 wt%
Nitrofurazone	21–22	0.5–10 wt%
Silver nitrate	23–24	0.5–10 wt%
Mafenide acetate	26–27	0.5–10 wt%
“Consists essentially of” antimicrobial limited set	25	0.5–10 wt% (for listed actives)

What generic entry risks exist under these claims?

For a generic or follow-on product to risk literal infringement, it must align on all three pillars:

Polymer system captured by the claim (hydrophilic water swellable acrylate/acrylamide; with likely PH...HEMA relevance)
PEG solvent as the specified water miscible PEG component with the required weight fractions
Hydrogen bonding plasticizer identity and amount (DMSO for claim 1/3; enumerated list for claim 2/29)

Additional risk increases if the product is:

preformed cured bandage/film (claim 3)
substrate-applied with stretchable substrate (claims 9–10)
medicated with one of the named actives at the claimed concentration ranges (claims 17–27, 28)

A design-around likely focuses on shifting at least one pillar:

swap PEG for a different solvent system, or
move plasticizer outside the enumerated set, or
move polymer outside the listed acrylate/acrylamide water-swellable range, or
keep ratios outside the stated weight windows.

How does this patent compare internally across its claim layers (broad independent vs narrow dependent)?

This patent is drafted with a typical layered claim architecture:

Independent claims (1–3, 29) establish the formulation “triad” and architecture.
Dependent claims add precision around:
- polymer identity (PH...HEMA)
- PEG MW band (200–2000; 200–800)
- DMSO-mediated set-up timing
- polymer crosslinking and MW
- substrate type (biaxially stretchable)
- actives and concentration windows

From a litigation posture perspective, independent claims are for broad coverage; dependent claims create additional “landing zones” that support infringement findings if the accused product matches more closely to the exemplified formulation.

Key Takeaways

US 4,563,184 claims a wound dressing platform centered on a PEG + hydrophilic acrylate/acrylamide polymer matrix plasticized by hydrogen-bonding compounds, with DMSO as a core embodiment.
The dominant enforceability test is the quantitative formulation window: polymer 30–55 wt%, PEG 20–60 wt%, plasticizer up to 20 wt%.
The patent covers both bonding-type dressings and preformed cured bandage/film constructions, and it extends to medicated formulations using named burn/wound actives at specified ranges.
Method-of-use claims require applying a dressing that is the claimed “consists essentially of” matrix to a wound site, with burn wound use explicitly addressed in dependent claims.

FAQs

1) What does “hydrogen bonding plasticizer” mean in the context of this patent’s claim language?

It is a defined functional requirement supported by an explicit enumerated plasticizer list (claim 2) and a DMSO-centered embodiment (claims 1 and 3), with a solubility-parameter limitation in claim 13.

2) Are silver sulfadiazine and mafenide acetate covered only in medicated embodiments?

Yes. The medicaments enter via claim 4 (medicament agent selection) and are then locked with concentration ranges in claims 17–18 (silver sulfadiazine) and 26–27 (mafenide acetate), plus a combined film claim in claim 28.

3) Can a product avoid infringement by replacing DMSO with another solvent but keeping PEG?

Claim 1 and claim 3 specifically require DMSO as the hydrogen bonding plasticizer. Replacing DMSO may still risk claim 2 (if the substitute is one of the enumerated plasticizers), and claim 29 (if the substitute is within the same list).

4) Does this patent cover only preformed bandages or also in-situ forming pastes?

Both. Claim 29 supports applying a film type bandage formed from the paste formulation. Dependent claims 30–33 address mixing into a settable paste and curing onto adherent or non-adherent surfaces to make preformed bandages.

5) What claim element is most likely to be dispositive in composition matching?

The polymer/PEG/plasticizer weight ranges (and, for narrower coverage, specific polymer identity like poly(2-hydroxyethylmethacrylate) and PEG molecular weight bands).

References (APA)

United States Patent 4,563,184. (n.d.). Synthetic resin wound dressings.

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Australia	3362384	⤷ Start Trial
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Summary for Patent: 4,563,184