United States Patent 8,871,809: Scope, Claims, and US Patent Landscape for Diclofenac Sodium + DMSO Topical Pain Treatment
What does US 8,871,809 claim, in enforceable terms?
US Drug Patent 8,871,809 claims a method of treating pain by administering a specific topical liquid/semi-liquid formulation with tightly bounded composition ranges, dosing frequency, and formulation rheology.
At the claim level, this is not a claim to diclofenac alone, DMSO alone, or generic topical pain therapy. It is a claim to the combination of:
- Diclofenac sodium at 1 to 5% w/w
- DMSO at 25 to 60% w/w
- Formulation viscosity at 500 to 5,000 cP
- Twice daily administration
- And dependent claims narrow the formulation to a multi-solvent system (propylene glycol, ethanol, optional glycerine) plus a thickening polymer system (cellulose or carbomer families)
Claim 1 (core independent claim) controls breadth
Claim 1 recites a pain-treatment method with the formulation defined by four critical parameters:
1) Diclofenac sodium: 1-5% w/w
2) DMSO: 25-60% w/w
3) Viscosity: 500-5,000 centipoise
4) Dosing: twice daily
5) Intended outcome: “effectively treat pain”
This creates enforcement leverage where an accused product is used as a topical twice-daily pain therapy and its formulation overlaps the 1-5% diclofenac / 25-60% DMSO / 500-5,000 cP window.
Dependent claims create a layered “composition fence”
Dependent claims then lock in ingredient families and narrower numerical windows that define commercial design space.
What is the practical claim scope across composition parameters?
Parameter matrix (from the claims you provided)
| Parameter |
Where it appears |
Claimed range / limit |
Effect on scope |
| Diclofenac sodium |
Claim 1 |
1-5% w/w |
Baseline diclofenac loading window |
| Diclofenac sodium |
Claim 2 |
1.5 to 5% w/w (and fractions) |
Narrows low end above 1% |
| Diclofenac sodium |
Claim 3 |
member in 1%, 1.5%, 2% w/w plus fractions |
Numeric membership style narrowing |
| DMSO |
Claim 1 |
25-60% w/w |
Broad enabling DMSO corridor |
| DMSO |
Claim 2 |
30-60% w/w |
Narrows below 30% |
| DMSO |
Claim 4 |
40-50% w/w |
Tight intermediate sub-range |
| DMSO |
Claim 5 |
40-50% w/w broken into 40-50% integers (and fractions) |
Tightens design around “midrange” DMSO |
| Propylene glycol |
Claim 2 |
1-15% w/w |
Locks in cosolvent presence |
| Ethanol |
Claim 2 |
1-30% w/w |
Locks in cosolvent presence |
| Ethanol |
Claim 6 |
23-29% w/w |
Tight solvent window |
| Ethanol |
Claim 12 |
23-29% w/w (explicit) and Claim 15 26.5% |
Very tight sub-range |
| Optional glycerine |
Claim 2 and Claim 9 |
optional; “glycerine is present” in dependent |
Optionality affects infringement depending on formulation |
| Thickening agent (polymer family) |
Claim 2 |
at least one thickener selected from cellulose polymer/cellulose derivative/carbomer family |
Requires qualifying rheology modifier class |
| Thickening agent (carbomer) |
Claim 7 |
carbomer polymer/carbomer derivative |
Restricts to carbomer family |
| Specific carbomers |
Claim 8 |
carbopol 971, 981, 941, 1342, ultrez 10 |
Very specific enumerations |
| Thickening agent (cellulose) |
Claim 10 |
cellulose polymer/cellulose derivative |
Restricts to cellulose family |
| Specific cellulose thickener |
Claim 11 |
hydroxypropyl cellulose |
Very specific material |
| Viscosity |
Claim 1 |
500-5,000 cP |
Requires rheological overlap to avoid Claim 1 |
| Twice daily dosing |
Claim 1 |
fixed frequency: twice daily |
Behavior-based limitation |
How do claims 2, 7, 10, and 12 define branching fallback coverage?
The claims are structured so that an accused product can land under one of multiple dependent branches.
Claim 2 sets a “multi-solvent + polymer thickener” formulation
Claim 2 adds the required thickening agent class and includes:
- Diclofenac sodium 1.5–5%
- DMSO 30–60%
- Propylene glycol 1–15%
- Ethanol 1–30%
- Optional glycerine
- Water
- Thickening agent from cellulose polymer / carbomer polymer / derivatives (including “mixtures thereof”)
Claim 7 narrows the thickener to carbomer family
Claim 7 narrows claim 2 by requiring the thickener be carbomer-based.
Claim 8 then enumerates specific carbopol/ultrez grades.
Claim 10 and 11 narrow the thickener to cellulose family
Claim 10 narrows to cellulose polymers/derivatives.
Claim 11 narrows further to hydroxypropyl cellulose.
Claim 12 constructs a specific “numerical recipe” with exact solvent windows
Claim 12 requires:
- Diclofenac sodium: 1.5–5%
- DMSO: 40–50%
- Ethanol: 23–29%
- Propylene glycol: 10–12%
This is a tight formulation corridor. Claims 13 to 15 tighten diclofenac selection and ethanol numeric point.
What do the dosing and viscosity limits do to infringement risk?
Twice-daily administration
Claim 1 is a method-of-treatment with a behavioral component: the formulation is administered twice daily.
In practical infringement analysis, an accused product must be used at that dosing frequency as a pain treatment. If a label instructs once daily, twice daily is still potentially met if real-world use is twice daily under a therapeutic regimen, but enforcement risk typically tracks labeled instructions and IFU.
Viscosity 500–5,000 cP
Viscosity is an objective formulation property in Claim 1. It creates a clear engineering “exit ramp” if viscosity can be tuned out of range, though dependent claims do not restate viscosity (they depend on claim 1). That means the viscosity limitation remains part of all dependent coverage.
Which dependent claims add the strongest “design lock” constraints?
Based on numerical tightness and specificity:
1) Claim 12 (recipe-level lock): DMSO 40–50%, ethanol 23–29%, propylene glycol 10–12% with diclofenac 1.5–5%
2) Claim 6 and Claim 15 (ethanol lock): ethanol 23–29% and “26.5%” dependent point
3) Claim 8 (thickener material lock): carbopol 971/981/941/1342/ultrez 10
4) Claim 11 (cellulose thickener lock): hydroxypropyl cellulose
5) Claim 5 (DMSO granular membership): integers 40–50% plus fractions
6) Claim 3 (diclofenac membership): 1%, 1.5%, 2% plus fractions
How is pain usage characterized (claim 17)?
Claim 17 limits the method to pain “due to osteoarthritis.”
This is an additional target indication. An accused pain therapy for non-osteoarthritis indications may still infringe Claims 1-16 depending on therapeutic use and label/label-adjacent claims. Claim 17 narrows risk for osteoarthritis-specific labeling.
What is the scope impact of claim 16 (improved absorption)?
Claim 16 adds a functional statement: “improved absorption on a per dose basis compared to a comparative liquid composition.”
This kind of limitation can affect enforceability if the claim is construed to require that performance property. Practically, it creates an additional litigation axis: whether the formulation demonstrates comparative per-dose absorption improvement. It also gives the patentee room to argue that the claimed formulation is defined and that improved absorption is inherent to the composition.
US patent landscape: what products and claim themes are most likely to collide?
Without the full prosecution history, specification, and family member data, the most reliable landscape read is to map the claimed themes to known competitive design routes: topical diclofenac, DMSO-assisted transdermal penetration, and high-solvent topical gels/creams with polymer thickening.
Likely collision zones (high probability in competitive portfolios)
1) Topical diclofenac combined with high % DMSO
- The claimed DMSO span (25–60%) is unusually high for typical topical diclofenac products. Any competitor using DMSO within or near that corridor is within the “core chemical corridor.”
2) Vehicles using ethanol and propylene glycol at the claimed high solvent fractions
- Claim 2-6 and Claim 12 put ethanol and propylene glycol into a defined co-solvent system. Products with ethanol 23–29% and propylene glycol 10–12% are particularly exposed.
3) Viscosity-controlled semi-gel systems (500–5,000 cP) with carbomer or cellulose rheology modifiers
- Competitors often tune viscosity using polymers. The claim’s viscosity band is a direct overlap constraint, while polymer family limitations narrow design alternatives.
4) Twice-daily regimen labeling for pain
- Most topical analgesics are once or twice daily. The claim fixes twice daily; competitors labeled once daily reduce alignment risk.
Where competitors commonly design around this claim family
1) Move diclofenac outside 1–5% w/w
- Even shifting from 4–5% to above 5% or below 1% can avoid Claim 1, but dependent claims also contain enumerated bands.
2) Move DMSO outside 25–60% w/w
- Lowering to below 25% or raising above 60% avoids the core range.
3) Tune viscosity outside 500–5,000 cP
- This is a non-trivial design variable because solvent systems and polymer levels affect rheology and stability. Still, it is an explicit claim constraint.
4) Avoid the specified thickener classes or avoid the specific exemplified polymers
- Use a different rheology system not falling under “cellulose polymer/cellulose derivative/carbomer polymer/carbomer derivative,” or use a polymer outside the enumerations where dependence requires those specific agents.
5) Change the dosing frequency
- Labeling and instructions that support once-daily dosing can be a practical mitigation for method claims tied to twice daily.
6) Avoid the osteoarthritis-specific instruction
- This only matters for Claim 17; Claims 1-16 can still be asserted for general pain treatment.
Litigation posture: what this claim set signals
This patent is structured for enforcement around formulation overlap, not around novelty of diclofenac or DMSO themselves. The claim architecture signals that the patentee expects competitors to attempt surface-level substitutes (different polymers, different solvent balances). The multiple dependent branches (carbomer vs cellulose; broad vs narrow solvent windows; granular membership lists) are designed to close gaps.
Key Takeaways
- Claim 1 is the anchor: it requires diclofenac sodium 1–5% w/w + DMSO 25–60% w/w + viscosity 500–5,000 cP + twice-daily use for pain treatment.
- Dependent claims create multiple “design corridors”:
- Claim 2 adds propylene glycol (1–15%), ethanol (1–30%), and cellulose or carbomer thickener families.
- Claims 7-8 and 10-11 lock thickener families and specific exemplified polymers.
- Claim 12 is a tight recipe (DMSO 40–50%, ethanol 23–29%, propylene glycol 10–12%) with further tightening in Claims 13-15.
- Competitor exposure is highest where products use high DMSO, ethanol/propylene glycol cosolvents, polymer-thickened semi-gels, and are positioned for twice-daily pain therapy.
- Design-around levers are explicit: shift diclofenac %, shift DMSO %, shift viscosity outside 500–5,000 cP, change thickener class, and/or change dosing frequency.
FAQs
1) Does this patent claim diclofenac as an active ingredient?
It claims a method of treating pain using a formulation that contains diclofenac sodium within 1–5% w/w.
2) Is DMSO required, and at what level?
Yes. Claim 1 requires DMSO 25–60% w/w (with narrower windows in dependent claims).
3) Is viscosity a required element for infringement?
Yes. Claim 1 requires the formulation viscosity to be 500–5,000 cP.
4) Does the patent cover osteoarthritis specifically?
Claim 17 limits a dependent method to pain “due to osteoarthritis,” while Claims 1-16 cover pain more generally.
5) What are the most constraining dependent claims to watch?
Claims 12-15 (specific DMSO/ethanol/propylene glycol recipe and ethanol/diclofenac numeric sub-ranges) and Claims 8 and 11 (specific thickener exemplars).
References
[1] USPTO. “US Patent No. 8,871,809.” United States Patent and Trademark Office. (Source implied by the user-provided claim text; no additional external citations were provided.)
