United States Patent 5,914,334: Scope, Claim-by-Claim Analysis, and US Patent Landscape

US Patent 5,914,334 is directed to a topical, stable gel formulation that co-treats acne and psoriasis using a specific active ingredient, Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate (the “active”). The core claim scope is built around a multicomponent pharmaceutical carrier that combines (i) water-phase gel components, (ii) solubilization and viscosity-control surfactants, and (iii) specific nonionic/emollient-type excipients at defined ranges (notably Polysorbate 40 ≤0.4% w/w, Poloxamer 407 ≤0.4% w/w, and hexylene glycol ≤2% w/w). Method claims lock in a specific manufacturing sequence using intermediate parts I to IV.

What do the independent claims actually cover?

Independent claim set

The provided claim set includes what functionally operate as independent claims: claims 1, 3, and 5 (with claims 2, 4, 6-8 as narrower dependent variants).

Claim 1 (formulation composition + excipient boundaries)

Claim 1 is the broadest composition claim you provided. It covers:

Product: “a stable gel formulation for topical treatment of both acne and psoriasis”
Active: Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate
Carrier comprising specific ingredients:
- (a) water
- (b) edetate disodium
- (c) ascorbic acid
- (d) Carbomer 934P
- (e) Poloxamer 407
- (f) polyethylene glycol
- (g) Polysorbate 40
- (h) hexylene glycol
- (i) butylated hydroxytoluene (BHT)
- (j) butylated hydroxyanisole (BHA)
- (k) benzyl alcohol
- (l) tromethamine (Tris base)
Critical quantitative limitations:
- Polysorbate 40 up to ~0.4% by weight
- Poloxamer 407 up to ~0.4% by weight
- hexylene glycol up to ~2% by weight

Scope implication: For claim 1, infringement requires matching the active plus a carrier that includes the listed excipients and hits the specified upper limits on the three highlighted excipients.

Claim 3 (process/method for preparation with defined part sequence)

Claim 3 is a process claim that depends on the same formulation constraints and manufacturing actions.

Method steps (locked sequence):

Mix purified water + edetate disodium + ascorbic acid + Carbomer 934P until carbomer disperses to form Part I
Mix purified water + Poloxamer 407 to form Part II
Add Part II to Part I; homogenize Part I and II
Separately mix polyethylene glycol + Polysorbate 40 + hexylene glycol + BHT + BHA; heat to dissolve
Cool to room temperature; add benzyl alcohol + active to form Part III
Mix purified water + tromethamine to form Part IV
Add Part III to parts I and II while stirring; then add Part IV and mix until homogeneous, with the same numeric ceilings:
- Polysorbate 40 ≤0.4% w/w
- Poloxamer 407 ≤0.4% w/w
- hexylene glycol ≤2% w/w

Scope implication: A party making the same final composition but using a different mixing order, different intermediate sequence, or different temperature/dispersion logic may avoid literal infringement of claim 3, depending on how strictly the claim is construed against process steps.

Claim 5 (composition claim focusing on solubilizing + gelling vehicle language)

Claim 5 reads like a broader “stable gel” composition claim again, but it is framed through a pair of functional vehicle roles:

active treatment of acne and psoriasis
active agent is the specific Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate
nonaqueous vehicles:
- solubilize active
- form a gel
- control release and solubility dynamics

Vehicle set in Claim 5 is narrowed to:

Polysorbate 40, Poloxamer 407, hexylene glycol (with the same upper limits)

Scope implication: Claims 5-8 are broader in the sense that they focus on a reduced vehicle set, but they are still tied to the same active and to stable gel behavior “enabling topical application” and “control release” language.

How do dependent claims narrow the scope?

Quantified “example” sub-ranges

The dependent claims you provided mostly do two things: (i) lock the three key excipient levels to specific values, and/or (ii) tighten functional statements.

Claims 2 and 4 (specific concentrations)

Claim 2: Polysorbate 40 = 0.32% w/w, Poloxamer 407 = 0.18% w/w, hexylene glycol = 2% w/w
Claim 4: same numeric values as claim 2 Scope implication: These are straightforward narrow “embodiment” captures. If a product targets these exact levels, it increases risk.

Claims 6, 7, 8 (vehicle functional control refinements)

Claim 6: vehicles control “solubility” of active in gel
Claim 7: vehicles control both “solubility” and “release”
Claim 8: adds fixed concentrations (same as above) while inheriting Claim 7’s functional control language

Scope implication: These claims broaden or narrow depending on construction. Functionally worded vehicle control language can be argued over (what qualifies as controlling solubility and release), but literal infringement still depends on meeting the excipient set and ranges, and on having the claimed stable gel composition.

What is the technical “center of gravity” of infringement risk?

Active specificity is non-negotiable

All provided claims require the same active chemical identity:

Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate

Any at-risk gel must use that active (or an obvious substitution that would still literally fail the claim’s chemical identity).

Vehicle set and concentration ceilings drive literal claim fit

A comparison across claims shows two different “vehicle framing” strategies:

Claim	Active required	Vehicle set emphasized	Quantitative limits for key excipients
1	Yes	Full carrier list includes: water, edetate disodium, ascorbic acid, Carbomer 934P, polyethylene glycol, Polysorbate 40, Poloxamer 407, hexylene glycol, BHT, BHA, benzyl alcohol, tromethamine	Polysorbate 40 ≤0.4% w/w; Poloxamer 407 ≤0.4% w/w; hexylene glycol ≤2% w/w
3	Yes	Same as Claim 1 but embedded in a specific manufacturing sequence	Same ceilings
5	Yes	Nonaqueous vehicles: Polysorbate 40, Poloxamer 407, hexylene glycol	Polysorbate 40 ≤0.4% w/w; Poloxamer 407 ≤0.4% w/w; hexylene glycol ≤2% w/w
6-7	Yes	Same reduced vehicle set	Same ceilings
2,4,8	Yes	Same as dependent vehicle set	Fixed: Polysorbate 40 =0.32%; Poloxamer 407 =0.18%; hexylene glycol =2%

Implication for design-arounds:

Staying below the “up to about” ceilings is part of literal avoidance, but whether “about” creates leeway is a claim-construction question not resolved by the text alone.
Swapping any of the three emphasized excipients out of the final vehicle system can break claims 5-8, but claim 1 still imposes a far broader full-carrier list.

What is the likely claim construction posture?

“Stable gel formulation” is functional but still compositionally constraining

All claims require a “stable gel formulation” and topical use for acne and psoriasis. That introduces:

a formulation characteristic (stability)
a dosage form classification (gel)
a therapeutic scope (acne and psoriasis)

In practice, “stable gel” is often used to avoid prior art that is not physically stable, not gel-like, or separates.

“Control release” vs “control solubility”

Claims 5 and 7 differ by functional emphasis:

Claim 5: “control release”
Claim 6: “control solubility”
Claim 7: “control both solubility and release”

A design that maintains gel stability but lacks the claimed release-control mechanism still creates infringement risk because claim construction may treat these as performance indicators rather than strict parameter thresholds. Literal infringement remains easier if the formulation uses the same vehicle system and is expected to behave similarly.

Process claim strictness

Claim 3 is the most “engineering-specific.” It recites:

discrete “Part I–IV” intermediate mixtures
specific mixing order
dissolution by heating in the Part III step

A manufacturing route that blends all ingredients together at once may not satisfy the step sequence in claim 3.

Patent landscape: what else matters around US 5,914,334?

How to map the landscape given the claim content

Even without enumerating every citation in the public record here, the landscape can be categorized by claim themes embedded in the patent:

Active-ingredient IP space
- The active chemical identity is the anchor. Any freedom-to-operate analysis must map:
  - compound patents covering Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate
  - salt/polymorph/formulation embodiments around it
  - later patents that use the same active for other dermatologic indications
Topical delivery technology space
- The claims target a topical stable gel using:
  - gel matrix former: Carbomer 934P
  - polymeric solubilizer/surfactant: Poloxamer 407
  - surfactant/emulsifier: Polysorbate 40
  - humectant/solubilizer: hexylene glycol
  - stabilizers/antioxidants/preservatives: BHT/BHA, benzyl alcohol
- Landscape clusters likely include:
  - Carbomer gel systems for topical drugs
  - Poloxamer/Polysorbate systems for solubilization of hydrophobic actives
  - preservatives and anti-oxidants combinations in topical vehicles
  - combinations for dermatologic indications (acne, psoriasis)
Formulation-process IP space
- Claim 3’s intermediate sequence suggests the patent is protecting not only the final product but a specific manufacturing approach.
- A landscape review would look for:
  - other patents describing partwise preparation routes for Carbomer dispersions and surfactant dissolution
  - manufacturing processes for gels using similar polymer and surfactant sets

Competitive risk bands based on how rivals usually design around

Given the claim set, the most direct competitive space threats come from products that match one of these bands:

Threat band	What competitor does	Which claims are most implicated
“Same active + same gel system”	Uses same active and the same three key excipients within ranges	Claims 1, 5-7 and dependent 2,4,8
“Same active + vehicle trimmed”	Keeps Polysorbate 40 / Poloxamer 407 / hexylene glycol but changes other carriers	Claims 5-8 more likely; claim 1 less likely if any carrier element is missing
“Same final composition, different process”	Makes a different Part I-IV sequence	Claims 1 and 5-7 more likely; claim 3 reduced
“Same active, different solubilization approach”	Replaces Polysorbate or Poloxamer system	Lower risk for claims 5-8; claim 1 depends on whether full carrier list still fits

Actionable claim-map: where to test an internal formulation or evaluate licensing

Literal claim check list (text-driven)

A formulation should be tested against these literal elements:

Active identity: must be Ethyl-6-2-(4,4-dimethylthiochroman-6-yl)-ethynyl nicotinate
Stable gel and topical acne + psoriasis therapeutic framing
For Claim 1: carrier must include all listed components (water, edetate disodium, ascorbic acid, Carbomer 934P, polyethylene glycol, Polysorbate 40, Poloxamer 407, hexylene glycol, BHT, BHA, benzyl alcohol, tromethamine)
For Claim 1 and 5-8:
- Polysorbate 40 ≤0.4% w/w
- Poloxamer 407 ≤0.4% w/w
- hexylene glycol ≤2% w/w
For Claim 3: manufacturing must follow the Part I-IV sequence with heating/dissolution in the Part III step and cooling before adding benzyl alcohol and active

Concentration lock-in risks

If any candidate product targets:

Polysorbate 40 at ~0.32%
Poloxamer 407 at ~0.18%
hexylene glycol at ~2% then claims 2, 4, and 8 become high-priority targets.

Key Takeaways

US 5,914,334 is built around a specific active plus a stable topical gel for acne and psoriasis.
The claim system uses two parallel scopes:
- Claim 1 + 3 protect a full carrier plus Part I-IV manufacturing sequence.
- Claims 5-8 protect a reduced vehicle set (Polysorbate 40, Poloxamer 407, hexylene glycol) that controls solubility and/or release while keeping the same excipient ceilings.
The most enforceable numeric anchors are Polysorbate 40 ≤0.4% w/w, Poloxamer 407 ≤0.4% w/w, hexylene glycol ≤2% w/w, with explicit embodiments at 0.32% / 0.18% / 2%.
For a competitor, the fastest path to reduced risk is changing either the active (not usually an option) or at least one of the three key vehicle excipients or their effective levels; process-only changes primarily reduce exposure only to claim 3.

FAQs

1) Does US 5,914,334 mainly protect the active ingredient or the formulation?

It protects the formulation and gel vehicle system using a specific active identity. The active is a required element in all provided claims, but the protected subject matter is the stable topical gel composition (and for claim 3, the preparation sequence).

2) What excipients are the most critical for infringement across claims 5-8?

Polysorbate 40, Poloxamer 407, and hexylene glycol. They are the emphasized nonaqueous vehicles and are tied to upper limits of ≤0.4%, ≤0.4%, and ≤2% by weight respectively.

3) What is the role of Carbomer 934P in the claim set?

Carbomer 934P appears as a required component in claim 1 (and in the Part I dispersion step in claim 3). Claims 5-8 emphasize the Polysorbate/Poloxamer/hexylene glycol vehicle trio rather than Carbomer.

4) Can a competitor avoid claim 3 by using the same final gel but a different mixing order?

Claim 3 is tied to a specific multi-part mixing sequence with intermediate steps. A different route can reduce risk for claim 3, while still leaving composition claims 1 and 5-7 at issue if the final product matches them.

5) Which dependent claims are “fixed formulation” versions?

Claims 2, 4, and 8 lock the three key vehicle components to 0.32% Polysorbate 40, 0.18% Poloxamer 407, and 2% hexylene glycol.

References

[1] United States Patent US 5,914,334. Claims 1-8 (as provided in the prompt).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
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Austria	336263	⤷ Start Trial
Australia	2821895	⤷ Start Trial
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Details for Patent: 5,914,334

Summary for Patent: 5,914,334