Patent 9,855,334 (US) clobetasol cream: What do the claims cover, what design-arounds exist, and where are the key barriers for generics?
US Patent 9,855,334 is directed to a propionate/clobetasol topical cream defined by (i) tight actives and excipient ranges, (ii) a specific penetration enhancer identity (diethylene glycol monoethyl ether, “DGME”), (iii) a constrained alcohol selection set, (iv) explicit propylene glycol exclusion, and (v) an explicit emulsion structure requirement in dependent form. The practical scope is narrow but compositionally crisp, making it well-suited for formulation infringement analysis and Paragraph IV / non-infringement strategies built around excipient substitution and/or emulsion-type changes.
What is the scope of US Patent 9,855,334 clobetasol cream claims?
Core independent claim theme (Claim 1)
- A topical cream composition with:
- 0.015% to 0.035% w/w clobetasol
- ≥ 60% w/w water
- ≥ one penetration enhancing agent comprising DGME (diethylene glycol monoethyl ether)
- ≥ one alcohol selected from a defined list:
- fatty alcohols
- PEGylated fatty alcohols
- long chain alcohols
- isopropyl alcohol
- benzyl alcohol
- branched aliphatic alcohols
- lanolin alcohol
- polyvinyl alcohols
- combinations thereof
- free of propylene glycol
Independent Claim 4 refines the active explicitly
- Same overall cream architecture, but specifies:
- 0.015% to 0.035% w/w clobetasol propionate
- ≥ 60% w/w water
- 0.01% to 15% w/w DGME
- same alcohol selection set
- free of propylene glycol
Key structural and formulation boundaries
- Actives: clobetasol or clobetasol propionate only, within a narrow potency bracket.
- Penetration enhancer identity: DGME is required (“comprising DGME”).
- Solvent/water content: large majority water, indicating an O/W cream (though emulsion is expressly claimed only in Claim 3).
- Propylene glycol exclusion: bright-line “free of propylene glycol” limitation.
- Alcohol carrier role: at least one alcohol from a closed list, not an open-ended set.
Immediate claim-interpretation consequences
- Any candidate infringement analysis must map a proposed product’s:
- clobetasol/clobetasol propionate concentration into the 0.015–0.035% window
- total water into ≥60%
- presence and amount of DGME
- whether propyl glycol is truly absent
- whether the formulation uses at least one qualifying “alcohol” category from the enumerated list
- whether the cream meets the “oil-in-water emulsion” limitation when evaluating Claim 3-dependent exposure.
How do Claims 1 and 4 differ, and why does that matter for infringement?
Claim 1
- Uses clobetasol (not propionate) as the active term.
- Requires DGME presence but does not explicitly state DGME wt% range in Claim 1.
Claim 4
- Uses clobetasol propionate as the active.
- Adds a quantitative DGME range: 0.01% to 15% w/w.
Practical outcome
- Products formulated with clobetasol propionate are directly evaluated against Claim 4 for both active and DGME range.
- If a product uses clobetasol base rather than propionate, it shifts risk toward Claim 1.
- Even if an infringing DGME amount exists, Claim 4 requires it to be within 0.01–15%; falling outside that range is an argument for non-infringement on the Claim 4 map (assuming DGME is still present).
What does “free of propylene glycol” do to the claim scope?
This is a high-impact limitation: “wherein the composition is free of propylene glycol.”
Scope effect
- It creates a clean exclusion: formulations containing propylene glycol cannot meet this limitation.
- It also enables straightforward manufacturing release spec and ingredient declaration arguments in litigation.
Design-around leverage
- Replace propylene glycol with alternative humectants/co-solvents that do not introduce propylene glycol contamination (including trace-level issues governed by specification and analytical detectability regimes).
Does the patent require DGME specifically, and how does “comprising DGME” constrain alternatives?
Both independent claim pathways require at least one penetration enhancing agent “comprising diethylene glycol monoethyl ether.”
Scope effect
- “Comprising” keeps the claim from being limited to DGME as the only penetration enhancer, but it still requires that DGME be present.
- Substituting other penetration enhancers while removing DGME can be a strong non-infringement route, provided the product truly contains no DGME.
Risk concentration
- Products that use DGME for penetration enhancement face structural infringement exposure unless another limitation fails (e.g., active range, water %, emulsion type, alcohol list, or propylene glycol exclusion).
How much does the water content limitation narrow the claim?
Independent claims require at least 60% w/w water.
Scope effect
- This tends to exclude:
- anhydrous creams
- low-water ointments
- heavier emulsion systems below the threshold
- It also aligns the claim to typical O/W cream water-heavy rheology.
Interaction with Claim 3
- Claim 3 adds “oil-in-water emulsion,” so water-heavy alone does not capture O/W requirement when evaluating Claim 3.
What does “oil-in-water emulsion” in Claim 3 cover?
Claim 3 depends on Claim 1 and specifies:
- “The composition of claim 1 is an oil-in-water emulsion.”
Scope effect
- Claim 3 is narrower than Claim 1.
- If a product meets Claim 1’s composition constraints but is not an O/W emulsion (e.g., W/O emulsion or gel/cream not classified as O/W), it can potentially avoid Claim 3.
Litigation mapping
- Emulsion classification often becomes a factual and expert-driven characterization issue: formulation droplet structure, phase distribution, and physicochemical characterization.
What are the dependent claim alcohol options, and do they create a closed list barrier?
Claims 5–12 and 13–20 partition alcohol selection into defined alternatives:
Claim 1 alcohol limitation (general)
- at least one alcohol selected from:
- fatty alcohols
- PEGylated fatty alcohols
- long chain alcohols
- isopropyl alcohol
- benzyl alcohol
- branched aliphatic alcohols
- lanolin alcohol
- polyvinyl alcohols
- combinations thereof
Dependent claim structure
- Claims 5–12 lock in at least one alcohol category:
- Claim 5: fatty alcohol
- Claim 6: PEGylated fatty alcohol
- Claim 7: long chain alcohol
- Claim 8: isopropyl alcohol
- Claim 9: benzyl alcohol
- Claim 10: branched aliphatic alcohol
- Claim 11: lanolin alcohol
- Claim 12: polyvinyl alcohol
Claim 4 mirrors those alternatives
- Claims 13–20 replicate those alcohol-category dependents for the Claim 4 architecture.
Scope effect
- This is not a vague “alcohol” term. It is a constrained enumeration, which strengthens non-infringement options:
- formulate without any enumerated alcohol-category component (or reclassify solvent system outside the defined categories, depending on claim construction).
- avoid using propylene glycol and still satisfy alcohol category is not optional. If you omit the alcohol category entirely, you miss the claim.
Risk
- Many creams use benzyl alcohol or fatty alcohols as preservatives/emulsifiers/co-solvents, so the dependent claims can “stack” over a wide range of real-world cream formulations.
What formulation variants are inside the claim “capture envelope”?
A product is likely within scope if it simultaneously satisfies:
- clobetasol or clobetasol propionate at 0.015–0.035%
- water ≥60%
- includes DGME (and for Claim 4, DGME at 0.01–15%)
- includes at least one alcohol category from the list
- contains no propylene glycol
- and for Claim 3, is an O/W emulsion
In-scope example profiles (taxonomy, not a literal recipe)
- DGME-containing clobetasol propionate cream (O/W, water-heavy) using:
- fatty alcohols or PEGylated fatty alcohols as emulsifier/co-emulsifier system
- benzyl alcohol or lanolin alcohol as part of preservative/emollient phase
- no propylene glycol
- Similar water-heavy systems formulated as O/W.
What design-arounds are most likely to avoid infringement of US 9,855,334?
Given the claim structure, the highest-leverage non-infringement routes are:
-
Remove DGME entirely
- Since DGME is required, removing it is the most direct path to avoid both independent claim frameworks.
-
Use an active level outside the 0.015–0.035% band
- Reformulate to a concentration below 0.015% or above 0.035% (while maintaining therapeutic equivalents).
- This may conflict with FDA labeling and bioequivalence requirements, but it is a clear claim boundary.
-
Fail the “free of propylene glycol” limitation
- Add propylene glycol-free compliance is required for infringement; adding propylene glycol can be a non-infringement trigger.
- This route depends on whether product development tolerates propylene glycol and maintains performance.
-
Avoid enumerated alcohol categories
- If a formulation excludes fatty alcohols, PEGylated fatty alcohols, long chain alcohols, isopropyl alcohol, benzyl alcohol, branched aliphatic alcohols, lanolin alcohol, and polyvinyl alcohols, it can fail the alcohol requirement.
- In practice, many creams rely on some member of this set, so this is a meaningful development shift.
-
For Claim 3 specifically: avoid classifying as “oil-in-water emulsion”
- If formulation classification changes (e.g., not O/W), Claim 3 can be evaded even if Claim 1/4 components align.
-
For Claim 4 specifically: put DGME outside 0.01–15%
- Keep DGME absent or out-of-range.
- Out-of-range strategy is a more complex development problem because DGME also affects penetration and stability.
How many claim paths exist, and what does that mean for licensing risk?
The patent’s claim set is compositional and layered:
- Independent coverage: 2 independent claims (Claims 1 and 4).
- Dependent alcohol variants: Claims 5–12 and 13–20.
- Emulsion limitation: Claim 3 (dependent on Claim 1).
Risk interpretation
- If a product fits Claim 1’s architecture, it may also satisfy multiple dependent alcohol variants depending on which alcohol category is present.
- Same for Claim 4.
- That means the patent can create broad coverage across “real-world” cream excipient selections, as long as it maintains DGME and avoids propylene glycol.
What is the likely patent landscape relevance beyond US 9,855,334?
A composition claim like this usually sits inside a larger ecosystem:
- one set of claims protecting the active level + excipient architecture
- one set protecting penetration enhancer selection
- one set protecting emulsion type and water content
- potentially additional claims protecting manufacturing methods or stability/processing windows
However, without the rest of the patent family (continuations, divisionals) and without cross-references, the scope assessment is constrained to the independent and dependent claims provided.
Key takeaways on scope and claim strength for business use
- US 9,855,334 defines a tight clobetasol/clobetasol propionate cream composition with required:
- 0.015–0.035% active
- ≥60% water
- DGME as a penetration enhancer
- a qualifying alcohol from an enumerated list
- propylene glycol absence
- Claim 4 adds a DGME wt% range (0.01–15%), narrowing that independent branch further.
- Claim 3 adds an oil-in-water emulsion limitation, creating a separate narrower infringement bucket.
- The most credible non-infringement levers are:
- remove DGME
- move the active concentration outside the defined window
- reintroduce propylene glycol (if allowed by formulation strategy)
- exclude all enumerated alcohol categories
- or for Claim 3, change emulsion classification.
FAQs
1. If a generic uses clobetasol propionate at 0.02% and no propylene glycol, is it still outside the patent if it omits DGME?
Yes. DGME presence is required in both independent claim paths; omitting DGME defeats the “penetration enhancing agent comprising DGME” limitation.
2. Does adding benzyl alcohol automatically satisfy the alcohol limitation?
If benzyl alcohol is present and the formulation otherwise satisfies the other limitations, it fits the alcohol selection set (benzyl alcohol is explicitly listed).
3. How does changing the emulsion type affect infringement of Claim 3?
If the product is not an oil-in-water emulsion, it fails Claim 3’s dependent limitation, though it could still be evaluated under Claim 1’s broader composition.
4. What happens if DGME is present but at 0.001%?
That fails Claim 4’s explicit DGME wt% range (0.01%–15%), but Claim 1 may still be implicated because Claim 1 does not state a DGME range in the provided claim text.
5. Can a formulation include additional penetration enhancers beyond DGME and still infringe?
Yes. The claim language uses “comprising,” so additional penetration enhancers do not avoid infringement if DGME is present and other limitations are met.
References
- US Patent 9,855,334 (claims as provided in prompt).
