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Patent landscape, scope, and claims: |
US Drug Patent 12,336,983: Scope, Claim Architecture, and Competitive Patent Landscape for Topical Roflumilast Crystals
What does US Patent 12,336,983 claim in plain scope terms?
US 12,336,983 claims topical pharmaceutical compositions that combine (1) roflumilast at specific loadings, with (2) a crystal-growth inhibitor system built around hexylene glycol as the essential anti-crystal-growth excipient, formulated (3) with water, (4) at least one surfactant and (5) at least one solvent, and delivered specifically as either a cream or foam. Claim 1 is the central independent claim and drives the landscape: any infringement analysis starts from whether the product has the same roflumilast/hexylene glycol/surfactant/solvent/water and cream/foam structure.
Independent claim 1 (core scope)
A topical pharmaceutical composition comprising:
- Roflumilast: 0.005% to 2% (w/w)
- Hexylene glycol: amount sufficient to inhibit roflumilast crystal growth (functional limitation)
- Water
- Surfactant
- Solvent
- Cream or foam format
This is a classic “formulation with functional excipient effect” claim set:
- Substance claim element: roflumilast
- Functional excipient effect: hexylene glycol’s role is defined by inhibition of roflumilast crystal growth
- Form factor: cream or foam
- Broad excipient freedom via a long list of surfactants and solvents
How do the dependent claims narrow the formulation space?
The dependent claims add quantitative and material constraints that create layers of narrower infringement hooks.
A. Concentration and form-factor narrowing
- Claim 4: composition is a cream
- Claim 5: composition is a foam
- Claim 6: roflumilast is 0.1% to 0.5% (w/w) (subset of Claim 1)
- Claim 17 / Claim 8: specific solvent and its level (diethylene glycol monoethyl ether at 25% (w/w) in Claim 8)
B. Surfactant selection narrowing (large genus, many named species)
- Claim 2: surfactant selected from a large genus list (dozens of surfactants)
- Claim 3: surfactant comprises cetearyl alcohol, dicetyl phosphate, or ceteth-10 phosphate (or combinations)
- Claim 12 / Claim 9: surfactant amount “sufficient to emulsify” (functional)
- Claims 20 and 23: repeat surfactant genus and “cetearyl alcohol / dicetyl phosphate / ceteth-10 phosphate” as a further narrowed set
Practical implication: Claim 1 already requires a surfactant but does not specify which. The dependent claims create the most direct mapping when a competitor uses common emulsion surfactant systems and thickening structures that match the named items (e.g., cetearyl alcohol and phosphate esters).
C. Solvent narrowing
- Claim 17: solvent selected from a broad list including diethylene glycol monoethyl ether plus many alternatives (acetone, ethanol, DMSO, NMP, glycols, etc.)
- Claim 7: solvent is specifically diethylene glycol monoethyl ether
- Claim 8: diethylene glycol monoethyl ether at 25% (w/w)
D. Optional formulation add-ons: moisturizer and polymer/thickener
Claims 10 through 14, and 18 through 19, and 21 through 22, 24 through 25, 26 through 29 add typical dermatologic excipient categories:
- Moisturizers / humectants / emollients (Claim 10 list; repeated in Claims 13, 18, 21, 24, 26, 27, 29)
- Polymers / thickeners (Claim 11 list; repeated in Claims 14, 19, 22, 25, 28, 29)
These are long lists of conventional cosmetic/pharma excipients: glycerin, PEG ranges, cyclomethicone/dimethicone, petrolatum, fatty alcohols, mineral oil, and typical polymer thickeners like carbomers and cellulose derivatives.
Practical implication: these dependent claims are typically easier for a formulator to satisfy and harder for a generic competitor to avoid if they already use mainstream skincare bases.
E. Fixed composition examples via petrolatum/isopropyl palmitate
- Claim 15: further comprises isopropyl palmitate and petrolatum
- Claim 16: isopropyl palmitate at 5% (w/w) and petrolatum at 10% (w/w)
This is a strong “product matching” limitation. If a competitor’s formula includes these exact levels, it creates a direct claim alignment with the narrow dependent layer.
What is the infringement-relevant claim “core”?
For enforcement and freedom-to-operate screen purposes, the essential claim-matching set is:
- Topical cream or foam
- Roflumilast at 0.005% to 2% (w/w) (or a narrower dependent range if targeted)
- Hexylene glycol present in an amount sufficient to inhibit roflumilast crystal growth (functional effect)
- Contains water
- Contains surfactant
- Contains solvent
Everything else (exact surfactant species, exact solvent, moisturizer, polymer/thickener, petrolatum/isopropyl palmitate, quantitative solvent) is additional narrowing.
The landscape is therefore governed less by “roflumilast topical” generally and more by whether a competitor’s roflumilast topical avoids:
- using hexylene glycol at meaningful levels tied to crystal-growth inhibition; and/or
- using cream/foam architectures with the same excipient functional roles.
How does the functional limitation on crystal growth affect claim scope?
Claim 1’s key novelty lever is: hexylene glycol is required at an amount sufficient to inhibit roflumilast crystal growth.
That design does two things:
- It makes hexylene glycol a required component (not merely an optional additive), and
- It ties the claim to a performance outcome (inhibition of crystallization), which can affect how courts interpret formulations where hexylene glycol is present but the amount or effect is debated.
From a landscape perspective, competitor formulas that swap hexylene glycol for other polyols/solubilizers may avoid Claim 1 if they do not use hexylene glycol in the required inhibitory manner. If hexylene glycol is present but positioned as a humectant rather than a crystal-growth inhibitor, infringement still depends on whether its amount is sufficient to inhibit roflumilast crystal growth.
Claim coverage map: independent to narrow dependent pockets
The following table extracts the main narrowing levers that define “hot spot” matching for product and formulation equivalence.
| Claim layer |
Constraint |
Narrowing effect on product matching |
| Claim 1 (independent) |
Roflumilast 0.005% to 2% (w/w); Hexylene glycol sufficient to inhibit crystal growth; Water; Surfactant; Solvent; Cream or foam |
Sets the minimum required formulation feature set |
| Claim 4 / 5 |
Cream or foam |
Eliminates incompatible dosage form if the product is gel/lotion/spray only |
| Claim 6 |
Roflumilast 0.1% to 0.5% |
Targets typical formulation concentration windows |
| Claim 7 / 8 |
Diethylene glycol monoethyl ether = solvent; 25% (w/w) |
Very specific solvent choice and level for a narrow pocket |
| Claim 3 / 23 |
Surfactant comprises cetearyl alcohol / dicetyl phosphate / ceteth-10 phosphate |
Directly relevant if competitor uses phosphate ester surfactants and cetearyl alcohol in the same system |
| Claims 15 / 16 |
Isopropyl palmitate 5%; petrolatum 10% |
Directly matched if competitor’s base is that exact petrolatum/emollient system |
| Claims 10-14; 18-19; 21-22; 24-26; 28-29 |
Moisturizers and polymers/thickeners from long specified lists |
These rarely block infringement because they are commonly used excipients; they add alternative narrower routes |
What does this patent mean for the broader US roflumilast topical landscape?
The claim structure indicates this US patent is drafted to sit in the overlap between:
- Topical roflumilast drug formulation patents (active + topical dosage forms), and
- Formulation stability and crystal control patents (excipient selection and performance outcome), and
- Dermal vehicle formulation patents (cream/foam base, surfactant and thickener selections).
Because Claim 1 is broad on:
- the surfactant (from a long list),
- the solvent (from a long list),
- moisturizers and thickeners (from long lists),
the principal design-around path for a competitor is primarily to avoid the hexylene glycol crystal-inhibition element while still delivering topical roflumilast.
From a competitive intelligence angle, the key question is whether other active+formulation competitors:
- use hexylene glycol as part of the vehicle, and
- position it at a level that could be argued to “inhibit roflumilast crystal growth,” not just to function as a humectant.
Patent landscape implications for product development and entry timing
A. Enforcement leverage
The patent provides multiple “entry points”:
- Direct claim 1 coverage for any cream/foam roflumilast formulation containing water, surfactant, solvent, and hexylene glycol at crystal-inhibiting levels.
- Multiple dependent claims that track conventional excipient systems (phosphate ester surfactants, cetearyl alcohol, typical polymers like carbomers, and common emollients like petrolatum).
This layering tends to widen the enforcement surface area against developers who converge on conventional dermatologic formulation bases.
B. Freedom-to-operate screening
A typical FTO screen based on this claim set focuses on:
- product format (cream vs foam),
- roflumilast concentration window,
- presence and role of hexylene glycol,
- whether the excipient system likely suppresses crystal growth (a functional element),
- surfactant identity when it matches the cetearyl alcohol/phosphate ester group, and
- whether the vehicle includes the tight petrolatum/isopropyl palmitate levels.
What is the scope of surfactants and solvents covered?
Surfactant genus coverage (Claim 2 / 20)
The claim lists numerous surfactants spanning:
- anionic surfactants (e.g., alkyl aryl sodium sulfonate, ammonium lauryl sulfate, sodium xylene sulfonate, various sulfosuccinates),
- nonionic surfactants (e.g., ceteareth series, PEG esters, poloxamers, polysorbates),
- amphoteric/zwitterionic surfactants (e.g., coco betaine),
- cationic surfactants (e.g., benzalkonium chloride),
- fatty alcohol and ester surfactants (e.g., cetearyl alcohol, sorbitan esters, polyoxyethylene stearate derivatives).
This expansive list reduces the ability to design around by swapping surfactants alone, unless the surfactant is fully outside this enumerated group.
Solvent genus coverage (Claim 17)
Claim 17 also enumerates a broad solvent set:
- polyols and glycols (propylene glycol, polyethylene glycol, glycerol),
- ketone/alcohol solvents (acetone, ethanol, isopropyl alcohol),
- aprotic solvents (dimethyl sulfoxide, N-methyl pyrrolidinone),
- glycol ethers (diethylene glycol monoethyl ether),
- esters (diethyl sebacate, diisopropyl adipate),
- combinations.
Design-around by swapping solvents is possible only if the solvent is outside the enumerated list. If a competitor uses diethylene glycol monoethyl ether at 25% (w/w), the product sits inside Claims 7 and 8.
Key Takeaways
- Claim 1 defines a broad formulation class: topical cream or foam with roflumilast 0.005% to 2%, water, surfactant, solvent, and hexylene glycol present at crystal-growth-inhibiting levels.
- Dependent claims create narrower enforcement pockets through roflumilast concentration (0.1% to 0.5%), solvent identity/level (diethylene glycol monoethyl ether at 25%), surfactant subgroups (cetearyl alcohol/dicetyl phosphate/ceteth-10 phosphate), and vehicle composition locks (isopropyl palmitate 5% + petrolatum 10%).
- Landscape risk concentrates on whether competitors’ roflumilast topical creams/foams include hexylene glycol in a manner that can be read as inhibiting roflumilast crystal growth; excipient substitutions limited to surfactant or general moisturizer/thickener categories may not materially avoid coverage because those elements are broadly enumerated.
- For product-specific screening, focus on (i) dosage form, (ii) roflumilast loading, (iii) hexylene glycol presence and functional role, then map against surfactant subgroup and solvent subgroup for faster “hit-rate” infringement assessments.
FAQs
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Is hexylene glycol required in US 12,336,983?
Yes. Claim 1 requires hexylene glycol in an amount sufficient to inhibit roflumilast crystal growth.
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Does the patent cover both creams and foams?
Yes. Claim 1 requires the composition be in the form of a cream or foam, with dependent claims specifying cream (Claim 4) and foam (Claim 5).
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What roflumilast concentration ranges are claimed?
Claim 1 covers 0.005% to 2% (w/w); Claim 6 narrows to 0.1% to 0.5% (w/w).
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Is diethylene glycol monoethyl ether specifically covered?
Yes. Claim 7 limits solvent to diethylene glycol monoethyl ether, and Claim 8 fixes it at 25% (w/w).
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Can a competitor avoid infringement by changing moisturizers or polymers?
Changing moisturizers/polymers alone may not help because those elements are broadly enumerated in dependent claims; the higher-impact design-around lever is avoiding hexylene glycol functioning as a crystal-growth inhibitor.
References
- United States Patent and Trademark Office. U.S. Patent No. 12,336,983.
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