Details for Patent: 9,161,914

Which drugs does patent 9,161,914 protect, and when does it expire?

Patent 9,161,914 protects NAFTIN and is included in one NDA.

This patent has three patent family members in three countries.

Summary for Patent: 9,161,914

Title:	Topical compositions and methods for making and using same
Abstract:	The present invention relates to improved topical gel compositions comprising an active agent, and uses thereof.
Inventor(s):	Bhushan Hardas, Donna Dalton
Assignee:	Legacy Pharma Inc
Application Number:	US14/297,293
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 9,161,914
Patent Claim Types: see list of patent claims	Use; Composition;

United States Patent 9,161,914 (Naftifine Gel) Claims Scope and U.S. Patent Landscape for Fungal Treatment

Executive summary: U.S. Patent 9,161,914 claims a naftifine (or naftifine salt) topical gel composition and a method of treating superficial fungal infections using a gel “consisting essentially of” defined solvent system (glycol + alkyl alcohol), hydroxy cellulose rheology modifier, polysorbate (20 or 80) solubilizer, and pH 4.5–6.0 with an amine base pH adjuster. Claim 1 defines the core composition for infringement leverage; dependent claims narrow to interdigital tinea pedis and specific organisms; dependent composition claims lock in propylene glycol, ethanol, hydroxyethyl cellulose, polysorbate 20/80, and naftifine hydrochloride, with a fully specified embodiment in claim 21 that includes benzyl alcohol and trolamine plus EDTA. The patent landscape around this type of asset typically clusters around (i) naftifine salts, (ii) topical delivery systems, (iii) solubilizer/rheology systems, and (iv) formulation process claims. For a freedom-to-operate or launch-risk screen, the highest-risk design-arounds are changes to the solvent pair, hydroxy cellulose, polysorbate identity, and pH system, because these are recited as quantitative ranges and product-defining limitations.

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What does US Patent 9,161,914 claim, and what is the infringement “center of gravity”?

Direct answer: The patent’s center of gravity is Claim 1: a method that requires administering a gel composition that is defined by an exact ingredient class architecture plus wt% ranges and a pH range.

Claim 1 scope: gel-based method of treating fungal infection

Claim 1 is a method claim, but infringement turns on whether the administered gel “consisting essentially of” the following elements:

1. Active: naftifine or pharmaceutically acceptable salt
   • 0.5–4.0 wt%
2. First solvent: glycol solvent
   • 10–25 wt%
3. Second solvent: alkyl alcohol solvent
   • 10–25 wt%
4. Rheology modifier (non-carbomer): hydroxy cellulose
   • 0.75–2.25 wt%
5. Solubilizer: polysorbate
   • 3–8 wt%
6. pH adjuster: an amine base
7. Optional components: water, preservative, chelating agent, coloring agent, fragrance
8. pH of the gel: 4.5–6.0

Practical read: “Consisting essentially of” means the claim tolerates some unrecited additives (explicitly enumerated options; and other minor additives may still be tolerated if they do not materially alter the basic and novel characteristics), but it constrains the composition to a framework that is clearly intended to be compositionally tight.

Dependent narrowing: infection type and organism specificity

The claim set narrows as follows:

• Claim 2: superficial fungal infection of skin
• Claim 3: enumerates multiple tinea and related superficial fungal conditions:
  • Tinea cruris, Tinea corporis, interdigital tinea pedis, moccasin-type tinea pedis, tinea manuum, tinea versicolor (pityriasis), tinea nigra, cutaneous candidiasis, tinea faciei, white and black piedra
• Claim 4: narrows to interdigital tinea pedis
• Claim 5: ties to organisms:
  • Epidermophyton floccosum, Trichophyton mentagrophytes, Trichophyton rubrum
• Claims 6–21: composition embodiment limitations (percent ranges, ingredient identities)

Claim 21: the fully specified “hard” embodiment

Claim 21 recites a specific gel composition:

• 2.0 wt% naftifine hydrochloride
• ~20 wt% propylene glycol
• ~19 wt% ethanol
• 5 wt% Polysorbate 20
• 1.75 wt% hydroxyethyl cellulose
• 1.0 wt% benzyl alcohol
• 0.17 wt% trolamine
• 0.02 wt% EDTA (or salt)
• water
• optionally coloring agent and fragrance

This claim functions as a benchmark recipe. Any generic or reformulated attempt that matches this “recipe” will land directly in dependent-claim infringement territory if the method is also used as claimed (topical use for superficial fungal infections).

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How do the quantitative ranges work in US 9,161,914, and where are the design-around tripwires?

Direct answer: The claim includes multiple overlapping quantitative ranges that act as design constraints. The most sensitive tripwires are (i) active wt%, (ii) both solvent wt% windows, (iii) hydroxy cellulose wt%, (iv) polysorbate wt%, and (v) pH 4.5–6.0 with an amine base.

Active dose window

• 0.5–4.0 wt% naftifine (or salt)
• Dependent narrowing:
  • Claim 6: 1.0–3.0 wt%

Design-around implication: A “thinner” or “thicker” gel formulation outside these windows risks claim non-literal infringement, but note the open-ended method context: a product outside wt% ranges may still infringe under doctrine of equivalents depending on the claim construction and factual record. From a risk perspective, staying well outside the ranges (not just marginally) is the cleaner approach.

Solvent system: two independent windows

• Glycol solvent: 10–25 wt%
• Alkyl alcohol: 10–25 wt%
• Dependent narrowing:
  • Claim 7: glycol 18–22 wt%
  • Claim 8: glycol is propylene glycol
  • Claim 9: alkyl alcohol 17–22 wt%
  • Claim 10: alkyl alcohol is ethanol

Tripwires:

• Removing one of the two solvent classes (glycol or alkyl alcohol) likely breaks the “essential” elements.
• Substituting different glycol solvents (e.g., butylene glycol, PEG variants) may avoid literal infringement if not within “glycol solvent” as construed, but the claim text is broad enough that many glycols may qualify as “glycol solvent.”
• Switching alcohol type (e.g., isopropanol) can avoid the dependent claims, but Claim 1 still covers “alkyl alcohol solvent” generically, so the substitution strategy must also address wt% and still satisfy pH constraints.

Rheology modifier: hydroxy cellulose only

• 0.75–2.25 wt% hydroxy cellulose (non-carbomer rheology modifier)
• Dependent:
  • Claim 11: hydroxyethyl cellulose

Design-around implication: Replacing the hydroxy cellulose with another rheology system (e.g., carbomer, HPMC alternative, PVP, xanthan gum) likely avoids the key limitation. But because the claim expressly says “non-carbomer,” carbomer-based systems might be outside the claim, depending on substitution and whether the replacement still qualifies as “hydroxy cellulose.”

Polysorbate: identity is flexible in Claim 1, narrower in dependents

• Polysorbate solubilizing agent: 3–8 wt%
• Dependent:
  • Claim 12: Polysorbate 20
  • Claim 13: Polysorbate 80
  • Claim 19: Polysorbate 20 or 80

Tripwires:

• Using a non-polysorbate solubilizer (e.g., poloxamer, Cremophor, solubilized cyclodextrin) is the most direct literal avoidance because Claim 1 requires “polysorbate.”
• If using polysorbate but changing type (e.g., polysorbate 60 vs 20/80), Claim 1 may still cover it if still “polysorbate” broadly. The dependents list 20/80 but Claim 1 already requires polysorbate generally.

pH 4.5–6.0 and amine-base pH adjuster

• Gel pH must be about 4.5–6.0
• pH adjuster is an amine base

Tripwires:

• Using non-amine pH adjusters (e.g., inorganic bases, buffering salts not characterized as an “amine base”) may avoid literal infringement.
• Formulating outside the pH window avoids Claim 1. The stability and microbiological tolerance often constrain pH in topical products, so in practice pH moves may create formulation tradeoffs.

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Which dependent claims most affect product design, and what do they lock in?

Direct answer: The dependent claims lock in exact ingredient identities and tighter ranges that map to common formulation choices. The highest practical lock-in is Claim 21’s full recipe.

Tightened compositional sub-ranges (Claims 6–10, 7–10)

• Naftifine: 1.0–3.0 wt% (Claim 6)
• Glycol: 18–22 wt% (Claim 7)
  • propylene glycol (Claim 8)
• Alkyl alcohol: 17–22 wt% (Claim 9)
  • ethanol (Claim 10)

These sub-ranges are particularly relevant to typical topical gels that use propylene glycol and ethanol as dual cosolvents.

Rheology identity (Claims 11, 18)

• Hydroxyethyl cellulose is specified (Claim 11 and Claim 18 in the claim 15/21 family)

If a candidate formulation uses a different hydroxy cellulose (e.g., hydroxypropyl methylcellulose, which is not a hydroxy cellulose in the same sense) it may step outside literal scope.

Polysorbate identity (Claims 12, 13, 19)

• Polysorbate 20 or 80
• Claim 19 ties specifically to 20 or 80

If Claim 1 covers any polysorbate, then only switching away from polysorbate avoids the core. Switching between 20 and 80 does not avoid Claim 1.

Salt form (Claims 14, 20)

• Naftifine hydrochloride (Claims 14 and 20)

A different salt form might avoid these dependents, but Claim 1 still covers “naftifine or pharmaceutically acceptable salt thereof,” keeping literal exposure unless the competitor moves away from naftifine altogether.

Fixed-ingredient recipe (Claim 21)

Claim 21 includes:

• benzyl alcohol (1.0 wt%)
• trolamine (0.17 wt%) as the amine base (consistent with pH adjustment)
• EDTA (0.02 wt%) as chelator

If the competitor’s formulation omits or replaces these excipients, Claim 21 is avoided, but Claim 1 may remain in play if the required classes and ranges are still met.

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How broad is the method-of-use coverage: does the patent require specific fungal species?

Direct answer: No. Species-level specificity is only in dependent claim 5. Claim 1 plus Claim 2/3 covers a broad set of superficial skin fungal infections and does not require species identification.

Clinical scope ladder

• Claim 1: fungal infection in a patient (general fungal method)
• Claim 2: superficial skin fungal infection
• Claim 3: enumerated diagnoses (tinea cruris, corporis, interdigital pedis, etc.)
• Claim 4: interdigital tinea pedis
• Claim 5: causative organisms (E. floccosum, T. mentagrophytes, T. rubrum)

Risk implication: A labeled indication tied to any listed superficial fungal condition can support infringement under independent claim coverage if the product formulation matches the gel limitations. Organism-specific labeling matters only if relying on dependent claim 5.

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How many patents typically cover this “naftifine topical gel” space around US 9,161,914, and what claim themes dominate?

Direct answer: Without the full patent family and prosecution/claims context (priority, assignee, continuation set, and citations), the exact “how many” cannot be computed from the claim text alone. What can be stated from the claim architecture is the dominant themes that usually cluster in this space.

Common US claim themes that overlap this architecture

1. Topical delivery formats for naftifine
   • gels, creams, solutions, sprays
2. Naftifine salt/form selection
   • hydrochloride vs free base and salt stability in topical vehicles
3. Dual solvent systems
   • glycol + lower alcohol for solubilization and skin penetration
4. Rheology system selection
   • hydroxy cellulose vs carbomer systems
5. Surfactant and solubilizer selection
   • polysorbate 20/80 vs poloxamer series, nonionic surfactants
6. pH window and buffer mechanism
   • amine-base adjusters aligned with naftifine’s stability and microbial safety
7. Preservative/chelator pairing
   • benzyl alcohol + EDTA are common in topical stability packages

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What does a “consisting essentially of” gel limitation mean for formulation competitors?

Direct answer: It constrains the gel to the recited composition framework while permitting additional components only if they do not materially alter the basic and novel characteristics of the claimed invention.

How this hits competitors

A generic or reformulation competitor can avoid Claim 1 by:

• changing one of the mandatory elemental classes (e.g., replacing polysorbate with another solubilizer class)
• removing or changing the dual solvent architecture such that the composition no longer includes a glycol solvent and an alkyl alcohol solvent at the claimed wt% ranges
• changing the rheology system so it is not a non-carbomer hydroxy cellulose
• adjusting pH outside 4.5–6.0 or using a non-amine base pH adjuster

Changing only “optional” elements (colorants, fragrance) rarely creates a safe harbor because Claim 1 is defined by required constituents plus quantified ranges and pH.

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Orange Book status, FDA exclusivity, and generic entry risk for a naftifine gel: what should be assessed?

Direct answer: This requires the product tied to the patent, including NDA/ANDA/BLA linkage, Orange Book listing, and regulatory exclusivity identifiers. That linkage is not included in the claim text provided, so no definitive Orange Book status can be produced here.

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Patent expiration and exclusivity timelines: what can be concluded from the patent number alone?

Direct answer: The actual expiration timeline requires:

• filing date, priority date, prosecution history (for term adjustments),
• whether the patent is subject to terminal disclaimer,
• and whether an active regulatory exclusivity or patent term extension applies.

A patent number alone is insufficient to compute an expiration date with business-grade precision.

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What is the litigation and settlement exposure pattern for this type of formulation patent?

Direct answer: Formulation “consisting essentially of” patents frequently drive settlement when an ANDA or topical generic is ready to launch and the proposed ANDA composition lands within the ingredient-class and wt% architecture. The key infringement and design-around leverage is usually:

• matching or avoiding the dual solvent + polysorbate + hydroxy cellulose + pH system
• changing surfactant class (polysorbate vs non-polysorbate) and buffer mechanism (amine base vs other bases)
• reformulating to exit the quantitative ranges rather than relying on ingredient substitution alone

No specific litigation docket can be asserted without pulling the USPTO/RECAP case mapping for 9,161,914.

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Which design-around strategies are most likely to avoid literal infringement of Claim 1?

Direct answer: The most plausible literal avoidance strategies are to break one of Claim 1’s required pillars: polysorbate, hydroxy cellulose, dual solvent wt% windows, or pH/amine base.

High-confidence avoidance levers

1. Replace polysorbate solubilizer
   • Move to a different solubilizer class not captured by “polysorbate”
2. Replace hydroxy cellulose rheology modifier
   • Use a non-hydroxy-cellulose gelling/thickening system
3. Remove or shift out of the dual solvent ranges
   • Eliminate glycol or alkyl alcohol class at claimed wt% ranges
4. Move pH outside 4.5–6.0
   • Or use a pH adjuster that is not an “amine base”

Lower-confidence levers

• Changing benzyl alcohol or EDTA levels: likely falls into “optional” components unless the changes also affect required pH or excipient roles.
• Swapping between polysorbate 20 and 80: still falls within “polysorbate” in Claim 1.
• Changing naftifine to another salt form: Claim 1 still covers naftifine “or pharmaceutically acceptable salt thereof.”

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Claim-by-claim scoping table for US 9,161,914 (infringement-relevant elements)

Claim	What it adds	Element-level constraint (infringement-relevant)
1	Core method + gel composition	Naftifine (0.5–4 wt%); glycol solvent (10–25 wt%); alkyl alcohol solvent (10–25 wt%); non-carbomer hydroxy cellulose (0.75–2.25 wt%); polysorbate (3–8 wt%); amine base pH adjuster; gel pH 4.5–6.0
2	Indication narrowing	Superficial fungal infection of skin
3	Diagnosis list	Covers multiple superficial tinea/candidiasis/piedra conditions including interdigital tinea pedis
4	Further narrowing	Interdigital tinea pedis
5	Organism list	E. floccosum, T. mentagrophytes, T. rubrum
6	Active sub-range	Naftifine 1–3 wt%
7	Glycol sub-range	18–22 wt% glycol
8	Glycol identity	Propylene glycol
9	Alcohol sub-range	17–22 wt% alkyl alcohol
10	Alcohol identity	Ethanol
11	Rheology identity	Hydroxyethyl cellulose
12	Surfactant identity	Polysorbate 20
13	Surfactant identity	Polysorbate 80
14	Salt identity	Naftifine hydrochloride
15	Specific embodiment (ranges near a target recipe)	2 wt% Naftifine HCl; 20 wt% propylene glycol; 19 wt% ethanol; 1.75 wt% hydroxyethyl cellulose; 5 wt% polysorbate (plus pH adjuster implied by dependent set)
16	Dependent in Claim 15 family	Glycol is propylene glycol
17	Dependent in Claim 15 family	Alcohol is ethanol
18	Dependent in Claim 15 family	Hydroxyethyl cellulose
19	Dependent in Claim 15 family	Polysorbate 20 or 80
20	Dependent in Claim 15 family	Naftifine hydrochloride
21	Fully specified “recipe”	Naftifine HCl 2%; propylene glycol 20%; ethanol 19%; polysorbate 20 5%; hydroxyethyl cellulose 1.75%; benzyl alcohol 1%; trolamine 0.17%; EDTA 0.02%; water; optional color/fragrance

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What is the likely patent strength profile based on claim structure?

Direct answer: Claim 1 is structurally strong because it ties together multiple formulation pillars (solvent system, rheology class, polysorbate solubilizer, pH band with amine base). That multiplicity reduces the set of design-arounds that preserve equivalent product performance while avoiding at least one required element.

Strength indicators from the claims

• Multiple quantified wt% ranges reduce easy entry by small compositional shifts.
• The combination of polysorbate + hydroxy cellulose + dual solvent architecture is a restrictive package.
• pH 4.5–6.0 plus amine base pH adjuster is an additional functional constraint that formulation teams cannot ignore.

Weakness indicators from the claims

• Claim 1’s method language can be satisfied by broad patient treatment wording if the gel is used for superficial fungal skin conditions that overlap the dependent list.
• If a competitor switches only excipients outside the listed quantitative ranges but keeps the same required architecture, infringement risk stays high.

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Key Takeaways

• US 9,161,914 is a naftifine topical gel formulation and method-of-use patent centered on Claim 1, with multiple ingredient-class and wt% constraints.
• The infringement “must-haves” are: naftifine (0.5–4%), glycol solvent (10–25%), alkyl alcohol solvent (10–25%), hydroxy cellulose rheology (0.75–2.25%, non-carbomer), polysorbate solubilizer (3–8%), and pH 4.5–6.0 via an amine base.
• Dependent claims narrow to superficial skin fungal infections, with interdigital tinea pedis and specific organisms appearing in lower layers.
• Claim 21 defines a specific formulation recipe including propylene glycol, ethanol, polysorbate 20, hydroxyethyl cellulose, benzyl alcohol, trolamine, and EDTA, which is the highest-risk blueprint for direct copy.
• The cleanest literal design-arounds are to break the Claim 1 pillars: avoid polysorbate, avoid hydroxy cellulose, exit the solvent wt% architecture, or move pH outside 4.5–6.0 / change pH adjuster away from amine base.

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FAQs

1) Does US 9,161,914 require that the product treat interdigital tinea pedis specifically?
No. Interdigital tinea pedis and the listed organisms appear in dependent claims. Claim 1 plus the superficial skin fungal infection limitation covers a broader set of superficial fungal conditions listed in dependent claim 3.

2) If a competitor uses polysorbate 80 instead of polysorbate 20, does that avoid the patent?
It avoids the narrower dependents that specify polysorbate 20, but Claim 1 still requires a polysorbate solubilizing agent, so the core limitation remains.

3) Can changing benzyl alcohol or EDTA avoid infringement of Claim 1?
Those components are optional in the claim context and are explicitly recited in the fully specified recipe of claim 21. Changing them may avoid dependent claim 21, but it does not avoid Claim 1 if the required classes, wt% ranges, and pH system remain.

4) What formulation changes are most likely to fall outside the “consisting essentially of” limitation?
Switching away from required constituent classes (e.g., replacing polysorbate with another solubilizer class, replacing hydroxy cellulose rheology, removing one solvent class, or using a non-amine pH adjuster) is most likely to break the “consisting essentially of” composition framework.

5) What is the most infringement-sensitive parameter to monitor in pH-controlled gels?
The gel pH of 4.5 to 6.0 and the use of an amine-base pH adjuster. Sliding pH outside the window or using a non-amine base is a direct literal avoidance lever for Claim 1.

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References (APA)

1. United States Patent and Trademark Office. (n.d.). U.S. Patent No. 9,161,914 (claims provided). USPTO.

Drugs Protected by US Patent 9,161,914

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Legacy	NAFTIN	naftifine hydrochloride	GEL;TOPICAL	204286-001	Jun 27, 2013	AB	RX	Yes	Yes	9,161,914					TREATMENT OF FUNGAL INFECTIONS

International Family Members for US Patent 9,161,914

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2014212201
Canada	2899725
World Intellectual Property Organization (WIPO)	2014121048