US Patent 9,861,698: Scope, Claims, Expiration and Patent Landscape for Nail Formulations

US Patent 9,861,698 protects a low-surface-tension, ethanol-rich topical formulation containing cyclomethicone, diisopropyl adipate and mixed C12-15 alkyl lactates. Its strongest commercial relevance is the vehicle used for topical delivery of antifungal agents to the nail and nail bed, including efinaconazole-type products. The patent does not claim a specific active ingredient in its independent formulation claim and does not protect the efinaconazole molecule itself.

The key limitations are:

Ethanol at least 50% w/w.
Cyclomethicone.
Diisopropyl adipate.
Mixed C12-15 alkyl lactates.
Surface tension of 40 dynes/cm or less.
No polymeric film-forming compound.
For the treatment claim, no solid film when applied to the nail.

The patent was granted on January 9, 2018. Based on its claimed priority framework, its projected ordinary patent expiration is in March 2034, subject to patent-term adjustment, terminal-disclaimer effects and the official USPTO patent-term calculation. [1]

What does US Patent 9,861,698 protect?

The patent protects a formulation architecture rather than a single active pharmaceutical ingredient.

Claim 1 covers a composition containing four mandatory vehicle components:

Required element	Claim limitation
Ethanol	At least 50% w/w
Cyclomethicone	Required, with a narrower 2%-15% w/w range in claim 6
Diisopropyl adipate	Required
Mixed C12-15 alkyl lactates	Required
Surface tension	40 dynes/cm or less
Film-forming polymers	Formulation must be free of polymeric film-forming compounds

The claim is broad in one important respect: claim 1 does not require an antifungal drug, a particular active ingredient, a specific dosage strength or a particular nail disease. It can therefore reach a vehicle sold for delivery of a drug to the nail even if the active ingredient differs from the commercial product associated with the patent.

The claim is narrower in another respect. A formulation that replaces any required excipient, uses a different alkyl lactate system, exceeds the surface-tension threshold or contains a polymeric film former may fall outside literal claim 1.

How do the individual claims differ?

Claims 1 through 5: surface-tension and vehicle claims

Claims 1 through 5 establish a descending surface-tension hierarchy:

Claim	Surface-tension limitation
Claim 1	40 dynes/cm or less
Claim 3	35 dynes/cm or less
Claim 4	30 dynes/cm or less
Claim 5	25 dynes/cm or less

Claims 3 through 5 are dependent claims. They retain every limitation of claim 1 while adding increasingly restrictive surface-tension thresholds.

A formulation at 28 dynes/cm could satisfy claims 1, 3 and 4, but not claim 5. A formulation at 24 dynes/cm could satisfy all four surface-tension claims if the remaining compositional requirements are met.

Surface tension is likely to be a central infringement issue because it depends on test method, temperature, instrument calibration, sample handling and formulation conditions. An accused product could dispute infringement by challenging either the measured value or whether the accused formulation contains the claimed excipient classes.

Claim 6: concentration ranges

Claim 6 requires:

Cyclomethicone at 2%-15% w/w.
Diisopropyl adipate and mixed C12-15 alkyl lactates together at 12%-60% w/w.

The claim does not require each of the latter two components to be present at a particular individual concentration, only that their combined concentration falls within the stated range. That creates design-around opportunities involving:

A cyclomethicone level above 15%.
A combined diisopropyl adipate and alkyl lactate level below 12% or above 60%.
Replacement of either component with a chemically different emollient or ester.

The separate presence of both diisopropyl adipate and mixed C12-15 alkyl lactates remains required.

Claim 7: preferred commercial formulation

Claim 7 identifies an approximate composition of:

13% w/w cyclomethicone.
Approximately 12% w/w diisopropyl adipate.
Approximately 10% w/w mixed C12-15 alkyl lactates.
Approximately 65% w/w ethanol.

The stated values total approximately 100% before adding any active ingredient. This creates a claim-construction issue if claim 7 is read as requiring those concentrations in the finished product while claim 10 adds an antifungal active. The term “about” may provide limited formulation flexibility, but it does not eliminate the need to reconcile the concentration requirements with the presence of an active ingredient and any residual excipients.

Claim 7 is commercially important because it identifies a narrow preferred vehicle. It is less valuable as a stand-alone barrier than claim 1 because a competitor can potentially vary one or more concentrations while remaining within the broader formulation concept or designing outside the patent altogether.

Claims 8 through 10: antifungal compositions

Claim 8 adds an antifungal active pharmaceutical ingredient.

Claim 9 narrows the active to an imidazole or triazole.

Claim 10 lists specific antifungals, including:

Miconazole.
Ketoconazole.
Clotrimazole.
Econazole.
Fluconazole.
Itraconazole.
Voriconazole.
Posaconazole.
Efinaconazole, identified by its chemical name in the final listed compound.

Claim 10 is significant because it ties the vehicle to a large set of known antifungal agents. It does not, however, create composition-of-matter protection for any of those molecules. A product using one of the listed drugs may infringe only if the complete formulation limitations are also satisfied.

Claim 11: method of treating nail disorders

Claim 11 covers a method involving:

A person suffering from a nail or nail-bed disorder.
Topical application to the nail surface.
An active pharmaceutical ingredient.
The four specified vehicle components.
Surface tension of 40 dynes/cm or less.
Ethanol at least 50% w/w.
No solid film when applied to the nail.
Application for an amount and duration sufficient to ameliorate signs and symptoms.

Claim 11 is narrower than claim 1 because it requires a therapeutic method and an active ingredient. It is also narrower than a conventional composition claim because infringement depends on the accused product’s use and labeling, although induced-infringement theories can apply where a manufacturer markets the product for the claimed nail treatment.

What technical problem does the patent address?

The patent’s technical focus is delivery through or across the nail plate without relying on a conventional polymeric nail lacquer film. Nail disorders present a delivery problem because the nail plate is dense, keratinized and relatively impermeable.

The claimed vehicle uses:

High ethanol content to promote rapid wetting and evaporation.
Cyclomethicone as a volatile silicone component.
Diisopropyl adipate as an emollient and penetration-related excipient.
Mixed C12-15 alkyl lactates as ester solvents or spreading agents.
Low surface tension to improve spreading across the nail surface.
No polymeric film-forming compound, which distinguishes the formulation from lacquer-based systems.

The patent therefore emphasizes surface coverage and penetration behavior rather than formation of a persistent solid film.

What formulations are protected by US 9,861,698?

A formulation is most exposed when it has the following profile:

Formulation characteristic	Exposure level
Ethanol at least 50% w/w	Required
Cyclomethicone present	Required
Diisopropyl adipate present	Required
Mixed C12-15 alkyl lactates present	Required
Surface tension no greater than 40 dynes/cm	Required
No polymeric film former	Required
Antifungal active	Increases commercial relevance
Nail or nail-bed indication	Relevant to claims 2 and 11
Surface tension no greater than 25 dynes/cm	Supports claim 5 exposure
Preferred concentration profile in claim 7	Highest formulation similarity

A product can avoid literal infringement by changing a mandatory component. Changing only the active ingredient may not be sufficient because the broad vehicle claims do not require a particular active.

How strong is the patent estate?

US 9,861,698 has moderate-to-strong formulation protection but does not provide broad drug exclusivity.

Strengths

The independent claim covers a vehicle independent of the active ingredient.
The claim combines composition, concentration and performance limitations.
The low-surface-tension requirement can capture products with materially similar spreading behavior.
Claims 8 through 10 extend coverage to multiple antifungal classes.
Claim 11 supports method-of-use enforcement for nail-disorder treatment.

Weaknesses

The claim requires four specific vehicle components.
Surface tension can be difficult to measure consistently and may create litigation over testing protocol.
A competitor can pursue a different solvent, ester or silicone system.
The patent does not claim the antifungal molecules themselves.
The “free of polymeric film-forming compounds” limitation may create a factual dispute over whether a formulation component has film-forming properties.
Claim 7’s approximate concentrations create a potential written-description and claim-construction issue when an active ingredient is added.

The estate is strongest against a product that copies the commercial vehicle closely. It is weaker against a reformulated product using a different spreading system or a formulation that creates low surface tension through alternative excipients.

When does US Patent 9,861,698 lose exclusivity?

Patent expiration timeline

Event	Date
Earliest priority framework	March 2013
Patent grant	January 9, 2018
Projected ordinary expiration	March 2034
Earliest practical generic-risk window	Before 2034 if validity, non-infringement or settlement issues remove the patent barrier
Statutory expiration adjustment	Confirmed by USPTO patent-term calculation

The effective loss of exclusivity does not necessarily occur on the expiration date. A generic applicant can submit an ANDA with a Paragraph IV certification before expiration and litigate the patent. FDA approval may occur before the patent expires, but commercial launch can remain subject to patent litigation, a court injunction, a settlement agreement or other enforceable restrictions.

What is the Orange Book status of the relevant product?

The commercial relevance of US 9,861,698 is principally associated with Jublia, the efinaconazole 10% topical solution marketed for onychomycosis. Jublia was approved by FDA in 2014 under NDA 203567. [2]

Orange Book analysis must distinguish among:

The approved drug product.
Listed formulation patents.
Listed method-of-use patents.
Pediatric exclusivity.
Any later patent listings or delistings.
Patent certifications submitted by ANDA applicants.

The Orange Book is the controlling public FDA source for approved-product patent listings and exclusivity data. US 9,861,698 should be evaluated together with the other Jublia-related patents listed for the approved product, rather than treated as the entire Jublia estate. [3]

The patent does not create biologic exclusivity because efinaconazole is a small molecule. A competitor would use the ANDA pathway, not the biosimilar pathway.

Which companies are challenging the patent?

No specific publicly established Paragraph IV challenger, settlement or launch date can be attributed to US 9,861,698 from the claim text alone. A reliable challenge assessment requires the current FDA Orange Book listing, ANDA patent-certification disclosures, court docket records and any public settlement filings.

The relevant legal question is whether an ANDA applicant challenges:

The patent’s validity.
The enforceability of the patent.
Whether the proposed formulation meets the claimed component requirements.
Whether the proposed product has surface tension of 40 dynes/cm or less.
Whether the proposed label induces use for a claimed nail disorder.
Whether the patent is properly listed for the reference product.

A Paragraph IV certification would create litigation risk under the Hatch-Waxman framework. A Paragraph III certification would defer approval until patent expiration. [4]

What patent litigation affects the product?

The principal litigation risk is formulation-based, not molecule-based. A patent suit would likely focus on:

Whether the accused product contains cyclomethicone.
Whether it contains diisopropyl adipate.
Whether it contains mixed C12-15 alkyl lactates.
Whether ethanol is at least 50% w/w.
Whether measured surface tension is 40 dynes/cm or less.
Whether any excipient is a polymeric film former.
Whether the proposed labeling directs treatment of a nail disorder.

The surface-tension limitation is likely to generate expert evidence. The parties would need to define the appropriate measurement conditions and determine whether the claim requires a specific method disclosed in the patent or an objectively reproducible industry method.

No settlement agreement should be assumed without a filed court document or public regulatory disclosure. A generic launch may occur through an agreed date, a license, a covenant not to sue, a successful non-infringement position or an invalidity judgment.

How does this patent compare with competing nail-antifungal estates?

Product or estate	Active	Principal protection type	Relationship to US 9,861,698
Jublia	Efinaconazole	Product, formulation and method patents	Closest commercial relationship
Kerydin	Tavaborole	Different active and formulation estate	Competes clinically but generally outside the claimed excipient combination
Penlac and generic ciclopirox	Ciclopirox	Older lacquer and method protection	Uses a different formulation platform
Oral terbinafine products	Terbinafine	Active and systemic-use history	Different route and delivery system
Generic topical antifungals	Various	Product-specific or unpatented formulations	May avoid the patent through different vehicles

US 9,861,698 is not a broad patent on topical antifungal nail treatment. It is a vehicle patent with dependent antifungal and nail-treatment coverage.

What generic launch risks exist?

The most credible launch pathways are:

Formulation design-around

A competitor can omit or replace one of the four required vehicle components. This is the cleanest route if the replacement product maintains adequate nail penetration without using the claimed excipient combination.

Surface-tension design-around

A formulation with surface tension above 40 dynes/cm may avoid claims 1 through 5, provided it does not infringe under the doctrine of equivalents. This route may affect spreading and delivery performance.

Film-forming design-around

A conventional lacquer or polymer-containing product may avoid the “free of polymeric film-forming compounds” limitation, although it could implicate other patents or regulatory comparability problems.

Active-ingredient substitution

Changing efinaconazole to another antifungal does not necessarily avoid the patent because claim 1 does not require a specific active. Substitution is more useful when combined with a different vehicle.

Method-label strategy

An ANDA applicant may seek a label that omits the patented method, subject to FDA approval requirements and induced-infringement risks. This strategy is fact-specific and cannot be evaluated solely from the claims.

What manufacturing and IP barriers matter?

The patent does not appear to require a complex manufacturing process. The main manufacturing controls are likely:

Accurate blending of volatile and nonvolatile excipients.
Control of ethanol concentration.
Uniform distribution of the silicone and ester components.
Container-closure compatibility.
Evaporation control.
Reproducible surface-tension testing.
Stability testing for the active ingredient and vehicle.

Manufacturing know-how may therefore provide a secondary barrier even where a competitor designs around the patent. The strongest practical barrier is likely product development and regulatory comparability, not an exclusive manufacturing process claim.

What is the revenue exposure?

The patent’s commercial exposure is tied to branded and authorized-generic sales of efinaconazole nail solution and potentially other antifungal products using the same vehicle. The patent does not by itself establish the revenue attributable to the formulation.

Revenue analysis should separate:

Sales of the reference product.
Authorized-generic sales.
Other products using the same active.
Products using the same vehicle with different actives.
Geographic sales outside the United States.
Revenue protected by other patents or regulatory exclusivity.

U.S. exposure is more direct because the patent is a U.S. right and Orange Book-listed patents can trigger Hatch-Waxman litigation. Foreign exposure depends on corresponding national patents, prosecution outcomes and local regulatory rules.

What is the geographic coverage?

US 9,861,698 provides protection only in the United States. International protection must be assessed through corresponding Patent Cooperation Treaty filings and national-phase patents.

Relevant jurisdictions for a commercial nail-antifungal product include:

Canada.
European Patent Convention states.
Japan.
South Korea.
China.
Australia.
Brazil.

A U.S. patent grant does not establish that the corresponding family members were granted, remain in force or have the same claim scope. Geographic freedom-to-operate analysis must compare the issued claims in each country.

Key Takeaways

US 9,861,698 is a formulation patent centered on a low-surface-tension, ethanol-rich nail-delivery vehicle.
Claim 1 requires ethanol, cyclomethicone, diisopropyl adipate and mixed C12-15 alkyl lactates.
The independent claim does not require an antifungal active or even a nail indication.
Claims 8 through 10 extend the formulation coverage to antifungal agents, including efinaconazole.
Claim 11 covers treatment of nail disorders using the claimed vehicle and a drug without forming a solid film.
The projected ordinary expiration is in March 2034, subject to the official USPTO patent-term calculation.
The main design-around options are excipient substitution, surface-tension modification and use of a polymeric film-forming system.
The patent does not protect the efinaconazole molecule itself and does not create biologic or biosimilar exclusivity.
Orange Book status and any Paragraph IV challenge must be assessed across the full Jublia patent listing, not this patent in isolation.
The strongest infringement case would involve a close copy of the preferred vehicle and a nail-antifungal indication.

FAQs About US Patent 9,861,698

Does US 9,861,698 cover efinaconazole itself?

No. It covers formulations containing a specified vehicle and, in dependent claims, antifungal actives including efinaconazole. It does not claim efinaconazole as a chemical compound.

Can a formulation infringe if it uses a different antifungal?

Yes. Claim 1 does not require an active ingredient. A different antifungal can still infringe if the complete vehicle and surface-tension limitations are met.

Does adding a polymer automatically avoid the patent?

It may avoid the “free of polymeric film-forming compounds” limitation, but the legal result depends on whether the added material is legally characterized as a polymeric film former and whether other claims or patents apply.

Is surface tension alone enough to determine infringement?

No. Surface tension is only one claim element. The accused product must also contain the required ethanol, cyclomethicone, diisopropyl adipate and mixed C12-15 alkyl lactates, together with the applicable concentration and film-forming limitations.

Can a generic launch occur before March 2034?

Potentially. A generic applicant could challenge the patent through a Paragraph IV certification, establish non-infringement or invalidity, obtain a settlement license, or launch after resolving applicable patent and regulatory barriers. Patent expiration is only one route to market entry.

References

United States Patent and Trademark Office. (2018). U.S. Patent No. 9,861,698, pharmaceutical formulation and methods for treating nail disorders.
U.S. Food and Drug Administration. (2014). FDA approves new treatment for toenail fungus.
U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2024). Hatch-Waxman amendments and ANDA patent certifications.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bausch	JUBLIA	efinaconazole	SOLUTION;TOPICAL	203567-001	Jun 6, 2014	AB	RX	Yes	Yes	9,861,698	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Summary for Patent: 9,861,698