US Patent 10,617,698: Calcipotriol-Betamethasone Sprayable Composition Patent Analysis

US Patent 10,617,698 protects a substantially anhydrous aerosol composition containing calcipotriol or calcipotriol monohydrate, betamethasone dipropionate, a high-volume propellant, a lipid carrier, and an antioxidant, with no propylene glycol. The patent is directed to sprayable topical formulations that improve calcipotriol permeation, and in some claim branches, betamethasone penetration, compared with a specified non-aerosol ointment.

The commercial product most closely associated with the claimed formulation is Enstilar, a calcipotriene and betamethasone dipropionate topical aerosol foam marketed by LEO Pharma. The patent is formulation-specific. It does not broadly cover every calcipotriol-betamethasone product, every aerosol dosage form, or every treatment method for psoriasis.

What does US Patent 10,617,698 protect?

The independent claim requires every one of the following elements:

Required element	Claim 1 requirement
Dosage form	Sprayable topical composition
Physical state	Substantially anhydrous
Vitamin D analog	Calcipotriol or calcipotriol monohydrate
Corticosteroid	Betamethasone dipropionate
Propellant	Pharmaceutically acceptable propellant
Propellant concentration	45% to 95% w/w
Lipid carrier	Pharmaceutically acceptable lipid carrier
Lipid-carrier concentration	5% to 55% w/w
Antioxidant	Pharmaceutically acceptable antioxidant
Exclusion	No propylene glycol
Functional result	Increased calcipotriol skin permeation versus the specified ointment comparator

The claim combines structural limitations with a performance limitation. A competing product must therefore be assessed both by its ingredients and concentrations and by the claimed Franz-cell permeation comparison.

The independent claim does not require a particular canister, valve, nozzle, foam density, or spray pattern. It also does not require dimethyl ether, butane, petrolatum, mineral oil, or a particular oily co-solvent. Those limitations appear in dependent claims.

How broad is the independent claim?

Claim 1 has meaningful breadth at the ingredient-class level but is narrower than a conventional composition claim because of the following constraints:

The product must be sprayable.
The formulation must be substantially anhydrous.
The propellant must constitute 45% to 95% of total composition weight.
The lipid carrier must constitute 5% to 55%.
An antioxidant must be present.
Propylene glycol must be absent.
The composition must satisfy the specified permeation comparison.

The claim covers multiple propellant systems. The dependent claims expressly identify C3-C5 alkanes, including n-butane, and dimethyl ether. A formulation using another pharmaceutically acceptable propellant may still fall within claim 1 if it satisfies the broader claim language.

The claim also covers both calcipotriol and calcipotriol monohydrate. The distinction matters because the claimed mass concentrations in claims 3, 18, and 19 are calculated differently depending on whether the active is measured as calcipotriol or as the monohydrate.

Which dependent claims cover Enstilar-type formulations?

Claims 3, 18, and 19 are particularly important because they recite concentrations corresponding closely to the approved calcipotriene and betamethasone dipropionate aerosol formulation.

Claim	Key limitation
3	52.2 mcg calcipotriol monohydrate and 0.643 mg betamethasone dipropionate per gram, excluding propellant
18	0.005% calcipotriol and 0.064% betamethasone dipropionate, excluding propellant
19	About 0.00522% calcipotriol monohydrate and 0.064% betamethasone dipropionate, excluding propellant
21	Dimethyl ether plus liquid paraffin and petrolatum
25	Petrolatum is white soft paraffin
26	Dimethyl ether, liquid paraffin, and white soft paraffin

The FDA-approved Enstilar label identifies calcipotriene hydrate at 0.005% and betamethasone dipropionate at 0.064% in an aerosol foam formulation. The label also identifies liquid paraffin, white petrolatum, polyoxypropylene-11 stearyl ether, and propellants among the inactive ingredients. Those facts create a close technical correlation with claims 19, 21, and 26, although infringement depends on the legally relevant product composition, claim construction, and current product specifications rather than label similarity alone. (U.S. Food and Drug Administration, 2015)

What formulations are protected by claims 4 through 16?

Claims 4 through 16 narrow the propellant, lipid carrier, and oily co-solvent categories.

Propellant limitations

Claims 4 through 6 cover C3-C5 alkanes:

Propane
Isopropane
n-Butane
Isobutane
Mixtures of those compounds

Claim 6 narrows the propellant to n-butane.

Claim 7 separately covers dimethyl ether. Claims 21 and 26 combine dimethyl ether with liquid paraffin and petrolatum or white soft paraffin.

A formulation using a hydrofluoroalkane or another propellant could avoid claims 4 through 7, but it would not necessarily avoid claim 1. The broader claim does not limit the propellant to an alkane or dimethyl ether.

Lipid carrier limitations

Claim 8 requires petrolatum. Claim 25 narrows petrolatum to white soft paraffin.

Claim 21 requires a mixture of liquid paraffin and petrolatum. Claim 26 narrows that combination to liquid paraffin and white soft paraffin.

A formulation with a non-petrolatum lipid carrier may avoid these dependent claims while remaining exposed to claim 1.

Oily co-solvent limitations

Claims 9 through 16 cover several oily co-solvent families:

Claim	Co-solvent category
9	Any pharmaceutically acceptable oily co-solvent with petrolatum
10	Polyoxypropylene-polyether compounds
11	Specific polyoxypropylene ethers
12	Isopropyl esters of C10-C18 fatty acids
13	Isopropyl myristate, palmitate, isostearate, linolate, or monooleate
14	C8-C24 alkanols or alkenols
15	Specific straight, unsaturated, or branched alcohols
16	Myristyl alcohol

Claim 20 specifically requires myristyl alcohol in the formulation branch established by claim 17.

These claims create a layered formulation estate. A generic or follow-on manufacturer could avoid some dependent claims by changing the co-solvent, while still facing claim 1 if the product retains the required active ingredients, propellant percentage, lipid carrier, antioxidant, anhydrous character, and permeation result.

What are the concentration limitations?

Claims 17 through 19 provide the principal concentration ranges and commercial-strength embodiments.

Claim 17 requires:

Calcipotriol or calcipotriol monohydrate: 0.001% to 0.05% w/w
Betamethasone dipropionate: 0.0005% to 1% w/w
Oily co-solvent: 0.1% to 10% w/w

Claim 18 specifies:

Calcipotriol: 0.005%, excluding propellant
Betamethasone dipropionate: 0.064%, excluding propellant

Claim 19 specifies:

Calcipotriol monohydrate: approximately 0.00522%, excluding propellant
Betamethasone dipropionate: 0.064%, excluding propellant

The phrase excluding propellant is commercially important. Because the propellant can represent up to 95% of total composition weight, active concentrations calculated on a total-canister basis can differ materially from concentrations calculated on the non-propellant formulation basis.

A product specification should therefore be analyzed using at least two calculations:

Active concentration per total composition weight.
Active concentration per non-propellant formulation weight.

An apparent concentration difference may not avoid the claim if the difference results only from the denominator used.

How does the skin-permeation limitation affect infringement?

Claim 1 requires increased calcipotriol permeation compared with a defined ointment. Claim 2 requires at least approximately two-fold increased permeation.

The test is defined by:

Full-thickness pig ear skin
Franz diffusion cell
Twenty-one hours of exposure
Percent of applied calcipotriol dose reaching receptor fluid

Claims 23 and 24 use a different performance endpoint for betamethasone:

Percent of applied betamethasone dipropionate in the dermis and epidermis
Full-thickness pig ear skin
Franz cell
Twenty-one hours
At least approximately two-fold increase for claim 24

These limitations create evidentiary issues in an infringement dispute. A patentee would likely need to establish that the accused composition satisfies the claimed comparative result under the claim-defined or scientifically equivalent protocol. A product that contains the same ingredients but fails the required permeation comparison may contest literal infringement of the relevant claim.

The functional limitations also create potential validity and construction disputes involving:

Reproducibility of the pig-ear-skin assay
Variability between Franz-cell laboratories
Selection and preparation of the ointment comparator
Statistical treatment of receptor-fluid measurements
Whether "increased" is an inherent property of the composition
Whether the comparison must be performed on the accused commercial product

A formulation can therefore have a high composition overlap but a weaker infringement position if its permeation profile differs materially.

What patent term and expiration issues apply?

US Patent 10,617,698 issued on April 14, 2020. Its enforceable term is generally governed by the 20-year term measured from the earliest relevant nonprovisional filing date, subject to patent term adjustment, terminal disclaimers, and any applicable patent term extension. The issue date alone does not establish the expiration date. (35 U.S.C. § 154)

The patent front page and USPTO Patent Center record should control the expiration analysis because the following factors can change the term:

Patent term adjustment
A terminal disclaimer over an earlier patent
Continuation or divisional relationships
Any patent term extension under 35 U.S.C. § 156
Maintenance-fee status
Reinstatement after lapse, if applicable

The patent is not a biologic patent and does not create biosimilar exclusivity. Its competitive significance is in small-molecule generic and authorized-generic entry, not the biosimilar pathway.

What is the Orange Book status of US 10,617,698?

Enstilar is an FDA-approved prescription drug containing calcipotriene and betamethasone dipropionate in aerosol foam form. Drug-product patents listed in the FDA Orange Book can impose certification obligations on an ANDA applicant under the Hatch-Waxman framework. (FDA, 2024; 21 U.S.C. § 355(j))

The relevant Orange Book questions are:

Issue	Business significance
Whether US 10,617,698 is listed against Enstilar	Determines whether an ANDA applicant must address it
Whether the listing is active	Affects current certification and litigation exposure
Listed claims	Determines whether the patent covers the proposed product
Patent expiration date	Determines potential generic launch timing
Pediatric exclusivity	Can extend the effective restraint period by six months
Paragraph IV certification	Can trigger patent litigation and a 30-month stay

A patent listing does not establish validity or infringement. An ANDA applicant may file a Paragraph IV certification asserting that the patent is invalid, unenforceable, or not infringed. The brand holder may then bring an action under 35 U.S.C. § 271(e)(2). A timely suit can trigger the statutory 30-month stay, subject to statutory exceptions and court action. (21 U.S.C. § 355(j)(5)(B)(iii))

The supplied claim text is not enough to establish the patent's current Orange Book listing, any delisting, or the exact remaining term.

Which companies are likely to challenge the patent?

The relevant challenger group consists of manufacturers seeking an ANDA for a generic calcipotriene and betamethasone dipropionate aerosol foam. Potential challengers would generally include:

Generic topical dermatology companies
Contract development and manufacturing organizations with aerosol capability
Companies marketing generic calcipotriene or betamethasone products
Authorized-generic partners
Specialty pharmaceutical companies seeking a non-ANDA 505(b)(2) route

A challenger must address more than active-ingredient identity. The principal technical barriers are:

Aerosol manufacturing and filling.
Propellant compatibility.
Uniform suspension or solution behavior.
Valve and actuator performance.
Anhydrous stability.
Low-dose content uniformity.
Antioxidant control.
Skin-permeation equivalence or bioequivalence strategy.
Patent claims directed to the formulation rather than only the active ingredients.

No specific Paragraph IV challenger, settlement agreement, or litigation outcome can be assigned from the claim text alone.

How strong is the patent estate?

The claim set has moderate-to-strong blocking value against close copies of the commercial aerosol formulation, particularly products containing:

Calcipotriol monohydrate at approximately 0.00522%
Betamethasone dipropionate at 0.064%
Dimethyl ether
Liquid paraffin
White soft paraffin
An oily co-solvent such as polyoxypropylene-11 stearyl ether
No propylene glycol

Its strength is lower against products that materially alter one or more claim-critical variables:

Design-around route	Potential effect
Replace aerosol propellant with a pump spray	May avoid the propellant limitations
Use a non-anhydrous formulation	May avoid claim 1
Add propylene glycol	Express exclusion may defeat claim 1
Change the lipid carrier	May avoid petrolatum-dependent claims
Change active concentrations	May avoid claims 3, 17, 18, and 19
Use a different co-solvent	May avoid claims 9-16 and 20-22
Use a different propellant	May avoid claims 4-7, but not necessarily claim 1
Use a formulation without the claimed permeation result	May challenge the functional limitation
Use a different dosage form	May avoid the sprayable-composition claims

The patent is therefore strongest against a product designed to reproduce Enstilar's formulation and aerosol architecture. It is less dominant against alternative topical delivery systems.

What manufacturing and intellectual-property barriers remain?

The patent claims create manufacturing barriers in addition to legal barriers. A noninfringing product would still need to solve:

Accurate metering of microgram-level calcipotriol
Homogeneous distribution of betamethasone dipropionate
Propellant-driven spray or foam formation
Container and valve compatibility
Oxidative stability
Control of water content
Residual solvent and extractables limits
Batch-to-batch delivery consistency
Topical product performance testing

A product can avoid the literal wording of claims 3 and 19 yet remain exposed to broader claim 1 or to other family patents covering aerosol delivery, vehicle selection, stability, or therapeutic use.

How does this patent compare with method-of-use and formulation patents?

US 10,617,698 is primarily a composition and formulation patent.

Patent category	What it typically protects	Relevance here
Active-ingredient patent	Calcipotriol, betamethasone, or a combination	Likely older and narrower by current date
Formulation patent	Vehicle, propellant, concentrations, stability, delivery	Core category for US 10,617,698
Method-of-use patent	Treating psoriasis or another dermatologic condition	May create separate launch risk
Device patent	Canister, valve, actuator, or dispensing system	May affect aerosol manufacturing
Process patent	Manufacturing, filling, mixing, or suspension control	May create production barriers
Regulatory exclusivity	FDA market protection	Separate from patent rights

A generic applicant may avoid a method-of-use patent through a section viii statement while still confronting formulation patents. Conversely, a formulation patent may remain relevant even where the applicant omits a patented indication.

What is the likely generic launch risk?

The principal launch scenarios are:

Scenario 1: Same-strength aerosol foam

This is the highest-risk pathway. A product matching the commercial concentration, propellant system, lipid carrier, and oily co-solvent would likely face the greatest exposure to claims 1, 2, 3, 17, 19, 21, and 26.

Scenario 2: Alternative aerosol formulation

A manufacturer could change the propellant, carrier, co-solvent, or active concentration. This may avoid some dependent claims but could remain within claim 1. The permeation limitation would become central to the infringement analysis.

Scenario 3: Non-aerosol topical product

A cream, ointment, gel, lotion, or pump spray could avoid the sprayable aerosol claims. It would still need to address other patents, regulatory requirements, and potential product-specific exclusivities.

Scenario 4: 505(b)(2) product

A 505(b)(2) applicant could pursue a modified dosage form or delivery system while relying partly on FDA findings for the reference product. This route may reduce some ANDA-specific issues but does not eliminate patent litigation risk.

What patent litigation and settlement issues matter?

For a Paragraph IV challenge, the key issues would likely include:

Whether the accused product is substantially anhydrous
Whether the propellant represents 45% to 95% w/w
Whether the carrier qualifies as a lipid carrier
Whether an antioxidant is present
Whether propylene glycol is absent
Whether the product meets the calcipotriol permeation limitation
Whether claims 2 and 24 are indefinite or insufficiently reproducible
Whether the comparative assay is an inherent property
Whether the claims are anticipated or obvious over prior aerosol and topical formulations
Whether the patent was properly listed in the Orange Book

A settlement could provide a licensed entry date, authorized-generic arrangement, supply agreement, or other commercial resolution. The supplied information does not establish a specific settlement, license, or active litigation outcome involving this patent.

Key Takeaways

US 10,617,698 is a formulation patent directed to a substantially anhydrous calcipotriol-betamethasone aerosol composition.
Claim 1 requires 45% to 95% propellant, 5% to 55% lipid carrier, an antioxidant, no propylene glycol, and increased calcipotriol permeation.
Claims 19, 21, and 26 closely track the composition profile of Enstilar aerosol foam.
The patent is strongest against a same-strength aerosol copy using dimethyl ether, liquid paraffin, petrolatum, and the specified active concentrations.
Alternative propellants, carriers, co-solvents, dosage forms, and active concentrations may create design-around opportunities.
The Franz-cell permeation limitations are central to both infringement and validity analysis.
The patent does not create biosimilar risk because calcipotriol and betamethasone dipropionate are small-molecule active ingredients.
Exact patent expiration, current Orange Book listing, Paragraph IV activity, litigation status, and settlement status require the controlling USPTO, FDA, and court records rather than the claim text alone.

FAQs

Does US 10,617,698 cover all calcipotriol and betamethasone dipropionate products?

No. The claims focus on sprayable, substantially anhydrous compositions with defined propellant and lipid-carrier requirements. Conventional creams and ointments generally fall outside the independent claim.

Can a formulation containing propylene glycol infringe US 10,617,698?

Literal infringement of claim 1 would be difficult because the claim expressly excludes propylene glycol. Other patent claims in the same family or separate patents could still be relevant.

Does changing n-butane to dimethyl ether avoid the patent?

No. The patent expressly covers dimethyl ether in dependent claim 7 and in the combination claims. A change between those propellants does not by itself establish a design-around.

Are claims 2 and 24 limited to a two-fold permeation increase?

Yes. Claim 2 requires at least approximately two-fold increased calcipotriol permeation. Claim 24 requires at least approximately two-fold increased betamethasone penetration under the stated skin assay.

Is US 10,617,698 a biosimilar patent?

No. It is a small-molecule topical formulation patent. A competing product would generally follow an ANDA or 505(b)(2) pathway rather than the biosimilar pathway.

References

U.S. Patent No. 10,617,698. (2020). Sprayable topical pharmaceutical composition comprising calcipotriol and betamethasone dipropionate. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2015). Enstilar aerosol foam prescribing information. FDA.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.
21 U.S.C. § 355. (2024). New drugs.
35 U.S.C. § 154. (2024). Contents and term of patent; provisional rights.
35 U.S.C. § 271(e)(2). (2024). Infringement of patent based on submission of an application under section 505 of the Federal Food, Drug, and Cosmetic Act.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Leo Pharma As	ENSTILAR	betamethasone dipropionate; calcipotriene	AEROSOL, FOAM;TOPICAL	207589-001	Oct 16, 2015		RX	Yes	Yes	⤷ Start Trial	⤷ 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

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2011264198	⤷ Start Trial
Brazil	112012030653	⤷ Start Trial
Canada	2800181	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,617,698

Which drugs does patent 10,617,698 protect, and when does it expire?

Summary for Patent: 10,617,698