US Patent 9,956,231: Clobetasol Topical Composition Claims, Patent Scope, and Market Landscape
US Patent No. 9,956,231 protects a narrow formulation platform for a non-foaming, propellant-free, propylene glycol-free topical clobetasol product. The patent does not broadly cover clobetasol, clobetasol propionate, or every clobetasol cream. Its commercial significance lies in the combination of four formulation elements: clobetasol, a defined emulsifier, a defined skin-penetration enhancer, a water-immiscible substance, and water.
The patent is most closely associated with Taro Pharmaceuticals' IMP0YZ, a clobetasol propionate 0.025% cream. The core composition claim is broad in ingredient categories but constrained by concentration ranges and negative limitations. A competing product can avoid infringement by omitting a required element, moving outside a claimed concentration range, using a materially different dosage form, or relying on a non-equivalent formulation architecture.
What does US Patent 9,956,231 cover?
The patent covers topical pharmaceutical compositions containing clobetasol in an oil-in-water or related emulsion system that is:
- Non-foaming;
- Free of propylene glycol;
- Free of propellant;
- Formulated with water;
- Formulated with a water-immiscible substance;
- Formulated with an emulsifying agent at approximately 0.25% to 45% by weight; and
- Formulated with a skin-penetration enhancer at approximately 0.001% to 15% by weight.
Independent claim 1 is the principal composition claim. Claim 9 is the principal method-of-treatment claim.
| Claim |
Subject matter |
Commercial relevance |
| 1 |
Topical composition with clobetasol, emulsifier, penetration enhancer, water-immiscible substance, and water |
Main formulation claim |
| 2 |
Claim 1 where clobetasol is clobetasol propionate |
Directly targets the principal marketed active |
| 3 |
Broad classes of cationic, anionic, zwitterionic, or amphoteric emulsifiers |
Expands formulation coverage |
| 4 |
Specific emulsifiers and surfactant systems |
Captures common commercial excipients |
| 5 |
Broad classes of penetration enhancers |
Expands chemical scope |
| 6 |
Specific penetration enhancers |
Captures named formulation options |
| 7 |
Specific water-immiscible materials |
Covers oils, triglycerides, waxes, and related materials |
| 8 |
Addition of an emollient |
Covers further cream and emulsion configurations |
| 9 |
Treatment of specified dermatologic conditions |
Method-of-use protection |
How broad is claim 1 of US 9,956,231?
Claim 1 is structurally broad but technically demanding. It uses open-ended "comprising" language, meaning additional ingredients generally do not avoid infringement. A product may contain preservatives, humectants, antioxidants, buffers, fragrances, stabilizers, or other excipients and still fall within the claim.
The required elements operate cumulatively. A potentially infringing product must contain:
- Clobetasol;
- An emulsifying agent within the stated range;
- A skin-penetration enhancer within the stated range;
- A water-immiscible substance;
- Water;
- No propylene glycol;
- No propellant; and
- A non-foaming dosage form.
The claim therefore has a broad positive-element scope but meaningful design-around limitations. A clobetasol foam containing a hydrocarbon propellant is outside the literal scope of claim 1 because it is propellant-containing and foaming. A propylene glycol-containing cream is also outside the literal scope of the express composition claim.
The phrase "about" creates some tolerance around the stated concentration boundaries. Its precise reach would depend on intrinsic evidence, specification examples, prosecution history, and expert testimony. Concentrations materially outside the listed ranges present a stronger non-infringement position than marginal deviations.
What formulations are protected by US Patent 9,956,231?
The dependent claims protect a wide range of emulsion formulations. The patent is not limited to one named commercial excipient.
Emulsifying agents
Claims 3 and 4 cover:
- Sorbitan fatty acid esters;
- Partial ester mixtures of sorbitol and its anhydrides;
- Polyethylene glycol stearates;
- Glycol stearates;
- Sodium lauryl sulfate;
- Cetyl trialkyl ammonium bromide;
- Polyoxyethylene sorbitan fatty acid esters;
- Glyceryl stearate; and
- Combinations of these materials.
This language reaches common nonionic and ionic emulsifier systems used in topical creams. Claim 4 is particularly important because it converts broad functional categories into named chemical classes.
Skin-penetration enhancers
Claims 5 and 6 cover penetration enhancers from several chemical families:
- Polyols and polyol esters;
- Ethers;
- Sulfoxides;
- Fatty acids;
- Fatty acid esters.
Named examples include butanediol, polyethylene glycol monolaurate, diethylene glycol monoethyl ether, dimethyl sulfoxide, decyl methyl sulfoxide, lauric acid, oleic acid, valeric acid, isopropyl myristate, isopropyl palmitate, methyl propionate, and ethyl oleate.
The penetration-enhancer limitation is a central infringement issue. A formulation can contain an oil and water yet avoid claims 1 through 6 if the accused material does not qualify as a skin-penetration enhancer under the claim construction and evidence applied in the case.
Water-immiscible substances
Claim 7 covers:
- Vegetable oils;
- Saturated paraffin oil;
- Mineral oil;
- Fatty acids;
- Fatty esters of natural fatty acids;
- Animal or vegetable triglycerides;
- Medium-chain triglycerides;
- Mono-, di-, and triglyceride mixtures;
- Waxes; and
- Hydrogenated vegetable oils.
The claim reaches both conventional emollient oils and structured lipid systems. A water-immiscible material is mandatory under claim 1, so a clear aqueous gel without an oil or comparable immiscible phase would not ordinarily satisfy the composition claim.
Does the patent cover IMP0YZ?
US Patent 9,956,231 is associated with the formulation technology used for IMP0YZ clobetasol propionate cream 0.025%, marketed by Taro Pharmaceuticals. IMP0YZ is an FDA-approved topical corticosteroid product for plaque psoriasis and related corticosteroid-responsive dermatoses. The product is a cream rather than a foam and is marketed without propylene glycol as a principal vehicle component.[1][2]
Claim 2 specifically recites clobetasol propionate. That claim is commercially more targeted than claim 1 because it narrows the active ingredient to the ester used in IMP0YZ and most high-potency clobetasol products.
The patent does not mean that every clobetasol propionate cream infringes. The accused product would also need to satisfy the emulsion, enhancer, water-immiscible phase, water, concentration, non-foaming, propellant-free, and propylene glycol-free limitations.
When does US Patent 9,956,231 lose exclusivity?
The patent issued on May 1, 2018. Based on the patent's US filing and priority framework, its ordinary 20-year patent term runs into February 2033, subject to any patent-term adjustment, terminal disclaimer, or other adjustment reflected in the official patent record.[3]
| Event |
Date or period |
| Earliest claimed priority |
February 2012 |
| US patent application period |
2013 filing period |
| Publication |
2014 publication period |
| Patent grant |
May 1, 2018 |
| Expected ordinary term endpoint |
February 2033 |
| Relevant commercial window |
FDA exclusivity and patent term through the early 2030s |
The grant date does not control expiration. For a utility patent, the term generally runs 20 years from the earliest effective nonprovisional filing date, not 20 years from issuance. Patent-term adjustment can extend the calculated expiration date.
What is the Orange Book status of US Patent 9,956,231?
US Patent 9,956,231 has been associated with the FDA-approved IMP0YZ product and is relevant to Orange Book patent analysis for clobetasol propionate cream 0.025%.[4] Orange Book relevance depends on the specific approved product, NDA, dosage form, strength, and listed patent use code.
The listing does not automatically block every generic clobetasol product. It gives the NDA holder a basis to invoke Hatch-Waxman procedures against an ANDA applicant that certifies under Paragraph IV that the listed patent is invalid, unenforceable, or not infringed.
A generic applicant could instead:
- File a Paragraph III certification and wait for patent expiration;
- Submit a Paragraph IV certification and litigate;
- Establish that its formulation does not meet the listed claim limitations; or
- Rely on a product or dosage form outside the patent's approved-product scope.
The Orange Book should be reviewed by NDA and strength because patent listings can differ between a cream, lotion, gel, solution, shampoo, and foam.
What Paragraph IV challenges and generic-entry risks exist?
The most important generic-entry risk is a formulation-specific Paragraph IV challenge directed to claim 1 or claim 2. The principal arguments would likely focus on:
- The accused formulation's use of propylene glycol;
- The absence of a water-immiscible phase;
- The absence or concentration of a qualifying penetration enhancer;
- A non-emulsified dosage form;
- Concentrations outside the claimed ranges;
- A foaming or propellant-containing architecture; or
- Invalidity based on obviousness in view of known clobetasol emulsions and penetration-enhancer systems.
The patent's vulnerability is greater if the prior-art record shows that clobetasol, emulsifiers, oils, water, and penetration enhancers were each well known and that the claimed combination produced no unexpected result. Its strength improves if the specification and prosecution record document a specific technical advantage from omitting propylene glycol while maintaining delivery, stability, tolerability, or clinical performance.
A generic product that copies the IMP0YZ composition closely faces greater risk than a product using a propylene glycol vehicle, a foam architecture, or a different non-emulsion delivery system.
How strong is the patent estate for clobetasol topical products?
The patent estate is stronger for a specific propylene glycol-free emulsion than for clobetasol generally. Its main strengths are:
- A composition claim with open-ended "comprising" language;
- Coverage of clobetasol propionate;
- Broad excipient classes;
- Numerous listed emulsifiers and penetration enhancers;
- Coverage of several oil and lipid systems; and
- A method claim directed to commercially relevant dermatologic conditions.
Its principal weaknesses are:
- The claim requires multiple formulation elements;
- The negative limitations create straightforward design-around routes;
- The patent does not broadly claim all clobetasol formulations;
- The concentration ranges may require detailed product testing;
- The method claim depends on use for specified conditions; and
- Known topical corticosteroid technology may create obviousness pressure.
The patent is therefore best characterized as a focused formulation patent, not a foundational active-ingredient patent.
How does US Patent 9,956,231 compare with competing clobetasol products?
| Product or platform |
Dosage form |
Propellant |
Propylene glycol relevance |
Relationship to US 9,956,231 |
| IMP0YZ |
Cream |
No |
Designed as a PG-free product |
Closest commercial embodiment |
| Temovate and generic clobetasol creams |
Cream |
No |
Vehicle varies by manufacturer |
Infringement depends on full composition |
| Clobetasol foam products |
Foam |
Typically yes |
Formulation varies |
Often outside claim 1 due to foaming or propellant |
| Clobetasol solutions |
Solution |
Usually no |
Vehicle varies |
May lack emulsifier, water-immiscible phase, or emulsion structure |
| Clobetasol shampoos |
Shampoo |
No |
Vehicle varies |
Product-specific analysis required |
| Clobetasol ointments |
Ointment |
No |
Often low or absent water |
May lack the required water component |
The patent creates the highest competitive barrier against a generic cream designed to replicate IMP0YZ's sensory profile and vehicle strategy. It creates a lower barrier against alternate dosage forms.
What litigation and settlement issues affect the patent?
A Paragraph IV notice concerning a listed patent can trigger a 30-month stay of FDA approval under the Hatch-Waxman Act, subject to statutory exceptions and litigation events.[5] The relevant litigation questions include:
- Whether the ANDA product contains a claimed emulsifier;
- Whether the penetration enhancer is present within the claimed range;
- Whether the product contains a water-immiscible substance;
- Whether propylene glycol is absent;
- Whether the dosage form is non-foaming;
- Whether the asserted claims are invalid for obviousness;
- Whether the listed patent properly corresponds to the approved product; and
- Whether a settlement restricts the generic launch date.
A settlement could provide an agreed launch date before patent expiration, an authorized generic arrangement, a license, or a covenant not to sue. No settlement term should be inferred from the patent claims alone. FDA approval timing, court dockets, and any publicly filed settlement documents control.
What manufacturing and intellectual-property barriers remain?
Manufacturing a non-foaming, water-containing clobetasol emulsion requires control over:
- Droplet size and phase distribution;
- Emulsifier concentration;
- Active uniformity;
- Microbial control;
- Physical stability;
- Viscosity and spreadability;
- Skin delivery;
- Preservation;
- Scale-up mixing conditions; and
- Container compatibility.
These manufacturing features may create practical barriers even where a competitor designs around the claims. They do not, by themselves, create patent protection. Separate process, stability, packaging, or manufacturing patents would need independent analysis.
Key Takeaways
- US Patent 9,956,231 is a formulation patent directed to non-foaming, propellant-free, propylene glycol-free topical clobetasol compositions.
- Claim 1 is the central claim and requires clobetasol, an emulsifier, a penetration enhancer, a water-immiscible substance, and water.
- Claim 2 specifically targets clobetasol propionate, the active ingredient in IMP0YZ.
- Claims 3 through 8 expand protection across common surfactants, oils, lipid materials, penetration enhancers, and emollients.
- Claim 9 covers treatment of specified dermatologic conditions.
- The patent is strongest against close copies of a propylene glycol-free clobetasol cream and weaker against foams, ointments, solutions, shampoos, and materially different emulsions.
- The expected ordinary patent-term endpoint is in February 2033, subject to official patent-term adjustment or disclaimer data.
- Paragraph IV risk turns on the accused formulation's complete qualitative and quantitative composition, not merely its use of clobetasol.
- The patent protects a delivery system, not clobetasol or clobetasol propionate as such.
FAQs
Does US Patent 9,956,231 cover all clobetasol creams?
No. The cream must satisfy every required limitation of an asserted claim, including the emulsifier, penetration enhancer, water-immiscible substance, water, non-foaming, propylene glycol-free, and propellant-free requirements.
Can a propylene glycol-containing generic avoid US 9,956,231?
It would have a strong literal non-infringement position against claims containing the express propylene glycol-free limitation. The complete formulation and any doctrine-of-equivalents argument would still require analysis.
Does the patent cover clobetasol foam?
Generally, a product that is genuinely foaming or contains a propellant would not satisfy the express limitations of claim 1. A foam product could raise separate issues under other claims or patents.
Is claim 9 a broad patent on treating psoriasis with clobetasol?
No. Claim 9 is tied to administering a composition according to claim 1. The method claim does not independently cover every topical clobetasol treatment.
What is the main design-around strategy for a generic manufacturer?
The clearest routes are to use propylene glycol, omit water, omit the water-immiscible phase, use a non-emulsion dosage form, alter the penetration-enhancer system, or develop a foaming or propellant-containing product.
References
- U.S. Food and Drug Administration. (2015). IMP0YZ (clobetasol propionate) cream, 0.025% prescribing information.
- Taro Pharmaceuticals U.S.A., Inc. (2015). IMP0YZ product labeling and prescribing information.
- United States Patent and Trademark Office. (2018). U.S. Patent No. 9,956,231, topical pharmaceutical compositions comprising clobetasol.
- U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- 21 U.S.C. ยง 355(j), abbreviated new drug applications and patent certifications.
