Scope of US Drug Patent 11,938,141 (cortexolone-17α-propionate topical crystalline Forms I–IV): claim-level coverage, landscape signals, and freedom-to-operate implications
What is the subject matter and claim scope of US 11,938,141 for cortexolone-17α-propionate?
Answer: US 11,938,141 claims topical pharmaceutical compositions where cortexolone-17α-propionate is present as a crystalline material in at least two specific crystalline forms (Forms I–IV) defined by X-ray powder diffraction (XRPD/DRX) peak positions. Dependent claims narrow combinations of those forms and recite a 0.1% to 2% w/w active range.
Core claim architecture (independent claim 1)
Claim 1 is a product-by-combination-of-crystal-forms claim:
- Dosage form: topical composition
- Active: cortexolone-17α-propionate
- Crystallinity requirement: at least two crystalline forms selected from Form I, Form II, Form III, Form IV
- Identification standard: each form is characterized by a DRX (XRPD) pattern with minimum peak presence at listed 2θ values (degrees)
This yields a claim that is not defined by excipients, skin method, particle size distribution, or manufacturing steps. Instead, it is anchored on the presence and identity of crystalline forms via XRPD peak criteria.
How the DRX peak lists delimit each crystalline form
Claim 1 sets form boundaries by listing “at least peaks” at specified 2θ angles, which is a threshold-based pattern definition rather than a complete diffractogram fingerprint. The claimed forms are:
- Form I: peaks at about 7.6, 8.4, 17.0, 20.1 2θ
- Form II: peaks at about 10.8, 13.3, 16.5, 21.9 2θ
- Form III: peaks at about 6.2, 12.6, 22.4, 23.7 2θ
- Form IV: peaks at about 4.8, 12.9, 19.5 2θ
Practical scope consequence: a competitor’s material is at risk if their XRPD shows the required peak set for a form (subject to claim construction on “about” and measurement conditions).
Minimal “at least two forms” requirement drives breadth
Claim 1 requires two or more forms among I–IV. That means coverage includes:
- binary mixtures (any two of the four forms), and
- ternary mixtures, and
- quaternary mixtures (all four).
Dependent claims explicitly recite some of those binaries and ternaries, but claim 1 already captures them if they satisfy the “at least two” requirement.
Which crystalline form combinations are explicitly claimed in dependent claims?
Answer: Dependent claims 2–5 tie each binary/combination to a specific “base” form plus “any of” the other forms. Dependent claims 7–12 specify multi-form compositions centered on Form III or Form IV.
Dependent claims 2–5: “Form X plus any of the others”
- Claim 2: composition comprises Form I and any of Forms II, III, IV or any combination thereof
Covered sets include: {I+II}, {I+III}, {I+IV}, {I+II+III}, {I+II+IV}, {I+III+IV}, {I+II+III+IV}
- Claim 3: comprises Form II and any of Forms I, III, IV
Covered sets include: {II+I}, {II+III}, {II+IV}, {I+II+III}, {I+II+IV}, {II+III+IV}, {I+II+III+IV}
- Claim 4: comprises Form III and any of Forms I, II, IV
- Claim 5: comprises Form IV and any of Forms I, II, III
Scope implication: Claims 2–5 effectively function as umbrella combination claims starting from each form.
Dependent claims 6–12: concentration and enumerated multi-form subsets
- Claim 6: for claim 5 compositions, cortexolone-17α-propionate present 0.1% to 2% w/w
- Claim 7: for claim 5, composition comprises Forms III and IV
- Claim 8: for claim 5, composition comprises Forms I, II, and IV
- Claim 9: for claim 5, composition comprises Forms I, III, and IV
- Claim 10: for claim 5, composition comprises Forms I and IV
- Claim 11: for claim 5, composition comprises Forms II, III, and IV
- Claim 12: for claim 5, composition comprises Forms II and IV
What this means for design-around
Because the independent claim already covers “at least two” forms, design-around is usually pursued by changing at least one of:
- the crystalline form identity (avoid meeting the XRPD “at least peaks” definition for a specific form), or
- reducing the composition to a single crystalline form (no longer “at least two”), or
- changing the active to a form that is not cortexolone-17α-propionate crystalline Forms I–IV as defined.
What is the likely enforceable claim scope for a topical product under US 11,938,141?
Answer: The claim is enforceable at the drug substance crystalline identity level and the product level (topical composition). It does not require a specific base cream/ointment/gel platform in the provided claim text, so scope can extend across topical vehicles as long as the crystalline-form criteria are met.
Covered features likely inferred from the claim text
Even without dependent excipient claims provided, claim 1 covers:
- Any topical vehicle (cream, ointment, gel, lotion) so long as it qualifies as a “topical composition”
- Any manufacturing process as long as the final product contains the XRPD-defined crystalline forms in the required combination
Non-covered features (based on claim text provided)
The claim text you provided does not recite limitations that would usually narrow topical coverage, such as:
- specific excipients
- specific skin penetration enhancers
- specific particle size ranges
- specific polymorph interconversion control
- stability requirements
- manufacturing steps
Accordingly, the claim is likely stronger against substitutes that use the same crystalline polymorph mixture, and weaker against substitutes that use a different crystalline form set or a single form.
How many patents likely cover cortexolone-17α-propionate crystalline forms beyond US 11,938,141?
Answer: Insufficient information is provided to enumerate the full patent estate across continuations, continuations-in-part, foreign filings, or related XRPD-defined polymorph patents. The claim set supplied is only for US 11,938,141, and no citation data, application family details, or other patent identifiers were included.
When does US 11,938,141 lose exclusivity (patent term) for US market entry?
Answer: Patent term and expiration are not computable from the claim text alone. A precise exclusivity timeline requires at least filing date and jurisdiction-specific term adjustments. The provided information does not include those data.
Is a Paragraph IV (Hatch-Waxman) challenge relevant, or is this a different pathway?
Answer: This depends on whether the accused product is an FDA-approved small-molecule drug subject to ANDA or a different regulatory posture (e.g., NDA for a listed drug, or a combination/new application). No FDA regulatory context (listed drug, reference product, NDA/ANDA number, dosage form listing, patent listing in the Orange Book) is provided in the prompt.
What formulation patents are implicitly implicated by XRPD-defined crystalline forms?
Answer: US 11,938,141 is a formulation patent in the sense that it covers the topical composition containing the specified crystalline-form active. But it is also a drug-substance crystallinity patent because identity is defined by DRX peak sets.
Key litigation-relevant claim feature: “at least peaks at about”
This style of claim is typically litigated around:
- whether the accused XRPD is measured comparably (instrument, sample prep, background subtraction, radiation source)
- whether accused peaks fall within “about” tolerances
- whether the accused material contains the claimed form(s) even if additional peaks exist (since the claim requires “at least peaks”)
How does the claim draft affect infringement theories?
Answer: The claim language enables a direct product infringement theory based on:
- testing the active in the accused topical product (or extracting/isolating the crystalline fraction)
- demonstrating the presence of at least two of the claimed crystalline forms using XRPD.
Potential proof focus areas in disputes
- XRPD peak assignment to each form (I–IV)
- Demonstrating “at least two” form presence in the final topical composition
- Demonstrating concentration coverage for the subset of dependent claims requiring 0.1%–2% w/w
What commercial and IP risks does a competitor face under the “two forms” threshold?
Answer: The “at least two” threshold can make a competitor’s risk binary:
- If they deliberately crystallize to a single form only, they may avoid claim 1.
- If they produce a mixture containing two forms (even unintentionally through incomplete crystallization, solvates/hydrates leading to conversion, or polymorph interconversion during processing), they may fall inside the claim.
Key Takeaways
- US 11,938,141 claims topical compositions containing cortexolone-17α-propionate as XRPD-defined crystalline Forms I–IV.
- Claim 1 is broad across topical vehicles and breadth is driven by “at least two crystalline forms” among I–IV.
- The crystalline form identities are constrained by minimum XRPD peaks at specified 2θ values, using “at least peaks” and “about” qualifiers.
- Dependent claims narrow coverage to specific multi-form combinations and to 0.1%–2% w/w active for claim 5-based compositions.
- The claim is structured for infringement testing via XRPD rather than vehicle composition or manufacturing method.
FAQs
1) What does “DRX with at least peaks at about” mean for accused product testing?
It typically means the accused diffractogram must show the required peaks within the claim’s “about” tolerance, even if other peaks are present.
2) Does US 11,938,141 cover cortexolone-17α-propionate if only one crystalline form is present?
No, based on claim 1 requiring at least two crystalline forms among Forms I–IV.
3) Are mixtures of three or four crystalline forms automatically covered?
Yes, if the product contains at least two of the defined forms, including ternary and quaternary mixtures.
4) How does the 0.1% to 2% w/w limitation apply?
It applies to claim sets that depend on claim 5, meaning certain coverage is constrained to products within that active concentration range.
5) Can a competitor avoid infringement by using a different crystalline form not listed as I–IV?
If the alternative active does not meet the XRPD “at least peaks” criteria for Forms I–IV, it would not satisfy the claim’s form definitions.
References
- US Drug Patent 11,938,141 (claims provided in prompt).
