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Patent landscape, scope, and claims: |
United States Patent 8,785,427: What Is Claimed, What It Covers, and Where the Landscape Tightens
United States Patent 8,785,427 claims a biocatalytic process to make cortexolone-17α-propionate (CPP) in crystalline form III, the form-III material itself defined by DRX/DSC/IR spectra tied to specific figures, and pharmaceutical compositions comprising that form.
What is the claim architecture and what does it practically cover?
The patent has three operational layers:
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Process claims to prepare CPP crystalline form III using:
- A lipase from Candida to catalyze a reaction between formula II and an alcohol reagent (formula III R′OH) in an organic solvent
- Crystallization of CPP form III from specific solvent systems
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Material claims to CPP crystalline form III, where the form is defined by the presence of specific DRX/DSC/IR spectral patterns referenced to figures.
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Composition claims to deliver the material (form III) in standard dosage forms with excipients.
This structure is designed to create coverage both for:
- Manufacturing steps (process claims)
- The product specification (crystalline form claims)
- Downstream commercialization (composition claims)
Claim 1 is the “master” process grant: what are the hard boundaries?
Claim 1 (core scope)
A process comprising:
(A) Biocatalytic reaction
- React compound of formula II with compound of formula III:
- Alcohol definition: R′ is a linear aliphatic chain containing 1-10 carbon atoms
- Specifically: R is CH3-CH2
- Reaction conditions:
- Organic solvent
- Presence of a lipase from Candida
- Outcome: gives cortexolone-17α-propionate
(B) Crystallization to obtain crystalline form III
- Crystallize CPP from one of three solvent-mixture sets:
- dichloromethane / n-hexane
- acetone / n-hexane
- ethanol / water
- Outcome: cortexolone-17α-propionate in crystalline form III
This claim is broad in that it allows:
- Any linear aliphatic alcohol with 1-10 carbons (subject to later dependent refinements)
- Choice among three crystallization solvent systems
- “Any organic solvent” at the claim-1 level (then narrowed in dependent claims)
It is narrow in that it anchors the end-product to crystalline form III, which is later spectrally defined by figure-based DRX/DSC/IR.
Immediate risk signals for design-arounds
- If an alternate process produces a product that does not meet crystalline form III spectral criteria, it may not infringe material claims, and may not satisfy the “process to give form III” requirement in claim 1.
- If an alternate route uses a different catalyst class or enzyme origin (non-Candida lipase), it may avoid the biocatalytic requirement.
- If crystallization uses a different solvent system than the three enumerated sets (or the final product shows a different form), infringement risk drops.
How do dependent claims tighten the scope? (Process)
Alcohol scope
- Claim 2: R′ is linear aliphatic chain containing 1-8 carbons
Narrowing reduces coverage for alcohols with 9-10 carbons.
- Claim 7: formula III alcohol is selected from methanol, ethanol, butanol, octanol (and combinations)
This locks into specific reagents, reducing “open-ended” coverage to four anchor alcohols.
- Claim 8: alcohol stoichiometry: 0.5 to 50 moles per mole of compound II
- Claim 9: specifically 5 moles per mole of compound II
Practical boundary: if a manufacturer uses a different alcohol (non-linear, different carbon count outside 1-10, or different alcohol identity not in the claim-7 list) and does not rely on claim-1’s general R′ range, infringement probability decreases across the dependent ladder.
Solvent scope
- Claim 3: organic solvent is aprotic
- Claim 4: solvent is selected from:
- toluene
- acetonitrile
- tetrahydrofuran
- dichloromethane
- chloroform
- combinations
Practical boundary: any process using a protic organic solvent falls outside claim-3; and any aprotic solvent outside the enumerated list may avoid claim-4 coverage while still possibly meeting claim-1 depending on how the claim-1 “organic solvent” is interpreted.
Starting material concentration
- Claim 5: formula II at about 0.01 to 0.15 M
- Claim 6: specifically about 0.025 M
Practical boundary: outside these ranges, you lose dependent coverage.
Candida lipase identity and unit activity
- Claim 10: Candida lipase is:
- Candida cylindracea, or
- Candida antarctica type B
- Claim 11: enzyme loading: 100 to 1,000,000 U/mmol
- Claim 12: different ranges by species:
- For C. cylindracea: 1,000 to 1,000,000 U/mmol
- For C. antarctica type B: 100 to 100,000 U/mmol
Practical boundary: using non-Candida lipase or an enzyme with different origin/classing is a direct design-around. Using Candida but outside the activity/loading ranges can avoid dependent claims.
Temperature
- Claim 13: reaction at 10 to 48°C
Crystallization solvent ratios + spectral proof
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Claim 14: CPP form III from dichloromethane/n-hexane characterized by:
- DRX: Fig. 7
- DSC: Fig. 8
- IR: Fig. 9
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Claim 15: dichloromethane/n-hexane ratio: about 1/30
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Claim 16: CPP form III from acetone/n-hexane characterized by:
- DRX: Fig. 10
- DSC: Fig. 11
- IR: Fig. 12
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Claim 17: acetone/n-hexane ratio: about 1/8
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Claim 18: CPP form III from ethanol/water characterized by:
- DRX: Fig. 13
- DSC: Fig. 14
- IR: Fig. 15
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Claim 19: ethanol/water ratio: about 1/2
Practical boundary: crystallization outside these solvent-mixture ratios may still fall under claim-1’s general solvent system list, but dependent claim infringement becomes easier to attack if the ratios differ materially. The form-III definition is anchored to the figure spectra.
What is the product coverage? (Crystalline form III material claims)
Claim 20 (form III defined by spectral sets)
- Crystalline form III of CPP having:
- DRX: Fig. 7 or 10 or 13
- DSC: Fig. 8 or 11 or 14
- IR: Fig. 9 or 12 or 15
Claims 21-23 (single-figure spectral sets)
- Claim 21: DRX Fig. 7 + DSC Fig. 8 + IR Fig. 9
- Claim 22: DRX Fig. 10 + DSC Fig. 11 + IR Fig. 12
- Claim 23: DRX Fig. 13 + DSC Fig. 14 + IR Fig. 15
Scope consequence:
- Material infringement does not require the biocatalytic route, only that the sold or used material matches crystalline form III as proven by those spectral attributes.
- If an alternative process produces a form that maps to one of these spectral sets, that can still land in claim-20/21/22/23 even when the pathway differs.
What is covered for pharmaceutical formulations?
Claim 24 (composition grant)
- A pharmaceutical composition comprising:
- crystalline form III (from claims 20, 21, 22, 23)
- plus at least one physiologically acceptable excipient
Dosage-form and physical-form dependent claims
- Claim 25: composition forms:
- tablet, capsule, powder, pellet, suspension, emulsion, solution, cream, gel, ointment, lotion, paste
- Claim 26: solid, semi-solid, or paste
- Claim 27: solid
- Claim 28: tablet, capsule, powder, pellet
- Claim 29: ointment
Scope consequence:
- The patent is not limited to one route of administration.
- Once a product is CPP crystalline form III, the patent reaches a wide set of presentation forms, leaving formulation teams limited room to pivot without changing the active form.
Where the landscape is likely to be most crowded (based on what this patent locks down)
This patent’s tightest leverage is not the general CPP chemistry; it is the combination of:
- crystalline polymorph identity (form III) verified by DRX/DSC/IR
- specific crystallization solvent systems and ratios tied to those spectral figures
- Candida lipase biocatalysis with defined enzymes and activity/loading ranges
- broad but structured reach into pharmaceutical formulations
In a typical crystalline-form landscape, competitors either:
- attempt to prepare different polymorphs (forms I/II or other variants), or
- reproduce the same form via alternate crystallization conditions (which is hard if the spectral target is strict), or
- switch to chemical or alternative enzymatic routes, hoping the final solid does not match the spectral pattern.
In a typical enzyme/process landscape, competitors may:
- avoid the claimed enzyme origins (Candida cylindracea / Candida antarctica type B)
- switch to other lipases or immobilized enzyme systems
- adjust solvent class (avoid “aprotic” restriction) or avoid the enumerated aprotic solvents
- change stoichiometry, concentration, temperature windows
Claim-to-design-around map (actionable infringement levers)
| Leverage point in 8,785,427 |
What it requires |
Common design-around direction |
| End-product must be crystalline form III |
Must meet spectral constraints tied to specific figure sets |
Target a different polymorph or solid form; control crystallization to avoid form III |
| Biocatalyst must be Candida lipase |
Candida cylindracea or Candida antarctica type B |
Use non-Candida lipase or non-listed Candida enzyme classification |
| Enzyme loading must fall within defined activity ranges (dependent claims) |
U/mmol windows by species |
Adjust enzyme amount or switch enzyme immobilization/formulation affecting activity basis |
| Solvent must be aprotic (dependent claims) |
“Aprotic” plus enumerated solvent list |
Use protic solvent or an aprotic solvent outside the enumerated list |
| Crystallization solvent systems are enumerated |
DCM/n-hexane, acetone/n-hexane, ethanol/water |
Use different solvent systems and verify solid form outcomes |
| Crystallization ratios are specified (dependent claims) |
DCM/n-hexane ~1/30; acetone/n-hexane ~1/8; ethanol/water ~1/2 |
Use different ratios materially shifting crystallization environment |
| Formulation includes crystalline form III |
Any pharmaceutical composition with form III + excipient |
Formulate a different polymorph/form variant or use a different solid form not matching the spectral target |
Risk concentration by claim set
Highest-risk: material claims (20-23)
- They attach to the sold or used solid, not just manufacturing.
- Any competitor producing CPP form III is exposed even with a different process.
High-risk: process claim 1 (and its dependent chain to spectrum-defined crystallizations)
- They require the process to yield form III.
- If a process uses different solvent ratios but still yields the same form III, it can still land in claim 1 unless the claim is interpreted strictly to those ratios and spectral definitions only appear in dependent claims.
Wider commercial reach: compositions (24-29)
- Once form III is present, the patent reaches many dosage forms.
- Formulation teams inherit the upstream crystalline risk.
Key Takeaways
- 8,785,427 is built around a polymorph strategy: it claims CPP crystalline form III defined by figure-linked DRX/DSC/IR spectra, plus processes designed to produce that form using Candida lipases and specific solvent systems.
- The claim set splits into (i) biocatalytic process, (ii) polymorph material definition, and (iii) formulation coverage, which makes it harder to avoid by changing only upstream synthesis.
- The most durable infringement exposure is the material layer (claims 20-23) because it does not require use of the claimed manufacturing route.
- The strongest design-around levers are: avoid producing form III as defined by the spectral patterns, and/or change catalysts, solvents, and crystallization systems to shift the final solid form away from form III.
FAQs
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Does the patent cover the production route or just the final solid?
Both. It covers a Candida lipase-based process (claim 1 and dependents) and also the solid itself as crystalline form III (claims 20-23), plus compositions.
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What defines “crystalline form III” in enforcement terms?
The patent defines it by DRX, DSC, and IR spectra referenced to specific figure numbers (e.g., DRX Fig. 7 or 10 or 13; DSC Fig. 8 or 11 or 14; IR Fig. 9 or 12 or 15).
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Can a competitor avoid infringement by using a different enzyme?
It can reduce risk for process claims, but the material claims can still apply if the competitor sells or uses CPP form III that matches the spectral definition.
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Are the crystallization solvents flexible?
Claim 1 enumerates three solvent systems for crystallization: dichloromethane/n-hexane, acetone/n-hexane, or ethanol/water. Dependent claims additionally lock in specific solvent ratios and spectral figure sets.
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Does the patent reach formulation and dosage forms?
Yes. Claims 24-29 cover compositions containing crystalline form III across multiple formats, including tablets, capsules, powders, pellets, and ointments.
References
[1] U.S. Patent 8,785,427.
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