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Patent landscape, scope, and claims: |
US Patent 8,367,701: scope, claim coverage, and US patent landscape for high-purity Formula I compound, crystalline Forms A–E, and inflammation-mediated formulations
Executive summary
- US 8,367,701 is a broad US composition-and-use patent anchored on a Formula I compound defined by high chemical purity (>90% and >98%), high S-enantiomer content (≥95% S), salt exclusions (not the calcium salt of the free acid), and a specific crystalline/amorphous solid-state taxonomy (Forms A–E plus amorphous).
- Claim breadth expands from compound identity and solid forms (composition claims) into solid-state manufacturing (crystalline isolation steps and solvent/wash conditions), formulation platforms (pharma compositions across multiple topical/ocular formats including specific gel/ointment/lotion/solution examples), and therapeutic method-of-use focused on inflammation-mediated diseases, with long, named sub-indications (not limited to ophthalmology).
- The practical exclusivity risk for competitors is driven by the patent’s multi-layer claim structure: even if challengers design around the exact solid form, they may still face infringement exposure through high-purity requirements, specific solid-state XRD signatures, and formulation/use claims that cover broad administration routes.
What is the scope of US Patent 8,367,701 claims 1–41 (Formula I purity, enantiomer, salt, solid-state Forms A–E)?
Core coverage (what the patent reads on)
US 8,367,701 is structured around four interlocking claim “pillars”:
-
Compound definition by chemical quality attributes
- Purity: claim 1 requires >90% purity; claim 2 tightens to >98% purity.
- Enantiomer: claim 3 requires ≥95% S-enantiomer.
- Salt limitation: claim 4 states the compound is not the calcium salt of the free acid.
- Byproduct limits: claims 13–14 cap chemical synthesis byproducts:
- <0.5% of any one byproduct
- <1.5% total byproducts
-
Solid-state identity via X-ray powder diffraction (XRPD)
- Claim 5: Form A with characteristic peaks at 2θ ~18.2, 21.4, 22.7°.
- Claim 8: Form B peaks at 2θ ~12.1, 17.1, 18.5°.
- Claim 9: Form C peaks at 2θ ~4.8, 17.8, 21.5°.
- Claim 10: Form D peaks at 2θ ~17.6, 21.7, 24.8°.
- Claim 11: Form E peaks at 2θ ~5.12, 8.26, 17.8°.
- Claim 12: amorphous form inclusion (no XRPD peak list required).
-
Solid-state thermal and process hooks
- Claim 6 adds a thermal feature: Form A has a predominant endotherm near ~145°C.
- Claim 7 recites how Form A is produced: isolating from a suspension in acetonitrile, methyl ethyl ketone, or water.
- Claim 15 is a dedicated method of producing the Form A crystalline product via:
- suspending Formula I in a solvent
- filtering to isolate crystals
- washing with water to obtain Form A
-
Downstream pharmaceutical formulations and therapeutic uses
- Claim 17: pharmaceutical composition = carrier + the claim 1 compound.
- Claim 19: composition may include amorphous or any crystalline Forms A–E, including combinations.
- Claim 23–26 provide exemplary topical/ocular delivery recipes:
- gel at ~1% W/V with specific excipient limits (DM isosorbide, Transcutol, hexylene glycol, methylparaben/propylparaben, hydroxyethyl cellulose, water)
- ointment at ~1% W/V with specific components (dimethyl isosorbide derivatives, BHT, Span 80, white wax, white petrolatum)
- water-based lotion at ~1% W/V with DM isosorbide, Transcutol, hexylene glycol, propylene glycol, trolamine and buffering to pH ~4.0–7.5
- aqueous buffered solution to pH ~6.0–8.0 using sodium phosphate monobasic, optionally EDTA and preservatives
- Claim 29: broad route coverage including instillation, aerosol, inhalation, oral, topical, transdermal, insert, injection.
- Claim 32–35: method of treating inflammation-mediated disease, including inflammatory eye disorders and allergic/dermatologic indications.
- Claim 36–40: formulation inside biocompatible matrices (including polyacrylate, polymethacrylate, polyolefin, polyamide, fluoropolymer, cellulose derivatives, PVA, PVP, coated zeolite, PLGA microsphere/nanosphere) with optional biodegradability and slow/sustained release profile.
Claim-level “hard points” likely to drive infringement or validity
- XRD fingerprinting (Forms A–E) is precise and can be both a strength (clear definition) and a vulnerability (if prior art or alternative characterization undermines discriminability).
- Purity and byproduct thresholds can be a meaningful design-around barrier: a competitor could attempt to market a lower-purity product, but that may be unacceptable clinically/regulatorily depending on tolerability and stability.
- “Not the calcium salt” is a narrow exclusion but still can matter for salt form development.
How does US 8,367,701 define crystalline Forms A–E and amorphous, and what does that mean for design-around?
Featured-snippet answer
US 8,367,701 locks compound solid-state coverage to specific XRPD peak sets for Forms A–E, includes an amorphous option, and adds thermal and process characteristics for at least Form A.
Solid form map (claims 5, 8–12)
| Form |
Claim |
XRPD characteristic peaks (2θ, degrees) |
Extra limitation |
| Form A |
5 |
18.2, 21.4, 22.7 |
6: predominant endotherm ~145°C; 7: produced from suspension in ACN/MEK/water |
| Form B |
8 |
12.1, 17.1, 18.5 |
none stated |
| Form C |
9 |
4.8, 17.8, 21.5 |
none stated |
| Form D |
10 |
17.6, 21.7, 24.8 |
none stated |
| Form E |
11 |
5.12, 8.26, 17.8 |
none stated |
| Amorphous |
12 |
not specified |
broad “amorphous form” coverage |
Design-around levers
- Switch solid state: moving to a different crystalline form not listed (or a different amorphous profile) can reduce direct claim 5/8/9/10/11 exposure, but claim 12 (amorphous) and claim 19 (form combination including amorphous and Forms A–E) remain relevant for formulation claims.
- Change purity/byproducts: avoiding >90% or >98% purity limits, or avoiding the byproduct constraints (<0.5% single, <1.5% total) can target claims 1–3 and 13–14, but this can be practically constrained by stability and manufacturing capability.
- Avoid excluded salt: if developers propose a calcium salt form, claim 4 blocks that specific salt. Other salt forms remain within the “pharmaceutically acceptable salt” language of claim 1, unless they effectively recreate the same compound definition plus solid form.
What manufacturing/process claims does US 8,367,701 cover (Form production and solvent/wash steps)?
Featured-snippet answer
US 8,367,701 contains a dedicated method claim for producing Form A crystals via suspension, filtration, and water washing, and a narrower solvent-based pathway for Form A isolation.
Method of producing crystalline Form A
- Claim 15: suspending Formula I in a solvent; filtering to isolate crystalline product; washing crystals with water to obtain Form A.
- Claim 16: solvent is acetonitrile or methyl ethyl ketone.
Practical infringement implications
- Process claims often shift infringement risk to CMO/manufacturing sites and contract operations, not just product formulators.
- A competitor can reduce product-claims exposure by using a different solid state, but process claims can still bite if they produce Form A crystals by similar suspension/filter/wash logic in covered solvents.
What pharmaceutical formulations are covered (gel, ointment, lotion, buffered solution, matrix systems)?
Featured-snippet answer
US 8,367,701 covers pharmaceutical compositions with the claim 1 compound across multiple delivery types, including specific topical/ocular gel, ointment, lotion, and buffered aqueous solution compositions, plus biocompatible matrix controlled-release systems.
Representative formulation examples
| Claim |
Dosage form |
Key parameters stated in claim |
| 23 |
Gel |
~1% W/V compound; DM isosorbide up to 15% W/V; Transcutol up to 25% W/V; hexylene glycol up to 12% W/V; methylparaben up to 0.15% W/V; propylparaben up to 0.05% W/V; hydroxyethyl cellulose up to 1% W/V; water |
| 24 |
Ointment |
~1% W/V compound; DM isosorbide up to 10% W/V; BHT up to 0.02% W/V; Span 80 up to 2% W/V; white wax up to 10% W/V; white petrolatum |
| 25 |
Lotion |
~1% W/V compound; DM isosorbide up to 15% W/V; Transcutol up to 25% W/V; hexylene glycol up to 12% W/V; propylene glycol up to 5% W/V; pH includes trolamine buffered to pH ~4.0–7.5 (with “pH 6.0 …” text present in the claim excerpt) |
| 26 |
Buffered aqueous solution |
pH ~6.0–8.0 with sodium phosphate monobasic; ~1% W/V compound; up to 0.1% EDTA; optional methylparaben up to 0.4% w/w; optional propylparaben up to 0.02% w/w |
| 27–28 |
Biocompatible solid/gel |
solid can be biodegradable |
| 36–40 |
Solid inside biocompatible matrices |
matrix materials listed; optionally biodegradable; release can be slow/sustained |
Broad route coverage
- Claim 29 allows administration via instillation, aerosol, inhalation, oral, topical, transdermal, insert, injection.
- Claim 30–31: local vs systemic delivery framing, enabling arguments around intended release distribution.
Form selection inside formulations
- Claim 19 and claim 36–37 tie formulation scope to the compound’s solid state, enabling infringement theories even when a competitor claims “same active” but uses one of the listed Forms or amorphous.
What therapeutic indications and method-of-use coverage does US 8,367,701 include?
Featured-snippet answer
The method-of-use claims cover administering the compound (claim 17 composition) for inflammation-mediated diseases, with an extensive enumeration spanning ocular inflammation, allergic disease, and dermatologic/immunologically mediated conditions.
Method-of-use claim tree
- Claim 32: inflammation-mediated disease.
- Claim 33: inflammatory eye disorders including intraocular/periocular/ocular surface inflammation:
- keratoconjunctivitis, KCS/Sjogren’s-associated KCS, allergic conjunctivitis, uveitis, ocular inflammation post-surgery (LASIK), retina inflammation segments, diabetic macular edema and diabetic retinopathy, corneal inflammation (including transplant rejection), Graves ophthalmopathy, retinitis, edema, retinopathies.
- Claim 34: allergic disease: allergic conjunctivitis, allergic rhinitis, allergic asthma, allergic contact dermatitis.
- Claim 35: psoriasis and dermatitis/immunologically mediated disorders and scar formation:
- psoriasis, irritant contact dermatitis, eczematous dermatitis, seborrhoeic dermatitis, cutaneous manifestations of immunologically-mediated disorders, alopecia, alopecia areata, scar formation.
Implication for competitor strategy
- Even if a rival product’s label focuses on a narrower subset, the claim language is broad enough that a court can look at evidence of intended use, medical practice, and promotional language tied to the inflammation-mediated disease framework.
How strong is the patent estate for this specific compound and solid-state space (claim architecture vs typical prior art risks)?
Featured-snippet answer
Strength is driven by stacked limitations: purity/byproduct and enantiomer constraints combined with specific XRPD peak fingerprints and expanded into process and formulation/use. That architecture reduces easy design-around by compound substitution, but also means validity can turn on whether prior art already teaches:
- the same high-purity/enantiomeric compound
- the same crystalline forms (Forms A–E) with the same XRPD peaks
- and the same isolation conditions and therapeutic framing.
What the claim architecture does well for enforceability
- Compound claims (1–4, 13–14) are narrow enough to avoid being “just a genus,” because they are locked to:
- high purity thresholds and enantiomeric enrichment
- byproduct caps
- and salt exclusion (calcium salt of free acid)
- Solid form claims are directly tethered to numerical XRPD peak locations.
- Downstream claims (17–31, 32–35) provide multiple infringement theories against:
- product composition (amorphous and listed Forms)
- formulation recipes within topical/ocular modalities
- and intended medical use.
Where challenges typically arise
- If prior art already contains a similar polymorph screening and indexing, XRPD peaks can become a factual battleground.
- Purity-byproduct limits can be contested as either not meaningfully distinguishing or not supported with clear measurement methods in the record.
- Process claims can be pressured by substitutions in solvent or washing steps, depending on how strictly the claims are construed and what “obtaining Form A” requires in practice.
What generic entry risks exist under the Hatch-Waxman framework for US 8,367,701?
Featured-snippet answer
The highest generic risk is when a generic applicant submits an ANDA with an ANDA product that uses the same Formula I compound at >90–98% purity, with ≥95% S-enantiomer, and includes amorphous or Forms A–E or makes them via the covered isolation/wash pathway. A label claiming treatment of inflammation-mediated disease in covered categories also increases method-of-use exposure.
Where a challenger may attempt to lower risk
- Choose a different solid form not within A–E and not amorphous as characterized.
- Reduce purity below the claimed thresholds or change byproduct profile. This can be difficult if the reference product or regulatory specifications require high purity.
- Avoid the specific formulation compositions, though claim 29’s broad route and claim 17/19’s composition coverage can still remain.
Practical litigation posture
- Expect infringement allegations to focus on:
- XRPD testing showing Forms A–E peak matches
- purity/byproduct analytics showing compliance above the thresholds
- and/or evidence of Form A manufacturing (solvent/filter/wash pathway).
What Orange Book status and listing-driven exposure matters for US 8,367,701?
No Orange Book status details, listed drug products, or FDA Orange Book identifiers are provided in the input. Without those identifiers, a product-by-product exclusivity and patent-list mapping cannot be constructed from the claim text alone.
How does US 8,367,701 compare with other solid-form or purity/enantiomer patents in the same portfolio?
No additional US patent numbers, related applications, family members, or continuations are provided in the input. A comparative landscape cannot be accurately derived without the patent family record and prosecution history.
Key Takeaways
- US 8,367,701 is a stacked-constraint patent covering: high-purity/high-S Formula I, exclusion of the calcium salt, specific XRPD-defined crystalline Forms A–E plus amorphous, and byproduct limits.
- The claims extend beyond the active into Form A production methods, multiple topical/ocular and other administration formats, and method-of-use for inflammation-mediated diseases across ocular, allergic, and dermatologic indications.
- Competitor risk concentrates around three infringement vectors: solid-state identity (XRPD), quality attributes (purity/enantiomer/byproducts), and use/label claims tied to inflammation-mediated indications.
FAQs
1) If a generic uses the same Formula I compound but a different crystalline polymorph, does US 8,367,701 still apply?
It depends on whether the product is amorphous or matches one of the listed Forms A–E by XRPD, and whether formulation and use claims are otherwise satisfied.
2) How can purity thresholds affect infringement under US 8,367,701?
If the accused product does not meet >90% (or >98%) purity and related byproduct limits, it may fall outside the compound definition in claims 1–2 and 13–14.
3) Does US 8,367,701 create risk for contract manufacturers?
Yes for operations that produce Form A via covered suspension/filter/water wash steps (claims 15–16), especially when solvents match.
4) Are method-of-use claims tied to ocular indications only?
No. The inflammation-mediated framework includes ocular, allergic, and psoriasis/dermatologic and immunologically mediated conditions with broad enumeration.
5) Can a formulation avoid infringement by changing gel/ointment excipients?
Changing excipients may avoid some recipe-specific examples, but broader composition claims (carrier + compound; inclusion of amorphous/Forms A–E) and route coverage can still create exposure.
References (APA)
- United States Patent No. 8,367,701.
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