US Patent 8,791,122 landscape: what crystals, compositions, and manufacturing steps are actually claimed?
US Patent 8,791,122 is a crystal-form patent centered on a defined solid-state form of a specific small-molecule active ingredient, plus downstream product-by-active and a production method. The claim scope is tightly anchored to (i) the identity of the API, (ii) the crystal definition via X-ray powder diffraction (XRPD) peaks at specified 2θ angles using Cu Kα radiation, and (iii) the specific crystallization route using an alcoholic/ketone solvent system under heating followed by gradual cooling.
Fast claim map (what each independent claim covers)
| Claim |
Category |
Core legal hook |
What is required to infringe (high level) |
| 1 |
Crystal (composition of matter) |
XRPD “showing diffraction peaks at least at” 2θ = 9.4°, 9.8°, 17.2°, 19.4° (Cu Kα) |
A solid/crystal form of the stated API that yields an XRPD pattern meeting the minimum peak set |
| 2 |
Pharmaceutical composition (product) |
“Active ingredient” = the crystal of claim 1 |
A drug product where the active ingredient is the claimed crystal form |
| 3 |
Method of producing crystal |
Dissolve API in alcoholic solvent or mixed alcohol/ketone, heat, then crystallize by gradual cooling |
The defined crystallization process using those solvent classes and the thermal profile |
This creates a landscape where the most important infringement risk is not the molecule itself (the API is specified), but the solid form and the process conditions that lead to that solid form.
What is the claimed crystalline form in US 8,791,122 and how is it defined?
Direct answer: Claim 1 defines a specific crystal of the API by its XRPD signature, requiring Cu Kα diffraction peaks at 2θ = 9.4°, 9.8°, 17.2°, 19.4° (presence is required; the wording is “at least at the following angles”). The claim does not limit particle size, polymorph label, or stoichiometry in the provided excerpt, and it is therefore evaluated on the XRPD evidence.
Claim 1 anchor: exact API identity
The crystal is of:
2-{4-[N-(5,6-diphenylpyrazin-2-yl)-N-isopropylamino]butyloxy}-N-(methylsulfonyl)acetamide
This is a hard boundary. A different salt, different substitution pattern, or a different substituted acetamide would generally fall outside claim 1 regardless of XRPD match.
XRPD definition: “at least” four peak positions under Cu Kα
The claim’s solid-state limitation is:
- XRPD peaks at least at 9.4°, 9.8°, 17.2°, 19.4°
- XRPD obtained using Cu Kα radiation
That phrasing matters:
- A competing crystal that has all four peak positions can fall within the claim even if it has extra peaks.
- A competing crystal that misses one of the four specified peaks may avoid literal infringement, assuming the peak absence is clear under the relevant measurement conditions.
Measurement and litigation relevance: XRPD can become the dispute
For enforcement and validity arguments, claim construction typically focuses on whether the defendant’s solid exhibits the required peaks when measured under comparable XRPD conditions. The claim’s explicit recitation of Cu Kα helps constrain the measurement standard in claim interpretation.
H3: Does the claim cover solvates or hydrates?
The excerpt does not mention hydrate/solvate descriptors. If the XRPD peaks match and the material is still the “crystal of” the API, a solvate could still test against the XRPD requirement. Practically, a solvate/hydrate can have additional peaks and potentially shift peak positions slightly. If those peaks still include the required four angles, risk increases.
How broad is claim 1 versus typical polymorph patents?
Direct answer: Scope is broad across materials that exhibit the specified XRPD peaks for the defined API, but narrow in that it is limited to crystals meeting the Cu Kα XRPD peak set. It is not limited to a particular preparation batch, morphology, or manufacturing example.
What claim 1 does not require
From the claim language provided, claim 1 does not expressly require:
- a specific crystallite size or particle size distribution
- a specific crystal habit
- a specific purity or impurity profile
- a specific solvent inclusion (no solvate/hydrate language)
- a specific method to make the crystal
That omission increases coverage across “made-by-whom” variants.
What claim 1 does require
- The API identity is fixed.
- The XRPD signature must show the minimum set of four peak angles.
- Cu Kα must be the radiation used for XRPD measurement.
What is claimed by claim 2 and how does it affect generic or formulation competitors?
Direct answer: Claim 2 covers any pharmaceutical composition whose active ingredient is the claimed crystal of claim 1. Excipients and dosage forms are not limited in the provided excerpt.
Infringement logic for claim 2
A product infringement theory generally ties back to whether the active drug substance used in the finished dosage form is the claimed XRPD-defined crystal.
That creates a two-step risk chain:
- Prove that the accused active ingredient matches claim 1’s XRPD peak requirements.
- Prove that the finished pharmaceutical composition includes that active ingredient as the “active ingredient.”
Practical implications for formulation strategy
- If a competitor uses a different polymorph or amorphous form that does not include the required peaks, claim 2 is less directly implicated.
- If a competitor sources the API in the same crystal form as the patent, claim 2 becomes the direct composition claim.
What does claim 3 cover: which solvent systems and thermal profiles are included?
Direct answer: Claim 3 is a method claim for producing the claimed crystal by:
- dissolving the API in an alcoholic solvent or a mixed solvent of an alcoholic solvent and a ketone solvent, while heating
- then crystallizing by cooling the solution gradually
Solvent scope in claim 3
The claim uses functional solvent classes:
- “alcoholic solvent” (examples not provided in the excerpt)
- “mixed solvent of an alcoholic solvent and a ketone solvent”
This is broader than listing specific solvents, which can matter for design-around. A competitor can attempt to avoid by using a different solvent class (non-alcoholic, non-ketone-containing system), but then the process must still yield the desired crystal form.
Thermal profile requirement
The claim includes:
- heating during dissolution
- crystallizing by cooling the solution gradually
The “gradually” qualifier is a process limitation likely assessed by the defendant’s cooling rate and crystallization conditions. In practice, this becomes fact-intensive.
How many distinct claim categories exist in US 8,791,122 and what does that mean for licensing?
Direct answer: At least three distinct enforcement handles exist: crystal identity (claim 1), drug product formulation (claim 2), and manufacturing process (claim 3). That is a typical structure for crystal estate licensing.
Licensing leverage from claim diversity
- A manufacturer using the exact crystal form in drug substance can face claim 1 and claim 2.
- A manufacturer producing via the specified alcohol/ketone gradual cooling route can face claim 3 even if they argue the final product differs, though the method claim is narrower in application than the crystal claim.
For licensing, this typically supports both:
- supply licensing for drug substance crystallization, and
- product licensing for finished dosage forms.
What is the likely patent estate approach around this crystal form?
Direct answer: US 8,791,122 is a crystal/polymorph estate member. The presence of XRPD-defined peaks implies related filings often exist around:
- related polymorphs (other XRPD signatures)
- solvates/hydrates
- amorphous or different drying conditions
- method-of-use or therapeutic use patents are separate estates (not shown in the excerpt)
However, no additional patents are provided in your prompt. Without specific bibliographic identifiers (assignee, applicants, related publication family members), the broader estate cannot be fully mapped here.
What is the risk of design-around: changing the XRPD pattern or the process?
Direct answer: The two main design-around paths are (i) avoid producing a crystal that includes the claimed peak set under Cu Kα XRPD, or (ii) avoid the specified alcohol/ketone gradual-cooling crystallization method.
Design-around via XRPD divergence
If a competitor uses a polymorph or amorphous form that does not show at least one of the four required peaks (9.4°, 9.8°, 17.2°, 19.4°), literal infringement of claim 1 is reduced.
But if a different solid form still shows the required peaks, the claim coverage can persist.
Design-around via process pathway
Avoiding claim 3 is possible if:
- dissolution and crystallization are done in a solvent system outside “alcoholic” and “alcoholic/ketone” combinations, or
- the cooling is not “gradual” (e.g., controlled temperature profile not meeting the claim interpretation), or
- no dissolution/heating step matching claim requirements is used.
Process changes, though, must still produce the target API form and maintain quality and stability.
What litigation arguments typically arise from XRPD-defined crystal claims like this?
Direct answer: The dominant factual dispute is whether the accused solid exhibits the specified XRPD peaks under Cu Kα at the stated positions. The dominant legal dispute is claim construction of the XRPD limitation (“at least,” peak position tolerance, and what counts as “showing” a diffraction peak).
Common fault lines (used in practice for similar crystal patents)
- Peak position tolerances: accused material shows peaks slightly shifted due to different instrumentation or sample prep.
- Peak detection threshold: whether a peak is truly present versus below detection.
- Background subtraction and processing: analysis settings can influence what is reported as a “peak.”
- Sample differences: polymorph interconversion during milling, drying, or humidity exposure.
The key point for scope: claim 1 is a “presence of specific peaks” test, so evidence quality and measurement comparability drive outcomes.
How does the claim language allocate burden between parties?
Direct answer: Claim 1 creates a product-by-definition limitation keyed to analytical results. In litigation, the patentee’s case typically relies on XRPD data demonstrating the required peaks, then argues that the accused material matches the claim. The defendant typically counters with XRPD data showing missing peaks or different peak positions.
For claim 3, the patentee’s case typically focuses on manufacturing records and process witnesses, establishing the use of alcohol/ketone solvent classes and gradual cooling.
Key takeaways
- US 8,791,122 is anchored on a single small-molecule API crystal form defined by Cu Kα XRPD peaks at 2θ = 9.4°, 9.8°, 17.2°, 19.4° (claim 1).
- Scope is broad across all makers and all downstream products, but narrow in solid-state definition: a material must meet the XRPD peak set to fall within claim 1.
- Claim 2 extends the protection to pharmaceutical compositions where the active ingredient is the claimed crystal.
- Claim 3 adds a method handle covering crystallization by dissolving in alcoholic solvent or alcohol/ketone mixed solvents under heating, then cooling gradually.
- Design-around is most realistically achieved by moving to a crystal/polymorph or solid form that does not show one or more of the required peaks under Cu Kα XRPD, or by changing the solvent class and cooling profile to avoid the process limitations.
FAQs
1) Can a competitor avoid claim 1 by using a different polymorph of the same API?
Yes, if the alternative polymorph does not “show” XRPD peaks at all required angles (9.4°, 9.8°, 17.2°, 19.4°) under Cu Kα.
2) Does claim 2 cover any dosage form containing the API?
No. It covers compositions where the active ingredient is the specific claimed crystal form from claim 1.
3) Is claim 3 limited to specific alcohols or ketones?
The excerpt limits solvent categories rather than listing specific chemicals: it covers an alcoholic solvent and mixtures of alcoholic solvent with a ketone solvent.
4) Does the patent cover amorphous material?
Not by name. Coverage depends on whether the amorphous material yields an XRPD pattern that meets the crystal peak requirement at the specified angles under Cu Kα.
5) If a process makes the crystal but cooling is not “gradual,” is claim 3 avoided?
Potentially, since claim 3 requires crystallizing by cooling the solution gradually. Evidence of cooling rate and temperature profile would be central.
References
No external sources were cited because no bibliographic record (publication details, assignee, family members, or prosecution history) for US 8,791,122 was provided beyond the claim text in the prompt.
