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Patent landscape, scope, and claims: |
US Patent 8,501,698 (Crystalline (S)-Propylene Glycol Solvate SC-3): Claims, Scope, and US Landscape
What is the core invention claimed in US 8,501,698?
US 8,501,698 claims pharmaceutical compositions and treatment methods built around a specific crystalline solvate: the crystalline (S)-propylene glycol ((S)-PG) solvate of “form SC-3,” defined by a tight set of analytical fingerprints. The claims are structured so that the solvate identity is established primarily by solid-state characterization (powder XRD, unit-cell parameters, 13C solid-state NMR, DSC endotherm window, and TGA weight loss profile), then used in combination with standard pharmaceutical formulation elements and broad metabolic/cardiovascular therapeutic targets.
Key claim anchor: the SC-3 crystalline (S)-PG solvate
Across the composition claims, the solvate is defined as having a powder XRD pattern with the following peaks (CuKα1 = 1.5418 Å) measured at room temperature:
| Claim element |
Required values (2θ, degrees) at room temperature |
| Powder XRD fingerprint |
3.8 ± 0.1, 7.6 ± 0.1, 8.1 ± 0.1, 8.7 ± 0.1, 15.2 ± 0.1, 15.7 ± 0.1, 17.1 ± 0.1, 18.9 ± 0.1, 20.1 ± 0.1 |
That XRD fingerprint is the principal “gate” in claim 1, and dependent claims layer alternate or additional structural proof modalities (unit cell parameters, 13C NMR peak positions, DSC endotherm range, and TGA weight loss).
What do claims 1-21 cover (composition scope)?
Claim 1: composition defined by powder XRD
Claim 1 is a pharmaceutical composition comprising a therapeutically effective amount of the crystalline (S)-PG solvate form SC-3, where identity is proven by the specified powder XRD peaks at room temperature.
Claims 2 and 7: solvate defined by crystallographic parameters and/or fractional atomic coordinates
- Claim 2 requires one or more additional solvate-defining characteristics; it includes:
- Unit cell: a = 11.2688(8) Å, b = 4.8093(3) Å, c = 46.723(3) Å; α = β = γ = 90°
- Space group: P212121
- Molecules/asymmetric unit: 1
- Room temperature measurement
- Fractional atomic coordinates “substantially as listed in Table 4”
- Claim 7 repeats the crystallographic unit-cell/space group/molecules-asymmetric-unit definition at room temperature.
Claim set includes multiple “alternative proof” routes
The dependent claim language provides multiple ways to establish that the solvate is the SC-3 crystalline (S)-PG solvate, including:
- Solid-state 13C NMR (claim 2 includes it; claim 12 is directly NMR-defined; claim 2 and 12 specify substantially similar peak positions on a 400 MHz spectrometer referenced to TMS at 0 ppm)
- DSC (claim 2 and claim 17 define an endotherm in 50 °C to 78 °C range or as shown in FIG. 7)
- TGA (claim 2 includes “about 18.7% weight loss from about room temperature up to about 240 °C” or as shown in FIG. 5)
Claim 3 and 8 and 13 and 18: allowed combination therapeutics
Claims add “one or more therapeutic agents selected from”:
- antidiabetic
- anti-obesity
- anti-hypertensive
- anti-atherosclerotic
- lipid-lowering
These are broad pharmacological categories, not specific molecule names.
Claims 4 and 9 and 14 and 19: generic formulation support
These cover addition of a pharmaceutically acceptable carrier or diluent.
Claims 5, 6, 10, 11, 15, 16, and 21: purity/phase homogeneity limitations
These require:
- “substantially pure form”
- “substantially pure phase homogeneity”
The claim effect is to constrain infringement to compositions where the SC-3 crystalline phase is sufficiently dominant/consistent.
How do the analytical definitions interlock across claims?
The claim set is effectively a “multi-modal identity” strategy: infringement can be argued via multiple experimental readouts (XRD or the other solid-state fingerprints), while still requiring the solvate to be the same crystalline form (SC-3).
Claim 1 vs. dependent “identity tests”
| Identity-defining feature |
Where it appears |
| Powder XRD peaks at specified 2θ list |
Claim 1 |
| Unit cell / space group / asym. unit / Table 4 coords |
Claim 2 (as part of one or more listed characteristics) and Claim 7 |
| Solid-state 13C NMR peak set |
Claim 2 and Claim 12 |
| DSC endotherm window |
Claim 2 and Claim 17 |
| TGA mass loss (~18.7% RT to ~240°C) |
Claim 2 |
| Purity / phase homogeneity |
Claims 5, 6, 10, 11, 15, 16, 21 |
13C NMR peak list (claims 2 and 12)
Claim 2 (and claim 12) specifies solid-state 13C NMR “substantially similar peak positions” at:
16.2, 17.6, 39.3, 60.9, 63.3, 69.8, 76.9, 78.7, 79.4, 113.8, 123.6, 129.3, 130.5, 132.0, 135.7, 139.1, 158.0 ppm (400 MHz, relative to TMS at 0 ppm).
What do claims 22-29 cover (method scope)?
Method claims are administration claims that reuse the composition claim identity, with broad diabetes- and cardiometabolic-related indication language.
Claim 22: broad diabetes and related metabolic/cardiovascular targets (using claim 1 composition)
Claim 22 covers treating (or increasing HDL levels) by administering a therapeutically effective amount of the pharmaceutical composition of claim 1 for:
- diabetes
- diabetic retinopathy, neuropathy, nephropathy
- delayed wound healing
- insulin resistance
- hyperglycemia, hyperinsulinemia
- elevated blood levels of fatty acids or glycerol
- hyperlipidemia, dyslipidemia
- obesity, hypertriglyceridemia
- Syndrome X
- diabetic complications
- atherosclerosis or hypertension
- increasing high density lipoprotein levels in a mammal
Claims 23, 24-27, 28-29: Type II diabetes and claim dependency variations
- Claim 23 narrows to “Type II diabetes” using claim 1-based composition.
- Claims 24-27 repeat the same target set using claim 7, claim 12, or other dependent basis compositions.
- Claims 28-29 repeat the set using claim 17 or narrow to “Type II diabetes” using claim 17-based composition.
Practical read-through for scope
- The method claims do not name a specific active ingredient beyond the SC-3 crystalline (S)-PG solvate composition identity.
- They do not impose administration route, dose regime, or treatment duration limits in the claim text provided.
- The indication set is broad, including both disease states and biomarkers/physiologic conditions (elevated fatty acids/glycerol, HDL increase).
How strong is the claim “net” around the solvate identity?
The infringement boundary is anchored to “crystalline (S)-propylene glycol solvate of the structure (form SC-3).” That identity is then supported by multiple experimental constraints. This usually increases defensibility because accused products must match the same solid form rather than merely use (S)-propylene glycol as a co-solvent.
Tightness indicators in the claim language
- Powder XRD peak list with narrow tolerances
- Each peak is specified with ±0.1 degrees at room temperature.
- Crystallographic specificity
- exact unit cell parameters with bracketed standard uncertainties, orthorhombic symmetry (α=β=γ=90), space group P212121, Z’=1 (molecules/asymmetric unit = 1), plus “substantially as listed in Table 4” fractional coordinates.
- Phase purity constraints
- “substantially pure form” and “substantially pure phase homogeneity”
- Multi-modal corroboration
- NMR peak list, DSC endotherm window, and TGA weight loss window.
What is likely the commercial and competitive risk shape in the US landscape?
Based on the claim structure alone:
- The patent targets solid-form IP (a specific crystalline solvate) rather than a general use of a compound with any hydrate/solvate.
- The practical competitive exposure for generics/salt/solvate entrants is highest when they:
- manufacture the same SC-3 phase, or
- can be shown to have it as an inherent or dominant solid form under normal manufacturing and storage conditions (phase homogeneity language supports this).
- The broad therapeutic indications increase enforcement leverage if the solvate is used in any diabetes/atherosclerosis/HDL-increasing product.
However, a complete “US patent landscape” map requires the actual publication number, assignee, earliest filing dates, related continuations, and how the SC-3 form relates to the underlying active pharmaceutical ingredient(s) and earlier polymorph/solvate filings. Those details are not present in the prompt content, so a full landscape cannot be produced from the claim text alone.
What parts of the claims are most actionable for freedom-to-operate (FTO)?
1) Solid-form match (high priority)
Accused products must be analyzed for whether their API is the same crystalline (S)-PG solvate form SC-3 by one or more of the provided criteria. The most defensible “comparison” targets in an FTO dossier are:
- powder XRD at room temperature with the nine specified 2θ peaks and tolerances,
- unit-cell and space group,
- solid-state 13C NMR peak list,
- DSC endotherm in the 50-78 °C range,
- TGA mass loss ~18.7% up to ~240 °C.
2) Product composition constraints (medium priority)
Even if the API solid form matches, infringement requires a pharmaceutical composition with “therapeutically effective amount” and optionally a carrier/diluent. Generic formulation carriers usually do not avoid infringement.
3) Purity/phase homogeneity (medium priority)
A strategy to avoid could be to keep the API as a mixture of phases. But the claims include “substantially pure phase homogeneity,” which can still capture products where SC-3 is dominant.
4) Indication-based method claims (secondary priority in FTO for formulation manufacturing)
If focusing on product manufacturing and composition use, method claim risk depends on how the product is marketed and used. Still, the method claims are broad on diabetes complications and cardiometabolic endpoints.
Claim-by-claim scope summary (US 8,501,698 provided claim set)
| Claim |
Type |
Core scope constraint |
| 1 |
Composition |
SC-3 crystalline (S)-PG solvate defined by powder XRD peak list (9 peaks, ±0.1°, RT) |
| 2 |
Composition (dep.) |
Additional solvate identity proof via unit cell/space group/Table 4 coords and/or 13C NMR and/or DSC and/or TGA |
| 3 |
Composition (dep.) |
Adds one or more therapeutic agent categories (antidiabetic, anti-obesity, anti-hypertensive, anti-atherosclerotic, lipid-lowering) |
| 4 |
Composition (dep.) |
Adds pharmaceutically acceptable carrier/diluent |
| 5 |
Composition (dep.) |
“Substantially pure form” |
| 6 |
Composition (dep.) |
“Substantially pure phase homogeneity” |
| 7 |
Composition (dep.) |
Unit-cell/space group/Z’ definition at RT (and Table 4-type coordinate requirement is not repeated in full text of claim 7, but crystallographic parameters are) |
| 8-11 |
Composition (dep.) |
Combination therapeutic categories, carrier/diluent, purity, phase homogeneity |
| 12 |
Composition (dep.) |
SC-3 defined by solid-state 13C NMR peak positions |
| 13-16 |
Composition (dep.) |
Add therapeutic-agent categories, carrier/diluent, purity/phase homogeneity |
| 17 |
Composition (dep.) |
SC-3 defined by DSC endotherm 50-78 °C (or FIG. 7) |
| 18-21 |
Composition (dep.) |
Add therapeutic-agent categories, carrier/diluent, purity/phase homogeneity |
| 22-23 |
Method |
Administer claim 1 composition for broad diabetes/complication/atherosclerosis/HTN endpoints and HDL increase; claim 23 narrows to Type II diabetes |
| 24-27 |
Method |
Administer claim 7, 12 compositions for same broad endpoint set; claims 25-27 narrow to Type II diabetes for those dependent compositions |
| 28-29 |
Method |
Administer claim 17 composition for same endpoint set; claim 29 narrows to Type II diabetes |
Key Takeaways
- The patent’s primary IP is solid-form specificity: it claims a crystalline (S)-propylene glycol solvate “form SC-3,” defined by a tight powder XRD fingerprint plus alternative confirmatory characterization (unit-cell/space group with fractional coordinates, solid-state 13C NMR peak list, DSC endotherm window, and TGA weight loss).
- Composition claims are broad in therapeutic use structure: they allow addition of broad therapeutic agent categories and standard carriers, while constraining the solvate purity/phase homogeneity.
- Method claims are broad in indications: diabetes complications, insulin resistance, dyslipidemia/atherosclerosis/hypertension, and HDL elevation are all expressly covered.
- FTO risk centers on the solid-state form: infringement hinges on whether the manufactured API is the same SC-3 crystalline phase, not on the dosing form or co-administered drug classes.
FAQs
-
Does US 8,501,698 claim any crystalline form besides (S)-PG solvate form SC-3?
The provided claim set limits the composition to “crystalline (S)-propylene glycol solvate … form SC-3” with specific analytical fingerprints.
-
What experimental tests are used to define the solvate identity?
The claims use powder XRD (nine 2θ peaks at specified tolerances), unit-cell/space group with fractional coordinates, solid-state 13C NMR peak positions, DSC endotherm range (50 °C to 78 °C), and TGA mass loss (~18.7% up to ~240 °C).
-
Are the therapeutic indication claims limited to one diabetes type?
No. The set includes broad “diabetes” and complications and also has dependent claims that explicitly cover “Type II diabetes.”
-
Can a product avoid infringement by adding different co-therapies?
The claims expressly cover compositions that include one or more therapeutic agents from broad pharmacological categories, so co-therapy changes do not inherently avoid infringement if the SC-3 solvate and composition elements are present.
-
What is the most practical infringement trigger for a manufacturer?
Whether the API solid form is the SC-3 crystalline (S)-PG solvate meeting the specified room-temperature solid-state fingerprints, including substantial purity and phase homogeneity.
References
[1] US Patent No. 8,501,698 (claim text provided in prompt).
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