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Patent landscape, scope, and claims: |
US Patent 3,982,021 (Coronary Disease Compounds): Scope of Claims, Claim Coverage Map, and US Patent Estate Landscape
US Patent 3,982,021 claims a pharmaceutical composition for coronary disease that is defined by a specific chemical structure class (including stereoisomers and salts) plus a set of substituent constraints (R1, R3–R7, R8–R10) and a pharmaceutically acceptable carrier. Claim 4 narrows to a single enumerated compound: 2,3-cis-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(tert-butylamino)propoxy]-2,3-naphthalenediol. The independent claim 1 is broad at the “composition” level (method not claimed, only “useful for treatment”) but narrow at the “active” level via the structure-defined substituent limits.
What is the scope of US Patent 3,982,021 claim 1 for coronary disease composition?
Claim 1 scope in one line: a composition for coronary disease that contains an “effective amount” of a structure-defined compound (or stereoisomer or salt) with constrained substituent patterns, formulated with any pharmaceutically acceptable carrier.
Claim 1 elements that define enforceable coverage
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Dosage form/claim type
- “Pharmaceutical composition,” not a method of treatment.
- Contains an “effective amount” of the active. This drives infringement toward commercial products intended to treat coronary disease, even though the mechanism is not claimed as a method.
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Therapeutic utility trigger
- “Useful for the treatment of coronary diseases in mammalian species in need thereof.”
- This is a composition-use statement. In US practice, it is often treated as limiting the intended use and can matter for labeling and regulatory positioning.
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Active ingredient definition by structure
- Active is any compound matching the structure in SPC33 (the patent’s structure rendering), with these constraints:
- R1 is lower alkyl
- R3, R4, R5, R6, R7 are each independently hydrogen or lower alkyl
- R8, R9, R10 are each independently hydrogen, lower alkyl, lower alkoxy, or cycloalkyl
- Coverage is therefore:
- Broad across the scaffold as long as the substituent pattern fits those allowable sets.
- Includes stereoisomers and salts of covered structures.
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Carrier
- “Pharmaceutically acceptable carrier therefor.”
- This is typically broad and does not meaningfully narrow beyond conventional formulation acceptability.
Practical breadth of the R-group limitations
- R1 (lower alkyl): permits multiple alkyl sizes/formats (e.g., methyl/ethyl/propyl/isopropyl), capped to “lower.”
- R3–R7 (H or lower alkyl): allows only hydrogen or alkyl, so it excludes halogens, nitriles, aryl groups, and heteroaryl substituents at those positions.
- R8–R10 (H, lower alkyl, lower alkoxy, cycloalkyl): permits alkoxy (O-alkyl) at those positions and cycloalkyl in addition to alkyl/H.
Net effect: claim 1 covers a family defined by a substituted tetrahydronaphthalenediol-type scaffold (as implied by claim 4’s naphthalenediol) with tightly controlled substitution sets, plus salts and stereochemistry.
What does claim 2 add: narrowing from claim 1 to formula-defined subgenus?
Claim 2 depends on claim 1 and specifies an active defined by the structure in SPC34 (a second formula). The claim is still a “pharmaceutical composition” with:
- effective amount of the SPC34 compound (or stereoisomer or salt),
- pharmaceutically acceptable carrier.
How claim 2 changes scope
- Claim 2 narrows from the broader R-group universe of claim 1 to a specific formula instance (the patent’s narrower substructure).
- Because it is dependent, it inherits all claim 1 constraints and additional specificity of the SPC34 formula.
Enforcement implication
- Products that use the claim 2 active (as a free base, stereoisomer, or salt) fall within both claim 2 and claim 1 if the SPC34 instance satisfies the claim 1 R constraints (which it does by construction, since claim 2 is written as “in accordance with claim 1”).
How much does claim 3 further narrow the active ingredient?
Claim 3 depends on claim 2 and specifies an active defined by SPC35.
How claim 3 changes scope
- Claim 3 narrows again to a further subgenus defined by SPC35.
- This creates a classic “tiered” coverage structure:
- claim 1: scaffold family by substituent rules
- claim 2: a subset by a more specific formula
- claim 3: a tighter subset by an even more specific formula
What does claim 4 protect exactly: composition containing the single enumerated compound?
Claim 4 depends on claim 3 and enumerates the active:
- 2,3-cis-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(tert-butylamino)propoxy]-2,3-naphthalenediol
How claim 4 narrows
- It fixes:
- stereochemistry: 2,3-cis
- the substituted side chain: 2-hydroxy-3-(tert-butylamino)propoxy
- the core: 1,2,3,4-tetrahydro-2,3-naphthalenediol with the specified 5-substitution
- It still allows:
- stereoisomers and salts? The claim 4 language is “comprising an effective amount of [the compound] …” as written. Dependent claim drafting in patents can still capture salts if separately defined in the earlier claims, but claim 4 as provided does not explicitly state “or stereoisomer or salt thereof” after the enumerated compound. In infringement analysis, this makes claim 4 inherently tighter than claims 1–3 as provided.
Market read-through
- Claim 4 is the “bullseye” claim: any commercial product whose active ingredient is this exact stereochemical compound (or, depending on the patent’s written dependence interpretation, its covered salt forms) can be directly targeted.
What is the patent’s claim strategy: structure-defined “composition” coverage versus method-of-use?
US 3,982,021 is framed as a composition patent using “useful for treatment” language rather than a direct method-of-treatment claim. That drafting choice matters in several ways:
- Infringement focus is on selling/importing/manufacturing a composition containing the covered compound in an intended clinical indication context.
- A generic that formulates the same active compound will generally face composition infringement theories more directly than under a method-of-use regime.
- If the same active is sold off-label for non-coronary indications, the “useful for treatment of coronary diseases” language can still matter, but proving intent/indication can be less straightforward than a method claim tied to administration steps.
How to map claim 1’s substituent constraints to chemical-variant “design-around” positions
Claim 1’s R-position constraints determine what changes are likely to fall outside the claim.
Likely outside-coverage changes (at R3–R7)
If a competitor modifies R3–R7 to anything other than hydrogen or lower alkyl, it likely exits claim 1 at those positions.
- excluded: halogens, aryl substituents, nitro, carboxy, amide, sulfonyl, CF3, heteroaryl, hydroxymethyl (unless treated as “lower alkyl” by broad interpretation), and other functional substituents.
Likely inside-coverage changes (at R3–R7)
- methyl, ethyl, propyl, isopropyl at R3–R7 positions are plausibly within “lower alkyl.”
- replacing H with lower alkyl (or vice versa) keeps coverage on-claim.
Likely inside-coverage changes (at R8–R10)
- hydrogen and lower alkyl are allowed
- lower alkoxy is allowed
- cycloalkyl is allowed
Likely outside-coverage changes (at R8–R10)
- large alkyl above “lower”
- aryl groups
- heteroaryl groups unless characterized as cycloalkyl/alkoxy/alkyl under the patent’s definitions
- charged substituents unless they still qualify as salts of the core covered compound
Design-around implication: a viable workaround often requires altering substitution at positions whose allowed sets are narrow, particularly R3–R7. A “side-chain cosmetically different but substituent-set equivalent” approach is less likely to avoid infringement if it still satisfies the same R definitions and scaffold identity.
What patent landscape surrounds US 3,982,021: continuation, related filings, and composition family risk?
The user-provided input includes only the claims, not:
- the patent’s title,
- filing/publication dates,
- the listed inventor/assignee,
- the full specification-defined chemical scaffold,
- or any family member patents.
Without those bibliographic details, a complete and accurate US patent landscape build (including family continuations/divisionals, related composition/formulation patents, and expiration mapping across jurisdictions) cannot be produced.
Therefore no landscape, filing chronology, or expiration timeline is provided here.
What is the Orange Book status of US 3,982,021 and what generic entry risks exist?
No drug product identity, NDA/ANDA/BLA reference listed, or Orange Book listing mapping is included in the input. Without matching the enumerated compound(s) to a specific FDA-approved product and its listed patents, an Orange Book status assessment and Paragraph IV risk analysis cannot be performed accurately.
Therefore no Orange Book status or generic entry risk is provided here.
How strong is the patent estate for this coronary disease composition: claim breadth and enforceability factors?
Based strictly on claim text provided:
Strength factors
- Independent claim (1) is broad on carriers and dosage-form class (“pharmaceutical composition,” “pharmaceutically acceptable carrier”).
- Substituent-defined scaffold coverage can capture multiple active variants without requiring literal repetition of exact compound names, as long as R-position constraints are met.
- Inclusion of stereoisomers and salts generally broadens practical infringement coverage.
Weakness factors
- The “useful for coronary disease” language is not a full method-of-treatment claim. If a competitor can position its product outside the claimed therapeutic framing, enforcement can be more complex.
- Claim 4 enumerates a single stereochemical compound. If a generic uses a different stereoisomer or different salt form, whether claim 4 captures it depends on the claim’s dependency wording and how the court reads it, with claim 1–3 doing most of the heavy lifting for stereochemical/salt variants.
Net assessment from claim architecture
- The estate strength, as far as these claims go, is driven by claim 1 breadth and the precision of the R-position definitions.
- Claim 4 is commercially valuable if the marketed active matches it exactly (2,3-cis form with the tert-butylamino side chain).
What formulations or salts are protected by US 3,982,021 claim set?
The claims provided do not list specific formulation technologies (e.g., sustained-release matrices, specific excipient sets), but they do cover:
- any pharmaceutically acceptable carrier, which typically includes conventional solid oral, liquid, and injectable carriers, depending on the compound’s stability and formulation art.
- salts of covered stereoisomer/scaffold actives, at least as expressly stated in claims 1–3.
What is not provided:
- explicit salt lists (e.g., hydrochloride, mesylate)
- explicit dosage forms (tablet, capsule, injection)
- explicit prodrug forms
So the protected universe is composition-level and salt-inclusive, not formulation-technology-specific.
Key Takeaways
- US 3,982,021 claim 1 covers a coronary-disease pharmaceutical composition containing a structure-defined active with R1 = lower alkyl; R3–R7 = H or lower alkyl; R8–R10 = H, lower alkyl, lower alkoxy, or cycloalkyl; plus stereoisomers and salts, formulated with a pharmaceutically acceptable carrier.
- Claims 2 and 3 narrow the active ingredient to progressively more specific formula instances (SPC34, then SPC35).
- Claim 4 is the tightest claim, enumerating 2,3-cis-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(tert-butylamino)propoxy]-2,3-naphthalenediol.
- Enforcement leverage is highest for products using actives that match the scaffold constraints of claim 1 and the exact stereochemistry/side-chain of claim 4.
- A complete US patent landscape (family members, continuation/divisional coverage, Orange Book status, Paragraph IV/ANDA risk, litigation timeline) cannot be generated from claims alone.
FAQs
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Does claim 1 cover both freebase and salt forms of the active compound?
Yes. Claims 1–3 expressly include “stereoisomer or salt thereof.”
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Are stereoisomers outside the exact 2,3-cis configuration protected?
Claim 4 enumerates 2,3-cis, but claims 1–3 include stereoisomers of the broader scaffold/formula actives.
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Can a generic design around by changing substituents at R3–R7?
Likely. Claim 1 restricts R3–R7 to hydrogen or lower alkyl.
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Is this a method-of-use patent or a composition patent?
The claims provided are composition claims with “useful for the treatment” language, not administration steps.
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What protects formulation-specific technologies under this patent?
The provided claims protect composition and carriers generally; they do not specify formulation technology, release profiles, or excipient systems.
References
- US Patent 3,982,021 (claims provided in user prompt).
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