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Patent landscape, scope, and claims: |
Executive summary
US 4,105,776 is a composition-of-matter patent centered on a broad structural genus of substituted proline/dipeptide-like (and related thio/alkanoyl) stereochemically defined compounds, with dependent claims narrowing to specific substituent sets and to the “L-form” isomer(s). It also claims full commercial packaging coverage via pharmaceutical compositions for “reducing blood pressure” and direct use claims tied to systemic administration. The claim set is dominated by genus breadth (multiple substituent options at several positions) plus a small number of species locks tied to named compounds (claims 26–27) and L-configuration language. Patent-landscape strength depends on whether later patents cover (i) specific active members within the genus, (ii) alternative salts/formats, (iii) improved syntheses, and (iv) formulation or dosing regimes that avoid literal overlap while remaining pharmacologically similar.
H1: US Patent 4,105,776 scope and claims analysis (composition-of-matter, salts, L-form, and blood-pressure methods)
What is US 4,105,776 claiming in plain scope terms?
US 4,105,776 claims three layers of coverage:
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Composition of matter (core genus and variants)
- Claims 1, 2, 3, 4, 5, 39: compound structural formulas with multiple variable substituents (R, R1, R2, R3, R4, R5, R6/R7, plus M, m, n, p).
- Claims are written to cover basic salts (claim 1) and physiologically acceptable salts (claims 5 and 39).
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Stereochemical species and named species
- Claims 21–22: explicitly claim the L-form of a claim-5 compound, and specific proline stereochemistry.
- Claims 26–27: explicitly recite named compounds:
- 1-(3-mercapto-2-D-methylpropanoyl)-L-proline (claim 26)
- 1,1’-[dithiobis(2-D-methyl-3-propanoyl)]-bis-L-proline (claim 27)
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Pharmaceutical use layer (blood-pressure reduction)
- Claims 30–34: compositions containing about 10–500 mg per dose unit range plus vehicle.
- Claims 35–38 and 42: method for reducing blood pressure via administering compositions containing specified claim compounds.
How broad are the genus claims (claims 1 and 39)?
Claims 1 and 39 are the broadest. They permit wide substitution patterns while still keeping the scaffold fixed.
Key breadth drivers:
- R (hydroxy, NH2, or lower alkoxy) in claim 1, and R (hydroxy or lower alkoxy) in claim 39. This supports multiple hydroxyl/alkoxy phenolic-like substitutions and amino substitution (claim 1 only).
- R1 and R4 each can be hydrogen, lower alkyl, phenyl, or phenyl-lower alkyl. This allows aromatic substitutions at two positions.
- R2 is the most expansive substituent bucket: hydrogen, lower alkyl, phenyl, substituted phenyl (with a very broad list of allowed ring substituents including halo, lower alkyl, lower alkoxy, phenyl-lower alkyl, triarylmethyl-like options, thioalkylmethyl options, and amide-like/alkanoylaminomethyl options).
- R6/R7: the text shows “R6 -S- or R7” as part of the scaffold options. These inclusions can expand sulfur-containing linkage variants.
- M is 0 or S: toggles a core heteroatom presence in the scaffold, a common “switch” that can materially expand literal coverage.
- m is 2: fixed in claim 1, but the scaffold is still broad via other variables.
- n and p each are 0, 1, or 2: allows missing or multiple additional substituents/units along the backbone or side-chain context.
- Salts are covered: claim 1 explicitly includes basic salts; claims 5 and 39 include physiologically acceptable salts.
Where do dependent claims narrow the universe?
The dependent claims function as “claim trees”:
- Claims 2–4: limit combinations of substituent choices (e.g., narrower R1/R3/R4/R2 categories; claim 3 and 4 lock R3 and/or R4 = hydrogen).
- Claims 6–20 and 5-dependent set: constrain to the claim-5 formula with explicit recitations (e.g., hydroxy vs lower alkoxy; R2 hydrogen vs acetyl vs benzoyl; n values 0/1/2; R1 hydrogen/methyl).
- Claims 21–22: narrow by stereochemistry (L-form proline).
- Claims 23–25 and 24–25: target specific substituent patterns that include lower alkylthio at R2 (claim 23) and a particular group format under claim 24 (and then a narrower set in claim 25: all R hydroxy, all R1 hydrogen, each n = 1).
The “named compounds” act like litigation anchors
Claims 26–27 create explicit, easily litigable targets:
- Claim 26: 1-(3-mercapto-2-D-methylpropanoyl)-L-proline
- Claim 27: 1,1’-[dithiobis(2-D-methyl-3-propanoyl)]-bis-L-proline
In practice, these named examples often become the core reference points in validity and infringement arguments because they can be tied to:
- specific chemical suppliers/manufacturing records,
- specific analytical profiles,
- and specific prior art disclosures.
Pharmaceutical claims: dosing range and vehicles
Claims 30–34 are standard composition claims:
- About 10 to 500 mg of the compound plus pharmaceutically acceptable vehicle.
Claims 35–38 and 42 are method claims:
- “administering a composition comprising” the compound plus vehicle.
The “blood pressure” limitation is the functional use hook. The claims do not tie dosing to pharmacodynamic endpoints in the text provided, but they do tie administration to a therapeutic intent and include a numeric dose band in the composition claims.
H2: Which compounds fall inside US 4,105,776 claims 1 and 39 (substituent-by-substituent infringement map)?
Claim 1 variable map (genus)
Claim 1 allows these degrees of freedom:
- R: hydroxy, NH2, lower alkoxy
- R1 and R4: hydrogen, lower alkyl, phenyl, phenyl-lower alkyl
- R2: hydrogen, lower alkyl, phenyl, substituted phenyl (very broad allowed substituents), including:
- halo / lower alkyl / lower alkoxy on phenyl,
- phenyl-lower alkyl, diphenyl-lower alkyl, triphenyl-lower alkyl,
- lower alkylthiomethyl / phenyl-lower alkylthiomethyl,
- lower alkanoylaminomethyl (text shows a capped anilide/aminomethyl-like option).
- R3: hydrogen, hydroxy, lower alkyl
- R5: lower alkyl, phenyl, phenyl-lower alkyl
- R6/R7 linkage options: includes “R6 -S- or R7” in the claim text
- M: 0 or S
- m: 2
- n and p: each 0, 1, or 2
- Salts: basic salts
Claim 5 variable map (narrower family with explicit dependent species)
Claim 5 shifts to:
- R: hydroxy or lower alkoxy
- R1: hydrogen or lower alkyl
- R2: hydrogen or lower alkanoyl
- n: 0, 1, or 2
- salts: physiologically acceptable salts
This claim anchors most of the dependent explicit species claims (claims 6–20).
Claim 39 variable map (separate genus with M fixed to m = 2)
Claim 39 is similar in structure but differs in substituent allowances:
- R: hydroxy or lower alkoxy
- R1 and R4: hydrogen, lower alkyl, phenyl, phenyl-lower alkyl
- R2: hydrogen, lower alkyl, phenyl, substituted phenyl (again broad) but with some different enumerated atoms (notably “lower alkanoylamidomethyl” appears, replacing part of the earlier list)
- R3: hydrogen, hydroxy, lower alkyl
- R5: lower alkyl, phenyl or phenyl-lower alkyl
- R6 options: lower alkyl, phenyl, substituted phenyl (including hydroxy-lower alkyl and amino(carboxy)lower alkyl)
- M: 0 or S
- m: 2
- n and p: each 0, 1, or 2
- salts: physiologically acceptable salts
Practical read-across: claims 1 and 39 together create overlapping coverage sets that differ primarily in the exact substituent enumerations for R2/R6/R7 linkage contexts.
H2: Does US 4,105,776 cover L-proline stereoisomers and specific named species?
L-form coverage (claims 21–22, 28–29)
- Claim 21: “The L-form of a compound of claim 5.”
- Claim 22: “The compound of claim 19 in which the proline is in the L-form.”
- Claim 28 and 29: proline in the L-form for the compounds of claims 18 and 17 respectively.
Scope effect: stereochemistry becomes a literal requirement for infringement of these dependent claims. A competitor using the D-form or racemate may avoid those narrower claims while still potentially falling under the broader genus claims if those broader claims are not stereochemically limited (the text you provided suggests the L-form is explicitly claimed in dependent claims, not necessarily baked into claim 1/39).
Named species (claims 26–27) are explicit infringement anchors
These are the strongest handles in litigation because the claims are not parameter-based; they name exact structures.
- Claim 26 identifies a thiol-containing moiety (“mercapto”) on a D-methylpropanoyl side chain attached to L-proline.
- Claim 27 identifies a disulfide-containing dimer (“dithiobis”) attached to two L-prolines.
In an IP challenge, these named claims often define what the inventor considered the “core” active members, affecting both novelty and obviousness arguments.
H2: What blood pressure formulation and method-of-use claims does US 4,105,776 include (mg range, vehicles, administration)?
Composition claims with dose band
- Claim 30: 10 to 500 mg of claim 1 compound + pharmaceutically acceptable vehicle
- Claim 31: same range for claim 19 compound
- Claim 32: same range for claim 18 compound
- Claim 33: same range for claim 26 compound
- Claim 34: same range for claim 27 compound
Scope effect: these claims are limited to compositions used for blood pressure reduction, with an explicit dosing band that can matter for design-around (e.g., lower or higher dose units, depending on claim interpretation and whether the “about” band is construed broadly).
Method claims
- Claim 35–38: administering compositions containing specified compounds (claim 1, claim 19, claim 18, claim 27)
- Claim 42: administering composition containing claim 26 compound
These method claims are tied to the same therapeutic intent and administration of the claimed compositions.
H2: What generic or biosimilar entry risks exist given this is a small-molecule patent (and not a biologic)?
US 4,105,776 is a small-molecule composition patent. There is no biosimilar construct for typical small-molecule generics.
Entry risk categories (relevant to US patent enforcement):
- Literal infringement risk: direct if the generic’s active ingredient matches a claim compound in the overlapping parameter space of claims 1/5/39, including stereochemistry where required.
- Salt/form coverage: physiologically acceptable/basic salts are covered in the claims. If the generic uses a different salt form that is still “physiologically acceptable” (or “basic” for claim 1), it likely remains within literal salt coverage.
- Method-of-use risk: even if a generic product is launched with a label that avoids “reducing blood pressure,” it may still face enforcement depending on labeling carve-outs and how courts interpret method-of-use claims and induced infringement theories. The claims you supplied are not tied to a specific FDA label wording, only the functional therapeutic result.
H2: When does US 4,105,776 lose exclusivity? (expiration and any enforceable term extensions)
No information was provided in your prompt about:
- filing date,
- patent issue/expiration date,
- patent term adjustments,
- PTA/extension eligibility (e.g., pre-1985 vs later term regimes),
- or any FDA pediatric exclusivity.
Per the constraints, no timeline can be produced from the provided data, so exclusivity-loss timing cannot be stated here.
H2: What is the Orange Book status of products tied to US 4,105,776?
Your prompt contains the patent claims only and does not provide:
- an Orange Book drug name,
- NDA/ANDA numbers,
- listed active ingredient name,
- or listed patents.
No Orange Book mapping can be constructed from the supplied information.
H2: How strong is the patent estate around US 4,105,776 (related filings, continuation coverage, and continuation-in-part scope)?
Your prompt does not include:
- application number,
- family members,
- continuations/divisionals,
- other US patents in the same family,
- or earlier/later priority-linked disclosures.
No estate strength analysis can be completed from the information provided.
H2: Which prior-art disclosures likely intersect US 4,105,776 claims (chemical space and obviousness risk)?
A prior-art risk analysis requires at least:
- the drug name/biological target,
- the exact chemical structure(s) beyond the variable placeholders,
- or the publication/patent references in the specification.
The prompt provides claim variable language but not the corresponding structural drawings or specification text that would anchor a prior-art search strategy. No defensible prior-art intersection can be stated.
H2: How do claims 1/5/39 compare in coverage breadth (what is gained by switching to claim 5)?
Breadth comparison
- Claim 1 and claim 39: broader because R2 and other substituent lists include wider chemical diversity (multiple phenyl substituent classes and more varied allowed groups).
- Claim 5: narrower because it restricts R2 to hydrogen or lower alkanoyl and R1 to hydrogen or lower alkyl, while also fixing n to 0–2 and limiting the overall parameter set used for the dependent explicit species claims.
Net effect: claim 5 functions as a “cleaner,” more litigable subset that is easier to match to specific examples (claims 6–20, plus L-form dependent claims). Claims 1 and 39 are the “reach” claims that can still capture unenumerated variants so long as they fit the allowed parameter buckets.
H2: What patent litigation issues would be most relevant for US 4,105,776 (claim construction, stereochemistry, salt scope, and functional use)?
Likely construction fault lines from the claims you provided
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Variable-definition interpretability
The claims depend on definitions like “lower alkyl,” “lower alkoxy,” and lists of substituted phenyl. Construction of those terms affects infringement reach.
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Stereochemical requirements
The L-form is explicitly claimed in dependent claims (21–22, 28–29). Claim construction will likely determine whether L-form limitations are limited to dependent claims or bleed into broader ones.
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Salt classification
Claim 1 includes “basic salts.” Claims 5/39 include “physiologically acceptable salts.” Competitor salt selection is a core design-around axis.
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Functional use (“reducing blood pressure”)
Use claims (35–38, 42) require the product to be used for that therapeutic effect and the claim structure includes administration plus a vehicle. Enforcement often turns on labeling and evidence of intended/induced use.
Key Takeaways
- US 4,105,776 is structured as a genus composition-of-matter patent with very broad substituent allowances (claims 1 and 39), plus a narrower, example-driven family (claim 5 and dependents 6–20).
- The claim set adds stereochemical constraints via explicit L-form dependent claims, and provides litigation anchors via named species in claims 26–27.
- Commercial coverage is completed through pharmaceutical composition claims with an explicit 10–500 mg dose band and method-of-use claims tied to “reducing blood pressure.”
- Without NDA/Orange Book mapping and family data, the exclusivity timeline, Orange Book status, and broader estate strength cannot be determined from the information provided.
FAQs
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Can a competitor design around US 4,105,776 by using a different salt form?
The claims explicitly cover basic and physiologically acceptable salts, so design-around must avoid those categories or avoid the underlying compound scope.
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Do the “L-form” dependent claims require L-proline for infringement?
Yes for claims that explicitly require proline in the L-form (claims 21–22 and related dependents).
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Does US 4,105,776 protect only compositions or also methods of use?
It protects both: composition claims for reducing blood pressure and method claims for administering the compositions to reduce blood pressure.
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Which claims are most enforceable in litigation: genus claims or named species claims?
Named species claims (claims 26–27) are typically the most straightforward infringement anchors; genus claims (1 and 39) provide broad reach.
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Is there a biosimilar pathway that avoids US 4,105,776?
The patent is for small-molecule compounds, so “biosimilar” is generally not the relevant entry route; the main risk is small-molecule generic entry and label/use-based enforcement for method claims.
References
- US Patent 4,105,776, claims as provided in the prompt.
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