Scope and claims analysis for US Patent 5,376,634, with the US patent estate map and claim-to-compound coverage
US Patent 5,376,634 claims a broad “polypeptide” antimicrobial genus defined by a specific structural formula with variable substituents (R1-R4) plus pharmaceutically acceptable salts, a specific embodiment reciting “SEQ ID NO: 1,” and a chain-extensive dependent claim series that narrows substituent class choices and, in later dependents, identifies specific R1 exemplars including 4-octyloxybenzoyl. The protection is strongest for (i) compounds that fall within the R1-R4 structural constraints and (ii) compositions using those compounds. The main legal boundary is the literal structural scope of the formula and the defined proviso excluding one specific R1 pairing under one R2/R3/R4 combination.
What exactly does US 5,376,634 claim: the antimicrobial polypeptide genus and the R1-R4 substitution limits?
Core independent claim (Claim 1) is a structural-coverage claim:
- Subject matter: “A polypeptide compound having antimicrobial activity”
- Structure: “of the following formula” (provided in your excerpt as a chemical formula)
- Substituent definitions:
- R1 is hydrogen or acyl group
- R2 is hydroxy or acyloxy
- R3 is hydroxysulfonyloxy
- R4 is hydrogen or carbamoyl
- Proviso (key carve-out): “with proviso that R1 is not palmitoyl, when R2 is hydroxy, R3 is hydroxysulfonyloxy and R4 is carbamoyl”
- Also claimed: “and a salt thereof”
Practical scope implications of Claim 1
- Genus is defined by a fixed backbone/formula with constrained handles. Only four variables are defined (R1-R4), while the rest of the scaffold is fixed by the formula.
- R3 is not variable. Claim 1 forces R3 = hydroxysulfonyloxy, which is the strongest structural anchor limiting design-around.
- R2 is restricted to only two functional states (hydroxy vs acyloxy).
- R4 is restricted to hydrogen vs carbamoyl, which limits the polar/charge state landscape relative to other antimicrobial chemotypes.
The single explicit exclusion is narrow but strategically meaningful
The proviso excludes one specific combination:
- R2 = hydroxy
- R3 = hydroxysulfonyloxy
- R4 = carbamoyl
- and R1 ≠ palmitoyl
This matters because many otherwise-in-scope analog strategies would keep the sulfate/sulfonyloxy motif and vary the acyl chain for potency or membrane activity. The patent says one specific “long-chain” variant (palmitoyl) is not covered under that particular substitution pattern.
How broad are the claim terms “acyl group,” “polypeptide,” and “having antimicrobial activity”?
“Acyl group” breadth
Claim 1 says R1 may be hydrogen or an acyl group. The dependent claims then greatly expand examples of what “acyl” may include (lower/higher alkanoyl, arylcarbonyl, sulfonyl, etc.). As written in the dependents, the patent is set up to capture:
- Aliphatic acyls (lower/higher alkanoyl, halo-substituted variants, alkenoyl variants)
- Aromatic acyls (benzoyl, naphthoyl, anthrylcarbonyl)
- Heteroaryl-linked acyls (pyridylthio(lower)alkanoyl, imidazolyl/thiazolyl alkanoyl classes)
- Sulfonyl/ sulfonamide-like acyl classes (lower alkylsulfonyl, arylsulfonyl)
- Carbamoyl-related substituents show up in the definitional lattice via R4 and via “alkoxyimino/carbamoyl-amide” type descriptions in dependents
“Polypeptide compound” breadth and likely enforcement posture
Even though the claim uses “polypeptide,” it is drafted as a chemical structure formula claim with substituents. In enforcement, the operator is typically the literal structure rather than sequence identity alone. Dependent claim 2 introduces SEQ ID NO: 1, but Claim 1 still anchors protection to the formula.
“Having antimicrobial activity”
This is a functional limitation in Claim 1. For infringement, the usual approach in chemical patent cases is to compare structures and then address whether the accused product falls within the claimed structure and is antimicrobial in fact. The patent’s dependent claim strategy suggests the antimicrobial activity is assumed for the genus and embodiments defined by R1-R4.
What does dependent Claim 2 (SEQ ID NO: 1) add: sequence-literal coverage or just another embodiment?
Claim 2 narrows Claim 1 by requiring the compound “is shown by the following formula (SEQ ID NO: 1).”
- This creates a second kind of coverage: besides the substituent genus, there is an explicit embodiment identified by SEQ ID NO: 1.
- In practice, Claim 2 is strong for enforcing against products that copy the specific SEQ ID NO: 1 structure, even if they were to argue novelty around substituent permutations.
- However, Claim 2 does not remove Claim 1’s genus; it adds an additional target.
Which R1 acyl classes are covered under Claims 3-10, and where do the claim dependents narrow the options?
Claims 3 onward are a cascade of R1 narrowing and exemplification. The dependents are important because they define how far R1 is pushed beyond generic “acyl.”
Claim 3: R1 exemplars include aliphatic, alkenyl, alkoxycarbonyl, arylglyoxyloyl, sulfonyl, and aroyl
Claim 3 requires the R1 acyl group be chosen from a long list including:
- lower alkanoyl (with possible substituents)
- higher alkanoyl
- lower alkenoyl (substituted)
- higher alkenoyl
- lower alkoxycarbonyl / higher alkoxycarbonyl
- aryloxycarbonyl
- aryl glyoxyloyl
- ar(lower)alkoxycarbonyl (substituted)
- lower alkylsulfonyl / aryl sulfonyl (substituted)
- ar(lower)alkylsulfonyl
- aroyl (substituted)
Claim 4: adds broad sub-substitution rules and increases the “space” of acceptable R1 substituents
Claim 4 requires the R1 be one of the classes in Claim 3 but with expanded enumerations of substituents (lower alkoxy, higher alkoxy, halo patterns, amino/protected amino, heterocyclic thio groups, etc.), including very specific count ranges for some substituent types.
Claims 5-10: progressively identify narrower aromatic and example R1 groups
The dependents move from broad classes to specific named acyl archetypes:
- Claim 5: R1 is restricted to a set including:
- lower alkanoyl classes,
- halo(lower)alkanoyl,
- phenyl(lower)alkanoyl,
- naphthyl(lower)alkanoyl,
- pyridylthio(lower)alkanoyl,
- imidazolyl(lower)alkanoyl,
- thiazolyl(lower)alkanoyl,
- phenyl(lower)alkoxyimino(lower)alkanoyl,
- higher alkanoyl, multiple phenyl lower alkenoyl/higher alkenoyl variants,
- lower/high alkoxycarbonyl and aryloxycarbonyl,
- phenylsulfonyl and naphthylsulfonyl,
- benzoyl / naphthoyl / anthrylcarbonyl with substituent count limits.
- Claim 6: focuses further to a smaller set:
- phenyl(lower)alkenoyl (with higher alkoxy), or
- benzoyl / naphthoyl / anthrylcarbonyl (with higher alkoxy-substituent patterns, halogen patterns, etc.)
- Claim 7: narrows to:
- phenyl(lower)alkenoyl with higher alkoxy, or benzoyl/naphthoyl with higher alkoxy/higher alkenyloxy, or phenyl with higher alkoxy.
- Claim 8: identifies benzoyl that “has higher alkoxy.”
- Claim 9: specifies benzoyl with higher alkoxy = 4-octyloxybenzoyl.
- Claim 10: adds an alternative path:
- phenyl(lower)alkenoyl with higher alkoxy; or
- naphthoyl with higher alkoxy or higher alkenyloxy
Enforceable outcome
- A product with R1 = 4-octyloxybenzoyl that also matches the Claim 1 scaffold (R2-R4 as required) is squarely inside dependent chain Claim 9.
- For design-around, changing R3 away from hydroxysulfonyloxy, changing R2 away from hydroxy/acyloxy, or changing R4 away from H/carbamoyl are the most direct structural exits.
- Adjusting R1 can still be risky because the dependents cover very large numbers of acyl archetypes and substituent ranges, not just one motif.
What does Claim 11 cover: formulation/composition protection and what that means for generic entry?
Claim 11 is a composition claim:
- “A pharmaceutical composition having antimicrobial activity”
- comprising an “effective amount” of:
- the compound of Claim 1 or its pharmaceutically acceptable salt
- in admixture with:
- pharmaceutically acceptable carrier or excipient
Composition scope implications
- This claim covers drug product formulations that use in-scope compound(s).
- A generic manufacturer facing this claim typically has to address both:
- whether the active ingredient matches the patented scaffold (Claim 1), and
- whether their dosage form uses that compound (Claim 11), even if carriers differ.
What US patent landscape surrounds US 5,376,634: continuations, related filings, and common co-owned antimicrobial polypeptide portfolios?
No bibliographic metadata (assignee, filing date, patent family member numbers, prosecution history, maintenance status) or citing/cited patent set is present in the prompt. Without those facts, a complete US landscape map (related applications, continuations-in-part, copending priority applications, or asserted/overruled patents) cannot be produced from the information provided.
When does US 5,376,634 lose exclusivity: expiration and patent term considerations?
No filing date, priority date, patent term adjustment, or terminal disclaimer details are provided. Without them, an accurate expiration timeline for US 5,376,634 cannot be computed from the claim text alone.
What Orange Book status, FDA approval pathway, and Paragraph IV / 505(b)(2) risks exist?
No drug product, NDC, FDA application number, or Orange Book listing information is provided. A compliant Orange Book status analysis and Paragraph IV generic risk assessment cannot be generated from the claim excerpt.
What patent claim strength indicators can be derived from the claim construction alone?
Strongest claim elements
- Rigid structural anchors: R3 is fixed at hydroxysulfonyloxy; R2 and R4 are binary; R1 is limited to hydrogen or an acyl group.
- Genus plus embodiment coverage: Claim 1 covers the genus; Claim 2 covers a specific SEQ ID NO: 1 embodiment; Claim 9 identifies a specific R1 example (4-octyloxybenzoyl).
- Composition protection: Claim 11 protects formulations using Claim 1 compounds.
Potentially litigated boundaries
- Proviso carve-out: the “R1 is not palmitoyl” exclusion under a particular R2/R3/R4 condition is a specific boundary that can drive infringement/noninfringement disputes.
- Meaning of “polypeptide compound having antimicrobial activity”: if accused products are structurally close but activity differs, Claim 1’s functional language may be litigated.
- Scope of “acyl group” and substituent ranges: the dependents are very broad; in litigation, the disputes tend to move to whether a particular accused R1 is within one of the enumerated classes and whether substituents fall inside the described counts and definitions.
Key takeaways
- US 5,376,634 is structured as a formula-based genus claim anchored on R3 = hydroxysulfonyloxy and R2/R4 binary choices, with R1 acyl flexibility expanded through dependent claim enumerations.
- Dependent claims 2 and 9 add embodiment-literal hooks: SEQ ID NO: 1 and R1 = 4-octyloxybenzoyl.
- The only explicit carve-out in the excerpt excludes R1 = palmitoyl only when R2 = hydroxy, R3 = hydroxysulfonyloxy, and R4 = carbamoyl.
- Claim 11 adds formulation-level coverage for pharmaceutical compositions containing Claim 1 compounds plus acceptable carriers.
FAQs
1) Does US 5,376,634 protect salts of the antimicrobial polypeptide?
Yes. Claim 1 expressly covers “a salt thereof,” and Claim 11 covers compositions using the Claim 1 compound or its pharmaceutically acceptable salt.
2) Is 4-octyloxybenzoyl explicitly within the claim set?
Yes. Dependent Claim 9 specifies R1 as 4-octyloxybenzoyl along the R1 narrowing chain.
3) What is the significance of the palmitoyl proviso in Claim 1?
It carves out coverage only for the palmitoyl R1 case under the specific R2/R3/R4 combination: R2 hydroxy, R3 hydroxysulfonyloxy, and R4 carbamoyl.
4) Does the claim require the exact SEQ ID NO: 1 sequence for all coverage?
No. SEQ ID NO: 1 is required only by dependent Claim 2. Independent Claim 1 covers the genus under the structural formula and R1-R4 definitions.
5) Does Claim 11 cover any antimicrobial formulation or only those containing Claim 1 compounds?
Claim 11 covers pharmaceutical compositions that include an effective amount of the Claim 1 compound (or its salt) plus acceptable carriers/excipients.
References
- US Patent 5,376,634. (Claims excerpt provided in prompt).
