United States Patent 5,095,030: Scope, Claim Architecture, and US Patent Landscape
What does US 5,095,030 claim cover at the compound level?
US 5,095,030 claims a class of chemical entities defined by a Markush-style core “formula” (multiple depicted structures in the claim set) with four variable substituent regions: R1/R2, R3, R4, and optional metalated and/or labeled forms. The claims are written to cover (i) the base compound class, (ii) salts/derivatives of the R3 region, (iii) derivatized/labeled variants (including metaled analogs), and (iv) pharmaceutical compositions.
The independent claims are claim 1 and claim 2, each of which covers “a compound of the formula … or the metalated and/or labeled form thereof” with different scope constraints on R4.
Independent Claim 1: R4 is a constrained “functional group” that includes tetrapyrrole/porphyrin linkers
Claim 1 requires the following:
- Core identity: compound of the formula shown in claim 1 (structure in STR17) or a metalated and/or labeled form.
- R1 and R2: each independently selected from:
- carbalkoxy (2-6C)
- alkyl (1-6C) sulfonyl
- aryl (6-10C) sulfonyl
- aryl (6-10C)
- cyano
- --CONR5CO--, where R5 = aryl (6-10C) or alkyl (1-6C)
- R3: each independently selected from:
- carboxyalkyl (2-6C) or a salt, amide, ester, or acylhydrazone thereof
- or alkyl (1-6C)
- R4: defined as a set of organic groups and, critically, a specialized branch:
- a variety of alkyl/vinyl/halogenated/oxygenated substituent patterns (e.g., CHCH2; substituted ethyl/propyl-like motifs with O, S, N; cyano substituted; halo-substituted versions)
- or R4 consists of 1–3 tetrapyrrole-type nuclei of the formula -L-P, where:
- -L is selected from the group shown in STR18
- P is selected from:
- Gp (a group of formula 1-6 but lacking R4, conjugated through the position occupied by R4 to L)
- or a porphyrin of the formula (STR19) with ring-join constraints: two adjacent unoccupied bonds are joined to R3, one unoccupied bond joins to R4, and the other joins to L
- Proviso: if R4 is CHCH2, then both R3 cannot be carbalkoxyethyl.
Scope effect: Claim 1 is not limited to one targeting modality. It sweeps a broad Markush substituent space and explicitly includes conjugates with tetrapyrrole-type and porphyrin units, implying use in targeting contexts (later supported by composition claim 12).
Independent Claim 2: R4 is broader but excludes the tetrapyrrole/porphyrin-specific limitation
Claim 2 mirrors the R1/R2 and R3 frameworks but differs in the R4 definition:
- R1 and R2: same as claim 1 except claim 2 lists aryl (6-10C) sulfinyl and aryl (6-10C) sulfinyl (vs. claim 1 listing “alkyl sulfonyl” and “aryl sulfonyl”).
- R3: each independently selected from:
- carboxyalkyl (2-6C) or a salt/amide/ester/acylhydrazone thereof
- or alkyl (1-6C)
- R4: “a non-interfering organic group of <12C resulting from direct or indirect derivatization of vinyl.”
Scope effect: Claim 2 is structurally broad in the R4 region (any non-interfering <12C derivatized-vinyl derived group) but does not expressly require the tetrapyrrole/porphyrin structure. It functions as a companion independent claim to keep “vinyl-derivatized” variants within the same core scaffold family.
How are dependent claims narrowing the substituent space?
Dependent claims 3–11 progressively pick specific options from R1/R2, R3, and R4.
Claims 3–6: constrain R1/R2 to carbalkoxy and R3 to smaller acid derivatives
- Claim 3: “R1 and R2 are carbalkoxy.”
- Claim 4: “R3 and R2 are carbomethoxy or carboxethoxy.”
- (Note the language “R3 and R2” ties both regions to the same carbalkoxy family.)
- Claim 5: “each R3 is --CH2CH2COOH or a salt, amide, ester or acylhydrazone thereof.”
- Claim 6: repeats claim 5 but framed with “each R3 is --CH2CH2COOH …”
Scope effect: These claims are narrow in the acid side chain: beta-carboxyethyl variants (and corresponding prodrug-like conversions).
Claims 7–8: tie to specific “formulae 3 or 4”
- Claim 7: compound is of formulae 3 or 4 (as numbered within the patent’s internal scheme).
- Claim 8: compound of claim 6 is of formulae 3 or 4.
Scope effect: This locks the core scaffold to particular sub-structures within the broader “formula” depiction.
Claims 9–10: lock R4 to tetrapyrrole-type nuclei
- Claim 9: “R4 is a group containing 1–3 tetrapyrrole-type nuclei of the formula -L-P.”
- Claim 10: same, tied to the narrower core scope of claim 8.
Scope effect: This is the formal dependent “bridge” from the general tetrapyrrole definition in claim 1 into the narrower enumerated core options.
Claim 11: identifies specific depicted formula with alkyl variable R
- Claim 11: selects from compounds of formula STR21, wherein R is alkyl (1–6C).
Scope effect: Claim 11 is an additional closure around another named family within the broader Markush set.
What is claimed at the formulation level?
Claim 12: pharmaceutical composition for targeting
- Claim 12: a pharmaceutical composition useful “in targeting specific biological material” comprising:
- an effective amount of the compound of claim 1 or 2
- in admixture with at least one pharmaceutically acceptable excipient
Scope effect: This is a straightforward composition claim that inherits compound coverage from claim 1/2. It does not add new chemical limitations, so its patentability and infringement hinge on proving the accused product contains a covered compound.
How strong is the “claim strategy” from a scope perspective?
US 5,095,030 uses four layered breadth levers:
- Core Markush scaffold (multiple structures shown; dependency points to “formula 3 or 4” and STR21).
- Two independent variable positions (R1 and R2) with multiple chemical families (carbalkoxy, aryl/alkyl sulfonyl or sulfinyl, aryl, cyano, and amide-like CONR5CO).
- R3 substituent class that includes not only free acids but also prodrug/derivative variants (salts, amides, esters, acylhydrazones).
- R4 bifurcation across two independent claims:
- claim 1 includes tetrapyrrole/porphyrin conjugation and an explicit structural set,
- claim 2 includes a broader “non-interfering <12C derivatized-vinyl” subset.
The proviso in claim 1 (R4=CHCH2 excludes R3=carboxyethyl on both positions) functions as a carve-out that reduces overbreadth and may preserve novelty against close prior art.
What does this imply for freedom-to-operate and design-around?
High-risk territory
- Products that contain the same core scaffold and include R1/R2 in the claimed families while using R3 as a carboxyalkyl (2-6C) or convertible derivatives and using R4 consistent with either claim 1 tetrapyrrole/porphyrin conjugation or claim 2 derivatized-vinyl <12C are within the claim language.
- “Metalated and/or labeled forms” extends risk beyond the neutral molecule, covering radiolabeled/complexed variants if they fall under “metalated” or “labeled” as interpreted by the patent.
Practical design-around angles (language-level)
- Break the R4 definition: for claim 1, avoid structures that satisfy “R4 consists of 1–3 tetrapyrrole-type nuclei -L-P” and avoid the porphyrin attachment topology described. For claim 2, avoid R4 that is “non-interfering <12C resulting from derivatization of vinyl” by using a larger or interfering group outside that defined “non-interfering” and “<12C derivatization of vinyl” envelope.
- Break the R3 “derivative” equivalents: R3 in the claims explicitly includes salts, amides, esters, and acylhydrazones. Avoid derivatives that are within those conversions while keeping the biological function via alternative chemistry outside the listed derivative classes.
- Constrain R1/R2 selection: if R1 and R2 are not in the listed sets (carbalkoxy, cyano, CONR5CO, aryl/alkyl sulfonyl or aryl/sulfinyl in claim 2, and aryl), the literal scope narrows.
US patent landscape context (what typically co-tracks with this scope)
Without the prosecution history, cited art list, and the patent’s original assignee/application details, only the internal claim architecture can be mapped with certainty here. What can be stated from the claim set itself is that the patent is built to capture:
- Conjugation constructs (tetrapyrrole/porphyrin linkage through defined bonding rules).
- Radiolabel/metal complex practice (explicit “metalated and/or labeled form” coverage).
- Biological targeting (explicit claim 12 “targeting specific biological material” language).
In practice, such patents usually sit in a clustered landscape that includes:
- related claims covering the “core scaffold” variations,
- follow-on patents for specific R4 conjugates (porphyrin or substituted tetrapyrroles),
- and additional patents for specific labeling/metalation methods and conjugation chemistries.
However, specific US continuation/related filings and their claim scopes cannot be enumerated from the claim text alone.
Key Takeaways
- US 5,095,030 claims a broad Markush scaffold with variable R1/R2, R3, and R4, plus metalated and/or labeled versions.
- Claim 1 is the tetrapyrrole/porphyrin-conjugated path: R4 consists of 1–3 tetrapyrrole-type nuclei (-L-P) with defined porphyrin bond-attachment topology and a CHCH2 proviso limiting simultaneous R3=carboxyethyl on both positions.
- Claim 2 is the vinyl-derivatization path: R4 is a non-interfering organic group (<12C) from derivatization of vinyl, without the explicit tetrapyrrole/porphyrin architecture.
- Dependent claims narrow to carbalkoxy R1/R2 and beta-carboxyethyl (CH2CH2COOH) R3 (with salts and derivative classes), and to specific numbered sub-formulae and tetrapyrrole-containing embodiments.
- Claim 12 covers pharmaceutical compositions for targeting, tying formulation scope directly to compounds of claim 1 or 2.
FAQs
1) Does US 5,095,030 cover salts and prodrugs?
Yes. Claim 1 and claim 2 include R3 “carboxyalkyl” as well as “a salt, amide, ester or acylhydrazone thereof.”
2) Is tetrapyrrole/porphyrin conjugation required for coverage?
Not for all coverage. Claim 1 expressly includes tetrapyrrole/porphyrin-type R4. Claim 2 covers a different R4 definition based on derivatized vinyl groups (<12C, non-interfering).
3) What is the role of the proviso in claim 1?
If R4 is CHCH2, then both R3 cannot be carbalkoxyethyl. It narrows that exact pairing to avoid overbreadth.
4) Are labeled and metalated forms included?
Yes. Both independent claims cover the compound “or the metalated and/or labeled form thereof.”
5) What does claim 12 add beyond the compound claims?
Claim 12 adds a pharmaceutical composition (effective amount of claim 1 or 2 compound plus pharmaceutically acceptable excipient) for targeting specific biological material.
References
[1] United States Patent 5,095,030.
