|
Patent landscape, scope, and claims: |
Scope and claims of US Patent 5,607,942 (1-cyclopropyl-7-([S,S]-2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylic acid)
US 5,607,942 is a composition-of-matter and direct-use patent that claims a specific enantiopure quinolonecarboxylic acid scaffold (and salts/hydrates), two closely related compound species defined by alternative naming/formal structure, plus antibacterial compositions and methods of use. The enforceable claim scope is primarily driven by (i) the stereochemical qualifier “substantially free of other enantiomers and stereoisomers,” (ii) the exact substituent pattern on the quinolone core (cyclopropyl at N-1, fluoro at 6, methoxy at 8, and a fused diazabicyclo moiety at 7), and (iii) broad salt coverage (alkali/alkaline earth/silver/guanidinium and acid addition salts), with composition claims that are not limited to a dosage form.
What is US 5,607,942 claiming: compound scope, salts, and enantiomer restriction?
Core independent claim 1: exact chemical entity with stereochemical qualifier
Claim 1 covers a defined compound of formula (as shown in the patent) identified by the systematic name:
- “1-cyclopropyl-7-([S,S]-2,8-diazabicyclo-[4.3.0]non-8-yl)-6-fluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylic acid”
and explicitly includes:
- the free acid,
- or salts: “alkali metal, alkaline earth metal, silver or guanidinium salt,”
- or “pharmaceutically utilizable hydrate or acid addition salt thereof,”
- where the compound is “substantially free of other enantiomers and stereoisomers.”
Scope implications
- The substituent framework is fixed. Design-arounds that change the 1-cyclopropyl, 6-fluoro, 8-methoxy, 3-carboxylic acid, or the specific 7-(2,8-diazabicyclo[4.3.0]non-8-yl) attachment are outside the literal scope of claim 1.
- The stereochemical qualifier creates a meaningful exclusion for mixtures with significant non-(S,S) content. A product that is racemic or only partially enriched can fall outside “substantially free” depending on how that term is construed.
- Salt coverage is broad across common pharmacological counterions plus specific categories (guanidinium, silver). Acid addition salts and hydrates are also captured.
Independent claim 2: same family, alternative structural expression
Claim 2 covers:
- “The compound (1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinolonecarboxylic acid)”
and includes:
- “or an addition product thereof with water, an acid or an alkali.”
Scope implications
- Claim 2 is broader in expressed salt/hydrate language than claim 1 in that it uses generic “addition product” with water, acid, or alkali rather than limiting the counterion class to alkali/alkaline earth/silver/guanidinium.
- Claim 2, on its face, does not repeat the explicit “substantially free of other enantiomers and stereoisomers” qualifier found in claim 1. The enforceable interpretation still ties back to the compound definition, but the absence of the stereochemical phrase in the claim text can matter in infringement analysis if both claims are asserted against a product with non-enriched stereochemistry.
Claim breadth vs. formulation
Neither independent claim is limited to route, dose, or dosage form. The compound claims (1 and 2) are composition-of-matter, so any marketed drug containing the same chemical entity in an infringing form can implicate these claims even if the formulation is different.
What antibacterial composition claims exist in US 5,607,942 and how broad are they?
Claim 3 and claim 4: antibacterial compositions with “a diluent”
- Claim 3: antibacterial composition comprising an antibacterially effective amount of a compound/addition product according to claim 1 and “a diluent.”
- Claim 4: same structure but using compound/addition product according to claim 2.
Scope implications
- The formulation limitations are minimal. The only explicit ingredient beyond the active is “a diluent.”
- No limits are stated on excipient types, dosage form, delivery system (tablet, suspension, injection), or other formulation variables in the claim text you provided.
- Any formulation that includes the active at an antibacterially effective amount plus a diluent can potentially satisfy the claim’s structure, subject to the underlying compound scope.
What method-of-use claims are in US 5,607,942 (patients and growth promotion)?
Claims 5–8: two use categories, tied to claim 1 vs claim 2
Antibacterial use
- Claim 5: method of combating bacteria in a patient by administering an antibacterially effective amount of claim 1 compound/addition product.
- Claim 7: same antibacterial method, tied to claim 2 compound/addition product.
Animal growth promotion
- Claim 6: method of promoting growth of an animal by administering a growth promoting effective amount of claim 1 compound/addition product.
- Claim 8: same animal growth promotion method tied to claim 2 compound/addition product.
Scope implications
- The method claims are direct medical/veterinary use. They do not require a specific pathogen, indication wording, or bacterial susceptibility profile.
- The animal claim is a significant enforcement lever in veterinary supply chains because growth-promotion approvals and off-label uses can drive infringement exposure depending on jurisdictional law and how “growth promoting effective amount” is practiced.
- If a competitor’s drug product is marketed for antibacterial treatment but used in veterinary contexts (or vice versa), infringement can be argued for the corresponding use claims.
How do claims 1 and 2 differ in a patentability and infringement sense?
Stereochemistry: claim 1 has an explicit enantiomer restriction
- Claim 1 includes “substantially free of other enantiomers and stereoisomers.”
- Claim 2, as provided, does not include the same explicit restriction.
Infringement leverage
- A competitor could attempt to position a product as not “substantially free” to avoid claim 1 while still falling under claim 2 if the compound otherwise matches.
- Conversely, if a product is enantiopure to the (S,S) form, both claim 1 and claim 2 become relevant, increasing infringement risk.
Salt/addition product language: claim 2 appears broader
- Claim 1 enumerates counterion categories for salts.
- Claim 2 uses generic “addition product … with water, an acid or an alkali.”
Enforcement leverage
- For salt forms outside the enumerated lists in claim 1, claim 2 may still cover them if they fit the “addition product” concept.
What “design-around” options are structurally meaningful against this claim set?
High-risk changes (likely outside literal scope)
- Removing or changing the quinolone core substitution pattern:
- 1-cyclopropyl
- 6-fluoro
- 8-methoxy
- 3-quinolinecarboxylic acid (carboxylic acid position)
- 7-(2,8-diazabicyclo[4.3.0]non-8-yl) group
- Substituting the 7-position linkage chemistry (changing the bicyclic amine identity or its attachment point).
Medium-risk changes (depends on construction)
- Producing different salt forms:
- For claim 1, counterion categories are constrained to certain classes.
- For claim 2, broader “addition product” framing may capture additional salt/hydrate variations.
- Adjusting stereochemical purity:
- Claim 1’s “substantially free” can be fought with analytical evidence and claim construction.
- Claim 2 may still capture the compound even if stereochemistry is challenged, because the provided text does not impose the same phrase.
Formulation-only changes
- Changing excipients is unlikely to avoid claims 3 and 4 because those claims require only an antibacterially effective amount plus “a diluent.”
What does the claim set imply about the patent estate and coverage strategy?
Even with only the claims provided, the structure indicates a classic two-layer coverage approach:
-
Compound coverage (independent claims 1 and 2)
A defined molecule and its salts/hydrates.
-
Downstream product and method coverage (claims 3–8)
Composition claim(s) tied to an active plus diluent, and method-of-use claims that cover both antibacterial treatment and veterinary growth promotion.
This is a strong enforcement posture because it can reach:
- the active API in an accused product,
- generic formulations made with the same API,
- and activity-based infringement on “intended and actual use” frameworks for antibacterial treatment and animal growth use.
Which therapeutic areas and markets are implicated (antibacterial vs animal growth promotion)?
Antibacterial
- The method claims are not limited to a particular indication label.
- Practical infringement risk arises when a product containing the claimed API is used for antibacterial treatment in a patient.
Animal growth promotion
- The inclusion of growth promotion in the claim set expands potential enforcement into veterinary use contexts.
- If a product is developed or marketed for growth promotion, the claims track that category directly.
How strong are these claims on their face? (Claim construction drivers)
Strength factors
- Single-entity chemical definition in claim 1 is typically enforceable because it pins the scaffold and stereochemistry tightly.
- Broad salt and hydrate capture reduces the impact of marketing in alternative forms.
- Composition claims 3 and 4 have minimal excipient constraints, which can limit generic formulation carve-outs.
- Method claims map cleanly onto usage practices.
Vulnerabilities
- “Substantially free of other enantiomers and stereoisomers” is a factual/technical term that can become contested in litigation.
- Claim 2’s lack of the explicit enantiomer phrase (as provided) can cut both ways:
- It can broaden coverage against non-enriched stereochemistry products.
- It can also create an interpretive fight if the specification and claim drafting history tie stereochemistry implicitly to the claimed compound family.
US 5,607,942 claim-by-claim matrix (scope checklist)
| Claim |
Category |
What is covered (from provided claims) |
Key limitation(s) |
| 1 |
Compound (independent) |
1-cyclopropyl-7-([S,S]-2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylic acid + salts/hydrates |
“substantially free of other enantiomers and stereoisomers”; enumerated salt categories |
| 2 |
Compound (independent) |
1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0]non-8-yl)-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinolonecarboxylic acid + addition products with water/acid/alkali |
No explicit stereochemical phrase in provided text; broader “addition product” language |
| 3 |
Composition |
Antibacterial composition with effective amount of claim 1 compound + diluent |
Tied to claim 1 active scope |
| 4 |
Composition |
Antibacterial composition with effective amount of claim 2 compound + diluent |
Tied to claim 2 active scope |
| 5 |
Method (patient) |
Combating bacteria by administering antibacterially effective amount of claim 1 compound |
No pathogen limitation stated |
| 6 |
Method (animal) |
Growth promotion in animal by administering growth promoting effective amount of claim 1 compound |
No species/dosage form limitation stated |
| 7 |
Method (patient) |
Same antibacterial method tied to claim 2 active |
No pathogen limitation stated |
| 8 |
Method (animal) |
Same growth promotion method tied to claim 2 active |
No species/dosage form limitation stated |
What is covered and what is not, based strictly on the claim text
Covered
- Any drug product (human or veterinary) containing the claimed compound(s) meeting the claim definitions.
- Salts and hydrates/addition products captured within claims 1 and 2.
- Formulations that include an antibacterially effective amount plus a diluent.
- Use methods: antibacterial in patients and growth promotion in animals.
Not covered (by the claim text provided)
- Delivery-system-specific technologies (no inhaler/infusion/transdermal limitations are stated).
- Specific dosage regimens, titration schedules, or treatment durations.
- Specific bacteria classes or resistance phenotypes (no targets stated).
- Alternative quinolone cores (changes to scaffold/substituents would evade literal claim scope).
Key Takeaways
- US 5,607,942 covers a defined enantiopure (S,S) quinolonecarboxylic acid scaffold (claim 1) plus a closely related structural expression with broader “addition product” language (claim 2).
- Salt/hydrate coverage is meaningful: claim 1 enumerates counterion categories; claim 2 broadly covers addition products with water, acids, and alkali.
- Downstream coverage extends beyond the API into antibacterial compositions (only “a diluent” required) and into method claims for both human antibacterial treatment and veterinary animal growth promotion.
- The main infringement fault lines are stereochemical purity (“substantially free” in claim 1) and structural fidelity to the fixed substituent pattern on the quinolone core.
FAQs
1) Do claims 3 and 4 require any specific dosage form?
No. The claims require an antibacterially effective amount of the claimed compound plus “a diluent,” without specifying tablet, capsule, suspension, or other dosage form.
2) Can a counterion change avoid claim 1?
Only if the new salt falls outside the enumerated salt categories in claim 1. Claim 2’s broader “addition product with water, an acid or an alkali” may still capture other forms.
3) Is stereochemical purity required for both independent claims?
The provided claim 1 includes an explicit “substantially free” stereochemical qualifier; claim 2 text provided does not repeat that phrase.
4) Are the method claims limited to a specific bacterial species?
No. The method claims use broad “combating bacteria” language and do not specify pathogen targets.
5) Does the patent cover veterinary growth promotion uses?
Yes. Claims 6 and 8 explicitly claim methods of promoting growth of an animal using “growth promoting effective amount” of the claimed compound species.
References
(No external sources were cited because only the claim text provided was used.)
More… ↓
⤷ Start Trial
|
