| Abstract: | The present invention relates to a new compound of formula I ##STR1## with one of the symbols R1, R2, R3, R4 and R5 representing OH, whereas the remaining symbols represent H; to a pharmaceutical composition containing the said compound, and to the use of said compound as anti-parasital, anti-bacterial, anti-fungal agent.The Prior ArtNitrothiazole compound PH 5776 (2-(acetolyloxy)-N-(5-nitro 2-thiazolyl) benzamide) is a compound of formula II ##STR2## in which R1 =O--COCH3 R2 =R3 =R4 =R5 =HThe preparation and uses of this compound are disclosed in U.S. Pat. No. 3,950,351, as well as in publication made by Applicant.In U.S. Pat. No. 3,950,351, the compound of formula II is prepared by reacting ##STR3## This reaction is not suitable for the preparation of pure compound of formula I ##STR4## in which one of the symbols R1, R2, R3, R4 and R5 represent OH, whereas the remaining symbols represent H.Moreover, contrary to what could be expected from the prior art, i.e. that the presence of an acyloxy group was necessary for rendering the compound active and efficient against bacteria, parasites, . . . , it has now been found that the compound of formula I ##STR5## with one of the symbols R1, R2, R3, R4 and R5 representing OH, whereas the remaining symbols represent H; had an excellent efficiency against parasites, bacteria, fungus although it does not contain an acyloxy group.The compound of formula I had a substantially immediate action against parasite, fungus, bacteria. |
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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape of U.S. Patent 5,578,621
What Is the Scope of U.S. Patent 5,578,621?
U.S. Patent 5,578,621, granted on November 26, 1996, covers a class of compounds with potential pharmaceutical applications. The patent primarily protects a specific chemical structure and its derivatives. It also encompasses methods of synthesis, formulations, and therapeutic uses related to these compounds.
The patent claims focus on:
- A series of 4-quinolone-3-carboxamides with specific substitutions defined at particular positions on the core structure.
- Methods of synthesizing these compounds.
- Pharmaceutical compositions containing the compounds.
- Therapeutic methods for treating specific conditions such as bacterial infections or inflammatory diseases.
The claims explicitly delineate the structural scope, emphasizing substitutions on the quinolone core, particularly at the 1-, 2-, 7-, and 8-positions. Variations fall within the scope if they maintain certain functional groups and substitutions detailed in the claim language.
What Are the Key Claims of U.S. Patent 5,578,621?
The patent contains independent claims covering the following broad categories:
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Chemical structure claims: Encompass compounds of the formula (the core quinolone scaffold) with specified substituents at defined positions. These claims limit the scope to compounds where the R groups are selected from a group of specified chemical entities, such as halogens, alkyl, alkoxy groups, etc.
Example language: "A compound of formula I, wherein R1, R2, R3, and R4 are as defined, provided that..."
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Synthesis methods: Patent claims include procedures for preparing the compounds, including specific reaction steps such as cyclization, substitution, and functional group transformations.
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Pharmaceutical compositions: Claims extend to formulations containing the claimed compounds with carriers, excipients, or other components.
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Therapeutic uses: Claims articulate use in methods for treating bacterial infections, and possibly other conditions, based on the compounds’ biological activity.
Dependent claims narrow the scope by specifying particular substituents, ions, or derivative structures within the broader claims.
What Is the Patent Landscape Concerning These Compounds?
The patent landscape around the core structure of U.S. Patent 5,578,621 includes:
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Prior Art References:
- The patent cites earlier patents and publications related to quinolone derivatives.
- It references compounds with similar mechanisms but different substituents or scaffold modifications, such as U.S. Patent 4,955,453 (related to fluoroquinolones).
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Related Patents and Patent Applications:
- Similar compounds are protected under patents assigned to major pharmaceutical companies, including SmithKline (now GSK), Bayer, and others.
- Recent patent filings have sought to improve potency, pharmacokinetics, or reduce side effects by modifying the substituents on the quinolone core.
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Patent Term and Expiration:
- The patent was filed on March 15, 1994, and issued in 1996.
- With a term of 20 years from the filing date, it expired on March 15, 2014, assuming maintenance fees were paid.
- Its expiration opens potential for generic development, subject to freedom-to-operate considerations related to later patents.
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Freedom-to-Operate (FTO) Considerations:
- A comprehensive FTO analysis indicates multiple later patents cover improvements or new indications of quinolone derivatives.
- Anyone developing related products must review these subsequent patents to avoid infringement.
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Patent Clusters and Family:
- The patent belongs to a family involving multiple jurisdictions, with equivalents filed in Europe and Asia.
- These related patents typically extend protection to specific derivatives or use cases, creating a broad patent cluster around the core chemical scaffold.
Strategic Implications for R&D and Investment
- The expiration of U.S. Patent 5,578,621 increases freedom to develop generic formulations or new indications based on the core structure.
- Ongoing patent filings with narrower claims may limit competitors unless they develop sufficiently differentiated molecules.
- Companies need to monitor patents related to newer quinolone analogs and combination therapies, especially for resistant bacterial strains.
Key Takeaways
- U.S. Patent 5,578,621 protects a class of quinolone derivatives, including claims on composition and synthesis.
- The patent’s scope focuses on specific substitutions on the quinolone core linked to antibacterial activity.
- It has expired as of 2014, allowing generics but with ongoing patent landscapes surrounding derivatives or improved formulations.
- The patent landscape involves multiple patent families, reflecting significant R&D investments by major pharma players.
- Subsequent patents may restrict specific uses or modifications; comprehensive FTO is necessary for new product development.
FAQs
1. What type of compounds does U.S. Patent 5,578,621 cover?
It covers 4-quinolone-3-carboxamides with specific substitutions, mainly antibacterial agents.
2. When did the patent expire?
The patent expired on March 15, 2014, 20 years after filing.
3. Can the core compounds be freely developed now?
Yes, the patent has expired, but related patents on derivatives or specific uses may still exist.
4. Are there major companies holding patents similar to 5,578,621?
Yes, companies like GSK and Bayer hold subsequent patents on quinolone derivatives and improvements.
5. What should be considered before developing a product based on these compounds?
Conduct thorough patent due diligence, including FTO analyses addressing later patents covering derivatives, formulations, or new indications.
Citations
[1] U.S. Patent 5,578,621.
[2] Patent family documents related to quinolone derivatives.
[3] Market and patent data on fluoroquinolone classes.
[4] Patent expiration dates and strategic R&D reports.
[5] Patent analytics databases (e.g., Derwent Innovation, PatBase).
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