Detailed Analysis of the Scope and Claims of United States Patent 5,447,926
Introduction
United States Patent 5,447,926, titled "Quinolone carboxylic acid derivatives," is a significant patent in the field of pharmaceuticals, particularly focusing on fluoroquinolone antibiotics. This patent, issued in 1995, covers various aspects of these derivatives, including their synthesis, properties, and therapeutic applications.
Background
Fluoroquinolones are a class of broad-spectrum antibiotics known for their efficacy against a wide range of bacterial infections. The patent in question addresses the development and characterization of specific quinolone carboxylic acid derivatives, which are crucial for treating infections caused by both Gram-negative and Gram-positive microorganisms.
Scope of the Patent
Chemical Structure and Synthesis
The patent describes the synthesis of quinolone carboxylic acid derivatives, specifically focusing on the compound (R)-(+)-7-(3-amino-2,3,4,5,6,7-hexahydro-1H-azepin-1-yl)-1-cyclopropyl-8-chloro-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid. This compound is a key example of the derivatives covered under this patent[5].
Characterization
The patent provides detailed characterization of the molecular crystal form of these derivatives using various analytical techniques such as:
- X-ray Powder Diffraction (XRPD): The patent specifies XRPD peaks at 2θ angles of 10.6, 15, 19.7, 21.1, and 22° ± 0.2°, which are indicative of the crystalline structure of the compound[4][5].
- Differential Scanning Calorimetry (DSC): A melting peak at 288°C is noted, indicating the thermal stability of the compound[4][5].
- Nuclear Magnetic Resonance (NMR): The 13C NMR spectrum shows peaks at 23.3, 27.7, 41.1, 54.5, 116.6, and 153.5 ppm, further characterizing the molecular structure[4][5].
Claims of the Patent
The patent includes several claims that cover different aspects of the quinolone carboxylic acid derivatives:
Compound Claims
- The patent claims the specific quinolone carboxylic acid derivatives, including their enantiomers and salts.
- It also claims the process for synthesizing these compounds[5].
Pharmaceutical Composition Claims
- The patent covers pharmaceutical compositions that include these derivatives, which are formulated for various routes of administration, such as ophthalmic, oral, or topical[5].
Therapeutic Claims
- The patent claims the use of these derivatives for treating infectious diseases caused by Gram-negative and Gram-positive microorganisms[5].
Patent Landscape
Related Patents
The patent landscape surrounding US 5,447,926 includes several related patents that build upon or are related to this initial work:
- Later Patents: Patents such as US 8604020B2 and US 8481526, which focus on the molecular crystal forms and other aspects of the same or similar compounds, indicate ongoing research and development in this area[1][2].
- Expired Patents: Earlier patents like US 6699492 and US 6685958, which have since expired, highlight the evolution of patent protection over time[2].
Exclusivities and Generic Launch
The exclusivity period for Besivance, a drug that utilizes these quinolone derivatives, has expired, but the patent protection remains in place until around 2030-2031. This timeline affects the potential generic launch of similar drugs[2].
Impact on Pharmaceutical Industry
Therapeutic Applications
The compounds described in this patent have significant therapeutic applications, particularly in the treatment of bacterial infections. The specificity and broad-spectrum activity of these fluoroquinolones make them valuable in clinical settings.
Research and Development
The detailed characterization and synthesis methods provided in the patent have facilitated further research and development in the field of fluoroquinolone antibiotics. This has led to the creation of more stable and effective formulations.
Legal and Regulatory Aspects
Patent Expiration and Generic Entry
The expiration of key patents, such as those related to Besivance, will open up the market for generic versions of these drugs. However, ongoing legal activities and potential term extensions can affect the exact timing of generic entry[2].
International Protection
While the patent in question is specific to the United States, similar patents and exclusivities exist in other countries, affecting the global market entry strategies for generic drugs.
Key Takeaways
- Detailed Characterization: The patent provides comprehensive characterization of quinolone carboxylic acid derivatives using XRPD, DSC, and NMR.
- Therapeutic Applications: These derivatives are effective against a wide range of bacterial infections.
- Patent Landscape: The patent is part of a larger landscape that includes later patents and expired patents, influencing the timeline for generic drug entry.
- Regulatory Impact: Exclusivities and patent expirations play a crucial role in determining market entry for generic versions.
FAQs
What is the main compound described in US 5,447,926?
The main compound is (R)-(+)-7-(3-amino-2,3,4,5,6,7-hexahydro-1H-azepin-1-yl)-1-cyclopropyl-8-chloro-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid.
What analytical techniques are used to characterize the compound?
The compound is characterized using X-ray Powder Diffraction (XRPD), Differential Scanning Calorimetry (DSC), and Nuclear Magnetic Resonance (NMR).
What are the therapeutic applications of the compounds described in the patent?
The compounds are used to treat infectious diseases caused by Gram-negative and Gram-positive microorganisms.
When are the patents related to Besivance expected to expire?
The patents related to Besivance are expected to expire around 2030-2031.
How does the patent landscape affect the generic launch of similar drugs?
The patent landscape, including the expiration of key patents and ongoing legal activities, determines the timing and feasibility of generic drug entry into the market.
Cited Sources:
- US8604020B2 - Fluoroquinolone carboxylic acid molecular crystals - Google Patents
- Besivance patent expiration - Pharsight
- Patent Analytics | Intellectual Property Law - SLWIP
- Fluoroquinolone carboxylic acid molecular crystals - Google Patents
- US5447926A - Quinolone carboxylic acid derivatives - Google Patents
