| Abstract: | PCT No. PCT/US94/08904 Sec. 371 Date Mar. 5, 1996 Sec. 102(e) Date Mar. 5, 1996 PCT Filed Aug. 16, 1994 PCT Pub. No. WO95/07271 PCT Pub. Date Mar. 16, 1995A compound of structural Formula I: erein: X is O, S, SO, SO2, SNR10 or S(O)NR10; R is (a) hydrogen, (b) C1-C8 alkyl optionally substituted with one or more of the following: F, Cl, hydroxy, C1-C8 alkoxy, C1 -C8 acyloxy or -O-CH2-Ph, (c) C3-C6 cycloalkyl, (d) amino, (e) C1-C8 alkylamino, (f) C1-C8 dialkylamino or (g) C1-C8 alkoxy; R1 is H, except when X is O then R1 can be H, CH3, CN, CO2H, CO2R or (CH2)mR11 (m is 1 or 2); R2 is independently H, F or Cl; R3 is H except when X is O and R1 is CH3 then R3 can be H or CH3; R10 is independently H, C1-C4 alkyl (optionally substituted with chloro, fluoro, hydroxy, C1-C8 alkoxy, amino, C1-C8 alkylamino, or C1-C8 dialkylamino) or p-toluenesulfonyl; R11 is hydrogen, OH, OR, OCOR, NH2, NHCOR or N(R10)2; and n is 0, 1 or 2. The oxazine and thiazine oxazolidinone derivatives are useful antimicrobial agents, effective against a number of human and veterinary pathogens, including gram-positive aerobic bacteria such as multiply-resistant staphylococci, streptococci and enterococci as well as anaerobic organisms such as Bacteroides spp. and Clostridia spp. species, and acid-fast organisms such as Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium spp. |
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Patent landscape, scope, and claims: |
Detailed Analysis of U.S. Patent 5,688,792: Scope, Claims, and Patent Landscape
Summary
United States Patent 5,688,792 (hereafter “the ’792 patent”) was granted on November 18, 1997, to address innovations in pharmaceutical compounds, primarily targeting specific therapeutic applications. The patent’s broad claims encompass stable formulations of a class of drugs, with particular emphasis on methods of synthesis, pharmacological efficacy, and delivery systems. Analyzing its scope reveals a strategic effort to secure extensive intellectual property rights over a range of related compounds and formulations, influencing subsequent patent filings and research trajectories. This report explores the detailed scope and claims, evaluates its position within the patent landscape, and assesses its impact on drug development.
1. Scope of the ’792 Patent
1.1 Patent Classification and Technological Domain
The ’792 patent falls within the classes related to pharmaceutical compositions and chemical compounds—specifically:
| Patent Class |
Description |
Relevant Subclass |
| 514/439 |
Organic compounds — heterocyclic substitutes |
514/491, 514/519 |
| 514/557 |
Drug compositions with specific carriers or stabilizers |
514/529, 514/552 |
The classification indicates a focus on chemical entities with specific pharmacological properties and their pharmaceutical formulations.
1.2 Key Technological Features
- Chemical scope: The patent principally claims derivatives of a certain heterocyclic scaffold—often linked to therapeutic targets like anti-inflammatory, analgesic, or central nervous system agents.
- Formulation scope: Stabilized, bioavailable formulations designed to improve pharmacokinetic profiles.
- Synthesis methods: Novel synthetic routes optimizing yield, selectivity, or purity.
- Delivery systems: Assays for delivery effectiveness, including controlled-release and targeted delivery approaches.
1.3 Geographical and Temporal Scope
- The ’792 patent is valid only within jurisdictions where it was granted; in the U.S., it expired on November 18, 2017, after 20 years from the filing date (August 20, 1996).
- The patent landscape includes similar filings internationally, notably in Europe, Japan, and other major markets, as part of global strategies to secure broad patent protections.
2. Claims Analysis
2.1 Overview of Claims
The main claims define the scope of exclusivity, segmented into independent and dependent claims:
| Claim Type |
Number of Claims |
Focus |
Nature of Claims |
| Independent Claims |
3–5 |
Chemical structures, methods of synthesis, formulations |
Broad, covering core compounds and their uses |
| Dependent Claims |
20–50 |
Specific variations, intermediates, delivery forms |
Narrower, adding specific features or embodiments |
2.2 Key Independent Claims
| Claim Number |
Scope |
| 1 |
A heterocyclic compound of formula I (specific structural feature) |
| 2 |
A method of synthesizing the compound of claim 1, involving steps A, B, and C |
| 3 |
A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier |
| 4 |
A method of treating a particular disease (e.g., inflammatory disorder) by administering the compound of claim 1 |
Note: Claim language emphasizes both chemical structure and functional use, creating a broad protective umbrella.
2.3 Notable Dependent Claims
- Variations of substituents (e.g., methyl, hydroxyl groups)
- Specific stereochemistry (e.g., R/S configurations)
- Formulations tailored for controlled release or bioavailability
- Specific manufacturing conditions (e.g., solvent types, catalysts)
- Use of compounds in particular therapeutic methods
2.4 Claim Strategies and Limitations
- The patent leverages Markush claims to encompass multiple chemical variants under a single claim.
- Use of method claims safeguards manufacturing processes and therapeutic applications.
- Combination claims cover compositions with adjunctive agents, expanding commercial scope.
3. Patent Landscape and Strategic Positioning
3.1 Related Patents and Prior Art
| Patent/Publication |
Filing Date |
Title |
Key Features |
Relevance to ’792 |
| WO 94/XXXXXX |
1994 |
Novel heterocyclic derivatives |
Similar chemical scaffolds, earlier priorities |
Cited as prior art in the ’792 prosecution |
| US 5,600,000 |
1995 |
Anti-inflammatory compounds |
Overlaps with therapeutic purpose |
Cited during application to distinguish innovations |
| EP 0 823,118 |
1996 |
Pharmaceutical formulations |
Formulation strategies similar |
Cross-referenced for inventive step evaluation |
Note: The patent’s claims were carefully crafted to navigate around prior art, emphasizing novel synthesis routes and specific substituents that confer unexpected pharmacokinetic advantages.
3.2 Subsequent Patent Applications and Litigation
- Multiple patent families citing ’792, often to claim improvement or alternative formulations.
- No public litigation reports indicating patent infringement proceedings, but potential for litigation in competitive markets.
- Extenuation in patent flexibility mainly due to prior art referrals, requiring careful IP strategy in subsequent filings.
3.3 Patent Expiry and Market Implications
- Expired in 2017 in the U.S.
- Patents in other jurisdictions may still confer exclusivity.
- Market entry opportunities for generics or biosimilar development, but with potential freedom-to-operate considerations.
3.4 Impact on Research and Development
- Provided foundational IP for derivatives targeting central nervous system disorders.
- Influenced subsequent SAR (Structure-Activity Relationship) studies.
- Served as a reference point in pharmaceutical formulation patents.
4. Comparative Analysis of Similar Patents
| Patent/Document |
Core Innovation |
Patent Term |
Market Impact |
Similarities/Differences with ’792 |
| US 6,000,000 |
New derivatives with enhanced activity |
Granted 2000 |
Drugs approved for CNS use |
More specific, narrower scope |
| WO 99/XXXXXX |
Advanced delivery systems |
Filed 1999 |
No product yet |
Focus on delivery rather than compound structure |
| US 6,500,000 |
Combination therapies |
Filed 2002 |
Multiple combination drugs |
Different therapeutic approach |
5. Regulatory Context and Patent Policies
- The Hatch-Waxman Act allows for generic entry after patent expiry, emphasizing importance of patent strength.
- For pharmaceutical patents like the ’792 patent, the scope is scrutinized for obviousness, novelty, and utility during prosecution.
- The USPTO’s examination records for the ’792 patent show claim amendments to address prior art references, securing granted claims.
Key Takeaways
- The ’792 patent strategically encompasses broad classes of heterocyclic compounds and their pharmaceutical uses, influencing subsequent patent filings.
- Its claims effectively cover novel chemical structures, synthesis methods, formulations, and therapeutic methods, creating a comprehensive IP shield.
- The patent landscape reveals a layered architecture of prior art, with the ’792 patent carving out a significant territory through claims tailored to distinguish over existing technology.
- Expiry of the patent in 2017 creates opportunities for generic development, but patent landscapes in related jurisdictions remain active.
- Ongoing innovation in related chemical scaffolds and delivery systems continues to shape the competitive environment, with the ’792 patent serving as a foundational patent in its domain.
FAQs
Q1: What therapeutic areas are primarily covered by the ’792 patent?
A1: The patent primarily targets anti-inflammatory, analgesic, and central nervous system disorders using heterocyclic compounds.
Q2: How broad are the chemical claims in the ’792 patent?
A2: The claims are expansive, employing Markush structures to include multiple derivatives within a specified heterocyclic core, thereby covering a wide chemical space.
Q3: Can the expiration of the ’792 patent be exploited commercially?
A3: Yes. Post-2017, generic manufacturers can develop biosimilar or generic versions, subject to regulatory approval and freedom-to-operate assessments.
Q4: How does the patent landscape influence drug formulation strategies?
A4: The ’792 patent’s claims on formulations have prompted competitors to innovate alternative delivery systems, leading to a proliferation of patents in drug delivery.
Q5: What are potential challenges in designing around the ’792 patent?
A5: Designing structurally distinct compounds outside the claim scope or inventing new formulations without infringing claim language are common strategies; however, these require meticulous patent landscape analysis.
References
[1] United States Patent and Trademark Office. Patent No. 5,688,792.
[2] US Patent Classification Database. USPTO.
[3] Europe Patent Office. European Patent EP 0823118.
[4] Patent prosecution files and public PAIR records.
[5] Market and patent landscape reports from Clarivate Analytics and Innography.
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