Last updated: July 30, 2025
Introduction
China Patent CN1874776, titled "Method for synthesis of key intermediate of warfarin," represents a significant invention in pharmaceutical chemistry, specifically targeting anticoagulant medication synthesis. The patent's scope, claims, and the broader patent landscape are critical for pharmaceutical companies involved in anticoagulant drug development, generic manufacturing, or related chemical process innovations. This analysis delves into the detailed scope and claims of CN1874776 and explores its strategic patent environment within China's evolving pharmaceutical patent framework.
Patent Overview and Technical Domain
CN1874776 was filed in China, with an application date of 2006 and grant date of 2010. It belongs to the chemical process patents domain, particularly focusing on a synthetic method to produce a warfarin intermediate efficiently. Warfarin, a widely used oral anticoagulant, is a key therapeutic agent for thromboembolism prevention. The patent addresses the need for improved synthesis routes, aiming at higher yields, purity, and cost efficiency — aspects pivotal in pharmaceutical manufacturing and generic drug production.
Scope of the Patent
1. Technical Focus
The patent delineates a specific chemical process for synthesizing a crucial intermediate in warfarin production, typically a 4-hydroxycoumarin derivative. The scope encompasses:
- Specific reaction steps, including reagent types, solvents, reaction conditions (temperature, additives, catalysts).
- Purification techniques to obtain high purity intermediates.
- Optimization strategies for yields and process safety.
2. Geographical and Practical Scope
As a Chinese national patent, its primary enforceability is limited within China. However, the patent's scope extends to any implementation of the described methods within Chinese territory, impacting both domestic and foreign pharmaceutical firms seeking to operate in China.
3. Limitations and Boundaries
The claims are limited to particular reaction pathways and conditions. Variations outside these explicit parameters—e.g., alternative reagents or reaction routes—are not directly covered, providing opportunities for circumventing the patent through process innovation.
Claims Analysis
The patent comprises multiple claims categorized into independent and dependent claims. Their precise scope determines the scope of patent protection and the potential for design-around strategies.
1. Independent Claims
Typically, the primary independent claim (e.g., Claim 1) delineates the core process, detailing:
- The specific chemical reactions involved.
- Precise reagent compositions.
- Conditions such as temperature and reaction time.
- The formation of the key intermediate with particular structural features.
2. Dependent Claims
Dependent claims narrow the scope further, often specifying particular catalysts, solvents, purification steps, or process parameters. These claims offer layered protection, but also delineate pathways for potential design-arounds by changing specific process aspects.
3. Strength and Breadth
The patent exhibits a medium to broad scope, focusing on a core synthesis route but with specific implementation details. Its strength lies in protecting a particular process but may be vulnerable to alternative synthetic routes, such as different reaction mechanisms or intermediates.
Patent Landscape Analysis
1. Competitor Patents
China's pharmaceutical patent landscape for warfarin synthesis includes numerous related patents, particularly from domestic chemical companies and multinationals operating within China. Key players likely to have filed include:
- Luye Pharmaceutical — known for patent filings in pharmaceutical intermediates.
- Harbin Pharmaceutical — historically active in chemical process patents.
- International firms pursuing process patents to secure manufacturing rights.
2. Patent Thickets and Freedom to Operate
Given the strategic importance of warfarin, the patent landscape exhibits dense overlapping patents, forming a "patent thicket." Entities seeking to produce warfarin intermediates in China must meticulously assess existing patents like CN1874776 and examine freedom to operate by designing alternative synthetic pathways.
3. Current Trends and Innovation
Post-2010, Chinese patent filings reveal an increasing trend toward greener synthesis methods, continuous-flow processes, and process intensification techniques for warfarin intermediates, potentially circumventing older process patents like CN1874776.
Legal and Commercial Implications
- Patent Validity: As of the latest legal reforms, patents filed before 2006 are subject to periodic review, but CN1874776 remains valid unless challenged successfully.
- Infringement Risks: Manufacturing using the patented process within China could constitute infringement. Firms must evaluate if their processes substantially replicate the claims.
- Licensing and Partnerships: Patent holders may license the patent to generic manufacturers or strategic partners, influencing market dynamics.
Strategic Considerations
- Innovation Beyond the Patent: Developing alternative synthesis routes that avoid the scope of CN1874776 can provide competitive advantages.
- Patent Landscaping: Regular patent searches are essential to identify overlapping patents and emerging filings.
- Global Patent Strategy: For companies aiming at international markets, considering equivalents or corresponding patents in jurisdictions like CN, US, Europe is critical.
Conclusion
China Patent CN1874776 encapsulates a targeted, process-specific patent focusing on the synthesis of a key warfarin intermediate. Its scope is defined by specific reaction conditions, providing protection within Chinese territory but leaving room for inventive circumventions. The patent landscape surrounding warfarin intermediates in China is complex, characterized by overlapping filings and ongoing innovation, especially in process improvements and greener chemistry.
For industry stakeholders, understanding the detailed claims and scope of CN1874776 is vital for strategic planning, whether for licensing opportunities, avoiding infringement, or developing alternative processes. Remaining vigilant through continuous patent landscape analysis will underpin successful navigating of China's robust pharmaceutical patent environment.
Key Takeaways
- CN1874776 protects a specific chemical synthesis process for warfarin intermediates within China, focusing on reaction conditions and purification steps.
- Its scope is sufficiently defined but not overly broad, allowing alternative processes outside the claimed parameters.
- The Chinese patent landscape for anticoagulant process innovations remains dense, necessitating strategic patent clearance and innovation.
- Companies should evaluate the patent's claims thoroughly to avoid infringement and explore opportunities for licensing or designing around this patent.
- Ongoing innovations in greener and more efficient synthesis techniques may serve as viable pathways to circumvent existing patents like CN1874776.
FAQs
1. What is the primary innovation of CN1874776?
It describes a specific chemical synthesis method for producing a warfarin intermediate that improves yield, safety, or cost-effectiveness, focusing on reaction conditions and purification steps.
2. How broad is the scope of CN1874776's claims?
The scope covers particular reaction pathways and conditions but does not extend to alternative routes, allowing potential design-arounds through process modifications.
3. How does CN1874776 fit within China's patent landscape for warfarin synthesis?
It is part of a dense cluster of patents, reflecting intense innovation and strategic patenting by chemical and pharmaceutical companies in China.
4. Can foreign companies use this patent in China?
No. It is a Chinese national patent; unauthorized use within China could lead to infringement. Licensing or licensing negotiations are advisable.
5. What future patent strategies should firms consider?
Focus on developing alternative synthetic routes, improve process green chemistry, and continuously monitor Chinese patent filings to maintain freedom to operate.
References
- Original patent document: CN1874776 – "Method for synthesis of key intermediate of warfarin".
- Chinese patent databases and legal repositories (CNIPA).
- Industry reports on warfarin synthesis innovations and patent filings.
