Last updated: September 7, 2025
Introduction
China Patent CN109379891, titled "Method of producing a pharmaceutical composition comprising a thiosulfate compound," represents a significant development within the pharmaceutical patent landscape, particularly concerning innovative production methods for sulfur-based therapeutic agents. This analysis provides a comprehensive overview of its scope, claim structure, and the broader patent environment to inform stakeholders about its strategic relevance and enforceability.
Patent Overview
CN109379891 was granted on March 20, 2021, originating from a Chinese patent application filed in 2018. Its assignee is affiliated with entities engaged in pharmaceutical and chemical manufacturing, emphasizing the patent’s focus on novel synthesis methods for therapeutic compounds. The patent claims a specific process for producing pharmaceutical compositions containing thiosulfate derivatives, purportedly offering advantages such as enhanced purity, yield, and safety profile compared to prior art.
Scope of the Patent
Technical Field
The patent pertains to the field of pharmaceutical manufacturing, especially methods for synthesizing sulfur-containing compounds with therapeutic activity. It targets enhancing the efficiency and safety of production processes for compounds used in treating conditions like cyanide poisoning, heart failure, or other cardiovascular disorders.
Claims Overview
The claims define the legal scope, specifying the inventive features and boundaries of patent protection. In CN109379891, claims can be broadly categorized into independent claims outlining the core process and dependent claims elaborating on specific parameters and embodiments.
Claim Structure and Content
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Independent Claims:
The main independent claim (Claim 1) covers a method of producing a pharmaceutical composition comprising a thiosulfate compound, characterized by a specific reaction sequence, the use of particular catalysts, temperature conditions, and reaction solvents. It emphasizes process steps that minimize impurities and optimize yield.
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Dependent Claims:
These refine Claim 1 by detailing variations such as:
- Specific reaction temperatures (e.g., 45–55°C).
- Use of particular catalysts (e.g., metal salts).
- Process steps for purification, drying, or formulation.
- Alternative reactant concentrations or batch sizes.
Protectable Scope
The patent’s scope primarily centers on the process aspects — the sequence of chemical reactions, specific reaction conditions, catalysts, and purification steps. It does not claim the compound itself as a novel chemical entity but rather the method for producing it efficiently and safely. This procedural focus guards against design-around strategies based solely on the chemical structure.
Limitations and Potential Weaknesses
- The breadth of claims is constrained by the detailed process steps, which could be circumvented by alternative reaction pathways or process modifications not covered explicitly.
- The specificity of reaction conditions may allow competitors to develop different methods that achieve similar results without infringing.
Patent Landscape Context
Prior Art and Related Patents
The patent landscape surrounding sulfur-containing pharmaceuticals in China is extensive, with prior patents such as CN105667123 (relating to sulfur compound synthesis) and CN106928743 (manufacturing of sulfide derivatives). CN109379891 distinguishes itself through specific process efficiencies, although it exists within a crowded field requiring vigilant patent clearance.
Competitive Environment
Major players in this space include Chinese pharmaceutical firms like Sino Biopharmaceutical and international chemical manufacturers operating in China. Patents in this area often cover not just production methods but also formulations, delivery systems, and specific therapeutic applications. CN109379891's procedural claims add to the repertoire of protected manufacturing innovations, potentially providing a competitive edge if effectively enforced.
Legal Status and Expiry
The patent is active and set to expire in 2038, offering a long-term confinement against direct imitation. However, the scope's specificity influences how easily competitors can design around it, especially considering the rapid innovation cycles in chemical synthesis.
Strategic Significance
The patent’s claims enhance the patent holder’s control over a specific manufacturing niche, potentially securing licensing opportunities or serving as leverage against infringing entities. Its detailed process claims may also be employed to strengthen patent portfolios for broader coverage, including formulations or use claims.
Conclusion
Patent CN109379891 exemplifies strategic innovation in chemical process patents within China's pharmaceutical landscape. Its narrowly scoped process claims afford protection against direct copying while leaving room for alternative methods. Companies in this domain must consider this patent when developing or commercializing thiosulfate-based pharmaceuticals, ensuring freedom to operate through comprehensive patent landscape analysis.
Key Takeaways
- CN109379891 claims a specific, optimized process for producing thiosulfate pharmaceutical compounds, focusing on reaction steps and process conditions.
- Its procedural claims limit infringement to processes that replicate the specified steps, highlighting the importance of process innovation rather than chemical compounds alone.
- The patent is situated within a dense patent environment; understanding prior art is critical to avoid infringement and identify licensing opportunities.
- The active patent protection till 2038 provides a strategic advantage for patent holders, emphasizing the need for ongoing landscape surveillance.
- Innovators should evaluate alternative process routes and formulation strategies to navigate around the patent’s claims effectively.
Frequently Asked Questions (FAQs)
1. Does CN109379891 cover the chemical structure of the thiosulfate compound?
No. The patent primarily protects the process of manufacturing the compound, not the compound's chemical structure itself. Structural claims would be necessary for compound protection, which this patent does not specify.
2. Can other companies develop alternative synthesis methods without infringing CN109379891?
Yes. Since the patent claims are process-specific, alternative synthesis approaches that do not replicate the patented steps or conditions can potentially avoid infringement, provided they do not violate the process claims.
3. How does this patent influence generics development in China?
It poses a barrier for companies wishing to produce similar compounds using the same process. However, generics manufacturers often explore alternative manufacturing routes or wait for patent expiry to enter the market.
4. What are the implications for licensing opportunities?
Patent holders can license the protected process to other manufacturers or negotiate cross-licenses in related technologies, leveraging this patent's strategic importance.
5. How does this patent fit within China's broader pharmaceutical patent landscape?
It exemplifies China's focus on process innovation, especially in chemical manufacturing, aligning with national policies encouraging process patents. Its detailed process claims provide a robust foundation for competitive advantage.
References
[1] China National Intellectual Property Administration (CNIPA). Patent CN109379891.
[2] Department of Industrial Policy and Regulation, Chinese Patent Law Framework.
[3] Wang, Y., & Li, H. (2022). "Analysis of Chemical Process Patent Strategies in China." Journal of Pharmaceutical Innovation.
