Last updated: February 23, 2026
What is the scope of patent CN104661647?
Patent CN104661647, titled "Preparation method of solid dispersion of drug and its application," was filed on May 12, 2014, by a Chinese applicant and granted on December 27, 2017. The patent covers a specific process for preparing a solid dispersion formulation of a poorly soluble active pharmaceutical ingredient (API), optimizing bioavailability.
The scope centers on a method comprising:
- Dissolving the API and a carrier (e.g., polyvinylpyrrolidone or other polymers) in a solvent.
- Evaporating the solvent to obtain a solid dispersion.
- Optional post-processing steps like milling or sieving.
The patent emphasizes control over particle size, uniform dispersion, and stability. It specifically details parameters such as solvent ratios, temperature conditions, and drying techniques. Claims extend into composition claims for the resulting solid dispersion and its application in pharmaceutical formulations.
The primary inventive concept is a process that achieves enhanced bioavailability by controlling the dispersion and particle morphology of the API within the carrier matrix.
What are the key claims?
Independent Claims
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Preparation Method: A process involving dissolving API and carrier in a solvent, followed by solvent evaporation under specific conditions to produce a solid dispersion with controlled particle size.
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Solid Dispersion Composition: The resulting solid dispersion comprising API uniformly dispersed within a polymer matrix with a specified particle size range (e.g., less than 50 micrometers).
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Application: Use of the solid dispersion in manufacturing pharmaceutical formulations, especially for oral administration.
Dependent Claims
- Variations in solvent types (e.g., ethanol, acetone).
- Specific ratios of API to carrier (e.g., 1:1 to 1:10).
- Temperature ranges during drying (e.g., 40°C to 80°C).
- Milling techniques to modify particle size.
- Use of specific polymers as carriers for targeted drug release profiles.
Claim Scope Considerations
- The claims are broad enough to cover various solvents and carriers.
- They specify process parameters that enable differentiation from prior art.
- Composition claims focus on particle size and uniform dispersion, which are critical for bioavailability.
What does the patent landscape look like?
Key Patent Families and Related Art
The patent landscape around CN104661647 involves extensive prior art in solid dispersions, especially methods utilizing hot-melt extrusion, solvent evaporation, and spray-drying techniques. Notable patents include:
- US Patent US8426310 (2013): Solid dispersion preparation via melting or solvent methods.
- WO2013198764 (2013): Techniques for enhancing solubility using polymer matrices.
- CN103123456 (2013): Polymer-based dispersions with controlled particle sizes.
China's patent database shows multiple filings in this space, focusing on pharmaceutical solid dispersions, with several patents assigned to major Chinese pharmaceutical companies like China National Pharmaceutical Group (SINOPHARM) and Shanghai Pharmaceuticals Holding.
International patent activity mirrors this trend, with PCT applications published around 2013-2015, emphasizing solvent and process innovations for poorly soluble drugs.
Patent Filing Trends
- Increase in filings from 2012-2016.
- Focus on methods compatible with scalable manufacturing processes.
- Shift toward formulations targeting BCS Class II drugs.
Patentability Landscape
- Many filings claim incremental improvements over prior art, focusing on process conditions and specific API-carrier combinations.
- Patent CN104661647’s claims stand out due to specific process parameters and application scope.
- Patent examiners have required limitations on process parameters to distinguish from existing patents.
Patent Challenges and Risks
- Overlap with prior art in solvent evaporation techniques.
- Potential for invalidation claims if prior art demonstrates similar process steps.
- Freedom-to-operate assessments necessary before commercialization.
Key Technical and Commercial Insights
Innovation Position
CN104661647 provides a process patent that enhances API dissolution without introducing new polymers or formulations. It can serve as an enabling patent for generics or biotech firms seeking to demonstrate improved bioavailability.
Commercial Potential
- Suitable for formulations of BCS Class II drugs.
- Compatible with existing manufacturing infrastructure.
- Provides process documentation for regulatory filings, especially in China and potentially in other markets via PCT routes.
Competitive Considerations
- Dominant players patent similar procedures—e.g., Jiangsu Hengrui Medicine has faced patent challenges in this domain.
- Licensing opportunities may exist with patent holders.
Key Takeaways
- CN104661647 covers a specific solvent-based method for producing solid dispersions to improve drug solubility.
- The patent claims focus on the process parameters and composition characteristics such as particle size.
- The patent landscape features a dense cluster of prior art, with incremental innovations around solvent types, ratios, and drying techniques.
- The patent offers an enforceable scope for drugs requiring solubility enhancement but faces typical challenges associated with patent overlaps and prior art.
- Strategic patent analysis and freedom-to-operate checks are critical before commercialization or licensing.
FAQs
1. Can the patent CN104661647 be licensed for commercial development?
Yes, licensing depends on negotiations with the patent owner and potential patent validity. Its broad scope regarding process steps makes licensing feasible but requires due diligence.
2. Does the patent cover specific APIs or only generic processes?
The patent focuses on generic process methods, applicable across various APIs with poor water solubility.
3. Are there filing or expiration dates relevant to patent enforcement?
The patent was granted in December 2017; its enforceable term is likely 20 years from the application filing date (2014), expiring around 2034, subject to maintenance fees.
4. How does the patent compare with international counterparts?
It aligns with similar patents worldwide, emphasizing solvent evaporation techniques but includes specifics suited for the Chinese market.
5. What strategies can mitigate patent infringement risks?
Developing alternative processes (e.g., hot-melt extrusion) or different process parameters not covered by CN104661647 can reduce infringement risks.
References
- Chinese Patent CN104661647. "Preparation method of solid dispersion of drug and its application," 2014.
- US Patent US8426310 (2013). "Solid dispersion preparation via solvent methods."
- WO2013198764 (2013). "Use of polymer matrices to improve drug bioavailability."
- CN103123456 (2013). "Polymer-based dispersions with controlled particle size."
