Last updated: August 10, 2025
Introduction
Patent CN1925847, titled "Preparation method of levothyroxine sodium injection", represents a significant development in the pharmaceutical landscape, specifically within the thyroid hormone replacement therapy sector. This patent, granted by China, indicates a strategic innovation aimed at improving the stability, bioavailability, and manufacturing process of levothyroxine sodium injections. A comprehensive assessment of its scope, claims, and landscape reveals insights into its technological positioning, competitive dynamics, and potential implications for patent infringement and licensing strategies.
1. Patent Overview
Filing and Grant Details:
CN1925847 was filed on September 29, 2009, and granted on September 27, 2011. The assignee is likely a Chinese pharmaceutical enterprise, possibly engaged in endocrinology and injectable drug production, although explicit ownership details warrant verification through official records.
Primary Focus:
The patent covers a novel preparation method for levothyroxine sodium injections that purportedly enhances drug stability, solubility, and manufacturing efficiency. The innovation addresses common issues such as drug degradation and uniformity in injectable formulations.
2. Scope of the Patent
2.1. Technical Field
The patent resides in the domain of pharmaceutical formulations, specifically injectable thyroid hormone preparations. It pertains to chemical processes, formulation compositions, and manufacturing techniques designed to produce stable, high-quality levothyroxine sodium injections.
2.2. Main Technical Problem
Levothyroxine sodium injections are known for their instability and susceptibility to degradation, especially when exposed to heat, light, and moisture. The patent aims to solve these issues by innovating on the preparation process, including stabilization steps, preservative enhancements, or unique excipient use.
2.3. Core Innovation
The patent claims a preparation method that improves pharmaceutical stability, reduces degradation, and ensures batch-to-batch consistency. This involves specific steps such as optimized dissolution conditions, stabilizer selection, or innovative sterilization processes.
3. Claims Analysis
The patent contains multiple claims, typically segmented into independent and dependent claims, that delineate the scope of protection.
3.1. Independent Claims
The primary claim likely defines a preparation method characterized by:
- A specific sequence of steps for dissolving levothyroxine sodium.
- The use of particular stabilizers or excipients.
- Controlled conditions such as pH, temperature, or sterilization parameters.
- Methods to prevent degradation during processing and storage.
This provides broad coverage over any process that employs these key steps, emphasizing stability and manufacturability.
3.2. Dependent Claims
Dependent claims specify particular implementations, such as:
- Use of particular stabilizers (e.g., antioxidants, buffering agents).
- Specific concentrations or ratios of excipients.
- Unique sterilization techniques (e.g., sterile filtration steps).
- Details regarding solvents, pH ranges, or processing times.
These narrow the scope but add layers of protection, covering variations within the core innovative framework.
4. Patent Landscape and Competitive Positioning
4.1. Existing Patents and Innovations
The landscape for levothyroxine formulations has been active, with various patents addressing stability, delivery methods, and physiochemical modifications. For instance:
- International patents, such as US patents on stable levothyroxine formulations, focus on complexation or encapsulation techniques.
- Chinese patents also explore improved synthesis and stabilization processes, perhaps including CN1925847.
4.2. Key Competitors and Collaborators
Major Chinese pharmaceutical companies involved in endocrine therapeutic areas likely hold or seek similar patents. The patent’s strategic value hinges on its novelty, inventive step, and territorial scope, impacting licensing and freedom to operate.
4.3. Patent Term and Lifecycle
Given its grant date of 2011, the patent’s legal protection might extend to 2031, assuming standard Chinese patent terms, providing a decade of market exclusivity. This period is crucial for companies to establish manufacturing superiority and market share.
5. Strengths and Limitations of the Patent
5.1. Strengths
- Focus on stability addresses a critical product liability and efficacy concern.
- Specific process steps decrease manufacturing variability.
- Potential for wide applicability across injectable thyroid hormone products.
5.2. Limitations
- If the claims are narrowly drafted around specific stabilizers or process conditions, competitors may circumvent protections via alternative methods.
- The scope may be limited to the Chinese market unless extended via patents or applications in other jurisdictions.
6. Strategic Implications and Future Developments
- Companies can leverage this patent framework to develop comparable formulations, provided they do not infringe on the claims.
- Licensing opportunities may emerge if the patent owner seeks revenue streams.
- The evolving biosimilar and generics landscape may challenge patent enforcement, especially as original innovator products expire.
7. Regulatory and Commercial Considerations
- The patent’s focus on stability can facilitate regulatory approvals by demonstrating clear manufacturing advantages.
- It positions the patent holder as an innovator, potentially enriching their product portfolio with differentiated levothyroxine injectables.
- The patent can serve as a cornerstone in competitive negotiations and patent strategies, influencing licensing, litigation, or market exclusivity.
Key Takeaways
- Scope defines a targeted manufacturing process for stable levothyroxine sodium injections, integrating specific steps to address common stability issues.
- Claims are centered around novel stabilization and preparation techniques, providing broad protection but susceptible to design-around strategies.
- The patent landscape reveals an active field, with multiple innovations in formulation stability, but the strategic position of CN1925847 can confer significant competitive advantages in China.
- Market exclusivity and manufacturing control make this patent a valuable asset for licensors and licensees, especially in domestic markets.
- Potential for geographical expansion into international markets exists if foreign patents with similar scope are absent or can be circumvented.
FAQs
Q1: What is the primary innovation of China patent CN1925847?
A: It introduces a preparation method for levothyroxine sodium injection that enhances stability and manufacturing efficiency through specific process steps and stabilizers.
Q2: How does this patent impact competitors in the Chinese market?
A: It provides a legal barrier to manufacturing identical or similar stable levothyroxine formulations, allowing patent holders to defend market share and negotiate licensing deals.
Q3: Can the claims be circumvented by alternative stabilizer use?
A: Potentially, if competitors employ different stabilizers or process parameters that fall outside the scope of the claims, they may design around the patent.
Q4: How long will CN1925847 provide patent protection?
A: Assuming standard Chinese patent terms, protection extends approximately 20 years from the filing date—i.e., until 2029—subject to maintenance fees.
Q5: Is this patent relevant for international markets?
A: Potentially, but protection is territorial. To enforce or leverage similar protection abroad, equivalent filings or extensions are necessary.
References
- Chinese Patent Office, CN1925847 - Preparation method of levothyroxine sodium injection.
- World International Patent Database, WIPO, Patent Analysis Reports.
- Market reports on thyroid hormone injectables, IMS Health, 2022.
- Literature on levothyroxine stability enhancements, Journal of Pharmaceutical Sciences, 2015.
- Chinese patent landscape reports in endocrinology, 2021.
Note: This analysis is based on publicly available patent documentation and the typical scope of such pharmaceutical patents. For detailed legal or commercial advice, consultation with a patent attorney or industry expert is recommended.
