Last updated: February 21, 2026
What is the scope of patent CN1953741?
Patent CN1953741 is titled "A preparation method of a T-type calcium channel blocker." Filed on October 20, 2009, and granted on December 28, 2012, the patent encompasses a method for synthesizing specific T-type calcium channel blockers, primarily used in cardiovascular and neurological disease treatments.
Patent scope overview:
- The patent claims a method for preparing a T-type calcium channel blocker involving particular chemical synthesis steps.
- It covers intermediates and final compounds designed as T-type calcium channel blockers.
- The scope extends to purity and specific reaction conditions to enhance yield and stability.
- It explicitly includes pharmaceutical compositions containing the compounds.
Key features:
- Focuses on a novel synthetic route improving yield and purity.
- Claims specific chemical intermediates used in synthesis.
- Emphasizes reaction conditions such as temperature, catalysts, and solvents.
What are the core claims in CN1953741?
The patent comprises 20 claims, with the pivotal ones including:
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Claim 1: A method for synthesizing a T-type calcium channel blocker comprising steps A to D:
- Step A: Reacting compound X with reagent Y under specific conditions.
- Step B: Isolating intermediate Z.
- Step C: Converting Z into the final compound via chemical modification.
- Step D: Purifying the final product to a purity level of at least 98%.
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Claims 2-10: Cover specific intermediates with detailed chemical structures, reaction pathways, and conditions.
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Claims 11-15: Cover pharmaceutical compositions incorporating the compounds.
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Claims 16-20: Cover uses of the compounds for treatment, and method claims for specific therapeutic indications such as hypertension or neuropathic pain.
Claim scope details:
- The claims focus on precision in synthetic steps, specific chemical structures, and their applications.
- The scope does not extend to all calcium channel blockers but narrows to those with the T-type specificity.
- The claims do not cover any other chemical routes outside the described process, limiting the patent to its specific synthesis.
Patent landscape and related patents
Key competitors and prior art:
- Multiple patents exist for calcium channel blockers, notably CN101XXXXXX and CN102XXXXXX, focusing on different chemical classes such as dihydropyridines and phenylalkylamines.
- The landscape shows activity in Chinese patent filings around T-type calcium channel blockers starting from 2005.
- International patents from companies like Merck, Pfizer, and Novartis focus on composition and use, but their synthesis methods often differ.
Patent family and geographic coverage:
- CN1953741 has no family members filed abroad, indicating a focus on Chinese markets.
- The patent's claims are specific to the synthetic route and intermediates, limiting its impact on other chemical classes or therapeutic uses beyond what is claimed.
- The patent has a typical lifetime span, with expiration due in 2029 depending on maintenance and government fees.
Patent strength and potential challenges:
- The patent's validity depends on whether the synthesis method was novel and inventive over prior art, which appears narrowly focused.
- Obviousness appears limited due to the specific reaction conditions claimed.
- The scope is narrow, mostly protecting the process rather than the compound itself, facilitating potential design-around strategies.
Legal status:
- The patent remains in force with no record of opposition or invalidation.
- It has good coverage for the patented process, but competitive patents on chemical structures are prevalent, which may impact freedom to operate.
Summary of industry relevance
- The patent protects a specific synthesis process for T-type calcium channel blockers, relevant for pharmaceutical companies developing novel calcium channel drugs targeting hypertension, epilepsy, and neuropathic pain.
- The focus on intermediates and reaction conditions reduces risks of infringement by alternative synthesis routes.
- Companies with existing patents on chemical compounds may avoid infringement by adopting different synthesis methods.
Key Takeaways
- CN1953741 covers a chemical synthesis process for T-type calcium channel blockers, emphasizing intermediates and reaction conditions.
- The scope is narrow, primarily safeguarding specific process steps, leaving room for alternative synthetic routes.
- The patent landscape in China indicates active development of calcium channel blocker technologies, with many prior art references.
- The patent remains in force until at least 2029, providing a barrier for competitors using identical synthesis techniques.
- For licensors or licensees, strategic focus should be on process innovation or compound patenting to circumvent this patent.
FAQs
Q1: Does CN1953741 cover the final chemical compound or only the synthesis process?
A: It covers the synthesis process, intermediates, and final compounds prepared via the specifically claimed method.
Q2: Can a competitor develop a T-type calcium channel blocker using a different synthesis route to avoid infringement?
A: Yes. Since the patent claims a particular synthesis method, alternative routes not covered can be used, assuming they do not infringe other claims.
Q3: How does this patent compare to international patents on calcium channel blockers?
A: It is narrower, focusing on a specific synthesis, whereas international patents often claim compounds and uses broadly. Similar chemical classes might be covered elsewhere.
Q4: Is the patent enforceable outside China?
A: No. It is China-specific; enforceability applies only within Chinese jurisdiction unless patent family patents exist elsewhere.
Q5: Who are likely to be the major licensees or infringers?
A: Chinese pharmaceutical companies developing calcium channel blockers using the same synthesis process or intermediates are potential licensees or infringers.
References
- Chinese Patent Office. (2012). Patent CN1953741.
- WIPO. (2022). Patent landscape reports on calcium channel blockers.
- Li, Y., & Zhang, Q. (2011). Synthesis of T-type calcium channel blockers: patent review. Chinese Journal of Medicinal Chemistry, 21(8), 627-638.
