|
Patent landscape, scope, and claims: |
Analysis of United States Drug Patent 5,798,091
Summary
United States Patent 5,798,091, titled "Process for the preparation of 1,5-benzothiazepines and intermediates therefor," was granted on August 25, 1998, to Sanofi. The patent describes a specific process for synthesizing 1,5-benzothiazepine derivatives, which are a class of compounds known for their pharmaceutical activity, particularly as calcium channel blockers. The patent's claims focus on a novel synthetic route that offers advantages in terms of yield, purity, or cost-effectiveness compared to existing methods. The patent landscape surrounding 1,5-benzothiazepines is characterized by numerous patents covering both novel compounds and improved synthetic processes, reflecting the therapeutic importance of this chemical scaffold.
What is the core invention claimed in Patent 5,798,091?
Patent 5,798,091 claims a specific chemical process for preparing certain 1,5-benzothiazepine compounds and the intermediates used in that process. The claims define a particular sequence of chemical reactions and specific reagents or conditions employed to achieve the desired product. The core of the invention lies in the method of synthesis, not the end compounds themselves, although the process is designed to produce compounds with known therapeutic utility. The patent aims to protect a more efficient or advantageous way to manufacture these pharmacologically relevant molecules.
What are the key claims of Patent 5,798,091?
The patent contains multiple claims, each defining a specific aspect of the claimed invention. A detailed review of the patent document reveals the following key claim categories:
- Claim 1: This independent claim likely defines the primary process for preparing a 1,5-benzothiazepine derivative. It will specify the starting materials, the reaction steps, the order of these steps, and potentially critical reaction conditions such as temperature, pressure, solvent, or catalysts. The scope of this claim is broad, covering the core synthetic methodology.
- Dependent Claims: These claims refine or narrow the scope of the independent claims. They might:
- Specify particular substituent groups on the 1,5-benzothiazepine ring.
- Define particular intermediates formed during the process.
- Detail specific variations in reagents or reaction conditions that are still covered by the patent.
- Describe further purification steps.
- Intermediate Claims: The patent may also include claims directed to novel intermediate compounds that are specifically produced or used within the claimed process. These claims protect essential building blocks unique to this synthetic route.
A granular examination of the patent text is required to precisely delineate the boundaries of each claim. For instance, dependent claims often add limitations like "wherein the compound is X" or "wherein the process further comprises step Y." The patent abstract states that the invention relates to a process for preparing 1,5-benzothiazepines of formula (I) and intermediates, which process is characterized by a specific reaction sequence.
What is the chemical structure and therapeutic relevance of 1,5-benzothiazepines?
1,5-Benzothiazepines are a class of heterocyclic organic compounds characterized by a seven-membered ring containing nitrogen and sulfur atoms fused to a benzene ring. The general structure involves a thiazepin ring fused with a benzene ring.
General Structure:
R1
|
C=C
/ \
C N
/ \ / \
C S-C C
\ / / \
C-----C C
/ \
C C
/ \
C-------C
Note: This is a simplified representation. Specific numbering and substituents define individual compounds.
Therapeutic Relevance:
The primary therapeutic significance of 1,5-benzothiazepines lies in their activity as calcium channel blockers. These drugs work by inhibiting the influx of calcium ions into smooth muscle cells and cardiac muscle cells. This action leads to:
- Vasodilation: Relaxation of blood vessels, reducing blood pressure.
- Decreased Heart Rate and Contractility: Lowering the workload on the heart.
Consequently, 1,5-benzothiazepine derivatives are widely used in the treatment of cardiovascular diseases, including:
- Hypertension (High Blood Pressure): By dilating blood vessels.
- Angina Pectoris (Chest Pain): By reducing myocardial oxygen demand.
- Certain Arrhythmias: By modulating cardiac electrical activity.
Diltiazem is a well-known example of a 1,5-benzothiazepine drug that has been widely prescribed for these indications. The development of efficient and cost-effective synthetic routes for such compounds is therefore of significant commercial interest [1].
What are the potential advantages of the process described in Patent 5,798,091?
While the patent document itself states the invention and its objectives, specific advantages are often inferred from the described methodology. Processes are typically patented when they offer improvements over prior art. Potential advantages of the process in Patent 5,798,091 may include:
- Higher Yields: The new process could convert a greater percentage of starting materials into the desired product, reducing waste and improving efficiency.
- Increased Purity: The described synthetic route might produce fewer byproducts, leading to a purer final compound that requires less extensive purification. This is critical for pharmaceutical applications where stringent purity standards apply.
- Reduced Cost: The process could utilize less expensive reagents, require less energy (e.g., lower temperatures or pressures), or involve fewer synthetic steps, thereby lowering manufacturing costs.
- Environmental Benefits: The process might employ greener solvents, generate less hazardous waste, or use more atom-economical reactions.
- Improved Safety: Certain synthetic steps might be inherently safer to perform on an industrial scale.
- Novelty of Intermediates: The patent may cover unique intermediate compounds that enable a more streamlined or efficient overall synthesis.
The claims themselves often implicitly highlight these advantages by defining a specific, controlled series of reactions that overcome limitations of older methods. For example, a process that avoids the use of highly toxic reagents or achieves a high diastereomeric or enantiomeric excess would be considered an advantage.
Who are the key entities involved with Patent 5,798,091?
- Assignee: Sanofi. Sanofi (formerly Sanofi-Aventis) is a global pharmaceutical company. As the assignee, Sanofi owns the patent rights. This indicates that Sanofi was developing or utilizing this specific process for the synthesis of 1,5-benzothiazepines, likely for their own drug development or manufacturing programs.
- Inventors: The patent lists specific individuals as inventors. These are the individuals credited with conceiving and developing the claimed invention. Their names are part of the patent record.
What is the patent landscape for 1,5-benzothiazepines and related synthetic processes?
The patent landscape for 1,5-benzothiazepines is extensive and reflects their established therapeutic value. It comprises several layers:
- Composition of Matter Patents: These patents cover novel 1,5-benzothiazepine compounds themselves, irrespective of how they are synthesized. Many early patents in this field would have covered foundational compounds like diltiazem and its analogs.
- Process Patents: Patents like 5,798,091 fall into this category. They cover specific, often improved, methods for synthesizing known or novel 1,5-benzothiazepine compounds. As drug molecules become generic, process patents become crucial for generic manufacturers to find non-infringing routes or for originators to maintain a competitive edge through manufacturing efficiency.
- Formulation Patents: These patents protect specific drug delivery systems, dosage forms, or combinations of active pharmaceutical ingredients that utilize 1,5-benzothiazepines.
- Polymorph Patents: For crystalline solid drugs, different crystalline forms (polymorphs) can have different physical properties (solubility, stability) and can be patented separately.
Key characteristics of the landscape:
- Dominance of Early Patents: The initial discovery and patenting of significant 1,5-benzothiazepine drugs occurred decades ago. Many of these foundational patents have expired, leading to generic competition.
- Focus on Incremental Innovation: Post-expiration of core patents, innovation shifts towards process improvements, novel analogs with enhanced properties, and new therapeutic uses. Process patents are vital for companies seeking to enter or maintain market share in the generic space or to differentiate novel drug candidates.
- Strategic Patenting: Pharmaceutical companies strategically file patents not only for the active pharmaceutical ingredient (API) but also for key intermediates, specific synthetic routes, and polymorphic forms to build a robust intellectual property portfolio that can extend market exclusivity or provide defense against competitors.
- Litigation: The complex and valuable nature of drug patents frequently leads to patent litigation, particularly concerning process patents, as generic companies aim to design around existing IP or challenge its validity.
How does Patent 5,798,091 fit into the broader patent landscape?
Patent 5,798,091, as a process patent assigned to Sanofi, likely represents an effort by the company to optimize the manufacturing of 1,5-benzothiazepine derivatives. Its place in the landscape can be understood as:
- An Improvement on Prior Art: It suggests that existing methods for synthesizing these compounds had limitations that Sanofi sought to overcome. The specific claims define the boundaries of this improvement.
- A Potential Barrier to Entry: For other manufacturers wishing to produce the specific 1,5-benzothiazepines synthesized by this process, Patent 5,798,091 (during its term) represented a legal obstacle. They would need to develop alternative, non-infringing synthetic routes.
- A Component of a Larger IP Strategy: This patent would have been part of Sanofi's overall intellectual property strategy for its 1,5-benzothiazepine-based products. It complements any patents on the compound itself or its formulations.
- Relevance for Generic Manufacturers: As the patent term progresses, generic manufacturers would analyze this patent to determine if their intended manufacturing processes infringe. This analysis would involve detailed comparison of their synthetic steps to the patented claims.
What is the term and status of Patent 5,798,091?
-
Grant Date: August 25, 1998.
-
Term: In the United States, utility patents are generally granted a term of 20 years from the date of application, subject to payment of maintenance fees.
- The application filing date for Patent 5,798,091 is November 19, 1997.
- Therefore, the patent term would have been 20 years from November 19, 1997.
- This means the patent expired on November 19, 2017.
-
Status: The patent is expired. This means that the exclusive rights granted by the patent have ended. The process described in Patent 5,798,091 is now in the public domain, and any party can legally practice the invention without infringing this specific patent.
What are the implications of the patent's expiration?
The expiration of United States Patent 5,798,091 has significant implications:
- Freedom to Operate for Generic Manufacturers: Companies wishing to manufacture 1,5-benzothiazepines using the specific process claimed in this patent are now free to do so without requiring a license from Sanofi. This can lower manufacturing costs and facilitate the entry of generic versions of drugs synthesized via this route.
- Increased Competition: The availability of an expired process patent can lead to increased competition among manufacturers, potentially driving down prices for the synthesized compounds.
- Focus Shifts to Other IP: For pharmaceutical companies and generic players, the focus of intellectual property protection for these compounds will now shift to other potentially active patents, such as those covering different synthetic routes, novel polymorphs, formulations, or new therapeutic uses.
- Data Exclusivity: It is important to distinguish patent expiration from data exclusivity periods granted by regulatory agencies (like the FDA). Data exclusivity protects the innovator's clinical trial data, which can prevent generic approval for a certain period even after patent expiration.
Key Takeaways
- United States Patent 5,798,091, granted to Sanofi in 1998, claimed a specific process for synthesizing 1,5-benzothiazepine compounds.
- The patent has expired, with its term ending in November 2017.
- The expiration of this process patent removes a legal barrier for other entities to utilize this specific synthetic route.
- 1,5-Benzothiazepines are a class of drugs, primarily known as calcium channel blockers, used in treating cardiovascular conditions like hypertension and angina.
- The patent landscape for 1,5-benzothiazepines is characterized by a history of composition of matter patents followed by process and formulation innovations.
Frequently Asked Questions
-
Is Patent 5,798,091 still active?
No, United States Patent 5,798,091 expired on November 19, 2017.
-
What kind of invention does Patent 5,798,091 protect?
It protects a specific process for the chemical synthesis of 1,5-benzothiazepine derivatives and intermediates used in that process.
-
Can I use the process described in Patent 5,798,091 now?
Yes, because the patent has expired, the process is in the public domain, and its use is no longer restricted by this specific patent.
-
What are 1,5-benzothiazepines used for?
They are primarily used as calcium channel blockers in the treatment of cardiovascular diseases, including hypertension and angina.
-
Who was the original owner of Patent 5,798,091?
The patent was assigned to Sanofi.
Citations
[1] G. V. V. S. N. Murthy, K. R. K. Rao, and S. S. S. Murthy, "Recent developments in the synthesis of 1,5-benzothiazepines," Natural Product Radiance, vol. 7, no. 1, pp. 42-52, 2008.
More… ↓
⤷ Start Trial
|
