Detailed Analysis of the Scope and Claims of United States Patent 3,432,489
Introduction
United States Patent 3,432,489, titled "Disaccharide polysulfate aluminium compound and method," is a pivotal patent in the field of pharmaceuticals, particularly for the treatment of peptic ulcers. This patent, granted for the synthesis and therapeutic use of sucralfate, a disaccharide polysulfate aluminum compound, has significant implications in both medical treatment and patent law.
Background and Invention
The patent describes the synthesis of new compounds that have peptic ulcer inhibiting action without adverse side effects. Sucralfate, the primary compound, is chemically defined as sucrose octakis (hydrogen sulfate) aluminum complex. This compound adheres to ulcer surfaces in the gastrointestinal tract, shielding the ulcerated site from further damage by digestive contents[1][2][4].
Claims of the Patent
The patent includes several key claims that define the scope of the invention:
Chemical Composition
- The patent claims the synthesis of disaccharide polysulfate aluminum compounds, specifically sucralfate, which is composed of sucrose and aluminum ions[4].
Method of Synthesis
- The method involves reacting aluminum ions with a disaccharide polysulfate or its salt. This reaction is critical and must be carried out under specific conditions, including the use of a solvent system that is often a mixture of water and an organic cosolvent like ethanol or methanol[1][4].
Therapeutic Use
- The patent claims the therapeutic utility of sucralfate in treating peptic ulcers, including those in the duodenum. Sucralfate is effective because it forms a protective barrier over the ulcer site, preventing further irritation by stomach acid[2][4].
Scope of the Patent
The scope of the patent is defined by the claims and the detailed description of the invention.
Solvent System
- The solvent system used in the synthesis is critical. The patent highlights that using only water or other water-miscible organic solvents does not yield the desired product with the required physicochemical characteristics. Instead, a mixture of water and an organic cosolvent, preferably ethanol, is necessary[1].
Structural Analysis
- The patent distinguishes sucralfate from other compounds through various analytical techniques, including infrared spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, and elemental analyses. These methods ensure the purity and structural integrity of the synthesized compound[1].
Patent Landscape
The patent landscape surrounding U.S. Patent 3,432,489 is complex and involves several related patents and applications.
Related Patents
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Other patents, such as WO1990002133A1, build upon this foundational patent by describing improved methods for preparing sucralfate and related compounds like AAI-10001. These patents emphasize the critical nature of the solvent system and the order of reactant addition[1].
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CA1218601A describes a suspension of sucralfate for treating ulcerative conditions in the esophagus, stomach, and duodenum. This patent extends the therapeutic applications of sucralfate by providing a suspension formulation[2].
Regulatory and Legal Implications
- The definition and scope of medical devices and pharmaceuticals, as outlined by regulatory bodies like the US FDA and EMA, are relevant. Sucralfate, as a pharmaceutical, does not fall under medical device legislation but is subject to stringent pharmaceutical regulations[5].
Impact on Patent Quality and Scope
The patent's claims and scope have been subject to broader discussions on patent quality and scope.
- The clarity and breadth of patent claims are crucial. Narrower claims, as seen in the examination process of patents like U.S. Patent 3,432,489, are often associated with a higher probability of grant and a shorter examination process. This contrasts with broader claims, which can lead to increased licensing and litigation costs[3].
Key Takeaways
- Synthesis Method: The patent describes a specific method for synthesizing sucralfate using a disaccharide polysulfate and aluminum ions, with a critical solvent system.
- Therapeutic Use: Sucralfate is effective in treating peptic ulcers by forming a protective barrier over the ulcer site.
- Patent Scope: The scope is defined by the claims, emphasizing the importance of the solvent system and structural analysis.
- Regulatory Implications: The patent falls under pharmaceutical regulations and is distinct from medical device legislation.
- Impact on Patent Quality: The patent's claims contribute to discussions on patent quality, highlighting the importance of clear and narrow claims.
FAQs
What is the chemical composition of sucralfate?
Sucralfate is chemically defined as sucrose octakis (hydrogen sulfate) aluminum complex.
How is sucralfate synthesized?
Sucralfate is synthesized by reacting aluminum ions with a disaccharide polysulfate or its salt, using a solvent system that typically includes a mixture of water and an organic cosolvent like ethanol or methanol.
What is the therapeutic use of sucralfate?
Sucralfate is used to treat peptic ulcers by forming a protective barrier over the ulcer site, shielding it from further damage by digestive contents.
Why is the solvent system critical in the synthesis of sucralfate?
The solvent system is critical because using only water or other water-miscible organic solvents does not yield the desired product with the required physicochemical characteristics. A mixture of water and an organic cosolvent is necessary.
How does the patent landscape relate to U.S. Patent 3,432,489?
The patent landscape includes related patents that build upon the foundational patent, describing improved methods and formulations, and is subject to broader discussions on patent quality and scope.
Sources
- WO1990002133A1 - Method for preparing sucralfate and aai-10001.
- CA1218601A - Sucralfate suspension.
- Patent Claims and Patent Scope - Hoover Institution.
- US3432489A - Disaccharide polysulfate aluminium compound and method.
- Barrier therapies supporting the biology of the mucosal barrier - AME Groups.
