United States Patent 8,193,196: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
The United States Patent 8,193,196, titled "Polymorphous forms of rifaximin, processes for their production and use thereof in the medicinal preparations," is a crucial patent in the pharmaceutical industry, particularly for the drug Xifaxan®. This patent is owned by entities associated with Salix Pharmaceuticals and is a key component in the patent landscape surrounding rifaximin, a antibiotic used to treat various gastrointestinal conditions.
Background on Rifaximin and Xifaxan®
Rifaximin is an antibiotic that has been widely used for treating conditions such as traveler's diarrhea, hepatic encephalopathy, and irritable bowel syndrome with diarrhea (IBS-D). Xifaxan®, the brand name for rifaximin, is marketed by Salix Pharmaceuticals and its affiliates, including Bausch Health Ireland Ltd. and Alfasigma S.p.A.[2][5].
Patent Overview
Patent Title and Number
The patent in question is U.S. Patent No. 8,193,196, titled "Polymorphous forms of rifaximin, processes for their production and use thereof in the medicinal preparations."
Patent Expiry
This patent is set to expire in September 2027, marking a significant milestone in the patent landscape for Xifaxan®[3].
Claims and Scope
Polymorphic Forms of Rifaximin
The patent covers various polymorphic forms of rifaximin, including processes for their production and their use in medicinal preparations. Specifically, it includes claims related to the α, β, and other polymorphic forms of rifaximin[3][4].
Pharmaceutical Compositions
The patent describes pharmaceutical compositions comprising these polymorphic forms of rifaximin, often in combination with vehicles, excipients, or other formulative ingredients. For example, it includes claims for tablets that contain a film coating and the rifaximin polymorphic mixture[4].
Specific Claim Details
- Claim 1 of the patent typically involves a rifaximin polymorphic mixture, often specified in a particular ratio of α and β forms.
- Other claims cover the methods of producing these polymorphic forms and their use in treating various medical conditions[4].
Patent Landscape and Related Patents
Family of Patents
The '196 patent is part of a larger family of patents related to rifaximin, including U.S. Patents No. 7,906,542, No. 8,741,904, and No. 10,556,915, among others. These patents collectively protect different aspects of rifaximin, such as its polymorphic forms, production processes, and therapeutic uses[3][4].
Other Relevant Patents
- U.S. Patent No. 7,906,542: Covers pharmaceutical compositions comprising polymorphic forms α, β, and γ of rifaximin.
- U.S. Patent No. 8,741,904: Also deals with polymorphous forms of rifaximin and their production processes.
- U.S. Patent No. 10,556,915: Part of the same patent family as the '196 patent, covering similar aspects of rifaximin polymorphs[3].
Litigation and Enforcement
The '196 patent has been involved in several patent infringement lawsuits. For instance, Salix Pharmaceuticals and its affiliates have filed complaints against various generic manufacturers, alleging infringement of this and other related patents. These lawsuits aim to protect the exclusive rights to Xifaxan® until the patents expire[2][5].
Recent Litigation Examples
- Curia IP Holdings, LLC v. Salix Pharmaceuticals, Ltd.: This case involves claims of infringement of multiple patents, including the '196 patent, by Curia IP Holdings against Salix Pharmaceuticals and its affiliates[1][4].
- Salix Pharmaceuticals, Inc. v. Zydus Pharmaceuticals (USA) Inc.: Salix Pharmaceuticals has also sued Zydus for patent infringement related to the '196 patent and other patents listed in the FDA's Orange Book for Xifaxan®[5].
Claim Construction and Court Decisions
In the context of patent litigation, claim construction is a critical step. Courts have held Markman hearings to construe the terms of the patents, including the '196 patent. These decisions are based on intrinsic evidence (the patent specification and file history) and extrinsic evidence (expert testimony)[4].
Key Court Findings
- The court has emphasized the importance of the patent specification in understanding the claims. For example, the court has noted that the specification is the single best guide to the meaning of a disputed term and that it informs the proper construction of the claims[4].
Impact on Generic Launch
The expiration of the '196 patent and other related patents will significantly impact the generic launch landscape for Xifaxan®. Generic manufacturers will be able to submit Abbreviated New Drug Applications (ANDAs) to the FDA once the patents expire, potentially leading to increased competition and reduced prices for the drug[3].
Conclusion
The United States Patent 8,193,196 is a pivotal patent in the pharmaceutical industry, particularly for the drug Xifaxan®. Its scope and claims cover critical aspects of rifaximin's polymorphic forms and their use in medicinal preparations. The patent landscape surrounding this patent is complex, with multiple related patents and ongoing litigation to protect these intellectual property rights.
Key Takeaways
- The '196 patent covers polymorphic forms of rifaximin and their production processes.
- It is part of a larger family of patents protecting Xifaxan®.
- The patent is set to expire in September 2027.
- Ongoing litigation aims to protect the exclusive rights to Xifaxan®.
- Court decisions on claim construction are crucial in patent infringement cases.
FAQs
What is the main subject of U.S. Patent 8,193,196?
The main subject of U.S. Patent 8,193,196 is the polymorphous forms of rifaximin, including processes for their production and use in medicinal preparations.
Who owns U.S. Patent 8,193,196?
The patent is owned by entities associated with Salix Pharmaceuticals, including Bausch Health Ireland Ltd. and Alfasigma S.p.A.
When is the patent set to expire?
The patent is set to expire in September 2027.
What are the implications of the patent's expiration?
The expiration of the patent will allow generic manufacturers to submit ANDAs to the FDA, potentially leading to increased competition and reduced prices for Xifaxan®.
Are there ongoing lawsuits related to this patent?
Yes, there are ongoing lawsuits related to this patent, with Salix Pharmaceuticals and its affiliates filing complaints against generic manufacturers for patent infringement.
Cited Sources:
- Curia IP Holdings, LLC v. Salix Pharmaceuticals, Ltd. - Casetext
- Salix Pharmaceuticals, Inc. v. Carnegie Pharmaceuticals LLC - Insight.RPXCorp
- Xifaxan patent expiration - Pharsight
- Case 2:21-cv-19293-ES-JRA Document 210 - GovInfo
- Salix Pharmaceuticals, Inc. v. Zydus Pharmaceuticals (USA) Inc. - Insight.RPXCorp
