United States Patent 9,271,968: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 9,271,968, titled "Crystalline polymorphous forms of the rifaximin (INN) antibiotic," is a significant patent in the pharmaceutical industry, particularly in the realm of antibiotic development. This patent, granted to Salix Pharmaceuticals (now part of Bausch Health), pertains to specific crystalline forms of rifaximin, an antibiotic used for various gastrointestinal conditions.
Background of Rifaximin
Rifaximin is an antibiotic that is primarily used to treat traveler's diarrhea, hepatic encephalopathy, and irritable bowel syndrome with diarrhea. The development of crystalline polymorphs of rifaximin is crucial for improving the drug's stability, bioavailability, and overall efficacy.
Scope of the Patent
The patent 9,271,968 focuses on the production and use of specific crystalline polymorphs of rifaximin, designated as rifaximin α and rifaximin β. These polymorphs are characterized by their unique crystal structures, which can affect the drug's physical and chemical properties.
Claims
The patent includes several claims that define the scope of the invention:
- Claim 1: This claim describes the crystalline polymorphs of rifaximin α and rifaximin β, including their specific crystal structures and X-ray powder diffraction patterns.
- Claim 2: This claim pertains to the process for preparing these crystalline forms, involving specific solvents and crystallization conditions.
- Claim 3: This claim covers the use of these crystalline forms in medicinal preparations, including oral and topical formulations[1][4].
Patent Claims Analysis
The claims in this patent are detailed and specific, ensuring that the invention is well-defined and distinguishable from prior art.
Independent Claim Length and Count
Research suggests that the length and count of independent claims can be metrics for measuring patent scope. In this case, the patent has a moderate number of claims, with detailed descriptions of the crystalline forms and their preparation methods. This specificity is indicative of a narrower patent scope, which is often associated with higher grant probabilities and shorter examination processes[3].
Patent Landscape
The patent landscape surrounding rifaximin and its crystalline forms is complex, involving multiple patents and litigation.
Related Patents
Several other patents related to rifaximin and its formulations are cited in the patent document. These include patents covering different aspects of rifaximin production, formulation, and use, such as US patents 8,183,196 B2, 8,309,569 B2, and 9,035,046 B2[4].
Litigation and Settlements
The patent has been involved in various litigation cases, particularly in the context of Abbreviated New Drug Applications (ANDAs). For instance, Salix Pharmaceuticals has engaged in litigation with generic drug manufacturers to protect its patent rights. These cases often result in settlements where the generic manufacturers agree not to infringe the patents until their expiration or as per the settlement terms[2][5].
Industry Impact
The patent 9,271,968 has significant implications for the pharmaceutical industry, particularly in the development and marketing of rifaximin-based products.
Market Exclusivity
By securing this patent, Salix Pharmaceuticals (now Bausch Health) has maintained market exclusivity for specific crystalline forms of rifaximin. This exclusivity is crucial for protecting the company's investment in research and development and for ensuring a competitive edge in the market.
Generic Competition
The patent has been a subject of interest for generic drug manufacturers. Litigation and settlements related to this patent have delayed the entry of generic versions of rifaximin into the market, allowing the patent holder to maintain market share and pricing power[2].
Expert Insights
Industry experts emphasize the importance of patent protection in the pharmaceutical sector. As noted by legal experts in the field, "Patent protection is a critical component of the pharmaceutical industry, enabling companies to recoup their significant investments in drug development and to innovate without fear of immediate generic competition"[2].
Statistics and Data
- Patent Maintenance Payments: Patents with narrower claims, like those in 9,271,968, tend to have lower maintenance payments, indicating a more focused and valuable invention[3].
- Forward Citations: The patent has been cited in several subsequent patents, indicating its influence on further research and development in the field[4].
Key Takeaways
- Specific Crystalline Forms: The patent covers specific crystalline polymorphs of rifaximin, which are crucial for the drug's stability and efficacy.
- Process and Use Claims: The patent includes claims for the preparation and use of these crystalline forms in medicinal preparations.
- Patent Landscape: The patent is part of a complex landscape involving multiple related patents and litigation.
- Industry Impact: The patent has significant implications for market exclusivity and the delay of generic competition.
FAQs
What is the main subject of United States Patent 9,271,968?
The main subject of this patent is the crystalline polymorphous forms of the antibiotic rifaximin, specifically rifaximin α and rifaximin β.
How does the patent protect the invention?
The patent protects the invention through specific claims that define the crystalline forms, their preparation methods, and their use in medicinal preparations.
What is the significance of this patent in the pharmaceutical industry?
This patent is significant because it allows the patent holder to maintain market exclusivity for specific forms of rifaximin, protecting their investment in research and development.
Has this patent been involved in any litigation?
Yes, this patent has been involved in several litigation cases, particularly in the context of ANDA filings by generic drug manufacturers.
How does the patent landscape affect generic competition?
The patent landscape, including this patent, delays the entry of generic versions of rifaximin into the market, allowing the patent holder to maintain market share and pricing power.
Cited Sources
- United States Patent and Trademark Office, "Crystalline polymorphous forms of the rifaximin (INN) antibiotic," US 9,271,968 B2.
- Robins Kaplan LLP, "ANDA Litigation Settlements Fall 2020," GENERICally Speaking Hatch-Waxman Litigation Bulletin.
- SSRN, "Patent Claims and Patent Scope," by G. S. Crespi and others.
- United States Patent and Trademark Office, "Production of medicinal preparations containing rifaximin for oral and topical use," US 10,703,763 B2.
- United States District Court for the District of Delaware, "Salix Pharmaceuticals, Inc. v. Sun Pharmaceutical Industries, Inc.," Case 1:19-cv-00734-UNA.
