Understanding the Scope and Claims of United States Patent 6,429,210
Introduction
The United States Patent 6,429,210, titled "Polymorphic clopidogrel hydrogenesulphate form," is a significant patent in the pharmaceutical industry, particularly in the context of cardiovascular medicines. This patent, held by Sanofi-Aventis, pertains to the novel polymorphic forms of clopidogrel hydrogen sulfate, a crucial active ingredient in the drug Plavix.
Background of Clopidogrel Hydrogen Sulfate
Clopidogrel hydrogen sulfate is a platelet aggregation inhibitor used to prevent heart attacks and strokes. It was first described in European Patent EP 281459[1][4].
Patent Overview
Publication and Legal Status
The patent was published on August 6, 2002, with the publication number US6429210B1. It has since expired, marking the end of its lifetime protection[1][4].
Key Claims and Scope
Polymorphic Forms
The patent primarily focuses on the discovery and preparation of different polymorphic crystalline forms of clopidogrel hydrogen sulfate. Specifically, it describes two main forms: Form 1 and Form 2.
- Form 1: This is the initial form of clopidogrel hydrogen sulfate obtained through a synthetic process described in the patent. It has specific physical and spectral characteristics[1][4].
- Form 2: This is a novel polymorph discovered during further research. Form 2 differs from Form 1 in terms of stability, physical properties, and spectral characteristics. The patent details the process for preparing and isolating this new form[1][4].
Preparation and Isolation
The patent outlines the synthetic processes and conditions necessary for preparing both Form 1 and Form 2 of clopidogrel hydrogen sulfate. It also describes the methods for isolating these compounds in their respective crystalline forms[1][4].
Pharmaceutical Compositions
The patent includes claims related to pharmaceutical compositions containing these polymorphic forms of clopidogrel hydrogen sulfate. These compositions are crucial for the formulation of drugs like Plavix, which is used to treat cardiovascular conditions[1][4].
Spectral and Physical Characteristics
X-Ray Powder Diffraction
The patent provides detailed X-ray powder diffraction data for both Form 1 and Form 2. For example, Form 2 has significant reflections at specific d-spacings (e.g., 4.11 Å, 6.86 Å, 3.87 Å)[1][4].
Infrared Spectroscopy
The patent also includes infrared spectroscopy data, highlighting the distinct spectral characteristics of each polymorphic form. For instance, Form 2 has specific absorption peaks that differentiate it from Form 1[1][4].
Regulatory and Litigation Context
FDA Approval and Patent Litigation
The patent is closely tied to the regulatory and litigation landscape surrounding Plavix. The approval process for generic versions of Plavix involved significant patent litigation, including cases like Kroger Co. v. Sanofi-Aventis. In such cases, the validity and infringement of patents like the `265 patent were contested, affecting the market entry of generic drugs[2].
Patent Landscape
Patent Scope and Quality
The scope of the patent is defined by its claims, which have been subject to scrutiny in terms of validity and infringement. The debate on patent quality, as discussed in other contexts, highlights the importance of clear and narrow claims to avoid litigation and ensure innovation[3].
Polymorphism in Pharmaceuticals
The discovery of polymorphic forms of active pharmaceutical ingredients (APIs) is a critical area in pharmaceutical research. Polymorphism can affect the stability, bioavailability, and overall efficacy of a drug. This patent exemplifies the importance of identifying and characterizing different polymorphic forms to ensure the optimal performance of the drug[1][4].
Impact on Pharmaceutical Industry
Market Dominance and Generic Competition
The patent protected Sanofi-Aventis's market dominance for Plavix until its expiration. The expiration of this patent allowed generic manufacturers to enter the market, significantly impacting the pricing and availability of clopidogrel-based medications[2].
Research and Development
The identification of novel polymorphic forms encourages further research into the physical and chemical properties of APIs. This research can lead to improved drug formulations and manufacturing processes, ultimately benefiting patients by providing more stable and effective medications[1][4].
Key Takeaways
- Polymorphic Forms: The patent describes two polymorphic forms (Form 1 and Form 2) of clopidogrel hydrogen sulfate, each with distinct physical and spectral characteristics.
- Preparation and Isolation: Detailed methods for preparing and isolating these forms are provided.
- Pharmaceutical Compositions: The patent includes claims for pharmaceutical compositions containing these polymorphic forms.
- Regulatory Context: The patent is linked to significant regulatory and litigation issues surrounding Plavix.
- Impact on Industry: The patent's expiration has allowed generic competition, affecting market dynamics and patient access to clopidogrel-based medications.
FAQs
What is the main subject of United States Patent 6,429,210?
The main subject is the novel polymorphic forms of clopidogrel hydrogen sulfate, specifically Form 1 and Form 2.
What are the key differences between Form 1 and Form 2 of clopidogrel hydrogen sulfate?
Form 1 and Form 2 differ in their stability, physical properties, and spectral characteristics.
How does the patent impact the pharmaceutical industry?
The patent protected the market dominance of Plavix until its expiration, after which generic competition increased, affecting pricing and availability.
What is the significance of polymorphism in pharmaceuticals?
Polymorphism affects the stability, bioavailability, and efficacy of drugs, making the identification and characterization of different forms crucial for optimal drug performance.
What regulatory issues are associated with this patent?
The patent was involved in significant litigation regarding FDA approval and patent infringement, particularly in cases like Kroger Co. v. Sanofi-Aventis.
Sources
- US6429210B1 - Polymorphic clopidogrel hydrogenesulphate form - Google Patents
- Kroger Co. v. Sanofi-Aventis, 701 F. Supp. 2d 938 - Casetext
- Patent Claims and Patent Scope - Hoover Institution
- US6429210B1 - Polymorphic clopidogrel hydrogenesulphate form - Google Patents
- United States Patent - googleapis.com - Patent Images Storage
