United States Patent 6,287,599: A Detailed Analysis of Scope and Claims
Introduction
United States Patent 6,287,599, titled "Sustained release pharmaceutical dosage forms with minimized pH dependent dissolution profiles," addresses a critical issue in pharmaceutical formulation: the development of drug delivery systems that maintain consistent release profiles regardless of the pH of the gastrointestinal tract. This patent is significant for its innovative approach to ensuring the stable and effective release of pharmaceuticals.
Background and Objectives
The patent aims to overcome the challenges posed by pH-dependent solubility profiles of many drugs. Drugs that are more soluble in acidic mediums than in basic mediums often exhibit variable dissolution rates, leading to inconsistent therapeutic effects. The invention seeks to provide a pharmaceutical composition that minimizes these pH-dependent dissolution differences[1].
Key Components of the Invention
Pharmaceutically Active Agent
The composition includes at least one pharmaceutically active agent with a pH-dependent solubility profile. This agent is typically more soluble in acidic mediums than in basic mediums[1].
Non-pH-Dependent Sustained Release Agent
To counteract the pH-dependent solubility, the composition incorporates a non-pH-dependent sustained release agent. This agent ensures a consistent release rate of the active agent over time, regardless of the pH environment[1].
pH-Dependent Agent
The composition also includes a pH-dependent agent that increases the dissolution rate of the active agent at a pH above 5.5. This agent helps to maintain a consistent dissolution profile across different pH levels in the gastrointestinal tract[1].
Formulation and Manufacturing
Bulking Agents
The composition may include various bulking agents such as microcrystalline cellulose, mannitol, xylitol, and others. These agents are present in amounts ranging from about 5% to 90% by weight, with a preferred range of 10% to 50%[1].
Binding Agents
Binding agents, which can be present in amounts from about 0.2% to 10% by weight, help in maintaining the integrity of the dosage form. Preferred binding agents include those present in amounts from 0.5% to 5% by weight[1].
Manufacturing Methods
The compositions can be manufactured using either direct compression or wet granulation methods. For direct compression, the active agent and other ingredients are sieved and blended before being compressed into tablets. The compressed tablets can be coated if necessary[1].
Dissolution Studies
Methodology
Dissolution studies were conducted using a Vankel dissolution tester (USP Apparatus II) with 0.1N hydrochloric acid (pH 1.2) and pH 6.8 phosphate buffer. Samples were analyzed using an HPLC system to determine the dissolution profiles of the compositions[1].
Results
The compositions of the present invention showed improved dissolution profiles compared to control compositions, indicating a more consistent release of the active agent across different pH environments[1].
Patent Claims and Scope
Claim Structure
The patent claims are structured to capture the essential components and their functions within the composition. The claims include:
- At least one pharmaceutically active agent with a pH-dependent solubility profile.
- At least one non-pH-dependent sustained release agent.
- At least one pH-dependent agent that increases the dissolution rate of the active agent at a pH above 5.5[1].
Scope of Protection
The scope of the patent is broad enough to cover various formulations that incorporate these key components but narrow enough to be specific and non-obvious. This balance is crucial in the pharmaceutical industry, where broad claims can be vulnerable to invalidation, and narrow claims can be easily circumvented by competitors[3].
Impact on the Pharmaceutical Industry
Extended Release Formulations
The invention contributes to the development of extended release formulations, which have been shown to improve patient compliance, increase therapeutic efficacy, and reduce side effects compared to immediate release formulations[4].
Competitive Landscape
The patent landscape in the pharmaceutical industry is highly competitive, with companies continually seeking to innovate and protect their intellectual property. Patents like US 6,287,599 are vital for companies to secure market exclusivity and protect their investments in research and development[3].
Legal and Regulatory Considerations
Patent Litigation
Patent claims, especially in the pharmaceutical industry, are often subject to litigation. The scope and breadth of the claims must be carefully drafted to ensure they are enforceable and not overly broad or too narrow. The Federal Circuit's stance on genus claims and the written description requirement can significantly impact the validity and enforceability of pharmaceutical patents[3][5].
Conclusion
United States Patent 6,287,599 represents a significant advancement in pharmaceutical formulation technology by providing a method to minimize pH-dependent dissolution profiles. The patent's scope and claims are carefully crafted to protect the invention while ensuring it remains relevant and enforceable within the complex legal landscape of the pharmaceutical industry.
Key Takeaways
- The patent addresses the issue of pH-dependent dissolution profiles in pharmaceuticals.
- It includes a combination of a pharmaceutically active agent, a non-pH-dependent sustained release agent, and a pH-dependent agent.
- The composition can be manufactured using direct compression or wet granulation methods.
- Dissolution studies show improved profiles compared to control compositions.
- The patent's scope is balanced to ensure protection while avoiding overly broad or narrow claims.
- The invention has significant implications for extended release formulations and patient compliance.
FAQs
What is the main objective of United States Patent 6,287,599?
The main objective is to provide a pharmaceutical composition with a minimized pH-dependent dissolution profile, ensuring consistent release of the active agent regardless of the pH environment.
How does the composition achieve a consistent dissolution profile?
The composition includes a non-pH-dependent sustained release agent and a pH-dependent agent that increases the dissolution rate of the active agent at a pH above 5.5.
What are the common bulking agents used in this composition?
Common bulking agents include microcrystalline cellulose, mannitol, xylitol, and others.
How are the compositions manufactured?
The compositions can be manufactured using either direct compression or wet granulation methods.
What are the benefits of extended release formulations like those described in the patent?
Extended release formulations improve patient compliance, increase therapeutic efficacy, and reduce side effects compared to immediate release formulations.
Sources
- US6287599B1 - Sustained release pharmaceutical dosage forms with minimized pH dependent dissolution profiles - Google Patents
- US20110217373A1 - Extended release pharmaceutical compositions of guanfacine hydrochloride - Google Patents
- Eviscerating Patent Scope - DigitalCommons@NYLS
- UNITED STATES SECURITIES AND EXCHANGE COMMISSION - Supernus Pharmaceuticals
- Shire LLC v. Mylan Pharms. Inc. - Casetext
