United States Patent 6,113,944: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 6,113,944, titled "Paroxetine tablets and process to prepare them," is a significant patent in the pharmaceutical industry, particularly in the field of antidepressant medications. This patent, granted to SmithKline Beecham Corporation (now part of GlaxoSmithKline), describes novel formulations and processes for preparing paroxetine tablets. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background of Paroxetine
Paroxetine, a selective serotonin reuptake inhibitor (SSRI), is widely used as an antidepressant. The compound was first described in earlier patents, such as U.S. Pat. 4,007,196, which highlighted its anti-depressant activity[2].
Scope of the Patent
The scope of U.S. Patent 6,113,944 is focused on the formulation and preparation of paroxetine tablets. Here are the key aspects:
Novel Formulations
The patent introduces novel formulations of paroxetine tablets that address a significant issue: the undesirable pink hue that often develops in tablets formulated using aqueous granulation processes. The new formulations use a water-free process, such as direct compression or dry granulation, to prevent this discoloration[2].
Process Improvements
The invention details a reliable and commercially viable method for preparing paroxetine tablets without using water. This innovation is crucial for maintaining the quality and appearance of the tablets, which is essential for patient acceptance and compliance[2].
Claims of the Patent
The patent includes several claims that define the scope of the invention:
Independent Claims
The primary claim describes the process for preparing paroxetine tablets using a dry granulation or direct compression method. This claim is critical as it distinguishes the invention from previous methods that used aqueous granulation[2].
Dependent Claims
Dependent claims further specify the components and steps involved in the process, including the types of excipients used and the conditions under which the tablets are prepared. These claims provide additional detail and help to narrow the scope of the invention to ensure it is distinct from prior art[2].
Patent Landscape
Prior Art and Related Patents
The patent is part of a larger family of patents related to paroxetine formulations. It is a divisional of application Ser. No. 08/676,331, which was filed in 1996 and abandoned. The patent also references earlier international applications, such as PCT/EP94/04164, filed in 1994[2].
International Protection
The patent has been granted in multiple countries, including the United States, Europe, Japan, Korea, and China, among others. This global protection is essential for maintaining intellectual property rights across different markets[2].
Cited By and Citing Patents
The patent has been cited by several other patents, indicating its influence on subsequent research and development in the field of pharmaceutical formulations. This citation history can be an indicator of the patent's significance and impact[2].
Legal Status and Litigation
Legal Status
The patent has expired due to fee-related issues, which means that the exclusive rights granted by the patent are no longer in effect. This expiration allows other companies to manufacture and sell paroxetine tablets using the described formulations without infringing on the original patent[2].
Litigation
There have been legal challenges related to paroxetine patents. For example, in the case of SmithKline Beecham Corp. v. Apotex Corp., the court ruled on the validity of a related patent, highlighting the complexities and challenges in patent litigation in the pharmaceutical industry[4].
Metrics for Patent Scope
Research on patent scope often uses metrics such as independent claim length and independent claim count to measure the breadth and clarity of patent claims. For U.S. Patent 6,113,944, these metrics would indicate that the claims are relatively specific and narrow, given the detailed description of the process and formulations. Narrower claims are often associated with a higher probability of grant and a shorter examination process[3].
Global Patent System and Search Tools
The patent landscape is supported by various global patent search tools and databases. For instance, the USPTO's Patent Public Search tool, the European Patent Office's esp@cenet, and the World Intellectual Property Organization's PATENTSCOPE provide comprehensive access to patent documentation, including international patent applications and machine translations. These resources are crucial for conducting thorough patent searches and ensuring that new inventions do not infringe on existing patents[1].
Conclusion
U.S. Patent 6,113,944 represents a significant advancement in the formulation and preparation of paroxetine tablets. The patent's scope is defined by its novel water-free process, which addresses a critical issue in tablet quality. The claims are specific and narrow, reflecting the detailed nature of the invention. The patent's international protection and citation history underscore its impact on the pharmaceutical industry.
Key Takeaways
- Novel Formulations: The patent introduces water-free processes for preparing paroxetine tablets.
- Process Improvements: Direct compression or dry granulation methods prevent undesirable discoloration.
- International Protection: The patent is granted in multiple countries.
- Legal Status: The patent has expired due to fee-related issues.
- Litigation: Related patents have been subject to legal challenges.
- Metrics for Patent Scope: Narrow claims are associated with higher grant probabilities and shorter examination processes.
FAQs
Q: What is the main innovation of U.S. Patent 6,113,944?
A: The main innovation is the use of water-free processes (direct compression or dry granulation) to prepare paroxetine tablets, preventing the undesirable pink hue that occurs with aqueous granulation.
Q: Why is the expiration of the patent significant?
A: The expiration of the patent means that the exclusive rights are no longer in effect, allowing other companies to manufacture and sell paroxetine tablets using the described formulations without infringing on the original patent.
Q: How does the patent's international protection impact its significance?
A: International protection ensures that the intellectual property rights are maintained across different markets, which is crucial for the global distribution and sale of the product.
Q: What metrics are used to measure patent scope?
A: Metrics such as independent claim length and independent claim count are used to measure the breadth and clarity of patent claims.
Q: What are the implications of narrower claims in patent applications?
A: Narrower claims are often associated with a higher probability of grant and a shorter examination process, indicating clearer and more specific claims.
Sources
- USPTO - Search for patents: https://www.uspto.gov/patents/search
- Google Patents - US6113944A: https://patents.google.com/patent/US6113944A/en
- SSRN - Patent Claims and Patent Scope: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2844964
- Casetext - Smithkline Beecham Corp. v. Apotex Corp.: https://casetext.com/case/smithkline-beecham-corp-v-apotex-corp-7
- Google APIs - United States Patent (19) 11 Patent Number: https://patentimages.storage.googleapis.com/2b/2d/f5/bc2702b83c3ca2/US6113944.pdf
