United States Patent 6,184,220: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 6,184,220, titled "Oral suspension of pharmaceutical substance," is a significant patent in the pharmaceutical industry, particularly in the development of orally administered suspensions of non-steroidal anti-inflammatory drugs (NSAIDs). This analysis will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background and Invention Overview
The patent, granted to Norbrook Laboratories Limited, pertains to the formulation and production of oral suspensions of pharmaceutical active substances, specifically NSAIDs like meloxicam. The invention focuses on creating a stable and homogeneous suspension with a unique three-dimensional siloid structure, ensuring accurate dosing and preventing particle agglomeration[5].
Scope of the Invention
The scope of the invention is defined by its ability to create an orally administered suspension that maintains its stability and homogeneity over time. Key aspects include:
- Particle Size and Dispersion: The active substance is ground to a specific particle size spectrum, with at least 90% of the particles smaller than 50 μm, and preferably at least 50% smaller than 10 μm[5].
- Dispersion Medium: The suspension is formulated in a physiologically inert dispersion medium where the active substance has very little solubility[5].
- Stabilization: The addition of highly dispersed silicon dioxide (e.g., Aerosil® 200) and a hydrophilic polymer (e.g., hydroxyethyl cellulose) ensures the formation of a three-dimensional siloid structure. This structure prevents particle agglomeration and maintains the suspension's homogeneity[5].
Claims of the Patent
The patent includes several claims that define the invention's boundaries:
- Claim 1: The patent claims an oral suspension of a pharmaceutical active substance of the NSAID type, characterized by the presence of a small amount of highly dispersed silicon dioxide and a hydrophilic polymer in a physiologically inert dispersion medium[5].
- Subsequent Claims: These claims specify the particle size spectrum, the composition of the dispersion medium, and the process for producing the suspension, including the grinding of the active substance and the addition of silicon dioxide and hydrophilic polymer under high shear forces[5].
Patent Landscape
Related Patents and Applications
The patent landscape around U.S. Patent 6,184,220 includes other patents and applications related to pharmaceutical suspensions and formulations. For instance, the USPTO's Patent Public Search tool and the Global Dossier service can be used to identify related applications and patents filed at participating IP Offices, such as the IP5 Offices (the USPTO, the European Patent Office, the Japan Patent Office, the Korean Intellectual Property Office, and the State Intellectual Property Office of China)[1].
Prior Art and Citations
The Common Citation Document (CCD) application is useful for consolidating prior art citations from multiple offices, providing a comprehensive view of the prior art landscape relevant to this patent[1].
Economic and Statistical Analysis
The Patent Claims Research Dataset provided by the USPTO can offer insights into the scope and trends of patent claims, including those related to pharmaceutical formulations. This dataset includes detailed information on claims from U.S. patents granted between 1976 and 2014 and U.S. patent applications published between 2001 and 2014[4].
Impact on the Pharmaceutical Industry
The invention described in U.S. Patent 6,184,220 has significant implications for the pharmaceutical industry:
- Improved Stability and Homogeneity: The unique three-dimensional siloid structure ensures that the suspension remains stable and homogeneous, which is crucial for accurate dosing and patient compliance[5].
- Enhanced Patient Experience: The suspension's low viscosity and lack of gel-like thickening make it easier to administer, improving the overall patient experience[5].
Legal and Regulatory Aspects
Patent Status
As of the current date, the patent has expired, which means that the invention is now in the public domain. This status is indicated by the legal status listed on patent databases, although it is always advisable to conduct a thorough legal analysis to confirm the status[5].
Infringement and Litigation
Historically, patents like U.S. Patent 6,184,220 have been involved in infringement cases. For example, Norbrook Laboratories Limited has been party to litigation related to patent infringement, highlighting the importance of robust patent protection in the pharmaceutical sector[3].
Conclusion
U.S. Patent 6,184,220 represents a significant advancement in the formulation of oral pharmaceutical suspensions. The detailed analysis of its scope, claims, and the broader patent landscape underscores its importance in the pharmaceutical industry.
Key Takeaways
- Unique Formulation: The patent describes a novel method for creating stable and homogeneous oral suspensions of NSAIDs.
- Stabilization Mechanism: The use of highly dispersed silicon dioxide and hydrophilic polymers is crucial for maintaining the suspension's stability.
- Impact on Industry: The invention has improved the stability and patient compliance of oral pharmaceutical suspensions.
- Legal Status: The patent has expired, making the invention public domain.
- Regulatory Considerations: Understanding the patent landscape and legal status is essential for avoiding infringement and ensuring compliance.
FAQs
Q: What is the main innovation of U.S. Patent 6,184,220?
A: The main innovation is the creation of a stable and homogeneous oral suspension of NSAIDs using a three-dimensional siloid structure formed by highly dispersed silicon dioxide and hydrophilic polymers.
Q: How does the siloid structure improve the suspension?
A: The siloid structure prevents particle agglomeration, ensures rapid and full wetting of the particles, and maintains the suspension's homogeneity over time.
Q: What are the key components of the suspension?
A: The key components include the ground active substance (e.g., meloxicam), highly dispersed silicon dioxide (e.g., Aerosil® 200), and a hydrophilic polymer (e.g., hydroxyethyl cellulose) in a physiologically inert dispersion medium.
Q: Is the patent still in force?
A: No, the patent has expired, making the invention public domain.
Q: How can one search for related patents and prior art?
A: Tools like the USPTO's Patent Public Search, Global Dossier, and the Common Citation Document (CCD) application can be used to search for related patents and prior art.
Sources
- USPTO - Search for patents: https://www.uspto.gov/patents/search
- USA.gov - U.S. Patent and Trademark Office (USPTO): https://www.usa.gov/agencies/u-s-patent-and-trademark-office
- Patent Docs - Norbrook Laboratories Limited et al.: https://www.patentdocs.org/2008/11/23/
- USPTO - Patent Claims Research Dataset: https://www.uspto.gov/ip-policy/economic-research/research-datasets/patent-claims-research-dataset
- Google Patents - US6184220B1: https://patents.google.com/patent/US6184220B1/en
