United States Patent 5,741,516: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 5,741,516, titled "Sphingosomes for enhanced drug delivery," was granted on April 21, 1998. This patent is significant in the field of pharmaceuticals, particularly in the development of liposomal drug delivery systems. Here, we will delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background
The patent describes a novel liposomal formulation known as sphingosomes, which are composed of sphingomyelin and cholesterol. These sphingosomes are designed to have extended circulation time in vivo and increased drug retention, making them more effective than traditional liposomal formulations[4].
Scope of the Patent
The scope of the patent encompasses the composition, method of preparation, and the therapeutic applications of sphingosomes.
Composition
The sphingosomes are formulated using sphingomyelin and cholesterol, which provide a stable and long-circulating liposomal structure. The patent also mentions the inclusion of various drugs such as vincristine, ciprofloxacin, and etoposide, which can be encapsulated within these sphingosomes to enhance their delivery and efficacy[4].
Method of Preparation
The method of preparing sphingosomes involves mixing sphingomyelin and cholesterol in appropriate ratios and then encapsulating the desired drug within these liposomes. The process ensures that the liposomes have a stable membrane that can withstand the biological environment and deliver the drug effectively[4].
Therapeutic Applications
The therapeutic applications of sphingosomes are vast, including the treatment of various cancers and infectious diseases. The extended circulation time and increased drug retention of sphingosomes make them particularly useful for targeted drug delivery, reducing the side effects associated with traditional drug delivery methods[4].
Claims of the Patent
The patent includes 35 claims that define the scope of the invention.
Independent Claims
The independent claims outline the core aspects of the invention, including the composition of sphingosomes, the method of their preparation, and their use in drug delivery. For example, Claim 1 describes a liposomal composition comprising sphingomyelin and cholesterol, with a drug encapsulated therein[4].
Dependent Claims
The dependent claims further specify the details of the composition, such as the ratio of sphingomyelin to cholesterol, the types of drugs that can be encapsulated, and the methods for preparing these sphingosomes. These claims provide a detailed description of the invention and its various embodiments[4].
Patent Landscape
Prior Art
The patent cites several prior art references, including other patents related to liposomal drug delivery systems. For instance, U.S. Patents 5,714,163 and other international patents are mentioned as prior art, highlighting the evolution of liposomal technology[4].
International Patent Offices
To understand the global patent landscape, it is essential to search international patent databases. Resources like the European Patent Office (EPO), Japan Patent Office (JPO), and the World Intellectual Property Organization (WIPO) provide access to international patent applications and grants. This helps in identifying similar inventions and understanding the global intellectual property environment[1].
Common Citation Document (CCD)
The Common Citation Document (CCD) application is useful for consolidating prior art citations from multiple patent offices. This tool helps in visualizing the prior art cited by different offices for the same invention, ensuring a comprehensive understanding of the patent landscape[1].
Economic and Research Implications
Patent Claims Research Dataset
The USPTO's Patent Claims Research Dataset provides detailed information on claims from U.S. patents, including those related to drug delivery systems. This dataset can be used to analyze trends in patent scope and claims, offering insights into the evolution of pharmaceutical technologies[3].
Economic Impact
The development of sphingosomes and similar liposomal drug delivery systems has significant economic implications. These technologies can lead to more effective treatments, reduced healthcare costs, and increased market competition in the pharmaceutical industry.
Legal Status and Expiration
The legal status of U.S. Patent 5,741,516 indicates that it has expired. This means that the invention is now in the public domain, and the technology can be freely used and built upon without infringing on the original patent[4].
Key Takeaways
- Composition and Preparation: Sphingosomes are composed of sphingomyelin and cholesterol, with a method of preparation that ensures stability and effectiveness.
- Therapeutic Applications: These liposomes are used for targeted drug delivery in treating various diseases, including cancers and infectious diseases.
- Claims and Scope: The patent includes 35 claims that define the invention, including independent and dependent claims.
- Patent Landscape: The invention is part of a broader landscape of liposomal drug delivery systems, with prior art and international patents playing a significant role.
- Economic and Research Implications: The technology has economic and research implications, contributing to the advancement of pharmaceuticals and healthcare.
FAQs
What are sphingosomes?
Sphingosomes are liposomal formulations composed of sphingomyelin and cholesterol, designed for enhanced drug delivery with extended circulation time and increased drug retention.
What is the significance of the ratio of sphingomyelin to cholesterol in sphingosomes?
The ratio of sphingomyelin to cholesterol is crucial for the stability and effectiveness of sphingosomes, ensuring they can withstand the biological environment and deliver drugs efficiently.
How do sphingosomes differ from traditional liposomes?
Sphingosomes have extended circulation time and increased drug retention compared to traditional liposomes, making them more effective for targeted drug delivery.
What are some of the therapeutic applications of sphingosomes?
Sphingosomes are used in the treatment of various cancers and infectious diseases, offering a more targeted and effective drug delivery system.
Is U.S. Patent 5,741,516 still in force?
No, U.S. Patent 5,741,516 has expired, and the technology is now in the public domain.
Sources
- USPTO - Search for patents: https://www.uspto.gov/patents/search
- US5741516 PDF: https://patentimages.storage.googleapis.com/pdfs/US5741516.pdf
- USPTO - Patent Claims Research Dataset: https://www.uspto.gov/ip-policy/economic-research/research-datasets/patent-claims-research-dataset
- Google Patents - US5741516A: https://patents.google.com/patent/US5741516A/en
- Google Patents - EP1169021B1: https://patents.google.com/patent/EP1169021B1/fr
