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Last Updated: December 22, 2024

Details for Patent: 6,074,666


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Summary for Patent: 6,074,666
Title: Liposome compositions of porphyrin photosensitizers
Abstract:Liposomal pharmaceutical formulations incorporating porphyrin photosensitizers useful for photodynamic therapy or diagnosis of malignant cells. The liposomal formulations comprise a porphyrin photosensitizer, particularly the hydro-mono benzoporphyrins (BPD) having light absorption maxima in the range of 670-780 nanometers, a disaccharide or polysaccharide and one or more phospholipids.
Inventor(s): Desai; Narendra Raghunathji (Danbury, CT), Agha; Bushra J. (Durham, NC), Kale; Kalidas Madhavrao (Harriman, NY)
Assignee: QLT Phototherapeutics, Inc. (CA)
Application Number:08/489,850
Patent Claim Types:
see list of patent claims
Formulation; Composition;
Patent landscape, scope, and claims:

United States Patent 6,074,666: A Detailed Analysis

Introduction

United States Patent 6,074,666, titled "Liposome compositions of porphyrin photosensitizers," is a significant patent in the field of pharmaceutical formulations, particularly in photodynamic therapy and diagnosis. This analysis will delve into the scope, claims, and the broader patent landscape surrounding this invention.

Scope of the Invention

The patent describes improved pharmaceutical formulations comprising liposomes that incorporate porphyrin photosensitizers. These formulations are designed for use in photodynamic therapy (PDT) or the diagnosis of tumors. The invention involves a freeze-dried pharmaceutical formulation that includes a porphyrin photosensitizer, a disaccharide or polysaccharide, and one or more phospholipids. Upon reconstitution with an aqueous vehicle, this formulation forms liposomes containing the porphyrin photosensitizer[1].

Key Components of the Formulation

  • Porphyrin Photosensitizers: The patent highlights the use of specific porphyrin derivatives, such as hydro-monobenzoporphyrins, particularly benzoporphyrin derivative (BPD), which have light absorption maxima in the range of 670-780 nanometers. These compounds are crucial for their therapeutic efficacy in PDT[1].
  • Liposomal Structure: The liposomes can be unilamellar, multilamellar, or other types, prepared either in suspension form or formed upon reconstitution of a lyophilized powder[1].

Claims of the Patent

The patent includes several claims that define the scope of the invention:

  • Claim 1: A freeze-dried pharmaceutical formulation comprising a porphyrin photosensitizer, a disaccharide or polysaccharide, and one or more phospholipids.
  • Claim 2: The formulation of claim 1, where the porphyrin photosensitizer is a hydro-monobenzoporphyrin.
  • Claim 3: The formulation of claim 1, where the porphyrin photosensitizer is BPD-MA.
  • Claim 4: A method of preparing the liposomal formulation by reconstituting the freeze-dried formulation with an aqueous vehicle[1].

Patent Landscape Analysis

To understand the broader context of this patent, a patent landscape analysis is essential.

Defining Scope and Keywords

The analysis begins by defining the technology field and identifying relevant keywords such as "porphyrin photosensitizers," "liposomal formulations," "photodynamic therapy," and "tumor diagnosis"[3].

Searching and Organizing Patents

Using patent databases like the USPTO's Patent Public Search tool, relevant patents are identified and organized based on factors such as filing date, assignee, and technology subcategories. Visual aids like heat maps can help in visualizing the distribution of patents over time and by assignee[4].

Identifying Trends and Key Players

The analysis reveals trends in patent filings and identifies key players in the field. For instance, the patent in question is part of a series of patents related to porphyrin photosensitizers and liposomal formulations, indicating a significant focus by the assignee on this technology[3].

Analyzing Citations and Evolution

Studying how patents reference each other helps in understanding their impact and development. The patent 6,074,666 references earlier patents related to porphyrin derivatives and their use in PDT, highlighting the evolutionary path of this technology[1][3].

Generating Insights for Decisions

The analysis provides practical guidance for strategic decisions. For example, understanding the competitive landscape and potential legal vulnerabilities can help in navigating the intellectual property landscape and making informed decisions about future research and development[3].

Key Players and Innovations

The patent landscape analysis identifies several key players and innovations in the field:

  • Assignees: The patent is assigned to companies that have a strong portfolio in pharmaceutical formulations and photodynamic therapy.
  • Technological Trends: There is a growing trend towards the use of liposomal formulations for delivering photosensitizers, indicating an area of ongoing innovation[3].

Impact and Applications

The invention has significant implications for photodynamic therapy and tumor diagnosis:

  • Therapeutic Efficacy: The use of liposomal formulations enhances the delivery and efficacy of porphyrin photosensitizers, leading to better therapeutic outcomes.
  • Diagnostic Capabilities: The fluorescence properties of these photosensitizers make them useful for detecting tumors, improving diagnostic accuracy[1].

Shelf Life and Stability

The patent highlights that the preferred porphyrin photosensitizer, BPD-MA, maintains its potency in the cryodesiccated liposome formulation for at least nine months at room temperature, with a projected shelf life of at least two years. This stability is crucial for practical clinical use[1].

Conclusion

United States Patent 6,074,666 represents a significant advancement in the field of photodynamic therapy and tumor diagnosis. The detailed analysis of its scope, claims, and the broader patent landscape provides valuable insights into the technological trends, key players, and potential future innovations in this domain.

Key Takeaways

  • The patent describes a freeze-dried pharmaceutical formulation of porphyrin photosensitizers for use in photodynamic therapy and tumor diagnosis.
  • The formulation includes a porphyrin photosensitizer, a disaccharide or polysaccharide, and one or more phospholipids.
  • The use of liposomal formulations enhances the delivery and efficacy of porphyrin photosensitizers.
  • The patent is part of a broader trend towards the use of liposomal formulations in pharmaceuticals.
  • Key players in the field include companies with a strong portfolio in pharmaceutical formulations and photodynamic therapy.

FAQs

What is the main purpose of United States Patent 6,074,666?

The main purpose of this patent is to describe improved pharmaceutical formulations comprising liposomes that incorporate porphyrin photosensitizers for use in photodynamic therapy and tumor diagnosis.

What are the key components of the formulation described in the patent?

The key components include a porphyrin photosensitizer, a disaccharide or polysaccharide, and one or more phospholipids.

How are the liposomes prepared according to the patent?

The liposomes can be prepared either in suspension form or formed upon reconstitution of a lyophilized powder containing the porphyrin-phospholipid-saccharide composition with an aqueous solution.

What is the significance of BPD-MA in this patent?

BPD-MA is a preferred porphyrin photosensitizer that maintains its potency in the cryodesiccated liposome formulation for at least nine months at room temperature, with a projected shelf life of at least two years.

How does the patent landscape analysis help in understanding this invention?

The patent landscape analysis helps in identifying trends, key players, and the evolutionary path of the technology, providing insights into the competitive landscape and potential future innovations.

Cited Sources

  1. US6074666A - Liposome compositions of porphyrin photosensitizers - Google Patents
  2. United States Patent (19) - googleapis.com
  3. How to Do Patent Landscape Analysis - Goldstein Patent Law
  4. Search for patents - USPTO

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Drugs Protected by US Patent 6,074,666

Applicant Tradename Generic Name Dosage NDA Approval Date TE Type RLD RS Patent No. Patent Expiration Product Substance Delist Req. Patented / Exclusive Use Submissiondate
>Applicant >Tradename >Generic Name >Dosage >NDA >Approval Date >TE >Type >RLD >RS >Patent No. >Patent Expiration >Product >Substance >Delist Req. >Patented / Exclusive Use >Submissiondate

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