United States Patent 6,132,766: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 6,132,766, titled "Multivesicular liposomes with controlled release of encapsulated biologically active substances," is a significant patent in the field of pharmaceuticals, particularly in the development of liposomal drug delivery systems. This patent, now expired, was a cornerstone in the intellectual property portfolio of companies like Pacira Pharmaceuticals.
Background and Invention
The patent was filed on March 20, 1998, and granted on October 17, 2000. It describes a multivesicular liposome composition that contains at least one acid other than a hydrohalic acid and at least one biologically active substance. This invention is crucial for controlled release drug delivery systems, which are designed to release the active substance over a prolonged period, enhancing the efficacy and reducing the side effects of the drug[4].
Claims and Scope
The patent includes several claims that define the scope of the invention. Here are the key aspects:
Claim 1: Multivesicular Liposome Composition
The primary claim describes a multivesicular liposome composition comprising:
- A plurality of lipid vesicles, each having an aqueous core and a lipid bilayer membrane.
- At least one biologically active substance encapsulated within the aqueous core.
- At least one acid other than a hydrohalic acid[4].
Subsequent Claims: Specific Embodiments
Subsequent claims provide specific embodiments of the invention, including:
- Different types of biologically active substances (e.g., anesthetics, antibiotics).
- Various acids that can be used (e.g., citric acid, lactic acid).
- Methods of preparing the multivesicular liposomes[4].
Legal Standard for Claim Construction
In patent law, the construction of claims is a critical process that determines the scope of the patentee's rights. The court looks to the actual words of the claims and interprets them in view of the specification. The ordinary and customary meaning of the terms, as understood by a person of ordinary skill in the art (POSA), is generally applied unless the patentee has defined the terms differently or disavowed their full scope during prosecution[1].
Intrinsic and Extrinsic Evidence
To ascertain the meaning of disputed terms, courts rely on intrinsic evidence, including the claims themselves, the specification, and the prosecution history of the patent. The specification is considered the single best guide to the meaning of a disputed term. Extrinsic evidence, such as expert testimony and technical dictionaries, may also be used but must not contradict the intrinsic evidence[1].
Patent Expiration and Impact
The patent 6,132,766 expired on November 16, 2013. This expiration has significant implications for the pharmaceutical industry, as it allows other companies to develop and market similar multivesicular liposome formulations without infringing on the original patent. However, it is important to note that subsequent patents related to the same technology, such as those held by Pacira Pharmaceuticals for Exparel, may still be in effect and protect similar formulations[3].
Related Patents and Family
The patent 6,132,766 is part of a larger family of patents related to liposomal drug delivery systems. Other patents in this family, such as U.S. Patent Nos. 8,182,835, 8,834,921, and 9,205,052, which have also expired, and newer patents like U.S. Patent Nos. 11,426,348, 11,278,494, and 11,357,727, which are still active, continue to protect various aspects of this technology[1][3].
Industry Impact and Generic Entry
The expiration of key patents like 6,132,766 opens the door for generic competition. However, the complex patent landscape surrounding Exparel and similar drugs means that generic entry is often delayed until all relevant patents and exclusivities expire. For example, the generic launch date for Exparel is estimated to be February 2, 2043, due to the extensive patent protection and exclusivities in place[3].
International Protection
While the focus here is on U.S. patents, it is crucial to understand that patent protection for drugs like Exparel extends globally. Patents in multiple countries, such as those listed in the family patents section, provide a broad scope of protection. Understanding this global landscape is essential for strategizing market entry and identifying potential generic entry points[3].
Recent Legal Activities
Recent legal activities, such as the recordation of patent certificates of correction and other post-issue communications, can affect the life and scope of related patents. These activities are important to track to ensure a comprehensive understanding of the current patent landscape[3].
Key Takeaways
- Patent Scope: The patent 6,132,766 covers multivesicular liposome compositions with controlled release of biologically active substances.
- Expiration: The patent expired on November 16, 2013.
- Related Patents: Part of a larger family of patents protecting various aspects of liposomal drug delivery systems.
- Industry Impact: Expiration allows for generic competition, but complex patent landscapes delay generic entry.
- Global Protection: Patent protection extends globally, affecting market entry strategies.
FAQs
What is the main invention described in U.S. Patent 6,132,766?
The main invention is a multivesicular liposome composition with controlled release of encapsulated biologically active substances.
When did U.S. Patent 6,132,766 expire?
The patent expired on November 16, 2013.
How does the expiration of this patent affect the pharmaceutical industry?
The expiration allows other companies to develop and market similar multivesicular liposome formulations without infringing on the original patent.
Are there other patents related to this technology still in effect?
Yes, subsequent patents related to the same technology, such as those held by Pacira Pharmaceuticals for Exparel, are still active.
What is the estimated generic launch date for Exparel?
The estimated generic launch date for Exparel is February 2, 2043, due to extensive patent protection and exclusivities.
Cited Sources
- Pacira Pharm. v. eVenus Pharm. Labs., United States District Court, D. New Jersey, Civil Action 22-00718 (D.N.J. Jun. 6, 2023).
- WO2016118652A1 - Multivesicular liposome formulations of tranexamic acid, Google Patents.
- Exparel patent expiration - Pharsight, Pharsight.
- US6132766A - Multivesicular liposomes with controlled release of encapsulated biologically active substances, Google Patents.
