United States Patent 6,759,059: A Detailed Analysis of Scope and Claims
Overview of the Patent
United States Patent 6,759,059, titled "Fentanyl composition for the treatment of acute pain," is a patent that describes a pharmaceutical composition designed for the sublingual administration of fentanyl to treat acute pain. Here is a detailed analysis of its scope, claims, and the surrounding patent landscape.
Invention Description
The patent describes a composition that includes fentanyl or its pharmaceutically acceptable salts, such as citrate or maleate, which are not readily soluble in water. The composition is formulated to be administered sublingually, utilizing bioadhesive and/or mucoadhesive carrier substances to enhance the delivery of fentanyl[1].
Key Components of the Composition
- Fentanyl Content: The composition contains from 0.05 to 20 weight percent of fentanyl, with preferred ranges of 0.05 to 5 weight percent, and especially 0.1 to 1 weight percent. In terms of dose units, each tablet should contain from 0.05 to 20 mg of fentanyl, preferably 0.1 to 5 mg[1].
- Carrier Particles: The fentanyl is mixed with bioadhesive and/or mucoadhesive carrier substances. These carrier particles are larger and have the fentanyl or its salts finely dispersed on their surfaces[1].
- Disintegrating Agents: The composition may include disintegrating agents such as cross-linked polyvinylpyrrolidone, carboxymethyl starch, natural starch, microcrystalline cellulose, and cellulose gum to accelerate the dispersion of the carrier particles[1].
Claims of the Patent
The patent includes multiple claims that define the scope of protection for the invention.
Independent Claims
- The patent claims cover the pharmaceutical composition itself, including the specific percentages and amounts of fentanyl and the types of carrier substances used.
- It also claims methods of treating acute pain using this composition[2].
Dependent Claims
- These claims further specify the characteristics of the composition, such as the particle size of the fentanyl and the carrier particles, and the inclusion of disintegrating agents.
- For example, the claims specify that the particles of fentanyl or its salts should have a maximum particle size of about 24 μm but preferably not greater than about 10 μm[1].
Patent Landscape and Litigation
Ownership and Expiration
The patent was owned by Orexo, a Swedish company, and expired on September 24, 2019[2].
Litigation and Infringement
Orexo engaged in litigation against Actavis (now part of Allergan) for patent infringement related to Actavis's submission of an Abbreviated New Drug Application (ANDA) for a generic version of Abstral®, which is a sublingual fentanyl product. Actavis had certified that the '059 patent was invalid or would not be infringed by their proposed product, leading to a legal dispute[2].
Technical Aspects and Formulation
Bio/Mucoadhesion
The patent emphasizes the use of bioadhesive and/or mucoadhesive carrier substances to enhance the retention of the composition in the sublingual cavity, ensuring rapid and effective delivery of fentanyl[1].
Ordered Mixture
The composition involves an ordered mixture where finer particles of the bio/mucoadhesion promoting agent are mixed with larger carrier particles. This mixture is achieved through a process of dry mixing or using a non-dissolving/non-swelling liquid like absolute ethanol[1].
Regulatory and Legal Context
FDA Approval and ANDA
The patent's validity and infringement were closely tied to the FDA's approval process for generic drugs. Actavis's ANDA submission included a Paragraph IV certification, which required them to certify that the '059 patent was invalid or would not be infringed by their generic product[2].
Patent Claims and Protection
The claims in the patent are designed to protect the full scope of the invention, including the composition, its formulation, and the method of administration. Each claim must be supported by the specification and drawings in the patent application to ensure validity[3].
Industry Impact
Market Competition
The expiration of the '059 patent allowed for the entry of generic competitors into the market, increasing competition and potentially reducing costs for patients. However, the litigation surrounding this patent highlights the complexities and challenges faced by pharmaceutical companies in protecting their intellectual property[2].
Innovation in Pain Management
The patent represents an innovation in pain management, particularly for acute pain, by providing a rapid and effective delivery method for fentanyl. This innovation has contributed to the development of more efficient pain relief treatments[1].
Key Takeaways
- Composition and Formulation: The patent describes a sublingual fentanyl composition using bioadhesive and/or mucoadhesive carrier substances.
- Claims and Scope: The patent includes claims covering the composition, its formulation, and the method of administration.
- Litigation and Expiration: The patent was involved in litigation over infringement and expired in 2019.
- Regulatory Context: The patent's validity was tied to FDA approval processes and ANDA submissions.
- Industry Impact: The patent's expiration has allowed for generic competition, impacting the market for pain management treatments.
Frequently Asked Questions (FAQs)
What is the primary use of the composition described in US Patent 6,759,059?
The primary use is for the treatment of acute pain through sublingual administration of fentanyl.
What are the key components of the composition?
The key components include fentanyl or its salts, bioadhesive and/or mucoadhesive carrier substances, and optional disintegrating agents.
Why is the particle size of fentanyl important in this composition?
The particle size of fentanyl is crucial for ensuring rapid dissolution and effective delivery; it should be no greater than about 10 μm.
What was the outcome of the litigation between Orexo and Actavis?
The litigation involved Actavis's certification that the '059 patent was invalid or would not be infringed by their generic product, leading to a legal dispute that was resolved before the patent's expiration.
How has the expiration of this patent affected the market for pain management treatments?
The expiration has allowed generic competitors to enter the market, increasing competition and potentially reducing costs for patients.
