Understanding the Scope and Claims of United States Patent 8,618,164
Introduction
United States Patent 8,618,164 is part of a series of patents related to the topical formulation of diclofenac sodium, specifically the PENNSAID® 2% formulation, which is used for the treatment of osteoarthritis pain in the knees. This patent is one of the nine patents asserted by Horizon Pharma in a Hatch-Waxman Act action against generic manufacturers.
Patent Background
The patent in question, U.S. Patent No. 8,618,164, is part of the "'450 Patent Family," which includes other related patents such as U.S. Patent Nos. 8,546,450, 8,217,078, and 9,132,110. These patents share substantially identical specifications and claim priority to the same provisional application filed on October 17, 2006[2][5].
Claim Construction and Disputes
Claim construction is a critical aspect of patent litigation, as it determines the scope of the patent's protection. In the case of U.S. Patent 8,618,164, the claim construction was a subject of dispute between Horizon Pharma and Actavis Laboratories UT, Inc.
Intrinsic Evidence
Claim construction begins with the intrinsic evidence of the patent, which includes the claims, the specification, and the prosecution history. The court relies on these elements to understand the inventor's intent and the scope of the claims[2].
Disputed Terms
Several terms within the patent were disputed, including:
"Consisting Essentially Of"
This term was found to be indefinite by the court. The court noted that the term "consisting essentially of" was problematic because one of the basic and novel properties of the claimed invention, "better drying time," was indefinite. The specification described two different methods for evaluating "better drying time," which did not provide consistent results, leading to the conclusion that a person of ordinary skill in the art (POSA) would not have reasonable certainty about the term[1].
"Favorable Stability"
Another disputed term was "favorable stability." The court found that the stability and degradation claims were indefinite. Specifically, the terms related to the formulation producing less than 0.1% impurity A after 6 months at 25°C and 60% humidity were deemed indefinite because the identity of "impurity A" was unknowable to a POSA, and the patent did not provide clear guidance on how to evaluate degradation[1].
"Topical Formulation Produces Less Than 0.1% Impurity A"
This term was also subject to dispute. The court found that the patent did not provide sufficient clarity on what constitutes "impurity A" and how to measure it, leading to indefiniteness[5].
Key Properties of the Invention
The patent describes several key properties of the diclofenac sodium formulation:
Better Drying Time
The formulation is supposed to have a better drying time compared to other formulations. However, the court found that the methods for evaluating this property were inconsistent and did not provide reliable results[1].
Higher Viscosity
The formulation is designed to have higher viscosity, which is one of the novel properties claimed.
Increased Transdermal Flux
The formulation is intended to have increased transdermal flux, enhancing the delivery of diclofenac sodium through the skin.
Greater Pharmacokinetic Absorption
The formulation aims to achieve greater pharmacokinetic absorption, ensuring that the drug is effectively absorbed by the body.
Favorable Stability
The formulation is supposed to have favorable stability, but as discussed, this term was found to be indefinite due to the lack of clear guidance on evaluating stability and degradation[1].
Impact of Indefiniteness
The finding of indefiniteness in key terms such as "consisting essentially of" and "favorable stability" significantly impacts the validity and enforceability of the patent. If a POSA cannot understand the scope of the claims with reasonable certainty, the patent claims are considered indefinite and may be unenforceable[1].
Patent Landscape
The patent landscape surrounding PENNSAID® 2% is complex, with multiple patents asserting different aspects of the formulation. The "'450 Patent Family" and the "'838 Patent Family" each cover various aspects of the diclofenac sodium formulation, including its composition, method of use, and properties[2][5].
Conclusion
The scope and claims of U.S. Patent 8,618,164 are intricately tied to the broader patent landscape of PENNSAID® 2%. The disputes over claim construction highlight the importance of clear and definite language in patent specifications to ensure that the scope of protection is well-defined and enforceable.
Key Takeaways
- Claim Construction: The court's construction of patent claims is crucial and relies on intrinsic evidence.
- Indefiniteness: Terms like "consisting essentially of" and "favorable stability" were found indefinite due to lack of clarity.
- Key Properties: The formulation's properties, such as better drying time, higher viscosity, and increased transdermal flux, are central to the patent.
- Patent Landscape: Multiple patents cover different aspects of the diclofenac sodium formulation.
- Enforceability: Indefiniteness can render patent claims unenforceable.
FAQs
What is the main subject of U.S. Patent 8,618,164?
The main subject is the topical formulation of diclofenac sodium for treating osteoarthritis pain in the knees.
Why was the term "consisting essentially of" found indefinite?
The term was found indefinite because one of the basic and novel properties, "better drying time," was indefinite due to inconsistent evaluation methods.
What is the significance of "favorable stability" in the patent?
"Favorable stability" is one of the key properties, but it was deemed indefinite due to the lack of clear guidance on evaluating stability and degradation.
How does the court determine the scope of patent claims?
The court determines the scope using intrinsic evidence, including the claims, specification, and prosecution history.
What is the impact of indefiniteness on the patent's enforceability?
Indefiniteness can render the patent claims unenforceable because a POSA must be able to understand the scope of the claims with reasonable certainty.
Sources
- UNITED STATES DISTRICT COURT DISTRICT OF NEW JERSEY: Horizon Pharma v. Actavis[1].
- United States District Court: Horizon Pharma Ireland Ltd. v. Actavis Labs., UT, Inc.[2].
- USPTO: Patent Claims Research Dataset[3].
- PubChem: Diclofenac topical formulation - Patent US-9539335-B2[4].
- Vlex: Horizon Pharma Ireland Ltd. v. Actavis Labs., UT, Inc.[5].
