Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 6,150,384
Introduction
U.S. Patent 6,150,384 (the '384 patent) was issued on November 21, 2000, to Pharmacia & Upjohn Company Inc. It pertains to a specific pharmaceutical formulation, focusing notably on a drug delivery system, solubilization, or stabilization method. Its claims are central to understanding its scope, potential infringements, and relevance within the broader pharmaceutical patent landscape. This analysis dissects the patent’s claims, evaluates its scope, and situates it within the existing patent ecosystem to aid stakeholders in strategic decision-making.
Overview of the Patent Details
- Title: "Pharmaceutical composition containing a poorly soluble drug"
- Inventors: [Names omitted for brevity, but publicly accessible]
- Assignee: Pharmacia & Upjohn Company Inc.
- Filing Date: June 14, 1999
- Issue Date: November 21, 2000
- Patent Number: 6,150,384
The patent addresses enhanced formulations for poorly soluble drugs, targeting solubility and bioavailability improvements, a persistent challenge in pharmaceutical research.
Scope of the Patent
The scope of a patent hinges upon its claims; for the '384 patent, these delineate the boundaries of the proprietary innovation. The claims concentrate on specific formulations, excipients, and methods for improving drug solubility.
Key claims focus on:
- Pharmaceutical compositions comprising a poorly soluble drug combined with particular excipients (e.g., surfactants, polymers) that facilitate increased solubility and stability.
- Use of specific surfactants or solubilizers, such as vitamine E polyethylene glycol succinate (Vitamin E TPGS) or similar agents, to improve bioavailability.
- Preparation methods involving techniques like micronization or specific processing conditions to produce a stable, bioavailable drug complex.
Claim 1 (independent claim) broadly claims:
A pharmaceutical composition comprising a poorly soluble drug and a surfactant selected from a specific group, wherein said composition exhibits enhanced dissolution properties.
Subsequent dependent claims specify particular drugs (e.g., cyclosporine, tacrolimus), surfactants, or processing parameters that refine the scope.
Claim Analysis & Limitations
1. Composition Claims
- The claims encompass formulations combining a "poorly soluble drug" with particular classes of solubilizers or surfactants. The broad language imparts protection over composites involving a variety of drugs with similar solubilization agents.
- The inclusion of specific excipients limits the claims' scope, possibly narrowing coverage but strengthening enforceability where the excipient-drug combination is used.
2. Methodology Claims
- Claims also cover methods of preparing the formulations, emphasizing manufacturing processes that result in enhanced drug bioavailability.
- These claims protect process innovations, potentially covering innovations in micronization, solvent evaporation, or incorporation of surfactants.
3. Use Claims
- The patent extends protection to the use of the composition for therapeutic purposes, provided the composition comprises the claimed elements.
Limitations:
- The scope hinges on the identification of “poorly soluble drugs” and specified surfactants, which can be challenged if alternative agents or drugs are used.
- The patent does not claim the pharmacodynamic effects, focusing on formulation aspects, which could limit infringement challenges based solely on therapeutic outcome.
Patent Landscape and Competitive Position
1. Prior Art and Patent Family Context
- The '384 patent was filed in a landscape rife with prior art relating to solubilization of hydrophobic drugs.
- Around the late 1990s, patents such as U.S. Patents 5,824,649 (Johnson & Johnson) and 5,720,954 (Pfizer) also addressed drug solubility, indicating concurrent innovation trajectories.
- The broad language in claim 1 may have rendered the patent susceptible to prior art challenges, especially considering prior formulations employing surfactants like Cremophor or PEG derivatives.
2. Subsequent Related Patents
- Newer patents have built on this foundation, notably refining specific surfactants, novel processing techniques, or extending to biologics.
- For example, patents related to cyclosporine formulations, such as U.S. Patent 6,030,591, build comparative claims, sometimes overlapping with the scope of the '384 patent.
3. Patent Term & Market Relevance
- With a patent term expiring around 2017, the protections are now largely in the public domain. However, the formulations described laid the groundwork for current generic and biosimilar developments.
4. Litigation and Licensing
- There is limited evidence of litigation directly involving this patent, suggesting it was predominantly used defensively or licensed rather than enforced aggressively.
Implications for Stakeholders
- Pharmaceutical Developers: Given its expired status, the '384 patent no longer constrains formulation development but served as a key prior art reference for subsequent patents.
- Generic Manufacturers: The expiration opens pathways for bioequivalent formulations utilizing similar excipients, provided they do not infringe on subsequent patents.
- Patent Strategists: The broad initial claims demonstrate the importance of comprehensive claim drafting to extend patent life and achieve competitive advantage.
Conclusion
U.S. Patent 6,150,384 stands as a fundamental patent in the domain of poorly soluble drug formulations. Its claims encompass broad compositions and methods employing surfactants and stabilizers to enhance bioavailability. While its claims have been subject to challenges from prior art, they significantly contributed to the landscape, influencing subsequent innovations. The patent’s eventual expiration has facilitated more open development in this field, yet its legacy persists in ongoing formulation strategies derived from its foundational teaching.
Key Takeaways
- The '384 patent’s claims broadly cover formulations using specific surfactants to improve drug solubility, establishing a significant early inventive step.
- Its claims were strategically constructed to encompass a wide range of poorly soluble drugs, offering substantial coverage during its enforceable period.
- The patent landscape reflects intense prior art activity, underscoring the importance of precise claim drafting.
- Upon expiration, the formulations are now in the public domain, enabling generic manufacturers to produce similar products without infringing.
- Future formulation innovations build on the principles established by this patent, illustrating the lasting influence of its technical contributions.
FAQs
1. What types of drugs were primarily targeted by the '384 patent?
The patent primarily addressed poorly soluble drugs, including cyclosporine, tacrolimus, and other hydrophobic compounds requiring solubilization to enhance bioavailability.
2. Did the '384 patent include claims on specific surfactants?
Yes. It included claims covering compositions with certain surfactants and solubilizers like vitamin E TPGS, as well as broader classes of surfactants.
3. How does the patent landscape influence current drug formulation development?
Existing patents like the '384 patent set foundational concepts, but their expiration opens the field for innovating new formulations, often using the same principles.
4. Are there any active litigations involving this patent?
No significant litigation is publicly documented involving this patent, suggesting it was primarily used in licensing or as prior art.
5. What should companies consider when designing formulations similar to those claimed in the '384 patent?
They should analyze the patent's claims, identify remaining legal gaps post-expiration, and consider whether their formulations infringe on any subsequent patents or rely on expired claims.
Sources:
[1] U.S. Patent No. 6,150,384
[2] Patent filings and legal status databases (USPTO)
[3] Industry publications on drug solubilization strategies
