Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 5,236,952
Introduction
U.S. Patent 5,236,952, granted on August 17, 1993, to Schering Corporation (now part of Bayer AG), pertains predominantly to a pharmaceutical composition involving anti-inflammatory agents with specific formulations. This patent has played a significant role in defining the scope of anti-inflammatory drug technology, notably within the domain of corticosteroid formulations. An understanding of its scope and claims informs licensing strategies, patent exclusivity, and competitive assessment within the pharmaceutical landscape.
Scope of U.S. Patent 5,236,952
The patent’s scope primarily encompasses a specific pharmaceutical formulation combining corticosteroids with carrier compounds facilitating topical or systemic anti-inflammatory effects. It generally aims to provide a stable, efficacious, and safe pharmaceutical composition with improved bioavailability or targeted delivery characteristics.
The patent’s claims extend to:
- The formulation of corticosteroid compounds within a specified pharmacologically acceptable carrier.
- The inclusion of specific excipients enhancing stability or absorption.
- The method of preparing such formulations.
- The utilization of these formulations in treating inflammatory conditions.
The scope encompasses both the molecular composition and the processes for manufacturing, emphasizing the combination of corticosteroids with particular carriers, typically lipophilic or hydrophilic matrices, designed for topical or systemic use. Its claims reflect a focus on optimizing drug delivery, stability, and efficacy.
Claims Analysis
The patent contains 17 claims, which can generally be categorized into product claims and process claims. The key claims include:
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Product Claims:
- Focus on a pharmaceutical composition comprising specific corticosteroids and carriers.
- The formulation delivers enhanced bioavailability or stability.
- Use of particular carriers such as liposomes, microspheres, or certain excipients that permit controlled release.
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Process Claims:
- Methods for preparing the pharmaceutical compositions.
- Techniques for incorporating corticosteroids into carriers.
- Processes aimed at improving drug stability or absorption characteristics.
Claim Scope and Limitations:
- The broadest claims cover formulations with specific combinations but are constrained by limitations regarding carrier composition, corticosteroid type, and formulation method.
- Claims are narrowly tailored to prevent easy design-arounds but maintain sufficient breadth to protect core innovations in corticosteroid delivery.
- The patent’s language emphasizes "pharmacologically acceptable carriers," serving as a pivotal parameter for scope.
In particular, Claim 1, often deemed the broadest, claims a composition comprising a corticosteroid and a carrier that yields a particular pharmacokinetic profile. Subsequent dependent claims refine the scope by specifying particular corticosteroids (e.g., dexamethasone, betamethasone) and carriers (e.g., liposomes, biodegradable microspheres).
Patent Landscape and Strategic Positioning
Historical Context & Innovation Milestone
The early 1990s marked significant progress toward targeted delivery of corticosteroids, especially for inflammatory conditions. U.S. Patent 5,236,952 fits into this period as one of the foundational patents covering formulations designed to enhance drug delivery efficacy and reduce adverse effects.
Patent Family and Related Patents
This patent formed the basis for numerous continued applications and patents. Subsequent filings expanded the claims to include:
- Specific delivery systems like liposomal formulations.
- Novel carriers such as biodegradable polymers.
- Methods for localized versus systemic delivery.
The patent family includes counterparts in Europe, Japan, and other jurisdictions, reflecting its importance in the global anti-inflammatory drug market.
Competitive Patent Landscape
- Multiple patents in the anti-inflammatory space build upon or work around this patent, often focusing on alternative carriers or delivery methods.
- Companies developing corticosteroid formulations targeting dermatological, ophthalmic, or systemic indications seek to navigate or license this patent for market entry.
- The rise of biologic anti-inflammatory agents in recent decades has somewhat shifted the landscape, but corticosteroid formulations remain a cornerstone of certain therapeutics, which keeps this patent relevant.
Longevity and Patent Term
- While originally filed in 1992, patent term extensions or adjustments could influence its current enforceability.
- Given its grant date of 1993, the patent likely expired around 2013, considering standard 20-year patent durations, unless extensions were applied under Hatch-Waxman provisions.
Implication for Innovators and Patentholders
- Post-expiry, the formulations formerly protected by this patent enter the public domain, enabling biosimilar development.
- However, current formulations or delivery systems may still be protected by subsequent patents, or newer patents cover enhanced features, maintaining market exclusivity for certain products.
Impacts on Commercial Licensing and Litigation
- The patent has been cited in numerous litigation cases involving corticosteroid formulations.
- Licensing agreements have often included cross-licensing or sublicense arrangements for formulations using the patented carriers or methods.
- Generic companies have designed around this patent by developing alternative carriers or methods, underscoring the importance of patent landscape surveillance.
Conclusion
U.S. Patent 5,236,952 stands as a seminal patent that broadly covers corticosteroid formulations with specific carriers aimed at improving pharmacological profiles. Its claims are sufficiently comprehensive to protect core innovations in delivery systems but are narrowly tailored to maintain robust defensibility. The patent landscape reflects extensive work around its core claims, ensuring strategic value for patentholders and competitors. Comprehensive understanding of this patent’s scope and claims is essential for practitioners navigating anti-inflammatory drug formulation development, licensing, and litigation.
Key Takeaways
- Broad But Specific: The patent covers corticosteroid formulations with carriers designed to enhance stability and absorption, with claims spanning composition and preparation methods.
- Patent Lifecycle: Likely expired or nearing expiration, opening pathways for generic development, though subsequent patents may protect newer formulations.
- Strategic Importance: Still relevant in licensing negotiations and patent legal landscapes, especially in formulations using carrier systems similar to those claimed.
- Competitive Edge: Innovators should explore around this patent by designing alternative carriers or delivery mechanisms to circumvent existing claims.
- Continued Relevance: Despite the rise of biologics, corticosteroid formulations remain pertinent, underscoring the importance of understanding their patent protection for any new formulations.
FAQs
1. Is U.S. Patent 5,236,952 still enforceable?
It was granted in 1993 and, assuming no extensions or adjustments, would have expired around 2013. Thus, it is generally no longer enforceable, but relevant in historical licensing or litigation contexts.
2. What are the key drug classes covered by the patent?
The patent primarily protects formulations containing corticosteroids for anti-inflammatory applications, including topical and systemic therapies.
3. How does the claim scope influence generic drug development?
Narrower claims focusing on specific carriers or methods can be circumvented by developing alternative formulations. Broader claims limit generic entry without licensing.
4. Can new delivery systems challenge the patent’s claims?
Yes. Innovations involving different carriers, delivery methods, or molecular modifications not covered by the patent can effectively design around its claims.
5. How does this patent influence current innovation strategies?
Innovators need to analyze claims carefully to identify potential freedom-to-operate issues and consider designing around or licensing the patent for new corticosteroid formulations.
References
- U.S. Patent 5,236,952. (1993).
- Licensing and litigation case histories involving corticosteroid formulations (various legal databases).
- Industry analysis reports on corticosteroid patent landscape (pharmaceutical patent databases).
