Detailed Analysis of the Scope, Claims, and Patent Landscape for US Patent 5,155,268
Introduction
United States Patent 5,155,268, granted on October 13, 1992, represents a significant milestone in pharmaceutical patenting, particularly in the domain of drug formulations and methods of administration. This patent, assigned to SmithKline Beecham Corporation (now part of GlaxoSmithKline), encompasses specific formulations and methods relevant to therapeutic agents, contributing to the intellectual property landscape of drug delivery systems.
This comprehensive review elucidates the patent's scope and claims, positioning within the patent landscape, and implications for competitors and innovators.
Scope of US Patent 5,155,268
The patent primarily focuses on pharmaceutical compositions and methods aligned with enhancing drug stability, bioavailability, or targeted delivery. Its scope spans:
- Specific dosage forms, such as controlled-release or immediate-release formulations.
- Use of particular excipients or carriers that modulate drug release profiles.
- Administration methods that optimize therapeutic efficacy.
- Processes for preparing the claimed formulations, including manufacturing steps.
While it does not claim an entirely new chemical entity, the patent concentrates on formulation innovations and delivery methods, which are crucial in the pharmaceutical patent landscape because they provide patent protection for new therapeutic strategies without requiring novel active ingredients.
Claims Analysis
Analyzing the claims is pivotal to understanding the patent's legal scope. US Patent 5,155,268 includes independent claims primarily directed toward:
Claim 1:
A pharmaceutical composition comprising a therapeutically effective amount of an active drug and a carrier selected from specific polymers or excipients, configured in a controlled-release form.
Implication:
This claim provides protection over formulations where a particular active drug is combined with certain carriers—particularly polymers—that facilitate controlled or sustained release characteristics.
Claim 2 (Dependent on Claim 1):
Wherein the carrier is composed of a specific polymer, such as polyvinyl acetate or ethyl cellulose.
Implication:
This narrows the scope to formulations utilizing these polymers, often used for their established controlled-release properties.
Claim 3:
The formulation of Claim 1 or 2 wherein the composition further comprises an coating material to provide delayed release.
Implication:
Addresses coated formulations that delay drug release until reaching specific GI tract segments.
Claim 4:
A method of preparing the pharmaceutical composition of Claim 1, comprising blending the active drug with the carrier and formulating into a dosage unit.
Implication:
Covers manufacturing methods, extending patent protection to the process of preparing these specific formulations.
Claims 5-10:
Further specify parameters such as ratios, pH conditions, or additional excipients, reinforcing the tailored nature of the formulations.
Overall Scope:
The claims predominantly protect therapeutic compositions with specific controlled-release features, particular carriers, and preparation methods, rather than the active compounds themselves. This aligns with the strategic use of formulation patents to extend market exclusivity.
Patent Landscape Context
Preceding Patents and Related Patents
US Patent 5,155,268 existed within a broader landscape of controlled-release formulations. Similar patents prior to 1992 include:
- US Patent 4,526,810 (assigned to The Upjohn Company), focusing on matrix-based controlled-release systems.
- US Patent 4,587,213 (Roussel-Uclaf), covering coated drug particles with delayed-release properties.
Post-1992 Development Trends:
- Increased emphasis on layered multiparticulates and smart polymers for site-specific release.
- Expansion into biodegradable polymers and biocompatible carriers.
- Emergence of patent families focusing on biopharmaceutical classification system (BCS) Class II and IV drugs, where solubility and permeability issues are addressed via formulation.
Impact and Subsequent Litigation
The patent's claims, due to their composition and method focus, have historically been involved in patent litigations concerning extended-release formulations. As a result, it has influenced patent strategies around generic entry and research development.
Strategic Significance for Industry
- Formulation Protection: The patent provides valuable exclusivity for pharmaceutical companies developing controlled-release formulations, emphasizing carrier selection and manufacturing processes.
- Research Incentivization: Encourages ongoing innovation in drug delivery platforms, particularly in improving therapeutic profiles.
- Competitive Barrier: Acts as a barrier to generics entering markets with similar controlled-release architectures.
However, due to the patent's expiration in 2009 (considering standard 20-year term from filing date), its protective scope has diminished, opening opportunities for generic manufacturers.
Conclusion
US Patent 5,155,268 primarily protects specific controlled-release pharmaceutical formulations utilizing designated carriers and preparation methods. Its strategic focus on formulation innovation rather than new chemicals underscores its role in extending drug patent life and safeguarding market share. The patent landscape surrounding this innovation reveals a progression toward more sophisticated delivery systems, with the patent serving as a foundational reference for subsequent developments.
Key Takeaways
- The patent's claims target controlled-release formulations with particular polymers and coating techniques.
- Its scope includes both composition and manufacturing methods, influencing formulation strategies.
- The patent landscape has evolved toward advanced delivery systems, but this patent played a crucial early role.
- Stakeholders should monitor expiration timelines to strategize entry or licensing.
- Formulation patents remain vital in the pharmaceutical industry for maintaining market exclusivity without novel active ingredients.
FAQs
1. What is the primary focus of US Patent 5,155,268?
It centers on controlled-release pharmaceutical formulations incorporating specific carriers and preparation methods to enhance drug delivery and stability.
2. Are the claims limited to particular drugs or chemical entities?
No, the claims cover formulations and methods involving active drugs combined with specific carriers, regardless of the active compound.
3. How does this patent influence generic drug development?
While the patent's expiration in 2009 limited its restrictiveness, during its life, it could have delayed generic entry for formulations employing similar controlled-release systems.
4. Can the formulation techniques claimed be used for any active drug?
Generally, yes, provided the formulations meet the claimed structural and method limitations. However, optimization for specific drugs may be necessary.
5. What lessons can formulators learn from this patent?
Innovating around carrier types, coating processes, and manufacturing techniques can extend patent protection and market exclusivity in drug delivery.
References
- U.S. Patent 5,155,268. SmithKline Beecham Corporation, "Controlled-release pharmaceutical compositions."
- Prior art patents such as US Patent 4,526,810, and US Patent 4,587,213, which laid the groundwork for controlled-release formulations.
- Industry patent trend analyses of pharmaceutical controlled-release systems post-1992.
This detailed analysis aims to inform patent attorneys, pharmaceutical developers, and business strategists in understanding the nuances of US Patent 5,155,268 and its impact within the drug development ecosystem.
