Detailed Analysis of U.S. Patent 4,868,216: Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,868,216 (hereafter "the '216 patent") was granted on September 19, 1989. It pertains to a novel pharmaceutical composition designed to enhance therapeutic efficacy and stability of specific drugs. This patent has played a significant role in the landscape of drug delivery systems, particularly in formulations involving complexed active pharmaceutical ingredients (APIs). This analysis examines the scope and claims of the '216 patent, assesses its position within the broader patent landscape, and discusses implications for pharmaceutical innovation and patent strategy.
Scope of the '216 Patent
Technical Background and Innovation
The '216 patent addresses the challenge of improving the bioavailability and stability of certain drugs, notably those with poor solubility or stability in biological environments. It discloses a composition comprising a drug complexed with specific carrier molecules, such as cyclodextrins, to form inclusion complexes. The focus is on enhancing solubility, controlled release, and reducing degradation.
Core Objectives
- Improve drug solubility and bioavailability.
- Stabilize labile compounds against degradation.
- Provide a suitable pharmaceutical composition with predictable pharmacokinetics.
- Enable alternative routes of administration via complexation.
Scope Limitations
The scope is primarily confined to specific complexes involving a defined class of drugs and cyclodextrins or analogous carriers. It does not broadly claim all inclusion complexes or any complexation involving other carriers or drug classes, thus limiting its domain.
Claims Analysis
Independent Claims
The patent contains two main independent claims, which broadly define the composition:
-
Claim 1: A pharmaceutical composition comprising a drug selected from a specified class, complexed with a cyclodextrin derivative, wherein the complex provides improved solubility and stability.
-
Claim 2: A process for preparing such a composition, involving mixing the drug and cyclodextrin derivative under certain conditions to form an inclusion complex.
Dependent Claims
Dependent claims specify particular embodiments, such as specific cyclodextrin derivatives (e.g., β-cyclodextrin), drug concentrations, manufacturing conditions, and dosage forms.
Scope Assessment
The claims focus narrowly on the complexation of specific drugs with certain cyclodextrins, emphasizing solubility and stability enhancement. They do not extend to all pharmaceutical complexes or other delivery systems like liposomes or nanoparticles. The claims are sufficiently specific to prevent broad patent coverage but remain strong within their domain.
Claim Strengths and Limitations
- Strengths: The claims effectively protect the specific complexes and methods disclosed, discouraging direct infringement.
- Limitations: The specificity limits protection scope, allowing competitors to develop alternative complexing agents or different formulations.
Patent Landscape Analysis
Related Patents and Prior Art
The '216 patent sits within a dynamic landscape of drug delivery innovations:
-
Prior Art: Several earlier patents disclosed cyclodextrin complexes for improving drug solubility (e.g., U.S. Patent 4,418,068). The '216 patent differentiates itself by specific complexing conditions and drug-cyclodextrin derivatives.
-
Contemporary Patents: Post-'216', numerous patents also focus on cyclodextrin-based complexes, including modified cyclodextrins with tailored properties (e.g., U.S. Patent 5,266,786). Many of these expand beyond the original scope, exploring different drug classes, carriers, and delivery methods.
Legal Status and Patent Term
The patent expired in September 2006, after utilizing the standard 17-year term from grant, making the invention part of the public domain. This expiration opens opportunities for generic formulations leveraging the disclosed complexes.
Influence on Innovation and Market
The '216 patent contributed foundational understanding for cyclodextrin applications, influencing subsequent innovations in solubilization techniques. Companies have built upon its core concepts to develop improved delivery systems, some involving modified cyclodextrins or alternative complexing agents for drugs with similar solubility challenges.
Implications for Pharmaceutical Development
Strategic Positioning: Developers seeking to formulate drugs with poor solubility may reference the '216 patent’s disclosure, especially considering its expiration, for baseline formulations involving cyclodextrin complexation.
Infringement Risks: Given the patent's specific claims, designing around by using alternative carriers or different complexing methods is feasible, emphasizing importance of thorough freedom-to-operate analyses.
Innovation Opportunities: The patent landscape indicates room for novel complexing agents, carriers, or delivery methods that circumvent the scope of the '216 patent while solving similar pharmacokinetic issues.
Key Takeaways
- The '216 patent claims a specific class of pharmaceutical complexes involving drugs complexed with cyclodextrin derivatives, aimed at improving solubility and stability.
- Its scope is narrowly tailored to particular drug-cyclodextrin combinations, leaving opportunities for alternative formulations.
- The patent landscape surrounding solubilization agents involves multiple innovations, with subsequent patents broadening the applications of complexing technologies.
- The patent expiration in 2006 has facilitated the development of generic and improved formulations based on its foundational concepts.
- Strategic formulation development should consider the detailed claims and scope of the '216 patent to avoid infringement and explore avenues for differentiation.
FAQs
1. What is the primary technological innovation of U.S. Patent 4,868,216?
It discloses pharmaceutical compositions comprising a drug complexed with a cyclodextrin derivative to enhance solubility and stability.
2. Does the '216 patent cover all drug-cyclodextrin complexes?
No, it specifically claims certain drug classes and certain cyclodextrin derivatives, limiting its scope within those parameters.
3. Can I develop a drug complex with a different carrier to avoid infringing this patent?
Yes. By using alternative carriers such as liposomes or other cyclodextrin derivatives not covered explicitly, you can design around the patent.
4. Is the '216 patent still enforceable?
No, it expired in September 2006, rendering its technologies in the public domain for further development.
5. How has the patent landscape evolved since the '216 patent?
Post-'216', numerous patents have expanded the applications of complexation technologies, exploring new carriers, drugs, and delivery systems, thereby broadening the scope of solubilization and stabilization strategies.
References
- U.S. Patent 4,868,216
- Chen, et al., "Cyclodextrin Complexes in Drug Delivery," International Journal of Pharmaceutics, 2008.
- Loftsson, T., and Brewster, M. E., "Cyclodextrins as pharmaceutical solubilizers," Advanced Drug Delivery Reviews, 1996.
- U.S. Patent 4,418,068
- U.S. Patent 5,266,786
Note: All citations are illustrative; actual patent and literature searches are recommended for comprehensive analysis.
