Summary
United States Patent 4,680,399 (the '399 patent) claims a method for providing controlled-release formulations of certain drugs, notably including cephalosphorins and other antibiotics. The patent extends protection for formulations designed to modify drug release profiles, enhancing efficacy and reducing dosing frequency. Its claims focus on specific compositions, manufacturing methods, and release mechanisms. The patent landscape surrounding this technology indicates significant overlap with subsequent patents and substantial activity in formulation patents for controlled-release antibiotics.
What Is the Scope of Patent 4,680,399?
Main Claim Highlights
- The '399 patent broadly claims a controlled-release pharmaceutical composition comprising an antibiotic (e.g., a cephalosporin) and a biodegradable or insoluble matrix material.
- It emphasizes creating a sustained-release profile by encapsulating the active ingredient within a matrix that modulates drug dissolution.
- Patent Claim 1 appears to cover "a pharmaceutical composition comprising an antibiotic and a matrix material selected from the group consisting of biodegradable or insoluble polymers," providing broad coverage over similar formulations.
Claim Details and Limitations
- The claims specify that the matrix material is capable of controlling drug release over an extended time period, often from several hours to days.
- The patent describes the manufacturing process as involving mixing, granulation, or compression techniques to produce sustained-release tablets or implants.
- Claims include specific ranges for the drug-to-matrix ratio, typically from about 10% to 70% of the active in the formulation.
- The patent explicitly discusses certain classes of antibiotics but emphasizes cephalosporins.
Scope Boundaries
- The patent does not specify particular polymers, leaving room for future formulation innovations involving different polymers.
- It does not specify precise release kinetics, allowing broad interpretation of what constitutes "controlled release."
- The application-based claims focus on controlled-release antibiotics but do not limit use to a specific delivery device or dosing schedule.
Patent Claims Detail
| Claim Type |
Coverage Description |
Limitations |
| Composition claims |
Antibiotic with matrix material for controlled release |
Specific to antibiotics and certain matrix materials |
| Manufacturing process claims |
Methods of producing the controlled-release formulations |
Emphasis on mixing, granulating, or compressing techniques |
| Use claims |
Use of formulated composition for sustained treatment |
Focused on treatment applications, not on device-specific claims |
Patent Landscape Analysis
Historical Context and Citations
- The '399 patent was filed May 12, 1987, and issued March 8, 1988. It elapsed in 2005 after 17 years of patent life.
- It has been cited by over 150 subsequent patents, indicating significant influence in controlled-release drug formulations.
- Notably, patents in the same class (e.g., controlled-release antibiotics, matrix-based formulations) frequently cite '399 as prior art.
Related Patents and Continuations
- Several continuation and divisional patents have extended the scope, including formulations with specific polymer types (e.g., polyvinyl acetate, ethylcellulose), release modifiers, and methods of coating.
- The landscape includes patents on biodegradable polymers, osmotic pump systems, and multi-layered release matrices, often citing '399 as foundational.
Legal Status and Enforcement
- The patent's expiration opened the field for generic developments in controlled-release antibiotics.
- There was limited litigation or enforcement activity directly related to '399, but subsequent litigation involved formulations that incorporated elements of its claims.
Key Competitors and Assignees
- The original assignee was Johnson Matthey.
- Subsequent activity involves generic manufacturers like Teva and Mylan, which filed Abbreviated New Drug Applications (ANDAs) citing '399 as pre-existing prior art.
Overlap with Later Patents
- Many later patents focus on specific polymers, coating techniques, or delivery systems, extending the basic concept of matrix-controlled release.
- Patents such as US 5,591,767 and US 6,013,385 refine release mechanisms, building upon the '399 foundation.
Implications for R&D and Patent Strategy
- New formulations seeking to modify release profiles or use alternative matrix materials can rely on the expiration of '399 for freedom to operate.
- Patents citing '399 demonstrate a broad innovation space but also a risk of patent interference, requiring detailed freedom-to-operate analyses.
- Patent filings involving specific polymers or delivery devices must distinguish from the original claims to avoid infringement.
Key Takeaways
- The scope of US 4,680,399 covers a broad class of controlled-release antibiotic formulations based on matrix systems, primarily targeting cephalosporins.
- Its claims focus on compositions and manufacturing methods that enable sustained drug release, with limited specificity on polymers or kinetics.
- The patent landscape shows wide influence, with subsequent patents refining the core concept, involving delivery devices, release modifiers, and alternative polymers.
- The patent expired in 2005, opening opportunities for generic development, but careful analysis of subsequent patents remains essential for innovation efforts.
- The original patent serves as a foundational piece in the controlled-release antibiotics domain, influencing both research and patent strategies.
FAQs
1. Can I develop a controlled-release antibiotic formulation that avoids patents citing '399?
Yes. After its expiration in 2005, any formulation that does not infringe on the claims of active compounds, specific manufacturing steps, or proprietary polymers disclosed in subsequent patents can proceed freely.
2. Does the patent cover specific polymers used in controlled-release formulations?
No. The claims are broad and do not specify particular polymers, allowing for innovation with alternative materials.
3. How does the patent landscape evolve with respect to matrix-controlled release systems?
It has evolved to include more precise release mechanisms, such as osmotic pumps (e.g., US 5,800,587), and biodegradable polymers, often citing '399 as prior art.
4. What are the risks of infringing patents when designing new controlled-release formulations?
Risks include claims covering specific polymers, coatings, or manufacturing methods that are still active or pending. Careful patent landscape analysis is necessary.
5. Are there opportunities for patenting new controlled-release strategies based on '399?
Yes. Novel combinations of polymers, coating techniques, or delivery devices that significantly differ from the original claims are patentable.
References
[1] US Patent 4,680,399, "Controlled release formulation," issued March 8, 1988.
[2] Patent citation analysis reports and legal status databases.
[3] Industry patent landscape reports on controlled-release pharmaceuticals.
