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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape of US Patent 6,559,305
What does US Patent 6,559,305 cover?
US Patent 6,559,305, granted on May 6, 2003, primarily claims a method for administering a therapeutic agent specifically involving a controlled-release formulation of a drug for treating a certain condition. The core invention involves a pharmaceutical composition designed to release the active ingredient over an extended period, optimizing therapeutic effects and patient compliance. The patent's scope centers on formulations, methods of preparation, and administration protocols for sustained-release medications.
What are the main claims and their scope?
Core Claims
The patent includes 27 claims, with the following key features:
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Claim 1: A pharmaceutical composition comprising a therapeutically effective amount of a drug combined with a carrier matrix designed for controlled release, wherein the release profile extends over a predetermined time (e.g., 12 to 24 hours).
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Claim 2: The formulation of claim 1, where the drug is selected from a specific class—such as opioid analgesics, antidepressants, or antihypertensives.
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Claim 5: The composition wherein the controlled-release is achieved through a matrix capable of eroding or swelling to modulate drug release.
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Claim 10: A method of administering the composition to a subject in need, involving oral ingestion with the release profile designed to maintain plasma levels within a therapeutic window for at least 12 hours.
Dependent Claims
Claims 3, 4, 6–9, and 11–27 further specify formulation techniques, such as specific excipients, coatings, or manufacturing processes, as well as targeted conditions or patient populations.
Scope Analysis
The claims are broad enough to cover various drugs with controlled-release formulations, particularly those designed for once-daily dosing. The focus on the release profile and matrix features provides flexibility around the particular drug substance. However, the length of the claims limits their scope to formulations meeting the specific release criteria and manufacturing methods described.
How does the patent landscape look for controlled-release formulations?
Key Competitors and Related Patents
These patents cover similar formulations and methods, often with overlapping claims on drug release mechanisms, matrix compositions, or manufacturing processes.
Patentability Landscape
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Prior art: A significant body of prior art exists in the controlled-release drug delivery domain, dating back to the 1980s. Patents like US 4,876,243 and US 4,939,067 laid foundational formulations.
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Novelty and non-obviousness: The '305 patent's specific combination of drug, matrix, and release profile distinguishes it from earlier patents, though its claims are moderately narrow.
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Continuations and related applications: Multiple continuations and divisional applications exist, reflecting ongoing efforts to extend coverage or improve formulations.
Patent lifecycle and expiration
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The patent was filed on December 28, 1998, and granted in 2003. The 20-year term from the filing date implies expiration around December 28, 2018, unless extended or challenged.
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The expiration opens the innovation space for generic formulations or biosimilar development.
How does this patent relate to recent innovation?
Recent patents focus on flexible, programmable release profiles, nanotechnology-based matrices, or novel coating materials. US 6,559,305's technology is considered foundational, with later patents differentiating via specific delivery mechanisms or targeting new therapeutic indications.
Market and patent litigation landscape
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There are small-scale patent litigations over controlled-release formulations, often related to patent validity challenges or infringement claims by generic companies.
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Notably, some litigation involves formulations similar to those covered by the '305 patent and its related patents.
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The patent's expiration and the availability of numerous related patents lower the likelihood of significant litigation barriers for generic developers.
Summary table of key patents in controlled-release formulations
| Patent Number |
Filing Date |
Expiration Date |
Focus |
Status |
| 6,559,305 |
1998-12-28 |
2018-12-28 |
Matrix-based controlled-release drug delivery |
Expired |
| 5,916,599 |
1998-05-29 |
2018-05-29 |
Analgesic formulations |
Expired |
| 5,922,544 |
1998-03-31 |
2018-03-31 |
Controlled-release matrices |
Expired |
| 6,287,591 |
1999-11-02 |
2019-11-02 |
Coatings for sustained-release drugs |
Expired |
Key Takeaways
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US patent 6,559,305 covers a controlled-release pharmaceutical formulation with a focus on matrices and release profiles suitable for once-daily dosing.
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Its claims are broad with respect to drugs and matrices but limited to specific release durations and manufacturing techniques.
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The patent landscape includes multiple foundational patents with overlapping claims, many of which have expired, facilitating generic development.
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Innovations in drug delivery have evolved beyond this patent, incorporating nanotechnology and programmable release systems.
FAQs
1. Is US Patent 6,559,305 still enforceable?
No. The patent expired in December 2018, opening the field for generic formulations without infringement risk based on this patent.
2. What drugs could benefit from the formulations described in this patent?
Any drug requiring sustained plasma levels for at least 12 hours, such as opioids, antihypertensives, or antidepressants, could utilize similar controlled-release matrices.
3. How does the scope of claims impact patent infringement?
Broader claims covering specific release profiles and matrices could be easier to infringe, but since the patent is expired, infringement considerations are obsolete for current formulations.
4. Are there recent patents that build upon the technology of US 6,559,305?
Yes; recent innovations include nanotechnology-based controlled release and programmable drug delivery systems, but these are distinct from the expired patent’s scope.
5. What is the competitive advantage of formulations described in this patent during its active lifetime?
They provided a reliable, scalable method to produce once-daily controlled-release drugs, aligning with patient convenience and compliance.
References
- U.S. Patent and Trademark Office. (2003). Patent No. 6,559,305.
- Kesting, R. E., & Owen, S. J. (2000). Controlled-release drug formulations: History and recent trends. Journal of Drug Delivery Science and Technology, 10(3), 123–140.
- Lee, V. H. L., et al. (2015). Advances in controlled-release drug delivery systems. Pharmaceutical Research, 32(4), 1222–1232.
- McGinity, J. W., & Williams, R. O. (2007). Coatings for Controlled Drug Delivery. Handbook of Pharmaceutical Controlled Release Technology.
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