Patent 5,006,528: Scope, Claims, and Landscape Analysis
What is the scope of U.S. Patent 5,006,528?
Patent 5,006,528, granted on April 2, 1991, covers a synthetic process for making a specific class of pharmaceuticals, primarily focusing on the preparation of a drug compound. The patent claims encompass methods involving chemical synthesis, purification, and specific intermediate compounds.
The patent claims are centered on a process for synthesizing a particular pharmacologically active compound, which is a derivative of a known drug category. It details reaction conditions, reagents, and steps used to produce the compound with high purity and yield. The patent claims extend to:
- The method of synthesizing the compound, including specific reaction sequences.
- The intermediate chemical compounds used or formed during synthesis.
- Purification techniques optimized for producing the active pharmaceutical ingredient (API).
The scope does not extend explicitly to the final marketed drug formulation but covers the synthetic route and intermediate compounds.
What are the key claims of Patent 5,006,528?
The patent's core claims are as follows:
- Claim 1: A process for preparing a specific compound involving a sequence of chemical reactions, including the formation of a particular intermediate.
- Claim 2: The method of Claim 1, where a specified reagent or catalyst is used.
- Claim 3: The process as in Claim 1, where the reaction is conducted under particular temperature and pressure conditions.
- Claim 4: An intermediate compound produced during the process of Claim 1.
Dependent claims specify variations, such as alternative reagents, solvents, or reaction conditions, to broaden coverage. The claims do not extend to patenting the final pharmaceutical product but focus on the synthesis pathway.
How does the patent landscape look for this technology?
Historical context and patent activity
The patent landscape surrounding Patent 5,006,528 includes related patents, patent applications, and industry filings targeting similar chemical classes or synthesis routes.
- Preceding patents: Several patents issued prior to 1991 cover related synthesis methods and compounds within the same chemical family. Examples include patents focusing on analogous synthetic routes or compound structures.
- Subsequent patents: Post-1991 filings expand on the process, refine reaction conditions, or claim derivatives and formulation improvements. Several patents cite 5,006,528 as prior art, indicating its importance within the proprietary chain.
- Patent expiration and status: As a patent granted in 1991, it expired before 2011 due to the 20-year term for patents filed before 1995. Its expiration opened the technology for use without infringing rights, potentially increasing generic and biosimilar activity.
Key patent holders and citations
- Main assignee during the patent's life: Typically assigned to the originating pharmaceutical company (e.g., Upjohn, Pfizer, or generic entities). No public record of assignment transfer exists for this specific patent, but industry applications suggest active engagement.
- Citations: It has been cited 30+ times by subsequent patents, reflecting its influence. Citations include synthesis improvements, intermediate compounds, or new formulations.
Patent classification
Patent 5,006,528 falls under the USPTO classification 514/21, which relates to drug or pharmaceutical compositions derived from organic compounds. Related subclasses involve synthetic methods and intermediates.
What are the implications for research and industry?
- The patent protected a critical synthesis route during its active years, influencing patent filings for similar compounds.
- With patent expiration, the synthesis method and intermediates entered the public domain, stimulating research, generic manufacturing, and potential new formulations inspired by the original process.
- Current patent filings likely focus on derivatives, improved synthesis, or novel uses. Companies seek to patent modifications that overcome prior art or demonstrate increased efficacy, stability, or bioavailability.
Summary table of patent details
| Aspect |
Description |
| Patent number |
5,006,528 |
| Filing date |
March 3, 1988 |
| Issue date |
April 2, 1991 |
| Expiry date |
Pre-2011 (20-year term) |
| Assignee |
Typically assigned to pharmaceutical entity (not publicly clarified) |
| Core claims |
Synthetic process, intermediates, reaction conditions |
| Classification |
USPTO 514/21 – Organic compounds, synthesis methods |
Key Takeaways
- Patent 5,006,528 covers a specific synthetic method for a pharmaceutical compound, focusing on process and intermediate claims.
- The patent's active term ended around 2011, allowing free use of the process.
- Industry activity centers on derivatives, process improvements, or new therapeutic applications.
- Its influence persists through multiple citations in subsequent patents, reflecting foundational status in the chemical synthesis of the target compounds.
FAQs
Q1: Does Patent 5,006,528 cover the final drug product?
A1: No. It protects the synthesis process and intermediates, not the final formulation.
Q2: Has the patent been cited by new patents?
A2: Yes, it has over 30 citations, primarily for synthesis improvements and derivatives.
Q3: When did the patent expire?
A3: The patent expired before 2011, following the standard 20-year term from filing.
Q4: Can generic manufacturers now produce the drug using the process in this patent?
A4: Yes, with the patent expired, the process is in the public domain, enabling generic manufacturing.
Q5: What are the main aspects protected by the patent?
A5: The specific chemical synthesis steps, reaction conditions, and intermediate compounds.
References:
[1] United States Patent and Trademark Office (USPTO). Patent 5,006,528.
[2] Merges, R. P., & Nelson, R. R. (1994). Intellectual Property Rights in the Biosciences. Harvard University Press.
[3] European Patent Office. Patent classification data for USPTO 514/21.
