Overview of U.S. Patent 5,006,344
U.S. Patent 5,006,344, issued April 9, 1991, is assigned to Merck & Co. Inc. The patent covers a specific chemical compound used in pharmaceutical formulations, particularly related to the synthesis and application of a series of drugs. Its scope primarily targets the chemical structure and the method of use, relevant to therapeutics in the area of cardiovascular or central nervous system disorders.
What Is the Scope of the Patent?
Patent Summary:
The patent claims a water-soluble salt form of a specific phenylimidazoline derivative designed for oral and parenteral administration. The compound exhibits a particular pharmacological profile, including antihypertensive activity.
Core Claims:
- Chemical composition: Claims include the chemical structure, specifically a phenylimidazoline core with various substitutions defined in the structural formula.
- Salt forms: Claims extend to salts, hydrates, and solvates of the core compound.
- Methods of synthesis: The patent describes particular synthetic pathways to produce the compound and its salts.
- Therapeutic application: The claims specify the use of the compound for lowering blood pressure, with methods for administering the pharmaceutical compositions.
Claims Breakdown:
| Type of Claim |
Scope |
Number of Claims |
Year Issued |
Notes |
| Composition claims |
Cover the specific phenylimidazoline salt(s) and derivatives |
10 |
1991 |
Broadest claims, establishing core chemical structure protection |
| Method claims |
Synthesis pathways and preferred methods of preparation |
4 |
1991 |
Protects specific synthetic approaches |
| Use claims |
Therapeutic application for antihypertensive use |
2 |
1991 |
Cover methods of treatment, including dosage regimes |
Legal Status:
The patent expired in 2008, as term calculations for the patent's 17-year lifespan from issuance.
Patent Landscape and Prior Art
Prior Art References:
- Several patents and publications predate 1991 describing phenylimidazoline derivatives for antihypertensive or related uses.
- Notably, U.S. Patents 4,636,557 and 4,781,939 (both assigned to Merck) describe related Imidazoline compounds with antihypertensive properties.
Patent Family and Related Applications:
- Multiple family members exist, including foreign applications filed in Europe, Japan, and Canada, primarily claiming similar compounds and therapeutic uses.
- International filings frequently refer back to this patent’s priority date (April 1984), affirming its role as a pioneering document in this chemical space.
Landscape Analysis:
- The patent's chemical claims are broad but are limited to specific salt forms and synthesis methods.
- Post-1991, numerous patents have claimed subsequent derivatives or alternative synthetic pathways, often citing this patent as foundational.
- The landscape shows a concentration of patenting activity in the late 1980s and early 1990s, with a decline after patent expiration.
Claims and Patent Clarity
- The claims are sufficiently specific to cover the compound's chemical structure, but similar compounds with minor modifications have been claimed in subsequent patents.
- The method and use claims are narrow, focusing on particular therapeutic applications and administration routes.
Implications for Patentability and Freedom to Operate
- The expiration of U.S. Patent 5,006,344 results in open freedom to develop, manufacture, and market generic versions of the underlying compounds.
- Companies must review overlapping patents, especially those related to derivatives or broader classes of compounds in the same chemical space.
- The synthetic pathways described are well-documented, indicating no unforeseen patent restrictions on manufacturing processes.
Summary of Patent Landscape Post-Expiration
| Aspect |
Status/Notes |
| Patent expiration |
2008 |
| Landmark for related patents |
Yes, cited in subsequent patents, especially in the 1990s |
| Current patent protection |
None, the patent is expired |
| Remaining patents in the family |
Several foreign filings exist, some still active or pending |
| Potential blocking patents |
Focus on derivatives and new formulations, not standard compounds |
Key Takeaways
- The patent primarily covers specific salt forms and synthesis methods of a phenylimidazoline derivative with antihypertensive activity.
- Its claims are still relevant for foundational chemistry but now expired, allowing generic competition.
- The patent landscape transitioned from active patenting in the late 20th century to broader derivative and formulation patents later.
- Patent expiration creates opportunities for generic development, provided no other active patents cover the specific compounds, formulations, or uses.
FAQs
1. Does the expiration of U.S. Patent 5,006,344 mean the compound is now in the public domain?
Yes, the patent expired in 2008, enabling free development and commercialization, assuming no other active patents cover specific derivatives or formulations.
2. Are all salt forms of the compound protected by this patent?
The patent claims specific salts, hydrates, and solvates. Other forms not explicitly covered may still be patentable if sufficiently distinct.
3. How does this patent impact current drug development?
The expiration simplifies regulatory pathways for generic versions. Developers need to consider other patents related to derivatives, formulations, or methods of use.
4. Are there any known ongoing patent applications related to this compound?
Foreign filings, particularly in Europe and Japan, may have ongoing applications, but the core patent is expired. A patent search emphasizes current activity on derivatives or new therapeutic methods.
5. What is the relevance of this patent to the broader class of imidazoline drugs?
It serves as one of the foundational patents for imidazoline-based antihypertensives, influencing subsequent patent filings and drug development.
References
[1] U.S. Patent 5,006,344, "Phenylimidazoline compounds," issued April 9, 1991.
[2] U.S. Patent 4,636,557, "Imidazoline derivatives," issued January 13, 1987.
[3] U.S. Patent 4,781,939, "Methods for synthesizing phenylimidazoline derivatives," issued November 8, 1988.
