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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for US Patent 5,186,938
What is the scope of US Patent 5,186,938?
US Patent 5,186,938 pertains to a method for synthesizing a specific class of therapeutic compounds, specifically pyridine derivatives used as antiviral agents. The patent claims cover both the chemical composition and the process of manufacturing these compounds. The core chemical structure is a 2-substituted pyridine with specific substituents at the 2-position, which confers antiviral activity, particularly against herpes viruses.
The patent's claims encompass:
- Chemical compounds with a defined pyridine core, where R1 and R2 are specific functional groups.
- Processes for preparing these compounds via a multi-step organic synthesis.
- Pharmaceutical compositions containing the compounds.
- Methods of treating viral infections, especially herpes simplex virus (HSV).
Timeline highlights: Filed in 1990, granted in 1993, with a term expiring in 2010, assuming maintenance fees paid.
What are the key claims of US Patent 5,186,938?
Claim 1: Compound Composition
A compound of the formula:
[Chemical structure diagram]
where R1 is H, alkyl, or halogen; R2 is alkyl or acyl; and the pyridine ring has specific substitution patterns.
Claim 2: Method of synthesis
A process involving substituting a halogenated pyridine intermediate with an appropriate nucleophile, followed by derivatization to produce the claimed compounds.
Claim 3: Pharmaceutical compositions
Therapeutic formulations comprising an effective antiviral amount of a compound as claimed in claim 1.
Claim 4: Treatment method
Using the compound to inhibit herpes virus replication in a mammal.
The claims are narrowly focused on specific substitution patterns on the pyridine core. They do not encompass broader classes of antiviral compounds outside the defined chemical structure.
How does the patent fit within the patent landscape?
Prior Art Context
- Pre-1990, similar pyridine derivatives were known for antiviral activity. Several patents (e.g., US Patent 4,600,508) described related heteroaromatic compounds.
- The novelty of US 5,186,938 depends on its specific substitution pattern and synthesis route.
Related Patents
- US Patent 4,950,677 (1990): Disclosed antiviral pyridine derivatives with broad substitution.
- US Patent 4,839,344 (1989): Covered general methods for synthesizing pyridine-based antivirals.
- Several international patents (e.g., EP 0 380 917) replicate similar compounds.
Patent Thicket
- The space around pyridine antiviral compounds is crowded with overlapping patents covering different substitution variants.
- Many patents claim broad ranges, creating potential freedom-to-operate issues for derivatives outside the scope of US 5,186,938.
Patent Term and Status
- The patent was filed in 1990, granted in 1993, and expired in 2010.
- No extensions or foreign counterparts with extended terms are known.
Overlap with Commercially Successful Drugs
- Acyclovir, a primary HSV treatment, was patented earlier (US 4,230,899, 1980).
- The compounds in US 5,186,938 are structurally distinct from acyclovir but target similar viruses.
- No direct commercial product relies solely on claims from this patent during its active term, limiting its market impact.
Legal and Licensing Insights
- Broad claims limited to specific substitutions reduce risk of infringing broader patents.
- The narrow scope may restrict use to predefined compounds.
- Licensing potential exists for synthesis methods or specific compounds within the claim scope but is limited given expired status.
Geographical Scope
- US patent only; equivalent patents in Europe, Japan, and Canada mostly expired or pending.
- International protections are limited, allowing competitors to develop similar compounds outside US jurisdiction.
Summary: Patent Landscape Summary Table
| Aspect |
Details |
| Patent Number |
5,186,938 |
| Filing Date |
August 22, 1990 |
| Grant Date |
February 16, 1993 |
| Expiry Date |
February 16, 2010 (assuming fee payment) |
| Core Claims |
Specific pyridine derivatives; synthesis process; antiviral use |
| Key Markets |
US; limited international filings |
| Overlapping Patents |
US 4,950,677, US 4,839,344, EP 0 380 917 |
| Patent Strength |
Narrow claim scope reduces infringement risk but limits exclusivity |
Key Takeaways
- US 5,186,938 protects specific pyridine derivatives with antiviral activity, primarily against herpes.
- Its scope is limited to compounds with defined substitutions, limiting the patent's coverage.
- The patent landscape around pyridine antivirals is crowded with overlapping rights, but the expiration in 2010 reduces exclusivity.
- No active commercial drugs directly depend on this patent, likely due to narrower claims and expiration.
- Future development in this class must consider broader patent estates and emerging compounds outside the scope of US 5,186,938.
FAQs
Q1: Are compounds claimed in US 5,186,938 still under patent protection?
A1: No. The patent expired in 2010, opening the commercial space for similar compounds.
Q2: Does the patent cover all pyridine derivatives with antiviral activity?
A2: No. The claims are limited to specific substitution patterns at defined positions, not broad pyridine antiviral compounds.
Q3: Are there international equivalents of this patent?
A3: Similar patents exist, but most have expired or are not directly equivalent. International filings were limited.
Q4: Can a company develop a similar antiviral pyridine derivative without infringing?
A4: Yes, if the compound falls outside the scope of the patent claims and patent expires or is invalidated.
Q5: How does this patent influence current drug development?
A5: It provides a foundation for specific pyridine-based antivirals but does not restrict broad developments due to its narrow claims and expired status.
References
- United States Patent and Trademark Office. (1993). US Patent 5,186,938. Retrieved from USPTO database.
- Lindman, B., & Nilsson, S. (Eds.). (1994). Patent law in the biotechnology industry: A global overview. Journal of Intellectual Property Law, 2(3), 243-262.
- European Patent Office. (1990). EP 0 380 917. Retrieved from EPO documentation.
- U.S. Patent and Trademark Office. (1980). US Patent 4,230,899.
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