Patent Scope and Claims Analysis for U.S. Patent 3,495,013
U.S. Patent 3,495,013, licensed for pharmaceutical compounds, was filed on December 12, 1967, and granted on February 10, 1970. The patent covers a class of substituted quinazoline derivatives intended for therapeutic use, specifically as antihypertensive agents. Its claims focus on a broad chemical genus with specific substitution patterns, aiming to secure intellectual property rights over a significant portion of the related chemical space.
Patent Scope Overview
The patent claims a chemical class characterized by the quinazoline backbone with specific substituents at designated positions (notably at the 2 and 4 positions). It encompasses compounds with a 2-alkylamino group and a 4-alkyl group, with optional substitutions on the quinazoline ring. The scope extends to salts, esters, and other derivatives of these compounds, explicitly covering the pharmaceutical compositions containing them.
The claims delineate the scope as follows:
- Chemical core: Quinazoline ring system.
- Substitutions: Alkylamino at the 2-position; alkyl group at the 4-position; optional substitutions on the aromatic ring.
- Pharmaceutical application: Use as antihypertensive agents.
- Formulations: Salts and derivatives suitable for administration.
The broad language across claims permits coverage over a wide range of substituted quinazoline compounds, emphasizing the antihypertensive utility.
Claims Breakdown
| Type of Claim |
Scope |
Details |
| Product claims |
Substituted quinazoline compounds |
Covering compounds with a specific substitution pattern at key positions. |
| Pharmaceutical composition |
Formulations containing claimed compounds |
Includes salts and esters, broadening commercial applicability. |
| Method of use |
Therapeutic methods involving the compounds |
Use in treating hypertension, establishing medical utility. |
Claims are primarily product-oriented but include method claims that specify therapeutic uses.
Patent Landscape Context
Prior Art and Novelty
The patent's novelty lies in the specific substitution pattern on the quinazoline ring, which prior art patents did not sufficiently describe or claim. Earlier compounds like reserpine or other antihypertensive agents did not share the chemical structure claimed, giving this patent a pioneering position for quinazoline derivatives.
Overlapping Patents and Patentability
Subsequent patents have cited this patent as prior art, especially patents covering similar quinazoline derivatives or related antihypertensive agents. Notably, the patent's 1970 priority date means later patents must navigate around or build upon its scope.
Patent Term and Expiry
The patent expired in 1987, restoring freedom to operate for research and generic development. The 17-year term from issuance grants a substantial period of market exclusivity post-grant, though public disclosure was immediate upon grant, limiting procedural extensions.
Patent Citations and Influence
The patent has been frequently cited in later research on quinazoline derivatives, particularly in patents concerning antihypertensive drugs like prazosin. Its broad chemical claims have guided subsequent innovation, often serving as a basis for compound optimization.
Key Takeaways
- The patent covers a broad chemical class of substituted quinazoline derivatives with therapeutic utility as antihypertensives.
- Claims encompass compounds, salts, derivatives, and therapeutic methods.
- The patent's breadth contributed to establishing quinazoline chemistry in antihypertensive drug development.
- Its expiration opened pathways for generic access and further research.
FAQs
1. Does the patent cover all quinazoline derivatives for hypertension?
No. It specifies a particular substitution pattern, limiting coverage to compounds within that scope.
2. Are salts and esters included in the patent claims?
Yes. Claims explicitly cover salts and derivatives, broadening commercial options.
3. How does this patent impact current drug development?
The patent's expiration allows for research and generic production; its broad claims historically influenced quinazoline-based antihypertensive compounds.
4. What was the significance of the 1967 filing date?
It predates many related patents, giving it priority in quinazoline antihypertensive chemistry.
5. Could similar compounds still infringe?
Potentially, if they fall within the specific substitution pattern and claims scope, especially if still under patent protection or patent term extensions.
References
- U.S. Patent 3,495,013. (1970). Substituted quinazoline derivatives. USPTO.
- Parker, R. (1972). Structural categories of antihypertensive agents. Journal of Medicinal Chemistry, 15(3), 267-272.
- Smith, J., & Lee, A. (1985). Patent landscape for quinazoline-based antihypertensives. Drug Development & Industrial Pharmacy, 11(7), 1059-1072.
