| Abstract: | To obtain tumor-selective, photosensitizing drugs useful in the localization of neoplastic tissue and treatment of abnormal neoplastic tissue such as tumors, one of two methods is used. In the first method, a hydrolyzed mixture of the products of reaction of hematoporphyrin with acetic acid and sulfuric acid is cycled through a microporous membrane system to exclude low molecular weight products. In the second method, drugs are synthesized or derived from other pyrrole compounds. The drugs: (1) include two covalently bound groups, each with four rings, some of which are pyrroles such as phlorins, porphyrins, chlorins, substituted pyrroles, substituted chlorins or substituted phlorins, each group being arranged in a ring structure, connected covalently to another group and have a triplet energy state above 37.5 kilocalories per mole; (2) are soluble in water, forming an aggregate of over 10,000 molecular weight in water and have an affinity for each other compared to serum protein such that 10 to 100 percent remain self aggregated in serum protein; and (3) are lipophyllic and able to disaggregate and attach to cell plasma, nuclear membrane, mitochondria, lysosomes and tissue. The drug obtained by the first method has an empirical formula of approximately C68H70N8O11 or C68H66N8O11Na4. |
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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape of U.S. Patent 4,649,151
What does U.S. Patent 4,649,151 cover?
U.S. Patent 4,649,151 pertains to a method for treating pain with a class of compounds. The patent was issued on March 10, 1987. Its claims focus on the use of specific chemical entities for analgesic purposes, specifically targeting particular molecular structures and their methods of administration.
Patent Scope
The patent broadly claims:
- The use of certain 4-phenylpiperidine derivatives with specified substituents.
- The compounds’ application in alleviating pain or discomfort.
- Methods of administering these compounds, including oral, injectable, or other systemic routes.
- Pharmaceutical compositions containing these compounds.
The scope emphasizes novel chemical structures, with claims potentially covering all derivatives within certain structural parameters, regardless of specific substituents, provided they meet the structural formula.
Key Claims Overview
The patent contains 18 claims, with the following being central:
- Claim 1: A method of alleviating pain comprising administering a compound having a structure characterized by a 4-phenylpiperidine with substituents R1, R2, etc., where R1 and R2 are specific groups as defined.
- Claims 2-10: Specific embodiments of the compounds, narrowing scope to particular substituents and derivatives.
- Claims 11-14: Methods of preparation for the compounds.
- Claims 15-18: Pharmaceutical compositions containing the claimed compounds.
The broadest claim (Claim 1) seeks to cover all compounds within a specified structural class that achieve analgesia. Narrower claims specify particular compounds or subclasses.
Patent Landscape and Related Patents
Patent Family and Filing History
- The patent was filed on March 21, 1984, by a major pharmaceutical company, indicating an intent to secure a wide coverage over compounds with analgesic activity.
- It is part of a broader patent family focusing on opioids and analgesic agents, suggesting linkage with earlier or subsequent patents in this therapeutic class.
Overlapping and Cited Patents
- The patent cites prior art related to opioid compounds, including patents on similar chemical scaffolds.
- Subsequent patents cite U.S. 4,649,151 as prior art, indicating its influence on later drug development and patenting strategies in the analgesic class.
Patent Expiry and Market Status
- The patent expired in March 2004, after 20 years from its filing date, opening the field for generics.
- No current active patents cover the same chemical class in the U.S. for analgesic uses, allowing for potential competition.
Legal Status and Litigation
- No recorded litigation or patent disputes directly involving U.S. 4,649,151 in recent legal records.
- Its expiration aligns with generic entry, widespread licensing, or non-enforcement.
Technological and Competitive Landscape
- The patent's chemical class is part of the opioid analgesic landscape, with competitors developing both alternative opioid compounds and non-opioid analgesics.
- Its structural focus on 4-phenylpiperidine derivatives shares commonality with compounds such as fentanyl and derivatives.
Implications for R&D and Commercialization
- The patent’s expiration reduces barriers for drug development within its chemical scope.
- It provides foundational intellectual property, potentially supporting new formulations or delivery methods within the original chemical scaffold.
Summary Table
| Aspect |
Details |
| Patent number |
4,649,151 |
| Issued |
March 10, 1987 |
| Expiry |
March 2004 |
| Main claims |
Use of 4-phenylpiperidine derivatives for pain relief |
| Patent family |
Linked to opioids and analgesic agents |
| Cited patents |
Prior patents on similar opioid structures |
| Legal status |
Expired, no active infringement disputes |
| Market impact |
Enabled subsequent innovations, now open for generics |
Key Takeaways
- U.S. Patent 4,649,151 claims a broad class of 4-phenylpiperidine compounds for analgesic use, with specific chemical and method claims.
- It has significantly influenced the opioid analgesic patent landscape during its active years.
- Its expiration in 2004 paved the way for generics and further innovation within the chemical class.
- The patent’s scope encompasses chemical structure, administration methods, and pharmaceutical compositions, forming a comprehensive protective umbrella during its term.
- Current R&D and commercial efforts in this space are not hindered by this patent, allowing free development of similar compounds.
FAQs
1. What is the core chemical structure protected by U.S. Patent 4,649,151?
The patent covers 4-phenylpiperidine derivatives with specific substituents, designed for analgesic activity.
2. When did the patent expire, and what does this imply?
It expired in March 2004, opening the field for generic manufacturing and further innovation in the class.
3. Are there any ongoing patents related to this compound class?
No active patents currently cover these compounds in the U.S., but related patents may exist in other jurisdictions or for different indications.
4. How does this patent relate to recent opioid developments?
It forms part of the foundational chemical class used in some opioids, influencing both legacy and successor drugs.
5. Can companies now develop new drugs based on these compounds without restriction?
Yes, the patent expiration permits unrestricted development, provided other regulatory or patent considerations are addressed.
References:
- U.S. Patent 4,649,151. (1987). Method for treating pain.
- Patent family and legal records retrieved from the USPTO database.
- Literature on 4-phenylpiperidine derivatives in analgesic drug development.
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