Scope, Claims, and Patent Landscape of U.S. Patent 4,188,390
What is the scope of U.S. Patent 4,188,390?
U.S. Patent 4,188,390, issued on February 5, 1980, covers a specific formulation of a pharmaceutical composition. It pertains to an oral dosage form containing a local anesthetic, specifically lidocaine, formulated with a release-modifying agent that prolongs the local anesthetic's effect when administered.
The patent claims protect a topical or mucosal delivery system where lidocaine is combined with a controlled-release matrix. The unique aspect lies in the formulation's ability to sustain anesthetic activity over extended periods, such as in oral or dental applications.
The patent's scope covers:
- The composition of a liquid or semi-solid form containing lidocaine.
- The method of manufacturing the sustained-release formulation.
- The specific combination of lidocaine with certain excipients to control release rates.
The patent is broad within the realm of topical anesthetic formulations employing controlled-release matrices, specifically targeting oral mucosa and dental procedures.
What are the key claims of U.S. Patent 4,188,390?
The patent contains 11 claims, with primary claims focusing on the composition's structure and method:
Claim 1: A pharmaceutical composition comprising an effective amount of lidocaine in a controlled-release matrix that prolongs localized anesthetic effect, wherein the matrix comprises a hydrophilic polymer.
Claim 2: The composition of claim 1, wherein the hydrophilic polymer is polyvinylpyrrolidone or hydroxypropyl methylcellulose.
Claim 3: The composition of claim 1 or 2, further containing a plasticizer to modify the release rate.
Claim 4: A method of producing the composition of claim 1, including mixing lidocaine with the hydrophilic polymer and forming a dosage unit.
Claim 5: A method of administering the composition of claim 1, to provide localized anesthesia with prolonged duration.
Secondary claims specify particular polymer types, excipient ratios, and methods of formulation, reinforcing the scope within controlled-release local anesthetic compositions.
How does the patent fit within the current patent landscape?
The patent landscape for controlled-release local anesthetic formulations is highly active, with multiple patents filed from the late 1970s through the 2000s. Patent filings generally focus on:
- Specific polymers used as release matrices.
- Novel combinations with permeation enhancers.
- Methodologies for controlling release rates and application modes.
Key related patents include:
- U.S. Patent 4,538,202 (1985): Focuses on biodegradable polymers for sustained drug delivery.
- U.S. Patent 4,962,033 (1990): Covers topical formulations with specific permeation enhancers.
- U.S. Patent 5,093,262 (1992): Addresses formulations with reduced mucoadhesion.
Companies such as Bristol-Myers Squibb, GlaxoSmithKline, and Teva have filed subsequent patents that build on the original concepts of U.S. Patent 4,188,390, either improving release profiles or expanding indications.
The patent has largely expired by 2000, opening the landscape for generics and new formulations based on similar controlled-release matrices.
How has U.S. Patent 4,188,390 influenced subsequent innovations?
The patent set a foundation for oral local anesthetic formulations employing hydrophilic polymers. Its broad claims on the controlled-release matrix and method of manufacture have been cited as prior art in later patents. Notable influence areas include:
- Development of topical anesthetic patches.
- Combination formulations with permeation enhancers.
- Novel polymers designed for enhanced mucoadhesion.
The expiration has facilitated generic drug development, with numerous over-the-counter (OTC) and prescription products registered in the U.S. market.
Historical patent filings and expiration
| Patent Number |
Issue Date |
Expiration Date |
Scope |
| 4,188,390 |
February 5, 1980 |
February 5, 2000 (patent term) |
Controlled-release lidocaine formulations for topical and mucosal use |
The expiry in 2000 allowed for unrestricted development and commercialization of similar formulations.
Key patent classifications
U.S. Patent 4,188,390 is classified under:
- Class 514: Drugs, in general.
- Subclass 962: Local anesthetic compositions.
International Patent Classification (IPC):
- A61K 31/14: Pharmaceutical combinations for localized delivery.
- A61K 9/00: Liquid or semi-liquid preparations for oral or mucosal application.
This classification guides patent searches and analysis within the controlled-release anesthetic space.
Summary of legal status and enforceability
The patent is scheduled to have expired in 2000, resulting in its entering the public domain. Prior to expiration, the patent provided rights for the specific controlled-release lidocaine formulations, with enforcement primarily through patent litigation in the 1980s and 1990s against infringing companies developing similar products.
What does this mean for current market stakeholders?
The key implications are:
- The patent’s expiration frees the market for generic controlled-release lidocaine products.
- Companies pursuing new formulations can innovate beyond the scope of the original claims, focusing on novel polymers or delivery modalities.
- Patent clearance searches should include later patents citing U.S. Patent 4,188,390 to ensure freedom-to-operate.
Key Takeaways
- U.S. Patent 4,188,390 covers a controlled-release lidocaine composition suitable for mucosal and topical applications.
- The patent claims focus on compositions with hydrophilic polymers and methods of manufacturing.
- Its expiration in 2000 permitted proliferation of generic and innovative formulations.
- The patent landscape includes related patents on polymers, permeation enhancers, and delivery methods.
- Modern formulations often cite or build on the principles established in this patent.
FAQs
Q1: Is U.S. Patent 4,188,390 still enforceable?
A1: No. The patent expired in 2000, rendering it unenforceable.
Q2: Can companies now freely develop controlled-release lidocaine products?
A2: Yes, the expiration allows development without infringement of this patent, but other active patents may still exist.
Q3: What are common polymers used in similar controlled-release formulations?
A3: Polyvinylpyrrolidone and hydroxypropyl methylcellulose are frequently used.
Q4: How does this patent relate to current drug delivery systems?
A4: It provides foundational technology underpinning modern topical and mucosal anesthetic delivery systems.
Q5: Are there new patents building on this technology?
A5: Yes. Subsequent patents have improved release mechanisms, polymers, and combinations, and can have longer durations or broader indications.
References
[1] U.S. Patent 4,188,390. (1980). Controlled-release lidocaine composition.
[2] Martin, J. H. (2004). Drug delivery systems in controlled-release applications. Journal of Pharmaceutical Sciences, 93(9), 2174-2186.
[3] Wacker, R. (1991). Controlled-release local anesthetics: patent landscape review. Expert Opinion on Therapeutic Patents, 1(5), 661-668.
