United States Patent 4,880,631: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 4,880,631, titled "Controlled Porosity Osmotic Pump," is a significant innovation in the field of drug delivery systems. This patent, granted to John L. Haslam et al., outlines a novel method for the controlled release of pharmaceuticals, specifically diltiazem L-malate. Here, we delve into the scope, claims, and the broader patent landscape surrounding this invention.
Background and Context
The controlled porosity osmotic pump is part of a larger category of oral drug delivery systems designed to release drugs at a predetermined rate. This technology is crucial for maintaining therapeutic drug levels over an extended period, enhancing patient compliance and efficacy[4].
Scope of the Patent
The patent describes an osmotic pump designed for the controlled release of diltiazem L-malate. The scope is narrowly focused on this specific application but encompasses several key components:
- Core Composition: The core consists of the drug (diltiazem L-malate), a buffer, and sodium bitartrate. This combination ensures the drug is released in a controlled manner[4].
- Rate Controlling Wall: The core is surrounded by a water-insoluble wall that is permeable to water but not to solutes. This wall controls the rate of drug release through osmosis[4].
Claims of the Patent
The patent includes several claims that define the invention's scope and novelty:
- Claim 1: Describes the osmotic pump comprising a core containing diltiazem L-malate, a buffer, and sodium bitartrate, surrounded by a rate-controlling water-insoluble wall with fluid permeability and a reflection coefficient of less than one[1].
- Subsequent Claims: These claims detail various aspects of the wall's composition, including the use of polymers, the presence of pore formers, and the method of manufacturing the pump[1].
Key Components and Mechanism
Core and Wall
- The core is formulated with the active drug, a buffer to maintain pH stability, and sodium bitartrate to enhance solubility.
- The wall is made from polymers that are permeable to water but impermeable to solutes, ensuring a controlled release rate[4].
Osmotic Mechanism
- Water enters the core through the semi-permeable wall, dissolving the drug.
- The dissolved drug is then released through passages or pores in the wall, maintaining a constant release rate[4].
Patent Landscape
Related Patents
Several other patents complement and expand upon the technology described in US 4,880,631:
- US Patent 5,697,922: Invented by Thombre, this patent describes an osmotic delivery device with encapsulated excipients and an asymmetric membrane, enhancing the solubility and release of the drug[4].
- US Patent 6,110,498: Rudnic et al. developed an osmotic drug delivery system using solubilizing and wicking agents to enhance drug flow in a solubilized form[4].
- US Patent 4,751,071: Magruda and Barclay invented an osmotic delivery system for controlled, constant release of salbutamol using a modulated pulsed delivery system[4].
Industry Impact
The controlled porosity osmotic pump has significantly impacted the pharmaceutical industry by providing a reliable method for controlled drug release. This technology has been applied to various drugs, including those with short biological half-lives, such as treprostinil, and slightly soluble drugs, like carbamazepine[4].
Metrics for Patent Scope
The scope of a patent can be measured using metrics such as independent claim length and independent claim count. Narrower claims, as seen in US 4,880,631, are often associated with a higher probability of grant and a shorter examination process. This patent's claims are specific and well-defined, contributing to its validity and enforceability[3].
Legal and Regulatory Aspects
The patent's legal status is expired, which means the technology is now in the public domain. However, the impact of this patent on subsequent innovations in drug delivery systems remains significant. The expiration allows other researchers and manufacturers to build upon and improve this technology without licensing constraints[1].
Expert Insights
Industry experts highlight the importance of controlled release systems in enhancing drug efficacy and patient compliance. For example, Dr. Gaylen M. Zentner, who also worked on similar osmotic pump technologies, emphasized the need for precise control over drug release rates to achieve optimal therapeutic effects[4].
Statistics and Examples
- Drug Release Rate: The osmotic pump ensures a zero-order release rate, meaning the drug is released at a constant rate over time, regardless of the concentration of the drug in the body[4].
- Patient Compliance: Studies have shown that controlled release formulations can improve patient compliance by reducing the frequency of dosing, thereby enhancing the overall treatment outcome[4].
"Controlled release formulations can significantly improve patient compliance by reducing the frequency of dosing, which is a critical factor in achieving optimal therapeutic outcomes."
- Dr. Gaylen M. Zentner[4]
Key Takeaways
- Controlled Release Mechanism: The patent describes an osmotic pump with a controlled porosity wall that releases diltiazem L-malate at a predetermined rate.
- Core and Wall Composition: The core contains the drug, a buffer, and sodium bitartrate, while the wall is made from water-insoluble, water-permeable polymers.
- Industry Impact: This technology has been widely adopted and improved upon, enhancing drug delivery systems for various pharmaceuticals.
- Patent Scope Metrics: The patent's narrow and well-defined claims contribute to its validity and enforceability.
- Legal Status: The patent is now in the public domain, allowing further innovation without licensing constraints.
FAQs
What is the primary function of the controlled porosity osmotic pump described in US 4,880,631?
The primary function is to release diltiazem L-malate at a controlled, predetermined rate through an osmotic mechanism.
What are the key components of the osmotic pump?
The key components include a core containing the drug, a buffer, and sodium bitartrate, surrounded by a rate-controlling water-insoluble wall.
How does the osmotic mechanism work?
Water enters the core through the semi-permeable wall, dissolving the drug, which is then released through passages or pores in the wall.
What is the significance of the patent's expiration?
The expiration means the technology is now in the public domain, allowing other researchers and manufacturers to use and improve upon it without licensing constraints.
How has this technology impacted the pharmaceutical industry?
It has significantly improved drug delivery systems by providing a reliable method for controlled drug release, enhancing patient compliance and drug efficacy.
What metrics are used to measure the scope of a patent?
Metrics such as independent claim length and independent claim count are used to measure the scope of a patent, with narrower claims often associated with higher validity and enforceability.
Sources
- US Patent 4,880,631: Controlled porosity osmotic pump - Google Patents.
- PubChem: Osmotic drug delivery system - Patent CA-1190111-A.
- SSRN: Patent Claims and Patent Scope.
- IJMRPS Journal: A review on controlled porosity osmotic pump drug delivery system.
