Expandable Drug Delivery Device With Sheath
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Solution Overview
Problem
Current localized drug delivery methods face challenges with premature or unintended release of therapeutic agents, leading to unwanted effects and adverse reactions, particularly due to particulation and uneven biodistribution, which can result in ischemia and other complications.
Innovation Solution
An expandable medical device with a hydrophilic coating and a variably permeable outer sheath that prevents drug release until expanded, allowing controlled and consistent delivery of therapeutic agents to specific treatment sites, minimizing particulation and ensuring uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a drug delivery balloon is coated with a drug and carrier matrix for localized delivery, then the therapeutic agent can be delivered to a specific treatment site, but premature or unintended release of the drug may occur during tracking and placement
Solution Approach 1:
The patent employs a nested structure where the drug-coated balloon is inserted within an outer sheath that remains collapsed during delivery. The sheath encapsulates the expanded balloon, preventing drug release during tracking. Upon deployment, the sheath is retracted or expanded away, allowing the coated balloon to expand and deliver the drug at the target site, thus resolving the contradiction between localized delivery and premature release prevention.
Solution Approach 2:
The outer sheath transitions from a collapsed state during delivery to an expanded or retracted state at the treatment site. This dynamic transformation allows the sheath to provide protection during tracking while enabling drug delivery at the destination, addressing the reliability issue of premature release while maintaining the capability for localized therapeutic agent delivery.
2Manufacturing precision
If the drug is released as solubilized molecules for uniform distribution, then uniform drug distribution and avoidance of particulation is achieved, but control over release timing and location becomes more difficult
Solution Approach 1:
The drug is pre-coated onto the balloon surface in solubilized form within the carrier matrix before delivery. This preliminary preparation ensures that the drug is ready for immediate release as solubilized molecules upon balloon expansion, achieving uniform distribution while maintaining control over release timing through the mechanical trigger of balloon expansion at the target site.
Solution Approach 2:
The patent replaces complex mechanical release mechanisms with a simpler system where the balloon expansion itself triggers drug release. The mechanical action of inflating the balloon at the treatment site automatically causes the carrier matrix to release solubilized drug molecules uniformly across the vessel wall, combining ease of operation with controlled release timing and uniform distribution.
3Reliability
If an outer sheath with closed microstructure is used to prevent premature drug release, then unwanted drug release is prevented, but the sheath must be expanded or opened to allow drug transfer at the treatment site
Solution Approach 1:
The outer sheath is constructed as a flexible, thin-walled structure that can be easily collapsed for delivery and expanded or retracted at the treatment site. This flexible design allows the sheath to provide effective protection during tracking while requiring minimal complexity for deployment, as the expansion or retraction can be achieved through standard balloon inflation mechanics already present in the delivery system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables controlled, on-demand delivery of therapeutic agents, reducing premature release and particulation, thereby enhancing treatment efficacy and safety by maintaining drug concentration at the target site and minimizing adverse effects.
Implementation Method 1
During use, the underlying hydrophilic coating becomes hydrated or partially hydrated and facilitates fluid transfer across the outer sheath
Implementation Method 2
said outer sheath's closed microstructure in the unexpanded state prevents unwanted, premature release of said therapeutic agent
Implementation Method 3
Upon expansion, the outer sheath disposed over the expandable member or structural layer transforms from a closed microstructure to an open microstructure allowing the hydrated or partially hydrated coating and said therapeutic agent to be transferred (e.g. pushed) outward
Data Source
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AI summary
The invention is directed to eluting medical devices that enable consistent "on-demand" delivery of therapeutic agents to a vessel. The medical device of the current invention comprises an expandable member, a hydrophilic coating comprising at least one therapeutic agent about the expandable member or structural layer and an outer sheath with a variably permeable microstructure. The design and methods disclosed herein ensures that therapeutic agent delivery occurs essentially only during expansion of the expandable member, minimizing coating and/or therapeutic agent loss to the bloodstream and providing controlled delivery to the treatment site.