Retractable Sheath Neckable Element for Controlled Drug Delivery
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Solution Overview
Problem
Current localized drug delivery methods face challenges with premature or unintended release of therapeutic agents during tracking and placement, leading to undesirable effects such as particulation and adverse biodistribution, especially when delivering soluble or hydrated agents to specific treatment sites within the body.
Innovation Solution
A medical device with a retractable outer sheath featuring a neckable element that is selectively permeable or impermeable, allowing controlled release of therapeutic agents upon expansion, preventing unwanted release during tracking and ensuring uniform drug distribution at the treatment site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drug delivery device is tracked to a treatment site through the body, then the device can be positioned at the desired location, but premature or unintended release of the therapeutic agent may occur during tracking
Solution Approach 1:
The device employs a nested structure where the drug-coated expandable member is contained within a delivery catheter and further protected by an outer sheath. The drug delivery balloon is inserted inside the catheter, which is then covered by the outer sheath, creating multiple layers of containment that prevent premature release during tracking and positioning
Solution Approach 2:
The outer sheath acts as a flexible protective barrier that completely covers the drug-coated expandable member during delivery. This thin film structure prevents drug release, particulation, and device contact with surrounding tissues during tracking, while allowing the device to maintain its flexible, trackable form
2Reliability
If the device is expanded to deliver the therapeutic agent, then localized drug delivery is achieved, but the device can no longer be retracted or removed
Solution Approach 1:
The device transitions from a dynamic, retractable state during delivery to a static, expanded state during treatment. The outer sheath and expandable member are designed to be flexible and collapsible for easy removal after drug delivery, allowing the system to adapt its mechanical properties based on the operational phase
3Reliability
If a coating comprising a therapeutic agent is applied to the expandable member, then localized drug delivery is enabled, but unintended release may occur due to drug diffusion or washing by blood flow
Solution Approach 1:
The drug-coated expandable member is nested within the outer sheath, creating a protective containment structure. This nested configuration prevents drug diffusion and washing by blood flow during the delivery phase, ensuring the therapeutic agent remains on the device until intentional release at the treatment site
Solution Approach 2:
The outer sheath serves as a protective barrier that prevents drug loss through diffusion or washing by blood flow. This thin film completely covers the drug-coated surface during tracking and positioning, eliminating exposure to bodily fluids that could cause unintended drug release
4Reliability
If the outer sheath is made impermeable to prevent drug release, then particulation is avoided, but the device cannot allow controlled drug release when needed
Solution Approach 1:
The outer sheath transitions from an impermeable, protective state during delivery to a permeable or open state during treatment. This dynamic change in permeability allows the sheath to prevent particulation during tracking while enabling controlled drug release when the device is expanded at the treatment site
Solution Approach 2:
The permeability parameter of the outer sheath is changed from closed/impermeable during delivery to open/permeable during treatment. This parameter change enables the sheath to provide particulation prevention when needed while allowing controlled drug release at the appropriate time
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 device enables controlled, on-demand delivery of therapeutic agents to specific sites within the body, minimizing premature release and ensuring consistent drug distribution, thereby reducing adverse effects and improving treatment efficacy.
Implementation Method 1
when said expandable member is expanded, said neckable element elongates and reduces in width, thereby exposing at least portion of said coating
Implementation Method 2
a flattened tubular form formed from a helically wrapped tape which is flattened and disposed around said expandable member
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The invention is directed to delivery medical devices that enable consistent "on-demand" delivery of therapeutic agents to a vessel. The medical device of the current invention comprises retractable sheath comprising neckable elements. 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 a retractable outer sheath with a selectively permeable microstructure. The design and methods disclosed herein ensures that therapeutic agent delivery occurs essentially only during retraction of the outer sheath, minimizing coating and/or therapeutic agent loss to the bloodstream and providing controlled delivery to the treatment site.