Sol-Gel Coated Expandable Devices for Drug Elution
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Solution Overview
Problem
Existing drug eluting medical devices face challenges such as long inflation times, high drug washout, and inadequate adhesion of bioactive materials to expandable members, particularly in aqueous environments like the human body, leading to ischemic events and inefficient drug release.
Innovation Solution
The development of drug eluting expandable devices coated with a sol-gel technology that includes an adjustable matrix composition of sol-gel materials and bioactive agents, allowing for robust adhesion, controlled release rates, and minimized washout, while enabling perfusion during deployment to reduce ischemic events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods are used to apply bioactive materials to expandable members, then the coating process is simple, but the adhesion of bioactive materials is inadequate particularly in aqueous environments
Solution Approach 1:
The patent employs a composite coating system consisting of silane coupling agents (such as γ-aminopropyltriethoxysilane) combined with bioactive materials embedded in a porous matrix. The silane layer chemically bonds to both the expandable member surface and the bioactive material, creating a composite structure that significantly improves adhesion in aqueous environments while maintaining a manageable coating process.
Solution Approach 2:
The silane coupling agent acts as an intermediary layer between the expandable member surface and the bioactive materials. This intermediary forms strong chemical bonds with both substrates, solving the adhesion problem without requiring complex multi-step coating processes. The silane layer serves as a molecular bridge that enhances interfacial bonding.
2Reliability
If drug eluting devices are deployed without perfusion capability, then the device structure is simpler, but ischemic events occur during deployment
Solution Approach 1:
The device is segmented into multiple functional zones: a proximal perfusion zone with pores allowing blood flow, a mid-section drug delivery zone, and a distal treatment zone. This segmentation enables simultaneous perfusion function and drug delivery, reducing ischemic events while maintaining reasonable structural complexity through zoned functionality.
Solution Approach 2:
The expandable member incorporates porous sections with controlled pore sizes that allow blood perfusion during device deployment. These porous regions enable physiological fluid flow through the device structure, preventing ischemic events while the overall device maintains a relatively simple expandable balloon or stent configuration.
3Productivity
If rapid drug release is achieved, then the treatment effectiveness increases, but drug washout increases leading to inefficiency
Solution Approach 1:
The bioactive materials are embedded in a porous sol-gel matrix with controlled pore size and distribution. This porous structure enables sustained drug release by providing a reservoir that gradually elutes the drug, achieving effective treatment while minimizing washout. The porous matrix acts as a controlled-release gateway, balancing release rate with retention.
Solution Approach 2:
The patent utilizes parameter changes in the sol-gel matrix composition, including varying porosity, cross-linking density, and hydrophilicity, to control drug release kinetics. By adjusting these parameters, the system achieves optimized release profiles that provide rapid initial efficacy while preventing excessive washout, thereby balancing productivity and substance retention.
4Quantity of substance
If thick coating layers are applied to ensure adequate drug loading, then the drug capacity increases, but device flexibility and profile are compromised
Solution Approach 1:
The coating utilizes a highly porous sol-gel matrix structure that provides large surface area and high drug loading capacity within a thin layer. The porous architecture allows substantial drug incorporation without requiring thick coating layers, thereby maintaining device flexibility and profile while achieving adequate drug capacity through increased surface area-to-volume ratio.
Solution Approach 2:
The sol-gel coating forms a thin, flexible film on the expandable member surface. This thin film structure, enabled by the sol-gel processing method, provides adequate drug loading capacity through its porous matrix while maintaining the flexibility and conformability of the underlying device, avoiding profile compromise that would result from thick rigid coatings.
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 sol-gel coated devices provide improved adhesion and controlled release of bioactive agents, reducing ischemic events and drug washout, and maintaining device flexibility and profile, effectively treating intravascular and endolumenal diseases.
Implementation Method 1
Sol-gel synthesis of materials offers several advantages over other synthetic routes. These advantages can include mild processing conditions (low temperature, low pressure, mild pH), inexpensive raw materials, no need for vacuum processing or other expensive equipment, and a high level of control over the resulting structure
Implementation Method 2
The in situ formed porous sol-gel matrix allows for adjustable release rates through diffusion and erosion
Implementation Method 3
The in situ formed porous sol-gel matrix allows for adjustable release rates through diffusion and erosion
Implementation Method 4
The use of a silane-based sol-gel allows for robust adhesion to the expandable member
Implementation Method 5
The in situ formed porous sol-gel matrix allows for adjustable release rates through diffusion and erosion
Data Source
AI summary
The present disclosure relates to drug eluting devices, and their uses. The drug eluting devices can allow for perfusion during deployment. The coatings the may contain bioactive materials which elute once deployed in a patient and can have anti-proliferative, anti-inflammation, or anti-thrombotic effects. Sol gel technology can be used to coat the devices.