Bioabsorbable Stent Laminate Coatings for Drug Delivery
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Solution Overview
Problem
Current drug-eluting stents face challenges such as residual physical, chemical, and therapeutic legacy in the vessel, thickness issues for deployment flexibility, access to small vessels, and minimized vessel wall intrusion.
Innovation Solution
A stent with a laminate coating comprising bioabsorbable polymers and pharmaceutical agents, particularly rapamycin, in crystalline form, is developed, where the coating is designed to minimize contact with the vessel wall and optimize deployment by varying the thickness and distribution of the polymer and pharmaceutical agent layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent coating thickness is increased to provide sufficient drug delivery, then therapeutic efficacy is improved, but deployment flexibility and access to small vessels deteriorate
Solution Approach 1:
The coating is divided into multiple discrete layers including polymer layers and pharmaceutical agent layers, with each layer serving a specific function. This segmentation allows optimization of each layer's thickness and properties independently, providing sufficient drug delivery while maintaining overall coating flexibility for deployment in small vessels.
Solution Approach 2:
The coating uses composite materials consisting of bioabsorbable polymers and pharmaceutical agents in crystalline form. This composite structure provides controlled drug release properties while the polymer matrix maintains mechanical flexibility, resolving the contradiction between therapeutic efficacy and deployment flexibility.
2Reliability
If the stent coating thickness is increased to ensure adequate drug supply, then therapeutic outcomes are improved, but vessel wall intrusion increases
Solution Approach 1:
The coating provides localized drug delivery through the laminate structure, where pharmaceutical agent layers are positioned to release drugs directly at the vessel wall interface. This localized approach ensures adequate drug supply to treat restenosis while minimizing bulk material intrusion into the vessel wall.
Solution Approach 2:
The polymer layers contain porosity that facilitates drug diffusion to the vessel wall without requiring thick coating layers. The porous structure allows adequate drug supply through controlled diffusion paths, reducing the need for increased coating thickness and thereby minimizing vessel wall intrusion.
3Reliability
If conventional drug-eluting stents are used, then restenosis is treated, but physical, chemical and therapeutic legacy remains in the vessel
Solution Approach 1:
The coating uses bioabsorbable polymers that degrade and are absorbed by the body over time, allowing the coating to perform its drug delivery function and then naturally disappear. This eliminates the permanent foreign body legacy associated with conventional stents, while still providing effective restenosis treatment through controlled drug release during the absorption period.
Solution Approach 2:
The polymer material undergoes parameter changes as it degrades from intact coating to absorbed byproducts. This transformation allows the coating to maintain structural integrity during drug delivery, then progressively break down and eliminate itself, removing therapeutic legacy while maintaining restenosis treatment efficacy.
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 reduces residual effects, enhances deployment flexibility, and ensures controlled drug delivery, minimizing vessel wall intrusion and optimizing therapeutic outcomes.
Implementation Method 1
bioabsorbable polymer
Implementation Method 2
bioabsorbable polymer
Implementation Method 3
pharmaceutical agent in powder form onto a substrate
Implementation Method 4
controlled drug delivery
Data Source
AI summary
Provided herein is a device comprising: a. stent; b. a plurality of layers on said stent framework to form said device; wherein at least one of said layers comprises a bioabsorbable polymer and at least one of said layers comprises one or more active agents; wherein at least part of the active agent is in crystalline form.