Segmented Drug-Coated Stent Coating for Controlled Elution

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Solution Overview

Problem

Conventional implants, particularly stents, face challenges with delayed integration into the vessel wall due to the absence of a polymer-based elution matrix, leading to long-term inflammatory reactions and increased risk of stent thrombosis, necessitating systemic anticoagulant therapy.

Innovation Solution

A structured coating with alternating strips or island patterns of active substance and auxiliary substance areas, where the auxiliary substance dissolves post-implantation to reveal the active substance, enhancing elution and preventing abrasion or washing out, applied abluminally to the implant surface with a thickness of 1 nm to 100 μm.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If no polymer-based elution matrix is used, then long-term inflammatory reactions are reduced, but delayed integration into the vessel wall occurs and initial elution characteristics are poor

Engineering Contradiction:
Improveinflammatory reactionsVSAvoidintegration into vessel wall
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The coating is segmented into multiple functional layers: a polymer-based elution matrix layer containing active substance, and an auxiliary substance layer. This segmentation allows the active substance to be released through controlled elution while the auxiliary substance provides structural support during implantation, resolving the contradiction between reducing inflammation and ensuring reliable integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary substance is applied preliminarily to cover the implant surface before the active substance is introduced. This preliminary action ensures that the implant surface is protected and structured in advance, enabling immediate elution of the active substance while maintaining structural integrity during the critical initial period after implantation.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If active substance is applied directly without polymer-based elution matrix, then long-term inflammatory reactions are reduced, but initial elution characteristics are poor

Engineering Contradiction:
Improveinflammatory reactionsVSAvoidinitial elution characteristics
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The physical and chemical parameters of the coating are changed by introducing a polymer-based elution matrix with specific degradation characteristics. This matrix controls the release rate of the active substance, ensuring rapid initial elution to achieve therapeutic effect while the polymer degrades over time to reduce long-term inflammatory reactions.

Inventive Principle:
Principle #35Parameter changes

3Strength

If structured coating with auxiliary substance is applied, then abrasion protection is improved, but coating complexity increases

Engineering Contradiction:
Improveabrasion resistanceVSAvoidcoating structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The coating is designed as a composite material system combining a polymer-based elution matrix with an auxiliary substance. This composite structure provides both the structural strength and abrasion resistance needed during implantation while allowing controlled elution of the active substance. The composite nature resolves the contradiction by integrating multiple functions into a unified coating system.

Inventive Principle:
Principle #40Composite materials

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

Accelerates ingrowth behavior of the stent into the vessel wall, reducing inflammatory reactions and the risk of thrombosis by improving initial elution characteristics and protecting the structure during implantation and fixation.

Implementation Method 1

the auxiliary substance dissolves immediately after implantation

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP2462962B1Implant comprising an active-agent-containing coating covering the implant at least in sections
Publication Date: 2017.09.20 BIOTRONIK AG
  • EP2462962B1 patent drawingFigure 1A~1D

AI summary

The invention relates to an implant with a drug-containing coating that covers at least part of the implant. The coating consists of at least two sub-areas, a first sub-area of ​​which contains the at least one active ingredient and a second sub-area of ​​which consists of an excipient.