Bioerodable Polymeric Layer for Drug-Eluting Stents

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Solution Overview

Problem

Biostable polymer-based medical devices, such as drug-eluting stents, can cause long-term foreign body effects and late stent thrombosis due to their non-biodegradable nature, necessitating the development of bioerodable alternatives that can modulate therapeutic agent release and mechanical properties.

Innovation Solution

A bioerodable polymeric layer comprising biodegradable polymers, therapeutic agents, and plasticizers is applied to a medical device substrate, allowing for controlled bioerosion and enhanced mechanical properties, which can influence the release behavior and degradation rate of the therapeutic agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If biostable polymer coatings are used for drug-eluting stents, then controlled drug release is achieved, but long-term foreign body effects and late stent thrombosis occur

Engineering Contradiction:

Improvecontrolled drug releaseVSAvoidforeign body effects and late stent thrombosis

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of polymer stability from biostable to bioerodable. The bioerodable polymer coating gradually degrades over time, allowing complete elimination of foreign body effects and prevention of late stent thrombosis while maintaining controlled drug release during the critical healing period

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material composition within the bioerodable polymer coating, combining biodegradable polymer matrices with therapeutic agents and plasticizers. This composite structure enables simultaneous achievement of controlled drug release, mechanical property enhancement, and gradual bioerosion

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If biodegradable polymers are used to eliminate foreign body effects, then long-term safety is improved, but ability to modulate therapeutic agent release and mechanical properties is reduced

Engineering Contradiction:

Improveforeign body effectsVSAvoidability to modulate therapeutic agent release and mechanical properties

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent utilizes parameter changes within the bioerodable polymer system, specifically incorporating plasticizers to modify glass transition temperature, degradation rate, and mechanical properties. This allows tuning of drug release kinetics and coating flexibility while maintaining bioerodibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymeric layer combining biodegradable polymer, therapeutic agent, and plasticizer. This composite formulation provides versatile control over drug release behavior, mechanical properties, and erosion rate, overcoming the limitations of simple biodegradable polymers

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If bioerodable polymeric layer with plasticizers is applied, then mechanical properties and drug release control are enhanced, but device complexity increases

Engineering Contradiction:

Improvemechanical properties and drug release controlVSAvoidpolymeric layer composition

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated bioerodable polymeric layer. The coating simultaneously provides drug delivery, mechanical property enhancement through plasticizers, and controlled bioerosion, eliminating the need for separate functional layers and simplifying the overall device structure

Inventive Principle:

Principle #5Merging (Combining)

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 bioerodable layer effectively reduces long-term foreign body effects, modulates therapeutic agent release, and improves mechanical properties, such as flexibility and resistance to cracking, while ensuring complete bioerosion of the polymer mass over time.

Implementation Method 1

the addition of plasticizers to biodegradable polymers... can have a profound effect on a number of important parameters including... the glass transition temperature

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

bioerodable polymeric layer... that contains (i) one or more biodegradable polymers

Methodology Applied

Scientific EffectBioerosion:

Implementation Method 3

because they erode over time, biodegradable polymers may reduce or eliminate long term effects

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Implementation Method 4

enhanced ability to modulate/influence one or more of the following: a) therapeutic agent release behavior of the bioerodable layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS9248219B2Medical devices having bioerodable layers for the release of therapeutic agents

Publication Date: 2016.02.02 BOSTON SCIENTIFIC SCIMED INC

AI summary

According to an aspect of the present invention, medical devices are provided which comprise: (a) a substrate and (b) bioerodable polymeric layer over the substrate that contains (i) one or more biodegradable polymers, (ii) one or more therapeutic agents, and (iii) one or more plasticizers.