Drug-Eluting Coating on Modified Medical Device Surface

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Solution Overview

Problem

Existing medical devices, such as balloon catheters, face challenges in delivering therapeutic agents effectively to target tissues due to issues like premature drug release, adhesion problems, and limited long-term efficacy, which complicates the treatment of vascular and nonvascular diseases like restenosis.

Innovation Solution

A medical device with a modified exterior surface that undergoes surface modification to lower its free energy, followed by a drug-releasing coating layer containing a hydrophobic therapeutic agent and additives, which includes a plasma-polymerized intermediate layer with etched depots to enhance drug retention and release kinetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drug adheres too strongly to the device, then the device can be withdrawn before drug release, but the drug cannot be released and absorbed by tissues at the target site

Engineering Contradiction:

Improvedrug retention on deviceVSAvoiddrug release rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies a preliminary coating treatment to the device surface that prepares it for controlled drug adhesion. The coating is applied in advance during manufacturing, creating a surface that will hold the drug during delivery but release it upon contact with tissue, resolving the contradiction between retention and release.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the surface energy parameters of the device coating to optimize drug interaction. By adjusting coating thickness, composition, and surface properties, the device achieves optimal drug adhesion strength that allows both secure retention during delivery and effective release at the target site.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the coating thickness is increased to improve drug retention, then drug adherence improves, but the device profile increases leading to poor trackability and deliverability

Engineering Contradiction:

Improvedrug retentionVSAvoiddevice profile

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent employs a thin film coating on the device surface that provides sufficient drug retention while maintaining device flexibility and low profile. The thin coating layer is engineered to be thin enough not to compromise device trackability but thick enough to retain and deliver the therapeutic agent effectively.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If functional layers are applied to increase drug adhesion, then drug retention improves, but long-term efficacy at the target site decreases

Engineering Contradiction:

Improvedrug adhesionVSAvoidlong-term drug efficacy

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent uses a preliminary surface treatment that prepares the device for optimal drug delivery. This preliminary coating creates conditions for initial drug adhesion during delivery while being designed to facilitate subsequent drug release and tissue absorption, ensuring both retention during transport and long-term efficacy at the target site.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a coating layer as an intermediary between the device and the drug. This intermediate coating serves dual functions: providing sufficient adhesion for drug retention during device delivery and enabling controlled release and tissue absorption at the target site, thereby maintaining long-term efficacy.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables increased initial uptake and prolonged long-term efficacy of therapeutic agents, maintaining effective drug concentration at the target site for up to 14 days or more, improving treatment outcomes for conditions like stenosis and restenosis.

Implementation Method 1

an exterior surface of the medical device is subjected to a surface modification to lower the surface free energy of the exterior surface before a drug-releasing coating is applied over the exterior surface

Methodology Applied

Scientific EffectSurface modification:

Implementation Method 2

The modified exterior surface includes a plasma-polymerized intermediate layer

Methodology Applied

Scientific EffectPlasma polymerization: Photopolymerisation

Data Source

PatentUS20220176084A1Medical device with drug-eluting coating on modified device surface

Publication Date: 2022.06.09 BARD PERIPHERAL VASCULAR INC

AI summary

Medical devices such as stents, stent grafts, and balloon catheters include a coating layer applied over a modified exterior surface of the medical device. The modified exterior surface comprises an exterior surface of the medical device subjected to a surface modification that decreases a surface free energy of the exterior surface before application of the coating layer an exterior surface. The coating layer comprises a hydrophobic therapeutic agent and at least one additive. The modified exterior surface may affect the release kinetics of the drug from the device, the crystallinity of the drug layer, the surface morphology of the coating and particle shape, or the particle size of drug of a therapeutic layer in the coating layer. For example, the effects caused by the modified exterior surface may increase the retention time and amount of therapeutic agent in tissue.