Solvent Pretreatment for Therapeutic Agent Embedding

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Solution Overview

Problem

Current methods for loading therapeutic agents into polymeric regions of medical devices are inefficient, often resulting in incomplete embedding of particles and suboptimal release mechanisms, which can lead to inadequate dosing and side effects.

Innovation Solution

A method involving pretreatment of the polymeric region with a solvent system followed by impacting therapeutic-agent-containing particles at effective velocities to embed them within the polymeric region, optimizing depth and amount of embedding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If therapeutic agent particles are loaded into polymeric region using conventional dissolution and diffusion methods, then the loading process is simple, but the embedding completeness and dosing efficacy are insufficient

Engineering Contradiction:
Improveparticle embedding completenessVSAvoidloading process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The polymeric region is pretreated with a solvent system before particle loading to modify its surface properties and increase permeability. This preliminary action prepares the polymeric region to receive and embed particles more effectively, resolving the contradiction by adding a preparatory step that improves embedding completeness without requiring complex loading mechanisms

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The solvent treatment changes physical and chemical parameters of the polymeric region surface, such as surface energy, permeability, and molecular chain mobility. These parameter changes enable better particle embedding and controlled release, improving manufacturing precision while maintaining process simplicity through chemical modification rather than mechanical complexity

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If solvent-only spray is used to soften polymeric region surface, then particle embedding is improved, but solvent evaporation and safety concerns increase

Engineering Contradiction:
Improveparticle embedding depthVSAvoidsolvent evaporation and safety risks
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A water-soluble polymer coating is introduced as an intermediary layer between the solvent system and the polymeric region. This intermediary absorbs the solvent, preventing direct contact between harsh solvents and the device, while still allowing the solvent to perform its softening function. This resolves the contradiction by mediating the interaction, improving embedding depth while reducing harmful solvent evaporation and safety risks

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The water-soluble polymer coating acts as a temporary, disposable intermediary that is applied only during the loading process and then washed away. This short-living coating enables effective particle embedding without the need for persistent solvent exposure, resolving the contradiction by using a temporary protective layer that improves embedding while eliminating ongoing safety concerns

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If high velocity impact is used to embed particles, then loading efficiency increases, but particle distribution uniformity decreases

Engineering Contradiction:
Improveloading efficiencyVSAvoidparticle distribution uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The solvent treatment creates local quality changes in the polymeric region surface, generating zones of different permeability and surface energy. This allows high-velocity particle impact to be effective in specific areas while maintaining uniform distribution through controlled local variations in the polymeric region properties, resolving the contradiction by creating spatially varying conditions that favor both efficiency and uniformity

Inventive Principle:
Principle #3Local quality

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

This method enhances the efficient loading and controlled release of therapeutic agents in medical devices, reducing side effects and improving dosing efficacy by optimizing particle embedding and release mechanisms.

Implementation Method 1

pretreating the polymeric region with a solvent system... effective for partially solvating and softening such polymers

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

the surface of a freshly painted panel is first softened using a solvent-only spray

Methodology Applied
Scientific EffectSoftening:

Implementation Method 3

impacting therapeutic-agent-containing particles into the pretreated polymeric region at a velocity that is effective to at least partially embed the particles

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 4

embed the particles within the pretreated polymeric region

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 5

the therapeutic agent is loaded (e.g., by leaching/diffusion) into the same

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 6

loaded (e.g., by leaching/diffusion) into the same

Methodology Applied
Scientific EffectLeaching:

Data Source

PatentUS8158151B2Solvent-assisted loading of therapeutic agents
Publication Date: 2012.04.17 BOSTON SCIENTIFIC SCIMED INC

AI summary

Methods are provided for loading polymeric regions of medical devices with therapeutic agents. In these methods, a polymeric region of a medical device is first pretreated with a solvent system. Subsequently, therapeutic-agent-containing particles are impacted into the pretreated polymeric region at a velocity that is effective to at least partially embed the particles within the pretreated polymeric region. The pretreatment step parameters (e.g., the particular solvent system employed, amount of time that the solvent system contacts the polymeric region, etc.) are typically selected such that the surface tack of the polymeric region is increased. Consequently, the depth, the amount, or both the depth and the amount of the particles that become at least partially embedded in the polymeric region is/are typically increased, relative to what would be achieved in the absence of the pretreatment step. Also provided are medical devices made by such methods.