Dissolution Media for Drug Elution from Polymeric Matrices

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Solution Overview

Problem

Current methods for assessing drug elution from polymeric matrices in medical devices are inefficient, particularly for water-soluble drugs like dexamethasone sodium phosphate, and lack effective means to control manufacturing variability and quality assurance, leading to prolonged testing times and potential inconsistencies in elution profiles.

Innovation Solution

A unique dissolution media comprising 20-40% isopropyl alcohol, 0.2-6% matrix swelling agents such as diisopropyl amine, and a phosphate buffer at pH 6-8 is used to enhance the elution of compounds like dexamethasone sodium phosphate from polymeric matrices, allowing for accelerated in-vitro studies and quality control, along with an apparatus to minimize evaporation and ensure accurate sampling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional dissolution media are used for eluting water-soluble drugs from polymeric matrices, then the testing process is simple to perform, but the elution efficiency is poor and testing time is prolonged

Engineering Contradiction:
Improveelution efficiencyVSAvoidtesting time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent modifies the chemical composition parameters of the dissolution media by incorporating specific lower alkanols (20-40%), matrix swelling agents (0.2-6.0%), and buffers (pH 6-8). This parameter optimization enables efficient elution of water-soluble drugs like dexamethasone sodium phosphate from polymeric matrices within a practical testing timeframe, resolving the contradiction between elution efficiency and testing duration.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If accelerated in-vitro elution studies are conducted to reduce testing time, then productivity improves, but manufacturing variability and quality control become more difficult to manage

Engineering Contradiction:
Improvetesting speedVSAvoidelution profile consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a controlled dissolution testing system that monitors elution profiles under standardized conditions (specific media composition, temperature, agitation). This feedback mechanism allows for detection and correction of manufacturing variability, enabling accelerated testing while maintaining quality control and consistency in elution profiles.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

By optimizing and standardizing the dissolution media parameters (lower alkanol concentration, swelling agent concentration, pH buffer), the patent creates a reproducible testing environment that accelerates elution while maintaining consistency. The standardized parameters ensure that manufacturing variability can be detected and controlled.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If matrix swelling agents are added to enhance drug elution, then elution efficiency improves, but the complexity of the dissolution media increases

Engineering Contradiction:
Improveelution rateVSAvoidmedia composition complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces matrix swelling agents at optimized concentrations (0.2-6.0%) to enhance drug elution from polymeric matrices. While this adds a component to the media formulation, the concentration range is carefully controlled to balance effectiveness with manageable complexity. The swelling agents work synergistically with the lower alkanols and buffers to achieve efficient elution without requiring overly complex media compositions.

Inventive Principle:
Principle #35Parameter changes

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 approach enables efficient and controlled elution studies, reducing testing time and variability, and ensuring consistent elution profiles, thereby improving the manufacturing process and quality control of drug-eluting medical devices.

Implementation Method 1

A unique dissolution media comprising 20-40% isopropyl alcohol, 0.2-6% matrix swelling agents such as diisopropyl amine, and a phosphate buffer at pH 6-8 is used to enhance the elution of compounds like dexamethasone sodium phosphate from polymeric matrices

Methodology Applied
Scientific EffectMatrix swelling:

Implementation Method 2

This approach enables efficient and controlled elution studies, reducing testing time and variability, and ensuring consistent elution profiles

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2376181B1Compositions and methods for eluting compounds from matrices
Publication Date: 2015.12.16 MEDTRONIC MINIMED INC
  • EP2376181B1 patent drawingFigure 1
  • EP2376181B1 patent drawingFigure 2
  • EP2376181B1 patent drawingFigure 3

AI summary

Embodiments of the invention provide to apparatuses and media used in drug elution studies and methods for making and using them. One embodiment of the invention is a drug elution method that can be used for in-vitro studies of a matrix impregnated with a compound such as a drug blended polymer matrix. Such methods and materials can be used for example to assess and control the manufacturing process variability of drug eluting implantable devices such as cardiac leads.