Anionic Polyelectrolyte Coating for Rapid Drug Release
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Solution Overview
Problem
Existing polyelectrolyte coatings for implantable medical devices are ineffective in achieving rapid and consistent release of bioactive drug agents, particularly for applications requiring drug delivery over short spans like drug-coated balloons for peripheral artery disease.
Innovation Solution
A hydrophilic coating system using a surface layer of anionic polyelectrolyte polymer that adsorbs and gradually releases cationic drug agents through ion exchange under saline conditions, allowing for controlled and rapid drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional polyelectrolyte coatings are used for drug delivery, then the coating provides biocompatibility and lubricious properties, but the drug release rate is slow and inconsistent
Solution Approach 1:
The patent changes the chemical parameters of the polyelectrolyte coating by incorporating specific functional groups (carboxylic acid, sulfonic acid, phosphate) that enable ion exchange mechanisms. This parameter change transforms the coating from passive physical adsorption to active ion exchange, achieving rapid and consistent drug release rates while maintaining biocompatibility and lubricious properties.
2Duration of action of moving object
If layer-by-layer polyelectrolyte coatings are used, then drug loading is achieved, but the release occurs over extended periods (days to months) rather than rapidly
Solution Approach 1:
The patent inverts the traditional layer-by-layer construction approach by using a single-layer polyelectrolyte coating with inherent ion exchange capability. Instead of building multiple alternating layers for drug entrapment, the invention uses a functionalized polyelectrolyte layer that actively exchanges ions with the drug, enabling rapid release within minutes rather than extended periods.
3Ease of manufacture
If physical mixture of drug and polymer is used, then drug loading is simple, but release rate depends on solubility and diffusion which are too slow for cardiovascular therapies
Solution Approach 1:
The patent replaces the passive physical mixture mechanism with an active ion exchange mechanism. Instead of relying on drug solubility and diffusion through the polymer matrix, the functionalized polyelectrolyte coating performs ion exchange with the cationic drug, dramatically increasing the drug delivery efficiency to rates suitable for cardiovascular therapies while maintaining ease of manufacture.
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 coating system achieves more rapid and consistent elution rates of drug agents, enabling effective treatment in situ at the intended site, particularly for vascular therapies requiring quick drug release.
Implementation Method 1
A hydrophilic coating system using a surface layer of anionic polyelectrolyte polymer that adsorbs and gradually releases cationic drug agents through ion exchange under saline conditions
Implementation Method 2
a charged polyelectrolyte with anionic functionality capable of adsorbing a cationic drug agent in a measured amount
Data Source
AI summary
The present invention is an implantable medical device comprising (i) a base coat layer having an inner and outer surface, the inner surface of the base coat layer contacting the implantable medical device; (ii) a top-coat layer of a hydrophilic polymer chemically crosslinked and covalently bonded to the outer surface of the base coat layer, the hydrophilic polymer comprising an anionic polyelectrolyte; and (iii) an amount of a hydrophilic cationic drug agent added to the top-coat layer sufficient to provide an effective dosage of the drug agent for delivery to a patient, whereby the hydrophilic cationic drug agent is initially adsorbed into the anionic polyelectrolyte of the top-coat layer and the hydrophilic cationic drug agent having a release rate after the medical device is implanted within a patient's body.