Cationic Drug Particulates for Dynamic Surface Transfer
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Solution Overview
Problem
Current drug delivery systems from implanted medical devices face challenges in effectively transferring drugs to target tissues, as existing polymer coatings may not be suitable for dynamic surfaces, leading to insufficient drug release or unintended site delivery.
Innovation Solution
A bioactive agent delivery composition comprising bioactive agent-containing particulates with a core particle coated by a first biocompatible polymer and a second polymer with negatively charged groups, where a cationic agent is associated to provide a positive zeta-potential, facilitating bulk transfer to tissues when associated with medical devices like balloon catheters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer coatings are used for drug delivery on static surfaces, then durable coating is achieved, but the coating is not suitable for dynamic surfaces leading to insufficient drug release
Solution Approach 1:
The invention applies a multi-layer polymer coating system where the inner layer provides durable drug entrapment while the outer layer provides adaptability to dynamic surfaces. The specific combination of polymers (e.g., polyesters in inner layer, polyacrylic acid in outer layer) creates a system that can adapt to surface expansion/contraction while maintaining structural integrity and drug release capability.
Solution Approach 2:
The invention uses composite material structure with multiple polymer layers having different properties. The inner layer (e.g., poly(lactic-co-glycolic acid)) provides mechanical stability and controlled drug release, while the outer layer (e.g., polyacrylic acid with negative charge) provides surface adaptability and facilitates drug transfer to tissue through electrostatic interactions.
2Productivity
If drug is released from polymer matrix, then drug delivery is achieved, but drug may be released at or move to a site other than the target tissue
Solution Approach 1:
The invention introduces a charged polymer layer (e.g., polyacrylic acid with negative charge) as an intermediary between the drug-containing core and the target tissue. This intermediary layer facilitates selective drug transfer to the target tissue through electrostatic interactions with positively charged cell membranes, preventing drug release at unintended sites while maintaining efficient drug delivery.
Solution Approach 2:
The invention creates local quality differences through the multi-layer structure where the inner layer provides controlled drug release and the outer charged layer provides site-specific targeting capability. This spatial differentiation of functional properties ensures drug is released and transferred precisely at the target tissue location rather than diffusing to unintended areas.
3Ease of operation
If cationic agent is associated with negatively charged groups, then positive zeta-potential is provided facilitating bulk transfer to tissue, but device complexity increases
Solution Approach 1:
The invention changes the surface charge parameter of the coating by incorporating negatively charged polymer groups (e.g., carboxyl groups in polyacrylic acid) that interact with cationic agents. This parameter change (from neutral to negatively charged surface) enables the coating to bind cationic agents and facilitate bulk drug transfer to tissue, while the systematic multi-layer design keeps the overall structure manageable.
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
Enhances the transfer of bioactive agents to target tissues, ensuring therapeutic levels are achieved while minimizing unintended drug distribution, particularly on dynamic surfaces, thereby prolonging device functionality and treating medical conditions effectively.
Implementation Method 1
A cationic agent is associated with the negatively charged groups of the particulate and provides the particulate with a positive zeta-potential
Data Source
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AI summary
The disclosure provides bioactive agent-containing particulates that include bioactive agent, biocompatible polymer, negatively charged groups, and a cationic agent. The particulates can be associated with a medical device, such as a balloon catheter, which can be used to move the particulates to a treatment site. Transfer of the particulates from the device to tissue is facilitated by the arrangement of the cationic and bioactive agent-containing particulates.