Plasticized Stent Coatings for Mechanical Integrity
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Solution Overview
Problem
Existing drug-polymer coatings for stents often fail to maintain mechanical integrity during deployment and expansion, leading to issues like cracking, flaking, or inadequate drug delivery due to insufficient mechanical flexibility and rapid drug elution, which compromises the effectiveness of timed-release drug delivery.
Innovation Solution
Incorporating plasticizers into the drug-polymer coating to enhance flexibility and control drug release, allowing for a tailored elution profile that reduces the burst effect and maintains mechanical integrity during stent deployment, while ensuring consistent and prolonged drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If plasticizers are added to the drug-polymer coating, then mechanical flexibility and controlled drug release are improved, but coating complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the coating - specifically incorporating plasticizers at controlled concentrations (typically 5-50 wt% of polymer) to alter the physical properties of the coating matrix. This changes the glass transition temperature and mechanical flexibility parameters, enabling the coating to maintain integrity during stent deployment while controlling drug release kinetics.
Solution Approach 2:
The patent employs composite materials by combining the base polymer matrix with plasticizer additives and dispersed drug particles to create a multi-component coating system. The plasticizer acts as a third component that modifies the interactions between polymer chains and drug molecules, providing both mechanical flexibility enhancement and controlled release functionality simultaneously.
2Duration of action of moving object
If plasticizers are incorporated to control drug release, then timed-release effectiveness is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the plasticizer with the polymer matrix before drug incorporation, or by selecting plasticizers that are pre-compatible with the polymer system. This preliminary compatibility assessment and preparation simplifies the overall manufacturing process by avoiding complex post-processing steps that would be needed to achieve uniform distribution and proper functionality.
Solution Approach 2:
The patent uses parameter changes in the manufacturing process by adjusting processing temperatures, mixing speeds, and solvent evaporation rates to optimize plasticizer distribution. These parameter optimizations enable standard coating equipment to be used without requiring specialized manufacturing facilities, maintaining ease of manufacture while achieving controlled release performance.
3Reliability
If the polymer coating is made more flexible with plasticizers, then mechanical integrity during deployment is improved, but drug release rate control becomes more complex
Solution Approach 1:
The patent applies parameter changes by selecting plasticizers with specific glass transition temperatures and compatibility characteristics that naturally provide the desired release profile. By carefully choosing plasticizer molecular weight, chemical structure, and concentration, the coating achieves both mechanical flexibility for deployment integrity and appropriate drug release kinetics without requiring complex release mechanisms.
Solution Approach 2:
The patent employs self-service by utilizing the inherent properties of the plasticizer-polymer-drug system to automatically achieve both mechanical flexibility and controlled release. The plasticizer's molecular structure and interactions with the polymer and drug create a self-regulating release mechanism that adapts to the coating's physical state changes during deployment and in-vivo conditions, eliminating the need for additional complex release control mechanisms.
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 use of plasticizers in drug-polymer coatings improves the mechanical flexibility and controlled release of bioactive agents, reducing the burst effect and ensuring effective, prolonged drug delivery, thus enhancing the therapeutic efficacy of stents by maintaining mechanical integrity and optimizing drug distribution.
Implementation Method 1
Incorporating plasticizers into the drug-polymer coating to enhance flexibility
Implementation Method 2
The plasticized drug-polymer coating includes a polymer, a drug, and at least one plasticizer
Implementation Method 3
When the drug-coated stent is deployed in a vessel in the body, the drug release is predominantly based on a diffusion mechanism
Implementation Method 4
the drug release is predominantly based on a diffusion mechanism. Drug diffusion is controlled in part by the molecular size, the crystallinity, and the hydrophilic-lipophilic balance of the drug, as well as the morphology of the polymeric coating, the glass temperature Tg of the polymer
Data Source
AI summary
The present invention provides a system for treating a vascular condition, including a catheter, a stent with a stent framework operably coupled to the catheter, and a drug-polymer coating on the stent framework including at least one plasticizer dispersed within the drug-polymer coating.