Layered Fluoropolymer Drug Coating for Stable Stent Release
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Solution Overview
Problem
Existing drug-eluting stents face challenges in achieving long-term, stable drug release in large-diameter blood vessels like peripheral arteries, with issues such as burst release and uneven drug distribution leading to insufficient or excessive drug delivery over time.
Innovation Solution
A drug coating with a non-degradable polymer matrix featuring an inner layer with higher drug loading and thickness, and an outer layer with lower drug loading and thickness, forming a controlled release mechanism to stabilize drug delivery over extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the drug loading concentration of the fluoropolymer coating is increased to extend drug release time, then the drug release duration is extended, but the initial drug release becomes excessively high and rapid causing drug waste or significant drug toxicity
Solution Approach 1:
The coating is divided into two distinct layers: an inner layer with high drug loading concentration (10-50 wt%, preferably 20-30 wt%) and an outer layer with low or no drug loading (0-5 wt%, preferably 0-2 wt%). This segmentation allows the inner layer to provide sustained drug reservoir while the outer layer controls the release rate, preventing burst release and extending effective drug delivery period beyond 30 days
Solution Approach 2:
Different regions of the coating have different drug loading concentrations tailored to specific functional requirements. The inner layer adjacent to the medical device surface has high drug concentration for sustained release, while the outer layer facing the bloodstream has low drug concentration to control release kinetics and prevent toxicity, creating a gradient structure that optimizes both duration and safety
2Quantity of substance
If the drug loading concentration is increased to achieve long-term drug release in large-diameter blood vessels, then the cumulative drug release increases, but the uniformity of drug coating decreases and burst release is exacerbated
Solution Approach 1:
The coating is divided into two distinct layers: an inner layer with high drug loading concentration (10-50 wt%, preferably 20-30 wt%) and an outer layer with low or no drug loading (0-5 wt%, preferably 0-2 wt%). This segmentation allows the inner layer to provide sustained drug reservoir while the outer layer controls the release rate, preventing burst release and extending effective drug delivery period beyond 30 days
Solution Approach 2:
The drug loading concentration parameter is varied through the coating thickness, creating a gradient from high concentration at the inner layer to low concentration at the outer layer. This parameter change optimizes both the cumulative drug release quantity and the uniformity of coating, preventing burst release while ensuring sufficient drug delivery for long-term treatment
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 drug coating achieves stable, controlled drug release for over 30 days, reducing initial burst release and maintaining therapeutic drug levels for long-term treatment of conditions like peripheral arterial disease.
Implementation Method 1
The inner layer has a drug loading concentration higher than that of the outer layer... The drug can be dispersedly distributed in the coating matrix and released outside the coating during the treatment cycle
Data Source
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AI summary
The present invention provides a drug coating and a medical device comprising the drug coating, a system, and a preparation method. The drug coating comprises a non-degradable fluorinated polymer matrix and a drug dispersed therein. An inner layer and an outer layer which have different drug-loading concentrations are formed along the thickness direction of the drug coating, the inner layer has a drug-loading concentration not less than 10 wt%, the outer layer has a drug-loading concentration less than 10 wt%, and the thickness of the outer layer is not greater than 20 µm. The drug coating of the present invention can allow for the release of a long-term stable amount of a drug into a tissue wall in contact with the drug coating, so as to achieve a long-term therapeutic or preventive effect on diseases such as luminal stenosis.