Stent Spray Coating Calibration for Uniform Drug Loading
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Solution Overview
Problem
Current stent coating methods struggle to achieve uniform coating thickness and accurate drug loading across a batch of stents, leading to potential coating defects and inefficiencies in the manufacturing process.
Innovation Solution
A method involving the calibration of a stent spraying device to apply a target mass per coating layer, adjusting spraying parameters as needed to ensure each stent receives the same total weight and number of layers, resulting in uniform coating thickness across a batch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spray coating methods are used to apply coating material to stents, then the coating process can be completed, but the coating thickness is non-uniform and drug loading varies across batches
Solution Approach 1:
The patent applies preliminary action by performing calibration of the spray coating device on test stents before actual production. The calibration process determines the relationship between spray parameters and coating mass, allowing optimization of coating uniformity before batch manufacturing. This preliminary calibration step ensures that subsequent production runs achieve consistent coating thickness and drug loading across all stents.
2Quantity of substance
If multiple spray passes are used to achieve desired coating mass, then adequate drug loading can be achieved, but the number of passes varies between stents leading to non-uniform coating
Solution Approach 1:
The patent implements feedback by measuring the mass of coating material applied to each stent and using this information to control the spray coating process. The system monitors the coating mass in real-time and adjusts spray parameters accordingly to maintain uniform coating thickness. This feedback mechanism ensures that each stent receives the precise target coating mass regardless of variations in spray conditions or stent geometry.
3Productivity
If spray parameters are not calibrated, then the coating process is faster, but coating defects occur and drug loading is inaccurate
Solution Approach 1:
The patent applies preliminary action by performing calibration of the spray coating device on test stents before actual production. The calibration process determines the relationship between spray parameters and coating mass, allowing optimization of coating uniformity before batch manufacturing. This preliminary calibration step ensures that subsequent production runs achieve consistent coating thickness and drug loading across all stents.
Solution Approach 2:
The patent applies parameter changes by systematically varying spray parameters (such as spray speed, nozzle distance, coating material flow rate) during calibration to identify the optimal settings that produce the target coating mass. By adjusting these parameters and measuring the resulting coating mass, the process identifies the precise parameter combination needed to achieve accurate and uniform drug loading while maintaining efficient production rates.
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 ensures consistent coating quality, minimizing defects and improving manufacturing efficiency by ensuring each stent has the same weight, number of layers, and thickness of coating material, thereby enhancing the effectiveness of drug delivery.
Implementation Method 1
spraying the composition onto the stent
Implementation Method 2
The solvent then evaporates, leaving on the stent surfaces a polymer coating impregnated with the drug or active agent
Data Source
AI summary
Various embodiments of methods for coating stents are described herein. One method is directed to a stent spraying apparatus calibration procedure. Another method is directed to obtaining a batch of stents where each stent has the same number of layers of coatings, and the same total amount of coating material.