Balloon Catheter Coating via Metered Flow and Rotation
Solution Overview
Problem
Current methods for coating balloon catheters result in non-uniform drug distribution and inconsistent drug doses due to inefficiencies in spraying and dipping techniques, leading to significant drug loss and measurement errors, especially for devices that cannot be precisely weighed.
Innovation Solution
A method involving a metering dispenser that applies a coating solution as a continuous flow onto the balloon catheter while rotating and moving, ensuring almost no solution is lost and allowing for precise control of the drug dose without weighing the device, using a solvent that evaporates uniformly to form a consistent coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spraying or dipping coating methods are used on balloon catheters, then the coating process can be completed, but the drug distribution becomes non-uniform and the dose becomes inconsistent
Solution Approach 1:
The patent changes the fundamental parameters of the coating process from spray/dip methods to a controlled flow coating method. The coating solution is applied as a continuous flow at controlled rates (0.01-10 mL/min) while the balloon rotates, transforming the uncontrolled spray/dip parameters into controlled flow parameters that ensure uniform drug distribution and consistent dosing.
Solution Approach 2:
The patent introduces dynamic motion by rotating the balloon catheter during the coating process. This rotation combined with the continuous flow of coating solution creates dynamic coverage that ensures uniform drug distribution across the entire balloon surface, eliminating the non-uniformity inherent in static spray or dip methods.
2Productivity
If spray coating is used, then the coating solution can be applied quickly, but large amounts of coating solution are lost and the amount deposited is not precisely controlled
Solution Approach 1:
The patent implements feedback control through a metering device that precisely measures and controls the flow rate of coating solution applied to the balloon. This feedback mechanism ensures that the coating solution is applied at controlled rates (0.01-10 mL/min), preventing excessive loss while maintaining efficient coating application and enabling precise dose control.
Solution Approach 2:
The patent replaces the mechanical spray system with a controlled flow delivery system using a metering device. This substitution transforms the uncontrolled spray mechanism into a precisely metered flow system that minimizes coating solution loss while maintaining productivity through controlled application rates.
3Quantity of substance
If dip coating is used to load large amounts of drug, then the drug load increases, but the drug already on the balloon dissolves away during subsequent dips
Solution Approach 1:
The patent employs continuous flow coating instead of intermittent dipping, maintaining continuous useful action on the balloon surface. This continuous application at controlled rates (0.01-10 mL/min) ensures uniform drug distribution and retention, preventing the dissolution problem that occurs with repeated dipping operations.
4Measurement precision
If weighing the balloon catheter is used to control drug dose, then the total dose can be measured, but the measurement error is large because the coating weight is negligible compared to the device weight
Solution Approach 1:
The patent replaces the mechanical weighing method with a volumetric flow control and metering system. By controlling the coating solution flow rate (0.01-10 mL/min) and measuring the volume applied, the system achieves precise drug dose control independent of the balloon catheter's weight, eliminating the measurement error problem inherent in gravimetric methods.
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 achieves a uniform and consistent drug distribution on the balloon catheter surface, ensuring the metered drug dose is accurately deposited, reducing variability and improving therapeutic efficacy by maintaining drug levels during deployment.
Implementation Method 1
The solvent is allowed to evaporate, leaving a coating of the polymer and therapeutic drug on the stent surfaces
Data Source
AI summary
Methods and apparatus for coating a medical device are provided. In one embodiment, the method for preparing a substantially uniform coated medical device includes (1) preparing a coating solution comprising a solvent, a therapeutic agent, and an additive; (2) loading a metering dispenser with the coating solution; (3) rotating the medical device about the longitudinal axis of the device and/or moving the medical device along the longitudinal or transverse axis of the device; (4) dispensing the coating solution from the metering dispenser onto a surface of the medical device and flowing the coating solution on the surface of the medical device while the medical device is rotating and/or linearly moving; and (5) evaporating the solvent, forming a substantially uniform coating layer on the medical device.