Uniform Drug Coating on Pre-Crimped Stents via Rotating Spray Nozzle
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Solution Overview
Problem
Existing methods for coating pre-crimped stents with drug particles are inefficient, particularly as they fail to achieve uniform deposition of drugs on the inner and outer surfaces, and there is a need for a method that uses a spray gun nozzle to coat pre-crimped stents effectively.
Innovation Solution
A coating system comprising a spray nozzle unit, a protection tube, and a mandrel fixture with a circular disc that rotates the protection tube and IMD, allowing the spray nozzle to uniformly coat the pre-crimped stent with drug particles, which can be atomized or nanomized for enhanced deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CVD method is used to coat pre-crimped stent, then coating can be applied to pre-crimped configuration, but drug particles are not uniformly deposited
Solution Approach 1:
The patent replaces the Chemical Vapor Deposition (CVD) method with a spray nozzle system that mechanically deposits drug particles. The spray nozzle unit delivers drug-containing fluid directly onto the pre-crimped stent, providing controlled and uniform particle distribution without relying on vapor-phase chemical reactions that fail to achieve uniformity on complex geometries.
Solution Approach 2:
The patent introduces rotational movement of the pre-crimped stent assembly during the spray coating process. The mandrel fixture rotates the stent to ensure all surfaces, including inner and outer walls, are evenly exposed to the spray nozzle, dynamically achieving uniform drug particle deposition across the entire stent surface area.
2Manufacturing precision
If spray gun nozzle is used to coat pre-crimped stent, then uniform coating can be achieved, but inner and outer surfaces are difficult to access simultaneously
Solution Approach 1:
The patent places the pre-crimped stent inside a balloon-catheter assembly, which is then inserted into the spray chamber. The balloon acts as a protective sheath that can be inflated to position the stent centrally, allowing the spray nozzle to access both inner and outer surfaces uniformly through the rotating assembly without requiring complex multi-angle nozzle configurations.
Solution Approach 2:
The mandrel fixture serves multiple functions: it holds the balloon-catheter assembly, provides rotational movement for uniform coating, and positions the stent centrally within the spray chamber. This multi-functional design simplifies the overall system by eliminating the need for separate positioning, rotation, and support mechanisms.
3Ease of manufacture
If stent is coated before crimping, then drug coating can be applied easily, but stent structure cannot be pre-crimped to balloon assembly
Solution Approach 1:
The patent performs the crimping action before the drug coating process. The stent is pre-crimped onto the balloon-catheter assembly in advance, creating a stable, space-constrained structure that is then coated using the spray nozzle system. This preliminary crimping enables subsequent uniform coating by ensuring the stent maintains its compressed configuration throughout the coating process.
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 system enables efficient and uniform coating of pre-crimped stents with drug particles, improving the distribution of drugs on both inner and outer surfaces, and allows for precise control over the coating process using CNC technology, enhancing therapeutic delivery.
Implementation Method 1
a spray gun nozzle deposits drug particles on the rotating stent
Implementation Method 2
the mandrel fixture is rotated. A spray gun nozzle deposits drug particles on the rotating stent
Implementation Method 3
a protection tube capable of holding the IMD
Data Source
Figure 1A
Figure 1B
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AI summary
A coating system for coating an Insertable Medical Device (IMD) with one or more drugs is disclosed. The coating system includes a spray nozzle unit for coating the IMD with one or more drugs. The IMD includes a guiding member, a coating member and a supporting member. The IMD is passed through a protection tube such that the guiding member is located within the protection tube and an end of the supporting member is connected to a holder to expose the coating member of the IMD to the spray nozzle unit. The protection tube is received by a mandrel fixture which includes a circular disc for holding and rotating the protection tube and the IMD within the protection tube. When the protection tube along with the IMD is rotated, the spray nozzle unit coats the coating member of the IMD with the one or more drugs.