Drug Delivery Stent Mounting via Heated Metallic Mold
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Solution Overview
Problem
Existing methods for mounting drug delivery stents on catheter balloons often damage the drug delivery layer or fail to securely retain the stent, leading to potential complications during angioplasty procedures.
Innovation Solution
A method involving a metallic mold with a polished bore to securely mount the drug delivery stent on the balloon catheter without damaging the drug layer, using controlled heating and pressure to ensure the stent is embedded without roughening or altering the drug release rate, and incorporating a stepped inner diameter to enhance stent retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent is strongly fixed to the balloon, then stent retention is improved, but balloon expansion and stent release are inhibited
Solution Approach 1:
The patent applies parameter changes by controlling temperature and pressure during the mounting process. The balloon is heated to a specific temperature range (37°C to 60°C) and pressurized to embed the stent into the balloon wall. These controlled parameter changes enable secure stent retention while maintaining the ability to expand and release the stent when needed.
Solution Approach 2:
The patent utilizes phase transitions of the balloon material through controlled heating. By heating the balloon to specific temperatures, the material undergoes temporary softening that allows stent embedding, then cools to restore its original properties, maintaining both retention and releasability.
2Reliability
If conventional mounting methods are used, then stent is secured to balloon, but drug delivery layer is damaged
Solution Approach 1:
The patent carefully controls temperature parameters during mounting, heating the balloon to a range (37°C to 60°C) that is sufficient to embed the stent into the balloon wall but below the threshold that would damage the drug delivery layer. This precise parameter control secures the stent while preserving drug integrity.
Solution Approach 2:
The patent uses the balloon material itself as an intermediary medium. The balloon is heated to become temporarily more compliant, allowing the stent to be embedded into its wall structure. This intermediary mechanism secures the stent without requiring direct mechanical contact that would damage the drug layer.
3Reliability
If heating and pressurization are applied to mount stent, then stent retention is improved, but drug release rate may be altered
Solution Approach 1:
The patent establishes specific parameter ranges for heating (37°C to 60°C) and pressurization that achieve adequate stent embedding while avoiding conditions that would alter the drug release rate. These controlled parameter changes ensure both secure retention and consistent drug delivery characteristics.
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 method securely and consistently mounts the drug delivery stent on the balloon catheter, maintaining the drug's integrity and release rate, and enhances stent retention without increasing the stent's profile, allowing for effective delivery and deployment in the patient's body lumen.
Implementation Method 1
The balloon is pressurized and heated within the mold to mount the stent on the balloon
Implementation Method 2
a conductive heating element which provides temperature control to the mold with a tolerance of about ±0.56 degrees C to about ±1.11 degrees C
Implementation Method 3
The mold radially restrains the stent from expanding when the balloon is pressurized therein
Implementation Method 4
The bore of the mold is defined by a polished inner surface with a polished finish which is sufficiently smooth so that contact and relative movement between the stent and polished inner surface of the mold does not roughen or otherwise damage or create a texture on the drug delivery layer
Implementation Method 5
The balloon is cooled in the mold prior to depressurization of the balloon
Data Source
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AI summary
A method of securely mounting a drug delivery stent (23) on a balloon (22) of a balloon catheter (20) without damaging the drug delivery layer of the stent. In one embodiment, the method generally comprises positioning a drug delivery stent on a balloon of a balloon catheter, and positioning the balloon with the drag delivery stent thereon within a polished bore of a mold formed at least in part of a metallic material. The balloon is pressurized and heated within the mold as the mold radially restrains the stent from expanding.