Gradient Coated Stent for Controlled Drug Release
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Solution Overview
Problem
Current stent coatings deliver drugs in a uniform manner, leading to burst release and ineffective long-term therapy due to incompatible drug and polymer combinations, and complex manufacturing processes that increase time and expense, while failing to address both initial inflammation and late-stage restenosis effectively.
Innovation Solution
A gradient-coated stent with varying therapeutic agent concentrations across its thickness, allowing for controlled drug release profiles and the use of incompatible materials in a single-step manufacturing process, enabling the delivery of different therapies over time and reducing labor and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform radial drug coating is applied to the stent, then the manufacturing process is simple, but burst release occurs causing local tissue damage and the drug delivery is ineffective in the long term
Solution Approach 1:
The patent applies local quality by creating a gradient coating where the drug concentration varies spatially across the coating thickness. The inner portion of the coating (adjacent to the stent) has a higher drug concentration while the outer portion has a lower concentration, enabling controlled release kinetics that prevent burst release while maintaining long-term effectiveness.
2Productivity
If a single drug coating is applied to the stent, then the manufacturing process is simple and quick, but it cannot effectively treat both initial inflammation and late-stage restenosis
Solution Approach 1:
The patent applies parameter changes by varying the drug concentration parameter across the coating thickness. The gradient profile allows different drug concentrations to be present at different depths, enabling the coating to provide both immediate anti-inflammatory effects (from the outer layer) and long-term anti-proliferative effects (from the inner layer), thus treating multiple stages of vessel healing with a single coating process.
3Reliability
If multiple coating layers with varying characteristics are applied to achieve gradient drug release, then the drug delivery effectiveness is improved, but the manufacturing time and expense increase
Solution Approach 1:
The patent applies merging by combining multiple coating solutions containing different drugs or drug concentrations into a single integrated coating layer. This gradient coating can be applied in one step, merging the functions of what would traditionally require multiple sequential coating layers, thus achieving controlled drug release without proportionally increasing manufacturing time and complexity.
4Reliability
If incompatible drugs and polymers are used in the coating, then the therapeutic effectiveness is improved, but the materials degrade when held in solution too long
Solution Approach 1:
The patent applies preliminary action by pre-mixing compatible components or preparing the coating solution in a way that allows incompatible drugs and polymers to be combined without premature degradation. The coating is applied quickly to the stent, minimizing the time the incompatible materials are held in solution together, thus preserving both therapeutic effectiveness and coating stability.
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 gradient coating prevents burst release, ensures long-term effective drug delivery, and simplifies the manufacturing process, addressing both immediate inflammation and late-stage restenosis by varying drug concentrations and using incompatible materials in a single step.
Implementation Method 1
the diffusion rate is generally proportional to the difference in drug concentration across the coating (ΔC)
Data Source
AI summary
The gradient coated stent 150 of the present invention provides a coated stent having a continuous coating 130 disposed on the stent elements. The continuous coating 130 includes a first coating component and a second coating component. The concentration of the first coating component varies continuously over at least part of the thickness of the continuous coating 130. The concentration of the second coating component can also vary over at least part of the thickness of the continuous coating 130. In one embodiment, the concentration of the first coating component decreases in the direction from the stent element towards the outer edge of the continuous coating 130 and the concentration of the second coating component increases in the direction from the stent element towards the outer edge of the continuous coating 130.