Stent Coating Local Quality for Targeted Drug Delivery
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Solution Overview
Problem
Medical devices like stents often require unnecessary coating of all surfaces with therapeutic agents, leading to undesired exposure and increased manufacturing costs, as not all surfaces come into contact with the target tissue.
Innovation Solution
A stent design where an inner coating composition is applied to all surfaces without a therapeutic agent, and an outer coating composition containing a therapeutic agent is selectively applied only to specific surfaces, optionally separated by a barrier coating, to ensure targeted delivery and reduce exposure and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all surfaces of the stent are coated with a coating composition containing a therapeutic agent, then the coating remains on the stent by wrapping around the struts, but this results in undesired exposure of the patient to the therapeutic agent and increased manufacturing costs
Solution Approach 1:
The patent applies different coating compositions to different surfaces of the stent based on their specific functional requirements. The luminal surface receives a coating composition with a therapeutic agent for treating the blood vessel wall, while the abluminal surface receives a different coating composition without the therapeutic agent. This local differentiation ensures that the therapeutic agent is only applied where it is needed for treatment, preventing undesired exposure while maintaining coating retention on all surfaces.
2Reliability
If all surfaces of the stent are coated with a coating composition containing a therapeutic agent, then the coating remains on the stent by wrapping around the struts, but this results in increased manufacturing costs associated with increased use of the therapeutic agent
Solution Approach 1:
The patent implements local quality by applying the therapeutic agent only to the luminal surface coating composition and not to the abluminal surface coating composition. This selective application reduces the total quantity of therapeutic agent required for manufacturing while ensuring that the coating retention function is maintained on all stent surfaces through the presence of coating compositions on both surfaces.
3Reliability
If the luminal surface of the strut is coated with a coating composition containing a therapeutic agent, then the therapeutic agent can treat the blood vessel wall, but the therapeutic agent is not needed on the abluminal surface where it does not come in direct contact with the blood vessel wall
Solution Approach 1:
The patent applies local quality by formulating the coating composition for the luminal surface with a therapeutic agent at a concentration effective for treating the blood vessel wall, while the abluminal surface coating composition is formulated without the therapeutic agent or at a significantly lower concentration. This ensures that the therapeutic efficacy is achieved at the luminal surface where it is needed, while minimizing the quantity of therapeutic agent used by not applying it to the abluminal surface where it would not contact the blood vessel wall.
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 solution ensures that therapeutic agents are targeted to specific body tissues, minimizing exposure and reducing manufacturing costs by applying coatings only where necessary, while maintaining adherence to the stent surfaces.
Implementation Method 1
an inner coating composition comprising a first polymer disposed on the abluminal surface, luminal surface, first and second side surfaces and any other surface of the strut
Implementation Method 2
an outer coating composition disposed on at least a portion of the inner coating composition that is disposed on at least one of the abluminal surface or first side surface or second side surface, in which the outer coating composition comprises a first therapeutic agent and the first polymer
Data Source
AI summary
The invention relates generally to a medical device for delivering a therapeutic agent to the body tissue of a patient, and methods for making such a medical device. More particularly, the invention is directed to a stent, such as an intravascular stent, having an inner and outer coating compositions disposed thereon. In another embodiment, the inner coating composition and outer coating composition are separated by a barrier coating composition.