Polylactide and Shellac Stent Coating for Drug Release
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Solution Overview
Problem
Current drug-eluting stents rely on polymeric coatings to achieve protracted drug release, which can induce inflammatory responses and increase the risk of late stent thrombosis and in-stent restenosis due to polymer-related adverse reactions, necessitating an alternative mechanism for modulating drug release kinetics.
Innovation Solution
A stent coated with polylactide and a biocompatible resin such as shellac, which retards the release of drugs like rapamycin, providing a safer and more effective alternative to polymeric coatings by using a natural product to control drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If polymeric coating is used to achieve protracted drug release, then drug release duration is improved, but inflammatory response and risk of late stent thrombosis increase
Solution Approach 1:
The patent removes the polymeric coating component from the drug delivery system, extracting the harmful element while preserving the therapeutic function. The drug is delivered directly from the stent surface without a polymer matrix, eliminating polymer-induced inflammation while maintaining controlled drug release through alternative mechanisms such as drug crystallization or direct coating formulations.
Solution Approach 2:
The patent employs composite coating formulations comprising the drug combined with biocompatible materials such as phospholipids, cholesterol, or other non-polymeric substances. These composite materials enable protracted drug release through mechanisms like slow dissolution, crystallization, or lipid-based delivery, achieving extended duration without the adverse effects of synthetic polymers.
2Duration of action of moving object
If polymeric coating is used to achieve protracted drug release, then drug release duration is improved, but risk of late in-stent restenosis increases
Solution Approach 1:
The patent eliminates the polymeric coating that is responsible for generating harmful factors leading to late in-stent restenosis. By removing the polymer component entirely, the source of chronic inflammation and adverse pathomechanisms is extracted, thereby preventing the development of late restenosis while maintaining effective drug delivery.
Solution Approach 2:
The patent introduces biocompatible intermediary substances such as phospholipids, fatty acids, or cholesterol as mediators between the drug and the stent surface. These intermediaries facilitate controlled drug release without triggering the adverse immune responses and pathological processes that lead to late in-stent restenosis, replacing the harmful polymer mediator with a biologically compatible alternative.
3Reliability
If polymer-free approach is used to eliminate inflammatory response, then safety is improved, but drug release control mechanism must be alternative
Solution Approach 1:
The patent alters the physical and chemical parameters of the drug coating formulation to achieve controlled release without polymers. By adjusting drug concentration, crystallization temperature, coating thickness, and using lipid-based carriers with specific phase transition temperatures, the system achieves protracted drug release through physical parameter control rather than polymer matrix degradation, maintaining safety while managing complexity.
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 combination of polylactide and shellac significantly prolongs drug release, reducing adverse reactions and achieving tissue concentrations comparable to polymer-based systems, thereby improving clinical efficacy and safety by minimizing polymer-related complications.
Implementation Method 1
A stent coated with polylactide and a biocompatible resin such as shellac, which retards the release of drugs like rapamycin
Data Source
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AI summary
The present invention relates to an implant or a part thereof coated with polylactide.