Crystalline Rapamycin Coating for Coronary Stent Drug Release
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Solution Overview
Problem
Current drug-eluting stents face challenges in minimizing physical, chemical, and therapeutic legacy in the vessel after a certain period, requiring a bioabsorbable polymer and pharmaceutical or biological agent coating that ensures minimal intrusion and optimal drug release profiles for effective healing and reduced thrombosis.
Innovation Solution
A coated coronary stent with a rapamycin-polymer coating comprising resorbable polymers, where rapamycin is in crystalline form and uniformly dispersed, providing a controlled elution profile and enhanced mechanical properties through a laminate structure formed using compressed fluid technologies and electrostatic capture methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drug-eluting stent uses a bioabsorbable polymer coating to minimize physical and chemical legacy in the vessel, then the therapeutic legacy is reduced and healing is promoted, but the coating thickness must be minimized to maintain flexibility and access to small vessels
Solution Approach 1:
The patent changes the physical state parameter of the drug from amorphous to crystalline form, which increases drug loading efficiency and allows for thinner coating thickness while maintaining effective drug delivery. This parameter change resolves the contradiction by enabling reduced coating volume without compromising therapeutic effectiveness
Solution Approach 2:
The patent uses a composite coating structure combining bioabsorbable polymer with crystalline drug particles, creating a multi-phase material system. This composite approach allows optimization of both mechanical properties (flexibility) and therapeutic function (drug release) simultaneously, resolving the contradiction between thin coating requirement and effective drug delivery
2Ease of operation
If the stent uses minimal cross-sectional thickness for flexibility and access to small vessels, then deployment flexibility is improved, but the drug loading capacity and controlled release profile are reduced
Solution Approach 1:
By changing the drug physical state to crystalline form, the patent increases the concentration of active drug per unit volume of coating. This parameter change allows sufficient drug loading capacity even in thin coatings, resolving the contradiction between minimal thickness for flexibility and adequate drug quantity for therapeutic effect
Solution Approach 2:
The patent creates local concentration of crystalline drug particles within the polymer matrix, achieving high drug density in specific regions of the coating. This local quality enhancement allows thin overall coating thickness while maintaining sufficient total drug loading capacity and controlled release characteristics
3Duration of action of moving object
If the stent provides prolonged drug release to minimize residual drugs, then therapeutic effectiveness is improved, but the coating structure complexity increases
Solution Approach 1:
The patent uses crystalline drug form with specific solubility characteristics to achieve prolonged release kinetics. The crystalline structure provides controlled dissolution rate, extending drug release duration without requiring complex multi-layer or staged release structures, thus resolving the contradiction between prolonged duration and structural simplicity
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 achieves a controlled and prolonged drug release, minimizing residual drugs and polymers that could inhibit healing, while providing a strong and flexible stent with optimized elution profiles and reduced thrombosis risk, addressing the limitations of current bioabsorbable stents.
Implementation Method 1
The coating is formed using compressed fluid technologies and electrostatic capture methods
Implementation Method 2
The coating is formed using compressed fluid technologies and electrostatic capture methods
Implementation Method 3
at least part of rapamycin is in crystalline form and the rapamycin-polymer coating comprises one or more resorbable polymers
Implementation Method 4
the at least part of said rapamycin forms a phase separate from one or more phases formed by said polymer
Implementation Method 5
the rapamycin-polymer coating comprises one or more resorbable polymers
Data Source
AI summary
Provided herein is a coated coronary stent, comprising: a. stent framework; b. a plurality of layers deposited on said stent framework to form said coronary stent; wherein at least one of said layers comprises a bioabsorbable polymer and at least one of said layers comprises one or more active agents; wherein at least part of the active agent is in crystalline form.