Hollow Wire Stent Drug Loading via Solvent Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drug-eluting stents face challenges in delivering increased quantities of therapeutic agents and controlling the elution rate due to limitations in polymer coatings, which can cause adverse reactions and incomplete drug delivery.
Innovation Solution
A method and apparatus for loading a therapeutic substance into a hollow wire stent with side openings, allowing for a reverse or forward fill process using solvents or dispersion media, followed by solvent extraction to ensure only the drug remains, enabling controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer coatings are used to deliver drugs, then the drug can be delivered to the target site, but the polymer material may cause adverse reactions and the elution rate is difficult to control
Solution Approach 1:
The patent removes the polymer coating entirely from the stent structure, extracting the harmful element while preserving the drug delivery function. The drug is delivered directly through the stent struts without any polymer carrier, eliminating adverse reactions associated with polymer materials.
Solution Approach 2:
The patent changes the physical and chemical parameters of the stent struts themselves, making them porous or hollow to enable drug delivery. This parameter change allows the stent material to directly deliver the drug without requiring a separate polymer coating, thereby eliminating polymer-related adverse reactions.
2Quantity of substance
If polymer coatings are used to deliver drugs, then the drug can be administered, but the quantity of drug delivered is limited by the coating capacity and device size
Solution Approach 1:
The patent changes the structural parameters of the stent struts to hollow or porous configurations, dramatically increasing the available volume for drug loading. This allows significantly larger quantities of drug to be delivered without increasing device complexity, as the drug is stored within the strut structure itself rather than on an external coating.
3Duration of action of moving object
If polymer coatings are used, then drug delivery is enabled, but the elution rate control is difficult
Solution Approach 1:
The patent changes the physical structure of the stent struts to hollow or porous forms, enabling control of drug elution rate through structural parameters such as pore size, strut wall thickness, and internal volume. This provides more precise and controllable drug release kinetics compared to polymer coatings, where the elution rate is determined by the polymer's degradation or diffusion properties.
4Length of moving object
If the lumen diameter of hollow struts is extremely small (e.g., 0.00381 cm), then the stent can be delivered through narrow vessels, but filling the lumen with drug becomes difficult
Solution Approach 1:
The patent employs hydraulic or pneumatic pressure systems to force the drug formulation into the small-lumen hollow struts. By applying controlled pressure during the manufacturing process, the drug can be effectively pushed into the narrow spaces that would otherwise be difficult to fill, while maintaining the small lumen diameter necessary for vascular delivery.
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
This approach allows for improved control over drug delivery, increased quantities of therapeutic agents, and safer elution profiles without polymer coatings, achieving similar clinical efficacy while minimizing adverse reactions.
Implementation Method 1
The drug(s) is released by a process of diffusion through the polymer layer for biostable polymers
Implementation Method 2
a solvent or dispersion medium extracting step is performed to extract the solvent or dispersion medium from within the lumenal space
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
Methods and apparatus are disclosed for loading a therapeutic substance or drug within a lumenal space of a hollow wire having a plurality of side openings along a length thereof that forms a hollow drug-eluting stent with a plurality of side drug delivery openings. Loading a drug within the lumenal space of the hollow stent includes a drug filling step, in which the drug is mixed with a solvent or dispersion medium. The lumenal space may be filled with the drug solution or suspension in a reverse fill process and/or a forward fill process. After the drug filling step, a solvent or dispersion medium extracting step is performed to extract the solvent or dispersion medium from within the lumenal space such that only the drug remains within the hollow stent. A stent cleaning step may be performed to an exterior surface of the hollow stent.