Porous High-Aspect-Ratio Crystal Composites for Vascular Drug Delivery
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Solution Overview
Problem
Existing drug-coated endovascular medical devices, such as those using paclitaxel, face challenges with unpredictable drug dosing and elution, poor coating robustness, and solubility issues, leading to ineffective treatment of vascular diseases due to variable drug levels and potential side effects.
Innovation Solution
Development of composite materials comprising high aspect ratio paclitaxel crystals that partially or fully extend into and project from a porous substrate, such as ePTFE, with controlled crystallization methods like solvent evaporation and vapor annealing, ensuring robust attachment during manufacturing and effective drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drug coating methods are used on endovascular devices, then the device can be manufactured, but the drug dosing becomes unpredictable and elution is variable
Solution Approach 1:
The patent changes the physical state and morphology parameters of the drug from conventional amorphous or fine crystalline coatings to large, controlled crystals with specific size ranges (10-100 micrometers). This parameter change in crystal morphology and size distribution enables predictable drug dosing and controlled elution kinetics, resolving the contradiction between manufacturing feasibility and dosing reliability.
Solution Approach 2:
The patent creates a composite structure where large drug crystals are integrated with the endovascular device surface or embedded in a porous substrate. This composite approach combines the mechanical properties of the device with the controlled release properties of the crystal structure, achieving both manufacturability and reliable, predictable drug delivery.
2Reliability
If drug is coated on endovascular device, then local treatment is achieved, but coating robustness is poor and drug may be washed away
Solution Approach 1:
The patent applies local quality by creating large drug crystals with specific size and shape characteristics that are optimized for adhesion to the device surface. The crystals are positioned and anchored in a way that provides localized robust attachment, preventing wash-away while maintaining the ability to deliver drug to the tissue interface.
Solution Approach 2:
The patent employs preliminary action by pre-attaching large drug crystals to the device surface before implantation. The crystals are secured to the device or embedded in the porous substrate in advance, ensuring robust attachment is established before the device encounters blood flow and mechanical stresses during the procedure.
3Strength
If drug crystals are made large and high aspect ratio, then attachment to substrate is improved, but crystal formation control becomes more difficult
Solution Approach 1:
The patent systematically changes crystallization parameters including solvent composition, temperature profiles, and evaporation rates to control the formation of high aspect ratio crystals. By adjusting these parameters, the process reliably produces crystals with the desired size range (10-100 micrometers) and aspect ratio, achieving both good attachment properties and manufacturing precision.
Solution Approach 2:
The patent uses an intermediary porous substrate or coating layer that facilitates controlled crystal growth and attachment. This intermediary structure provides a template or surface that guides crystal formation into the desired high aspect ratio morphology while ensuring reliable attachment to the device, mediating between the crystallization process and the final crystal properties.
4Reliability
If conventional crystalline drug forms are used, then solubility is limited, but with high aspect ratio crystals drug delivery consistency is improved
Solution Approach 1:
The patent changes the physical parameters of the drug delivery system by using large, high aspect ratio crystals with controlled surface area to volume ratios. This parameter change in crystal morphology provides consistent drug delivery through controlled dissolution kinetics, overcoming the limitations of conventional fine crystalline or amorphous forms that show variable solubility and unpredictable release.
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 composite materials provide consistent and reproducible drug delivery, enhancing treatment efficacy by maintaining appropriate drug concentrations at the treatment site while minimizing side effects, thus improving the treatment of vascular diseases.
Implementation Method 1
causing the solvent to evaporate to form the drug crystal
Implementation Method 2
exposing the paclitaxel to a vapor phase solvent to cause the paclitaxel to form acicular crystal habits
Data Source
AI summary
The present disclosure is directed toward composite materials comprising high aspect ratio habits of drug crystals which can be partially or fully extending into a substrate, and additionally, can be projecting from a substrate at an angle of about 20° to about 90°. The present disclosure is directed toward medical devices, such as medical balloons, comprising said composite and methods of using and making the same. The described composite can be used for the local treatment of vascular disease. The present disclosure is also directed toward paclitaxel crystals with a hollow acicular habit.