Drug-Permeable Implant Structure for Extended Diffusion Release
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Solution Overview
Problem
Existing implantable drug delivery devices face challenges in achieving extended, controlled drug release for drugs with low water solubility, particularly over several days or weeks, while maintaining a minimally invasive design to avoid patient discomfort and ensuring the device remains small enough for comfort and safety.
Innovation Solution
The devices utilize a housing with a first impermeable wall structure and a hydrophilic, drug-permeable second wall structure to control drug release through diffusion, avoiding osmotic mechanisms and ensuring compliance with bladder movements to minimize discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a drug delivery device uses osmotic mechanisms for controlled release, then extended drug delivery is achieved, but patient discomfort increases due to device size and bladder movement compliance issues
Solution Approach 1:
The patent replaces osmotic mechanisms with a passive diffusion-based drug delivery system. The device uses a hydrophilic matrix that allows drug molecules to diffuse through wall structures without requiring osmotic pressure generation, thereby eliminating the need for complex osmotic pumps or reservoirs that would increase device size and cause discomfort during bladder movements.
Solution Approach 2:
The patent changes the drug delivery mechanism from active osmotic transport to passive diffusion by modifying the wall structure properties. The wall structures are designed with specific permeability characteristics that enable controlled drug diffusion rates, achieving extended delivery through material property optimization rather than mechanical osmotic systems.
2Volume of moving object
If the device is made small for minimally invasive insertion, then patient discomfort is reduced, but achieving extended controlled release for low water solubility drugs becomes difficult
Solution Approach 1:
The patent employs wall structures with controlled porosity and permeability that allow small-volume devices to achieve extended drug release. The porous/hydrophilic wall materials provide large surface area for drug diffusion relative to the compact device volume, enabling sustained release of low water solubility drugs without requiring large device size.
Solution Approach 2:
The device utilizes composite wall structures combining hydrophilic and non-hydrophilic materials to achieve both compact size and extended drug release. The composite structure allows optimization of drug diffusion pathways while maintaining small overall device volume suitable for minimally invasive insertion.
3Duration of action of moving object
If the device uses a hydrophilic permeable wall structure for drug diffusion, then controlled drug release is achieved, but water solubility requirements limit drug selection
Solution Approach 1:
The patent applies local quality by creating wall structures with spatially varying properties - hydrophilic regions for water absorption and drug diffusion, and non-hydrophilic regions for structural integrity. This localized differentiation allows the device to handle drugs with varying water solubility characteristics by optimizing different wall regions for specific drug properties.
Solution Approach 2:
The device wall is segmented into multiple functional layers or regions with different permeability characteristics. This segmentation allows the structure to accommodate drugs with varying solubility requirements by providing different diffusion pathways - hydrophilic pathways for water-soluble drugs and alternative mechanisms for low water solubility drugs.
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 enables a zero-order drug release rate for extended periods, maintaining therapeutic drug levels without causing discomfort, and allows for a compact design suitable for intravesical insertion and retention.
Implementation Method 1
releasing a drug from the drug reservoir lumen via diffusion through the second wall structure
Implementation Method 2
a hydrophilic second wall structure
Data Source
AI summary
Implantable drug delivery devices include a housing having a closed drug reservoir lumen bounded by a first wall structure and a hydrophilic second wall structure, and a drug contained in the drug reservoir lumen, wherein the first wall structure is impermeable to the drug and the second wall structure is permeable to the drug. Methods of providing controlled release of drug to a patient include deploying a drug delivery device in the patient releasing a drug from the drug reservoir lumen via diffusion through the second wall structure.