Drug-Permeable Housing Wall for Sustained Intravesical Release
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Solution Overview
Problem
Existing intravesical drug delivery devices face challenges in maintaining consistent drug release rates beyond a few days, with osmotic pressure mechanisms failing to sustain effective drug concentrations, and conventional coatings complicating manufacturing and delaminating during device deformation.
Innovation Solution
The devices utilize a drug-permeable polymer component within the housing to control drug release through diffusion, employing a dual-wall structure of polyurethane compositions that are elastically deformable and manufactured via coextrusion, allowing for controlled drug release rates without altering mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conformal coating or sheath is added over the housing to reduce water-permeability, then the drug release rate is controlled, but manufacturing complexity increases and coating reliability decreases during device deformation
Solution Approach 1:
The housing wall is segmented into two distinct wall structures: a first wall structure (impermeable to drug, water-permeable) and a second wall structure (permeable to both drug and water). This segmentation eliminates the need for separate conformal coatings while achieving controlled drug release, thereby reducing manufacturing complexity while maintaining release consistency.
Solution Approach 2:
The device employs composite wall structures combining different material properties: the first wall structure uses water-permeable materials (e.g., polyurethane) to control water entry, while the second wall structure uses drug-permeable materials to enable controlled drug diffusion. This composite approach integrates multiple functions into the housing itself, eliminating additional coating layers and simplifying manufacturing.
2Ease of operation
If the housing is made elastically deformable for insertion and retention, then ease of operation improves, but coating integrity deteriorates during deformation
Solution Approach 1:
The housing wall structures are integrally formed and connected with the elastically deformable housing, merging the drug delivery function directly into the housing structure. This eliminates separate coatings that would delaminate during deformation, while maintaining both elastic deformability for insertion and reliable drug release kinetics.
3Productivity
If osmotic pressure mechanism is used for drug release, then initial drug release is achieved, but release duration is limited to three to four days
Solution Approach 1:
The device replaces the osmotic pressure mechanism (mechanical system) with a diffusion-based drug release mechanism through the second wall structure. This substitution enables sustained drug release over extended periods (beyond 36 hours) by controlling drug diffusion through the permeable wall structure, eliminating the rapid decline associated with osmotic mechanisms.
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
Achieves sustained zero-order drug release for therapeutic periods up to 7-14 days, maintaining effective drug concentrations in the bladder and minimizing device size and manufacturing complexity.
Implementation Method 1
water from the bladder diffusing into drug reservoir lumen to solubilize the drug
Implementation Method 2
the solubilized drug out of the device through a release aperture
Implementation Method 3
the second wall structure is permeable to the drug, such that the drug is releasable in vivo by diffusion through the second wall structure
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~6
AI summary
Drug delivery devices (1000) having a drug-permeable component and methods of making and using the same are provided. Drug delivery devices include a housing (1002) having a first (1012) and second wall (1014) structures that are adjacent one another and together form a tube (1010) defining a drug reservoir lumen (1004). The second wall structure, or both the first wall structure and the second wall structure, are permeable to water, and the first wall structure is impermeable to the drug while the second wall structure is permeable to the drug, such that the drug is releasablein vivoby diffusion through the second wall structure.