Implantable Analgesic Depots With Diffusion-Opening Control Regions
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Solution Overview
Problem
Existing implantable drug delivery systems lack a true controlled release mechanism, often resulting in a burst of drug upon contact with physiologic fluids followed by residual release, which is inadequate for sustained therapeutic effects.
Innovation Solution
A depot for controlled release of therapeutic agents, comprising a therapeutic region with an analgesic and a bioresorbable polymer mixed with a releasing agent, configured to provide sustained release over 7 to 14 days, with specific release profiles and ratios, and a control region that forms diffusion openings in vivo to manage drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydrophilic polymers are added as wetting agents to accelerate drug release, then immediate release of hydrophobic drug is enhanced, but controlled sustained release is lost
Solution Approach 1:
The implant is divided into distinct functional regions: a hydrophobic core region containing the therapeutic agent and a hydrophilic shell region containing wetting agents. This segmentation allows the core to provide sustained release while the shell facilitates controlled wetting and drug diffusion, resolving the contradiction between rapid release and sustained duration.
Solution Approach 2:
Different regions of the implant have different material properties: the core is hydrophobic to maintain structural integrity and provide sustained release, while the shell is hydrophilic to enhance wetting and facilitate controlled drug diffusion. This local differentiation of material properties allows simultaneous achievement of both rapid initial release and sustained duration.
2Object-affected harmful factors
If biocompatible polymers are used for localized delivery, then systemic side effects are avoided, but burst release followed by residual release occurs
Solution Approach 1:
The implant structure is segmented into a hydrophobic core containing the therapeutic agent and a hydrophilic shell containing wetting agents. This segmentation enables localized delivery through the shell while controlling the release kinetics to prevent harmful burst release, thereby maintaining both localized delivery benefits and reliable controlled release.
Solution Approach 2:
The hydrophilic shell acts as an intermediary layer between the hydrophobic core and the physiological environment. This intermediary facilitates controlled wetting and drug diffusion, preventing direct contact between the hydrophobic drug and physiological fluids that would cause burst release, thus ensuring reliable controlled release while maintaining localized delivery.
3Duration of action of moving object
If large dose of therapeutic agent is implanted, then extended release period is achieved, but initial burst release increases
Solution Approach 1:
The implant is segmented into a hydrophobic core containing the large dose of therapeutic agent and a hydrophilic shell containing wetting agents. This segmentation allows the core to provide extended release duration while the shell controls the release kinetics to minimize initial burst release, resolving the contradiction between large dose loading and burst release magnitude.
Solution Approach 2:
The hydrophobic core provides the large dose storage capacity for extended duration, while the hydrophilic shell provides controlled wetting and diffusion properties to minimize burst release. This local differentiation of material properties allows simultaneous achievement of large dose loading and controlled release kinetics.
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 depot achieves a highly controlled, sustained release of analgesics at surgical or interventional sites, minimizing initial burst release and ensuring consistent drug delivery over an extended period.
Implementation Method 1
a releasing agent configured to dissolve when the implant is placed in contact with physiologic fluids to form diffusion openings in the control region
Implementation Method 2
form diffusion openings in the control region... release the therapeutic agent at the treatment site
Data Source
AI summary
The present technology relates to depots for the treatment of postoperative pain via sustained, controlled release of a therapeutic agent. In some embodiments, the depot may comprise a therapeutic region comprising an analgesic, and a control region comprising a bioresorbable polymer and a releasing agent mixed with the polymer. The releasing agent may be configured to dissolve when the depot is placed in vivo to form diffusion openings in the control region. The depot may be configured to be implanted at a treatment site in vivo and, while implanted, release the therapeutic agent at the treatment site for no less than 3 days.