Biodegradable Vascular Stent with pH Buffering Agent
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Solution Overview
Problem
Bioabsorbable medical devices, particularly those for vascular and cardiovascular applications, face challenges in controlling the acidic effects of degradation, which can lead to local tissue inflammation due to the release of acidic byproducts during polymer breakdown, with existing solutions failing to provide a self-regulating mechanism to mitigate these effects.
Innovation Solution
A biodegradable and bioabsorbable medical device comprising a first biodegradable material and a second bioabsorbable material that encapsulates a buffering agent, which is released in response to hydrolysis to neutralize acidic byproducts, maintaining pH levels within a safe range and potentially incorporating a therapeutic agent for delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If bulk eroding polymeric materials are used for bioabsorbable implants, then the materials can be effectively broken down over time, but acidic byproducts are released that cause local tissue inflammation
Solution Approach 1:
A buffering agent is introduced as an intermediary substance that mediates between the degrading polymer and the surrounding tissue. The buffering agent neutralizes acidic byproducts released during polymer degradation, preventing direct contact between the acid and tissue, thereby eliminating inflammation while preserving the degradation function
Solution Approach 2:
The harmful acidic byproducts of polymer degradation are converted into a beneficial neutralization process. The buffering agent transforms the acidic environment into a neutral pH environment, converting the harmful degradation byproducts into a controlled chemical reaction that protects surrounding tissue
2Object-affected harmful factors
If surface eroding polymers are used to avoid tissue inflammation, then the amount of acid released is minimized, but the degradation control mechanism is lost
Solution Approach 1:
The invention changes the chemical parameter of the degradation environment by introducing a buffering agent that maintains pH within a specific range (6.0-8.0). This parameter control allows bulk eroding polymers to degrade reliably without causing tissue inflammation, as the buffering system ensures acidic byproducts are neutralized
3Duration of action of stationary object
If biodegradable materials are used in vascular applications, then the devices can be absorbed over time, but pH control during degradation is not maintained
Solution Approach 1:
The buffering agent creates a feedback mechanism where acidic byproducts released during degradation automatically trigger neutralization. As pH drops due to acid release, the buffering agent reacts to raise pH back toward neutral, creating a self-regulating system that maintains pH control throughout the device absorption period
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 device effectively regulates the acidic environment, reducing inflammation and maintaining pH levels between 5 to 7.4, thereby enhancing biocompatibility and therapeutic efficacy by ensuring a neutral pH that prevents tissue inflammation and supports localized drug delivery.
Implementation Method 1
a buffering agent, which is dispersed from the at least one second biodegradable and/or bioabsorbable material in response to hydrolysis of the first biodegradable and/or bioabsorbable material
Implementation Method 2
These bulk eroding materials breakdown over time due to chemical hydrolysis to produce water-soluble, low molecular weight fragments
Data Source
AI summary
A vascular or cardiovascular medical device for placement at a site in a patient's body and for controlling pH levels at the site in the patient's body includes one or more structural components made of a biodegradable and/or bioabsorbable material, or alternatively, a coating thereon made of a biodegradable and/or bioabsorbable material. A buffering agent is provided on or in the biodegradable and/or bioabsorbable material and the buffering agent is dispersed from the biodegradable and/or bioabsorbable material in response to hydrolysis of the biodegradable and/or bioabsorbable material. Additionally, the vascular or cardiovascular medical device can include a drug that is included with the biodegradable and/or bioabsorbable material. The vascular or cardiovascular medical device can also be a stent or a valve.