Drug Delivery System with Inert Intermediary Layer
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Solution Overview
Problem
Existing drug delivery systems often experience initial burst release and variable release rates due to saturation issues, leading to unpredictable drug concentrations and wastage, which is problematic for maintaining therapeutic efficacy and economic efficiency.
Innovation Solution
A drug delivery system comprising a core with a therapeutically active substance, an intermediary layer of inert material such as silica or talc, and a membrane, which prevents direct contact and creates an additional diffusion layer, ensuring a constant release rate over a prolonged period by delaying drug migration until exposure to body fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active agent saturates the membrane during storage, then the membrane is ready for immediate release, but burst release occurs when placed in release medium
Solution Approach 1:
The patent introduces an intermediary layer between the core containing the active agent and the membrane. This intermediary layer acts as a mediator that prevents direct contact and saturation of the membrane with the active agent during storage, thereby eliminating the burst release effect while maintaining reliable and consistent drug delivery over time.
2Reliability
If the membrane thickness is increased to control release rate, then the release becomes more constant, but the initial lag time increases
Solution Approach 1:
The patent divides the membrane system into two separate components: a thin membrane for rapid drug passage and an intermediary layer for controlled saturation and release. This segmentation allows the thin membrane to minimize lag time while the intermediary layer provides the necessary control for constant release rate, resolving the contradiction between release constancy and induction period.
3Reliability
If the drug loading concentration is increased towards the center of the device, then the release consistency is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the active agent in the core region while using an intermediary layer with different properties at the membrane interface. This creates distinct functional zones: the core provides high drug concentration for sustained release, while the intermediary layer provides controlled release kinetics, achieving release consistency without complex overall device structure.
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 system achieves a consistent and prolonged release of the active substance with minimal initial burst, reducing drug wastage and maintaining therapeutic levels, as demonstrated by experiments with levonorgestrel implants showing stable release profiles over several years.
Implementation Method 1
creates an additional diffusion layer, ensuring a constant release rate over a prolonged period by delaying drug migration until exposure to body fluids
Data Source
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AI summary
The present invention provides a novel drug delivery system for the controlled release of therapeutically active substances at a predetermined, essentially constant release rate over a prolonged period of time. The delivery system comprises at least one core comprising said therapeutically active substance(s), at least one membrane encasing the core and an intermediary layer of a substantially inert material, wherein the intermediary layer is applied between the core and the membrane or between two membrane layers.