Three-Layer Vaginal Ring for Stable Multi-Drug Release
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Solution Overview
Problem
Existing vaginal ring drug delivery systems for contraception and hormone replacement therapy face challenges in maintaining a constant release ratio of multiple active substances over time, requiring special storage conditions and prone to burst releases due to steroid crystallization.
Innovation Solution
A three-layer vaginal ring design comprising a medicated thermoplastic polymer core, an intermediate layer with both crystalline and dissolved active substances, and a non-medicated thermoplastic polymer skin, which maintains physical stability at room temperature and allows independent adjustment of release rates for multiple active compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vaginal ring system releases two or more active substances simultaneously, then the therapeutic effect is improved, but maintaining a constant release ratio over time becomes difficult
Solution Approach 1:
The vaginal ring is divided into multiple compartments, with each compartment containing a different active substance. This segmentation allows independent control of each substance's release characteristics while maintaining their simultaneous delivery, resolving the contradiction between maintaining constant release ratio and managing device complexity.
Solution Approach 2:
Different compartments are designed with locally optimized properties including specific polymers, porosity levels, and thicknesses tailored to each active substance's release requirements. This local quality approach enables precise control over release ratios while keeping the overall device structure manageable.
2Ease of operation
If the vaginal ring is stored at room temperature, then storage convenience is improved, but steroid crystallization occurs leading to burst release
Solution Approach 1:
The patent modifies critical parameters including polymer composition, drug-polymer ratio, and ring structure to expand the stable storage temperature range. By changing these parameters, the system maintains physical stability at room temperature without steroid crystallization, enabling convenient storage while preserving release stability.
Solution Approach 2:
The vaginal ring employs composite materials consisting of specific polymer blends and optimized drug-polymer formulations. These composite materials provide enhanced thermal stability and prevent crystallization at room temperature, resolving the contradiction between storage convenience and release stability.
3Manufacturing precision
If separate reservoirs are used for different active substances, then release ratio control is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple compartments containing different active substances are merged into a single integrated vaginal ring structure. This combining approach maintains precise release ratio control through controlled porosity and polymer composition while simplifying manufacturing by eliminating separate assembly steps for multiple independent reservoirs.
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 design ensures a stable and prolonged release of active substances, preventing burst releases and allowing for flexible adjustment of release rates while maintaining physical stability at room temperature, enhancing the effectiveness and convenience of the drug delivery system.
Implementation Method 1
transport (diffusion) of active material from one reservoir to the other takes place through the wall of the tube
Data Source
AI summary
The subject invention provides a drug delivery system comprising at least one compartment consisting of (i) a drug-loaded thermoplastic polymer core, (ii) a drug-loaded thermoplastic polymer intermediate layer and (iii) a non-medicated thermoplastic polymer skin covering the intermediate layer, wherein said intermediate layer is loaded with (a) crystals of a first pharmaceutically active compound and with (b) a second pharmaceutically active compound in dissolved form and wherein said core is loaded with said second compound in dissolved form.