Elastomeric Drug Core Coating for Thin Membrane Adherence
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Solution Overview
Problem
Existing methods for coating drug-containing cores with elastomeric membranes are inadequate for very thin membranes, leading to insufficient drug release rates and adherence issues, particularly for poorly soluble drugs like NSAIDs, and are cumbersome in manufacturing.
Innovation Solution
A method involving dipping a core in a coating solution containing 5-40 wt-% elastomer and 60-95 wt-% solvent, with a filler like silica, to achieve a continuous coating thickness of 5-100 μm, using a pulling speed of 2.5-25 mm/s, and curing with light or heat to ensure adherence and controlled drug release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional coating methods (extrusion or vacuum expansion) are used, then coating can be applied to thicker membranes (150 μm or more), but these methods fail to achieve complete adherence and controlled release for very thin membranes (below 100 μm)
Solution Approach 1:
The patent applies parameter changes by modifying the physical state of the coating material from solid rubber to dissolved state in a solvent. The coating material is dissolved in a solvent to create a coating solution that can be uniformly applied to thin membranes, enabling complete adherence even at thicknesses below 100 μm. After application, the solvent evaporates to leave the coating material adhered to the membrane.
Solution Approach 2:
The patent uses a solvent as an intermediary substance to facilitate the coating process. The solvent acts as a medium that carries the coating material to the membrane surface, enables uniform distribution, and then evaporates to leave the coating material properly adhered. This intermediary approach solves the adherence problem for thin membranes that cannot be coated by traditional direct methods.
2Ease of manufacture
If membrane thickness is increased to improve structural integrity, then manufacturing becomes easier, but drug release rate becomes insufficient particularly for poorly soluble drugs like NSAIDs
Solution Approach 1:
The patent employs composite materials by combining the elastomeric membrane with a coating layer made of different material properties. The coating material (such as polyethylene vinyl acetate or polyurethane) has different permeability characteristics than the base membrane, creating a composite structure that controls drug release while maintaining structural integrity. This allows thin membranes to achieve both strength and controlled release performance.
Solution Approach 2:
The patent applies local quality by creating a distinct coating layer with specific properties on the surface of the membrane. This coating layer has different permeability and mechanical properties than the bulk membrane, allowing localized control of drug release at the membrane surface while the bulk membrane provides structural support. This enables thin membranes to have both integrity and controlled release.
3Manufacturing precision
If filling is reduced to achieve thinner membranes, then drug release control improves, but manufacturing complexity increases and adherence problems occur
Solution Approach 1:
The patent replaces mechanical coating methods (extrusion, vacuum expansion) with a chemical/solution-based coating approach. Instead of mechanically forming and adhering a coating layer, the coating material is dissolved in a solvent, applied as a solution that penetrates and bonds to the membrane, then the solvent evaporates. This substitution simplifies the manufacturing process for thin membranes and eliminates adherence problems associated with mechanical methods.
4Manufacturing precision
If coating material is applied to control initial release and limit burst effect, then drug release profile improves, but coating may not completely adhere to outer surface causing trouble during use
Solution Approach 1:
The patent changes the physical state parameter of the coating material from solid to dissolved state during application. By applying the coating material as a solvent-based solution, it can uniformly penetrate and bond to the membrane surface at molecular level. After solvent evaporation, the coating material remains completely adhered, eliminating the partial adhesion problems that cause reliability issues during use.
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
This method enables complete adherence of the silicon-based membrane to the core, modifying drug release based on physicochemical properties, and achieving consistent drug delivery with membrane thicknesses of 10-100 μm, improving release rates for drugs like indomethacin.
Implementation Method 1
dipping the core to a coating solution contains 5-40 wt-% elastomer and 95-60 wt-% solvent... using a pulling speed suitable for providing a coating thickness of 5-100 μm
Implementation Method 2
curing the dipped core to provide a coated core
Data Source
AI summary
The present invention relates to a method for modifying release of a therapeutically active agent from an elastomeric matrix, comprising providing a core comprising an elastomeric matrix and a therapeutically active agent; dipping the core to a coating solution of an elastomer, wherein the elastomer comprises 20-35 wt-% of a filler, calculated from the total amount of filler and elastomer; curing the dipped core to provide a coated core. In this method the dipping is provided as a continuous process by pulling the core through the coating solution, using a pulling speed suitable for providing a coating thickness of δ-IOO the filler is selected from silica, titanium dioxide, barium sulphate, carbon and mixtures thereof; the elastomer comprised in the core and the elastomer comprised in the coating solution are independently selected from poly(dimethyl) siloxanes, polyethylene vinyl acetates (EVAs), polyurethanes (PUs), polyhydroxyethyl methacrylates (PHEMAs) and polymethyl methacrylates (PMMAs).