Transdermal Adhesive Formulation Stability via Solvent Extraction
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Solution Overview
Problem
Commercially available transdermal therapeutic systems face issues with reduced availability and chemical degradation of active ingredients due to interactions with polymer matrices and solvents, leading to decreased storage stability and potential skin irritation.
Innovation Solution
A method involving the use of a carboxylic acid ester-based solvent replacement with an organic solvent lacking ester groups, along with removing residual monomers, to enhance the availability and stability of active ingredients in the adhesive formulation, specifically using ethyl acetate as the solvent and tetrahydrofuran for redissolution, and incorporating active ingredients with hydroxyl, carboxyl, or amino groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercially available pressure-sensitive adhesives containing carboxylic acid ester-based solvents and unreacted monomers are used, then the adhesive formulation can be easily manufactured, but the active ingredient undergoes reactions and interactions leading to reduced availability and degraded storage stability
Solution Approach 1:
The patent removes the harmful components (carboxylic acid ester-based solvents and unreacted monomers) from the adhesive formulation through extraction processes. This eliminates the substances that cause reactions with the active ingredient, thereby resolving the contradiction between ease of manufacture and storage stability by sacrificing the convenient commercial adhesive formulation for a purified, stable system.
Solution Approach 2:
The patent changes the chemical parameters of the adhesive formulation by replacing carboxylic acid ester-based solvents with alternative solvents that do not react with the active ingredient. This parameter change (solvent composition) maintains manufacturability while dramatically improving storage stability and active ingredient availability.
2Ease of manufacture
If commercially available pressure-sensitive adhesives are used, then the manufacturing process is simple, but reaction products form that cause skin irritation and reduce therapeutic effectiveness
Solution Approach 1:
The patent extracts and removes the harmful reaction products and unreacted monomers from the adhesive formulation. By eliminating these harmful substances through purification steps, the patent resolves the contradiction between simple manufacturing and the generation of skin-irritating byproducts.
Solution Approach 2:
The patent converts the harmful interaction between adhesive components and active ingredient into a benefit by deliberately designing a formulation where the adhesive matrix protects the active ingredient from degradation, ensuring only the intended therapeutic substance is delivered to the skin without harmful byproducts.
3Ease of manufacture
If the adhesive formulation contains carboxylic acid ester-based solvents and monomers, then the polymer matrix can be easily formed, but the concentration of active ingredient decreases over time due to reactions
Solution Approach 1:
The patent removes the reactive components (carboxylic acid ester-based solvents and monomers) that cause active ingredient degradation. This extraction preserves the active ingredient concentration over time while maintaining a workable manufacturing process for the purified adhesive matrix.
Solution Approach 2:
The patent changes the chemical composition parameters of the adhesive formulation by substituting reactive solvents with non-reactive alternatives. This parameter change prevents the chemical reactions that would otherwise deplete the active ingredient, maintaining consistent concentration throughout the product shelf life.
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 approach significantly increases the availability of active ingredients and reduces reaction products, thereby improving the storage stability and skin absorption of active ingredients, ensuring a higher and more consistent release over extended periods.
Implementation Method 1
redissolving the mass obtained in step b) in an organic solvent that does not contain ester groups
Implementation Method 2
applied to a carrier, and then the solvent is removed, resulting in an adhesive polymer matrix on the carrier
Implementation Method 3
applied to a carrier, and then the solvent is removed, resulting in an adhesive polymer matrix on the carrier
Data Source
AI summary
The invention relates to a process for preparing an active-principle-containing adhesive formulation for use in a transdermal therapeutic system, comprising the following steps: a) providing an adhesive formulation containing a carboxylic acid ester-based solvent and a self-adhesive polymer matrix containing monomers of the compounds on which the polymer matrix is based, b) removing the carboxylic acid ester-based solvent and the monomers from the adhesive formulation, c) re-dissolving the compound obtained in step b) in an organic solvent that does not contain any ester groups, and adding a pharmacologically active principle having at least one hydroxyl group, carboxyl group, amino group and/or ester group so that the active-principle-containing adhesive formulation is obtained. The invention also relates to a transdermal therapeutic system containing the active-principle-containing adhesive formulation. The invention further relates to the use of said transdermal therapeutic system and to a kit containing the transdermal therapeutic system.