Rotigotine Patch Adhesive Layer Crystallization Prevention
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Solution Overview
Problem
Rotigotine-containing patches face challenges with rotigotine precipitating into crystals over time, reducing skin permeability and stability, especially when using conventional adhesives like silicone or acrylic-based agents, and antioxidants do not adequately address these issues.
Innovation Solution
Incorporating rotigotine and its pharmaceutically acceptable salts into an adhesive layer with a styrene-based thermoplastic elastomer, petroleum-based or terpene-based resins, an aliphatic alcohol, and cross-linked polyvinylpyrrolidone, maintaining a specific mass ratio to ensure rotigotine remains dissolved and stable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If rotigotine is contained in an amorphous form in the presence of rotigotine alone or polyvinylpyrrolidone, then the drug can be incorporated into the patch, but the amorphous form transforms into a crystal form over time causing precipitation
Solution Approach 1:
The patent introduces cross-linked polyvinylpyrrolidone as an intermediary substance that mediates between rotigotine and the adhesive base agent. This cross-linked polymer prevents the transformation from amorphous to crystalline form by acting as a stabilizing matrix, thereby maintaining rotigotine in a dissolved state without precipitation while still allowing adequate drug incorporation into the patch.
Solution Approach 2:
The patent changes the physical and chemical parameters of the polyvinylpyrrolidone by using its cross-linked form rather than the conventional non-cross-linked form. This parameter change (from linear to cross-linked structure) fundamentally alters the polymer's ability to stabilize rotigotine in an amorphous state, preventing crystallization while maintaining drug solubility and patch integrity.
2Ease of manufacture
If conventional adhesives like silicone-based or acrylic-based agents are used, then the patch can be manufactured, but rotigotine does not dissolve or precipitates over time reducing skin permeability
Solution Approach 1:
The patent creates a composite adhesive system by combining a rubber-based adhesive base agent with cross-linked polyvinylpyrrolidone. This composite material integrates the adhesive properties needed for patch manufacturing with the stabilizing properties that prevent rotigotine precipitation. The synergistic combination ensures both ease of manufacture and reliable drug dissolution with maintained skin permeability.
3Stability of the object's composition
If antioxidants are used to prevent decomposition, then some stability is improved, but they do not adequately prevent crystal precipitation and reduce skin permeability
Solution Approach 1:
The patent uses cross-linked polyvinylpyrrolidone as an intermediary that addresses the limitations of antioxidants. While antioxidants prevent chemical decomposition, the cross-linked polymer provides an additional stabilization mechanism by preventing physical transformation from amorphous to crystalline form. This dual approach maintains both chemical stability and physical solubility, ensuring adequate skin permeability is preserved.
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 patch achieves high skin permeability and long-term stability of rotigotine, preventing crystallization and maintaining effective drug delivery.
Implementation Method 1
the adhesive agent layer contains rotigotine and/or a pharmaceutically acceptable salt thereof in a dissolved form, and further contains a styrene-based thermoplastic elastomer, a petroleum-based resin and/or a terpene-based resin, an aliphatic alcohol, and cross-linked polyvinylpyrrolidone
Implementation Method 2
a rotigotine-containing patch comprising: a backing layer; and an adhesive agent layer, wherein the adhesive agent layer contains rotigotine and/or a pharmaceutically acceptable salt thereof in a dissolved form
Data Source
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AI summary
The present invention provides a rotigotine-containing patch comprising: a backing layer; and an adhesive agent layer, wherein the adhesive agent layer contains rotigotine and/or a pharmaceutically acceptable salt thereof, the adhesive agent layer further contains a styrene-based thermoplastic elastomer, a petroleum-based resin and/or a terpene-based resin, an aliphatic alcohol, and a cross-linked polyvinylpyrrolidone, and in the adhesive agent layer, a mass ratio of a content of the rotigotine and/or the pharmaceutically acceptable salt thereof in terms of rotigotine free form and a content of the cross-linked polyvinylpyrrolidone (content of the rotigotine and/or the pharmaceutically acceptable salt thereof in terms of rotigotine free form : content of the cross-linked polyvinylpyrrolidone) is 10 : 3 to 1 : 3.