Ropinirole Patch Adhesive Layer Optimization
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Solution Overview
Problem
Conventional ropinirole transdermal patches face challenges in achieving sufficient skin permeability and adhesiveness due to the use of ropinirole acid addition salts, which reduce skin permeability and stability, and increasing the concentration of ropinirole in the adhesive agent layer to improve permeation complicates adhesive properties.
Innovation Solution
A ropinirole-containing patch with an adhesive agent layer containing 5-13.2% ropinirole by mass and 0.12-2.7 mg/cm² per unit area, combined with specific additives like benzyl alcohol and isopropyl palmitate, and a support layer, sealed with a deoxidizer to enhance stability and skin permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the concentration of ropinirole in the adhesive agent layer is increased to improve skin permeability, then the amount of ropinirole permeated through the skin increases, but the adhesive properties deteriorate and adhesiveness is reduced
Solution Approach 1:
The patent optimizes the concentration parameters of ropinirole free form in the adhesive agent layer, specifying it should be 1-10% by mass. This parameter control ensures sufficient ropinirole permeation while preventing excessive plasticizing effects that would compromise adhesive properties. The patent also controls the content of ropinirole acid addition salt to 90-99% by mass to balance stability and permeability.
Solution Approach 2:
The patent introduces a metal salt produced by reaction of ropinirole acid addition salt with a metal-ion containing desalting agent as an intermediary substance. This metal salt acts as a mediator that facilitates ropinirole permeation through the skin without directly using high concentrations of free ropinirole that would harm adhesive properties. The desalting agent converts the acid addition salt to the free form in a controlled manner.
2Stability of the object's composition
If ropinirole acid addition salt is used to improve handleability and stability, then storage stability improves, but skin permeability is reduced
Solution Approach 1:
The patent incorporates a desalting agent in the adhesive agent layer that preliminarily converts ropinirole acid addition salt to ropinirole free form before application. This preliminary conversion action ensures that the stable acid addition salt form is transformed into the highly permeable free form at the application site, achieving both stability during storage and permeability during use.
Solution Approach 2:
The patent specifies precise compositional parameters: ropinirole acid addition salt at 90-99% by mass and desalting agent at 0.1-10% by mass. This parameter control creates an optimal balance where the majority component provides stability while the smaller component enables permeability conversion through desalting reaction.
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 excellent skin permeability and adhesiveness while maintaining ropinirole stability over time, ensuring effective plasma concentrations for treating Parkinson's disease and restless legs syndrome.
Implementation Method 1
the present inventors have found out that by sealing and storing such a ropinirole-containing patch together with a deoxidizer, the ropinirole stability over time is further improved
Implementation Method 2
the skin permeability of ropinirole still has not been sufficient, making it difficult to keep the ropinirole concentration in the plasma at a sufficiently high level
Data Source
AI summary
A ropinirole-containing patch comprises an adhesive agent layer and a support layer, the adhesive agent layer containing ropinirole and/or a pharmaceutically acceptable salt thereof, wherein a content of the ropinirole and/or the pharmaceutically acceptable salt thereof in terms of free ropinirole in the adhesive agent layer satisfies the following two conditions:5 to 13.2% by mass relative to a total mass of the adhesive agent layer, and0.12 to 2.7 mg/cm2 per unit area of the adhesive agent layer.