Adhesive Skin Patch Preventing Ropinirole Analogue Formation
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Solution Overview
Problem
The production of transdermal preparations with enhanced transdermal absorbability of ropinirole is hindered by the formation of ropinirole analogues in the adhesive layer, which affects the stability of the preparation.
Innovation Solution
A patch comprising a backing layer and a pressure-sensitive adhesive layer containing ropinirole, a metal salt produced by reacting a ropinirole acid adduct with a metal ion containing desalting agent in an equivalent mole or less, and an adhesive base without hydroxyl or carboxyl groups, along with an adsorbent to prevent analogue formation and enhance absorbability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ropinirole acid adduct salt is used as a starting material for producing a transdermal preparation and desalting is performed during production or after production, then transdermal absorbability of ropinirole is enhanced, but ropinirole analogues are formed in the adhesive and stability of the preparation deteriorates
Solution Approach 1:
The harmful byproduct (ropinirole analogue) is extracted/removed from the system by using an adhesive base that does not contain hydroxyl or carboxyl groups, preventing the analogue formation reaction from occurring in the first place. This resolves the contradiction by eliminating the source of instability while maintaining the desired transdermal absorbability through proper desalting during production.
Solution Approach 2:
The chemical composition parameters of the adhesive base are changed by selecting materials without hydroxyl or carboxyl groups. This parameter change prevents the formation of ropinirole analogues while allowing the desalting process to proceed effectively, thus maintaining both high transdermal absorbability and preparation stability.
2Reliability
If a free form of ropinirole is used for transdermal administration, then transdermal absorbability is improved, but the handleability and stability of the drug deteriorate
Solution Approach 1:
The desalting action is performed preliminarily during the production process rather than after production. By converting the acid adduct salt to free form ropinirole in advance and removing the salt, the preparation achieves high transdermal absorbability while maintaining ease of manufacture through controlled production conditions.
3Stress or pressure
If an adhesive base containing hydroxyl groups or carboxyl groups is used, then adhesion properties are improved, but ropinirole analogues are formed and preparation stability deteriorates
Solution Approach 1:
The chemical parameters of the adhesive base are changed by selecting materials without hydroxyl or carboxyl groups. This prevents analogue formation and maintains stability. The adhesion properties are maintained through selection of alternative adhesive materials that provide sufficient bonding without the problematic functional groups.
Solution Approach 2:
A composite adhesive system is used that combines materials providing adhesion through mechanisms other than hydroxyl or carboxyl groups. This composite approach maintains necessary adhesion properties while eliminating the chemical groups that cause ropinirole analogue formation, thus resolving the stability issue.
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 effectively prevents the formation of ropinirole analogues, ensuring excellent transdermal absorbability and stability of ropinirole, with the use of specific metal salts and adsorbents like talc or fumed silica preventing aggregation and improving patch appearance.
Implementation Method 1
adsorbent which adsorbs a polar solvent contained in the pressure-sensitive adhesive layer
Implementation Method 2
ropinirole and a metal salt produced by a reaction of a ropinirole acid adduct and a metal ion containing desalting agent
Data Source
Figure 1
AI summary
A patch 1 comprising a backing layer 2 and a pressure-sensitive adhesive layer 3 formed on the backing layer 2, wherein the pressure-sensitive adhesive layer 3 contains (i) ropinirole and a metal salt produced by the reaction of a ropinirole acid adduct and a metal ion containing desalting agent in an equivalent mole or less to the acid adduct and (ii) an adhesive base free of a hydroxyl group and a carboxy group.