Free Ropinirole Adhesive Patch Formulation

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Solution Overview

Problem

Transdermal absorption preparations using acid addition salts of ropinirole have lower absorbability and stability compared to free ropinirole, and can cause skin irritation due to metal salt precipitation, affecting the physical properties of patches.

Innovation Solution

A transdermal absorption patch containing free ropinirole in an adhesive base with a styrene-isoprene-styrene (SIS) block copolymer, rosin-based tackifier resin, and a softener, with a specific compounding ratio of rosin-based resin to free ropinirole, ensuring complete dissolution and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acid addition salt of ropinirole is used in transdermal preparation, then stability and handleability are improved, but transdermal absorbability deteriorates

Engineering Contradiction:

ImprovestabilityVSAvoidtransdermal absorbability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the chemical form parameter of ropinirole from acid addition salt to free base form, and optimizes the pH parameter of the adhesive base to 6.0-8.0 to maintain free ropinirole in dissolved state, thereby achieving both high transdermal absorbability and stability without requiring desalting agents

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite adhesive base system comprising SIS block copolymer, rosin-based tackifier resin, and softener, where the specific combination of materials creates an environment that dissolves and stabilizes free ropinirole while maintaining transdermal delivery capability

Inventive Principle:

Principle #40Composite materials

2Productivity

If desalting agent is used to convert acid addition salt to free ropinirole, then transdermal absorbability is improved, but metal salt precipitation occurs causing skin irritation and deterioration of patch physical properties

Engineering Contradiction:

Improvetransdermal absorbabilityVSAvoidskin irritation

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent completely eliminates desalting agents and metal salts from the formulation by using free ropinirole base form from the beginning, thereby removing the source of metal salt precipitation and skin irritation while maintaining high transdermal absorbability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harm of using acid addition salts (which require desalting and cause metal precipitation) into a benefit by directly using the free base form that is inherently suitable for transdermal delivery without requiring conversion, thus eliminating all associated problems

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If amount of drug in adhesive base is limited, then physical properties of patch are maintained, but continuous transdermal absorbability cannot be provided

Engineering Contradiction:

Improvephysical propertiesVSAvoidcontinuous transdermal absorbability

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The patent optimizes the pH parameter of the adhesive base to 6.0-8.0 and controls the compounding ratio of rosin-based resin to free ropinirole (3.5:1 to 8.0:1 by weight), which maximizes the dissolution capacity of the adhesive base for free ropinirole, allowing high drug loading while maintaining physical properties and enabling continuous transdermal absorption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite adhesive system where SIS provides structural framework, rosin-based tackifier resin provides dissolution medium for free ropinirole, and softener adjusts viscosity, creating a synergistic system that can accommodate high drug concentrations while maintaining patch integrity and continuous delivery

Inventive Principle:

Principle #40Composite materials

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 transdermal absorbability, stability, and adhesiveness, effectively delivering ropinirole for Parkinson's disease treatment while preventing crystallization and skin irritation.

Implementation Method 1

free ropinirole being contained in a specific compounding ratio... complete dissolution of the free ropinirole in the adhesive base

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

transdermal absorbability... favorable and continuous transdermal absorbability

Methodology Applied

Scientific EffectTransdermal absorption: Absorption (physical)

Data Source

PatentEP2926814B1Ropinirole-containing adhesive patch

Publication Date: 2019.03.27 TEIKOKU SEIYAKU CO LTD

AI summary

A patch containing free ropinirole (ropinirole in free form) in an adhesive base is provided, in which the patch exhibits favorable and continuous transdermal absorbability, high drug stability, and excellent adhesiveness. A transdermal absorption patch includes free ropinirole added to an adhesive base that contains a styrene-isoprene-styrene block copolymer (SIS), one or two or more tackifier resins containing a rosin-based resin, and a softener. The transdermal absorption patch is characterized in that the compounding ratio of the rosin-based resin to the free ropinirole represented as the ratio of the weight of the combined rosin-based resin to the free ropinirole is 3.5 to 8.0. In particular, a ropinirole-containing patch wherein the rosin-based resin is a hydrogenated rosin glycerol ester and the softener is liquid paraffin is provided.