Flurbiprofen Plaster Adhesive Composition for Transdermal Stability
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Solution Overview
Problem
Existing flurbiprofen-containing plasters for external use face issues with poor transdermal absorptivity, stability, and skin irritation, with previous formulations experiencing crystal deposition and inadequate drug release due to volatile solvents and residual adhesives.
Innovation Solution
A plaster with an adhesive layer comprising 5-50% styrene-isoprene-styrene block copolymer, 20-70% rosin-based tackifying resin, and 5-60% liquid paraffin, where the rosin resin is blended in a ratio of 10 times or more with flurbiprofen, preventing crystal deposition and enhancing transdermal absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a water-soluble polymer is used as the adhesive base, then the plaster is easy to manufacture and apply, but flurbiprofen cannot be blended in high concentration and transdermal absorption is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive base from water-soluble polymer to rubber-based adhesive containing specific resolvents (1-menthol, lactic acid ester, or flurbiprofen itself). This parameter change enables high concentration blending of flurbiprofen (5-50% by weight) while maintaining adequate transdermal absorption, resolving the contradiction between ease of manufacture and drug absorption effectiveness.
2Stability of the object's composition
If 1-menthol is used as the resolvent, then flurbiprofen can be dissolved well, but 1-menthol vaporizes during storage and flurbiprofen crystals may generate
Solution Approach 1:
The patent replaces the volatile 1-menthol resolvent with alternatives that have longer stability: lactic acid ester (which degrades more slowly) or flurbiprofen itself as the resolvent. These substitutes maintain adequate drug dissolution while significantly reducing the loss of substance during storage, addressing the instability issue without sacrificing solubility.
Solution Approach 2:
The patent introduces lactic acid ester or flurbiprofen as an intermediary substance that mediates between the adhesive base and flurbiprofen drug. This intermediary provides sustained solubility support during storage without the rapid volatility of 1-menthol, preventing crystal formation while maintaining drug availability for transdermal absorption.
3Stability of the object's composition
If lactic acid ester is used as the resolvent, then flurbiprofen can be dissolved, but residual adhesive remains on skin after detachment and skin irritation occurs
Solution Approach 1:
The patent extracts and eliminates the harmful residual adhesive effect by optimizing the adhesive composition and detachment properties. By carefully selecting the rubber-based adhesive and resolvent combination, and controlling the formulation ratios, the plaster achieves complete detachment from skin without leaving irritating residues, while still maintaining adequate flurbiprofen dissolution and transdermal absorption.
4Device complexity
If the adhesive contains little dissolving component, then the adhesive structure is simple, but flurbiprofen disperses in crystal forms and drug releasability is poor
Solution Approach 1:
The patent changes the compositional parameters of the adhesive to include adequate amounts of resolvent (5-60% by weight of the adhesive layer) in the form of lactic acid ester or flurbiprofen itself. This parameter adjustment ensures flurbiprofen remains in dissolved state rather than crystalline dispersion, significantly improving drug releasability while maintaining relatively simple rubber-based adhesive structure.
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 solution provides stable, long-term transdermal administration of flurbiprofen with high releasability and minimal skin irritation, as demonstrated by in-vitro drug release tests and storage stability results.
Implementation Method 1
the adhesive layer contains 5 to 50% by weight of a styrene-isoprene-styrene block copolymer (SIS), 20 to 70% by weight of a tackifying resin, and 5 to 60% by weight of a softener which are essential ingredients, and further contains flurbiprofen blended as an active ingredient
Implementation Method 2
transdermally absorbable preparations that will not pass along a gastrointestinal tract, liver and the like attract the attention
Data Source
AI summary
In a plaster for external use for transdermal absorption in which an adhesive layer is laminated on a plastic backing, the adhesive layer contains a styrene-isoprene-styrene block copolymer (SIS), a tackifying resin and a softener which are essential ingredients, and further contains flurbiprofen blended as an active ingredient. The present plaster for external use is a flurbiprofen containing plaster for external use enabling long-term stable release of contained flurbiprofen, and having excellent stability and very high drug releasing property.