Rivastigmine Transdermal Patch Using Saturated Fatty Acid
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Solution Overview
Problem
Existing rivastigmine patches face challenges with variable skin permeability depending on drug concentration, thickness of the drug layer, and type of tackifier resin, which affects affixing feeling and pressure-sensitive adhesive properties.
Innovation Solution
A non-aqueous patch with a drug-containing pressure-sensitive adhesive layer comprising rivastigmine, 0.3% to 1% by mass of a saturated fatty acid with 20 to 24 carbon atoms, and a rubber-based pressure-sensitive adhesive containing a styrene-isoprene-styrene block copolymer and polyisobutylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the drug layer is increased to enhance skin permeability, then the skin permeation rate of rivastigmine is improved, but the affixing feeling deteriorates due to changes in preparation weight and stiffness
Solution Approach 1:
The invention changes the chemical composition parameter by introducing a specific saturated fatty acid (20-24 carbon atoms) at an optimized concentration (0.3-1% by mass) to enhance skin permeability without increasing layer thickness, thereby maintaining proper mechanical properties and affixing feeling
Solution Approach 2:
The invention creates a composite pressure-sensitive adhesive system combining rubber-based adhesive with saturated fatty acid and SIS block copolymer, where the fatty acid acts as a penetration enhancer while the copolymer maintains adhesive properties, achieving both high permeation and good affixing feeling
2Reliability
If a complex multi-layer structure is used to improve drug delivery control, then the skin permeability is enhanced, but the manufacturing cost increases and the attachment property deteriorates due to increased thickness
Solution Approach 1:
The invention merges multiple functions into a single integrated pressure-sensitive adhesive layer that simultaneously provides drug delivery, skin permeation enhancement, and adhesive attachment, eliminating the need for separate controlling membrane and adhesive layers while reducing overall thickness and complexity
Solution Approach 2:
The pressure-sensitive adhesive layer is designed to perform multiple functions: serving as the drug reservoir, providing skin permeation enhancement through fatty acid, and maintaining attachment properties, thereby replacing multiple specialized layers with a single multi-functional layer
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 a high skin permeation rate of rivastigmine while maintaining improved pressure-sensitive adhesive force, ensuring long-term drug efficacy with satisfactory affixing feeling.
Implementation Method 1
R. Jayachandra Babu, et al. , Percutaneous Penetration Enhancers Chemical Methods in Percutaneous Penetration Enhancement : Modification of the Stratum Corneum, Berlin Heidelberg, Springer-Verlag, (2015), pages 133 - 144, 9, ISBN 978-3-662-47039-8, discloses fatty Alcohols, fatty Acids, and fatty acid esters as penetration enhancers.
Data Source
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Figure 3
AI summary
Provided is means capable of enhancing the skin permeability of rivastigmine without adversely affecting the pressure-sensitive adhesive property of a patch. Specifically, provided is a non-aqueous patch, comprises: a support; a drug-containing pressure-sensitive adhesive layer; and a release liner, wherein the drug-containing pressure-sensitive adhesive layer comprises: rivastigmine; 0.3 % by mass or more of a saturated fatty acid having 20 to 24 carbon atoms; and a rubber-based pressure-sensitive adhesive.