Transdermal Patch Adhesive Layer with Hydrocarbon Oil
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Solution Overview
Problem
Transdermal drug patches often face issues with skin irritation and low adhesiveness, particularly for drugs like rivastigmine, which can lead to adverse reactions, especially in elderly patients with dry skin, due to the use of tackifiers and rubber-based adhesive matrices.
Innovation Solution
A patch design incorporating a thermoplastic elastomer and non-volatile hydrocarbon oil at specific weight ratios, with reduced tackifier content, to enhance skin adhesiveness and reduce irritation, while maintaining effective drug permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rubber-based adhesive matrix is used to ensure sufficient skin adhesiveness, then adhesiveness is improved, but skin irritation increases
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive matrix by using polyacrylate and polymethacrylate instead of rubber-based adhesives. This parameter change maintains sufficient adhesiveness while reducing skin irritation, as the acrylic-based polymers are less irritating to skin compared to rubber-based adhesives.
Solution Approach 2:
The patent employs a composite adhesive system combining polyacrylate and polymethacrylate with specific functional additives. This composite material approach creates an adhesive matrix that balances adhesiveness and skin compatibility, achieving both strong bonding and reduced irritation through synergistic material combinations.
2Quantity of substance
If a large amount of drug is contained in the adhesive matrix, then drug delivery capacity is improved, but adhesiveness decreases due to drug exusion
Solution Approach 1:
The patent applies local quality by creating distinct functional zones within the patch structure. The adhesive layer contains polyacrylate and polymethacrylate with specific properties optimized for bonding, while the drug reservoir layer separately manages high drug content. This spatial separation allows the adhesive layer to maintain strong adhesiveness without being compromised by drug exusion from the high-concentration drug layer.
Solution Approach 2:
The patent segments the patch into functionally distinct layers: an adhesive layer containing polyacrylate and polymethacrylate for bonding, and a separate drug reservoir layer for high drug content. This segmentation prevents drug from interfering with adhesive properties, allowing both high drug delivery capacity and strong adhesiveness to coexist in different zones of the same patch.
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 sufficient skin adhesiveness and low skin irritation, along with good drug permeability and transdermal absorbability, as demonstrated by skin permeability tests and primary irritation tests.
Implementation Method 1
the drug is added to an adhesive matrix and the like and a patch is formed... transdermal absorption type preparation containing rivastigmine together with an antioxidant in an adhesive substrate
Implementation Method 2
the patch shows high skin permeability of a drug, good transdermal absorbability... a non-volatile hydrocarbon oil in more than 50 parts by weight and not more than 800 parts by weight per 100 parts by weight of the thermoplastic elastomer
Data Source
AI summary
A patch containing a storage layer retaining a drug or a pharmaceutically acceptable salt thereof and an adhesive layer which are formed on a support, wherein the adhesive layer contains a thermoplastic elastomer, and a non-volatile hydrocarbon oil in more than 50 parts by weight and not more than 800 parts by weight per 100 parts by weight of the elastomer, and the adhesive layer optionally further contains a tackifier at a content of not more than 10 wt %.