Adhesive Skin Patch Corner Protrusion Prevents Cold Flow
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Solution Overview
Problem
Adhesive patches experience 'cold flow' during storage, leading to drug content reduction and adhesion issues with packaging, as well as skin irritation and peeling problems due to the oozing of adhesive components.
Innovation Solution
The adhesive patch is designed with a rectangular planar shape, featuring a protrudent part on the support-side surface at the corner and a thinner peripheral part, along with a split release liner that does not traverse the protrudent part, to minimize contact with the package and prevent drug and adhesive component oozing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the adhesive layer contains a large quantity of liquid component to enhance soft touch and reduce skin irritation, then the softness and skin compatibility are improved, but cold flow occurs during storage causing drug loss and adhesion problems
Solution Approach 1:
The adhesive layer is divided into a first adhesive layer and a second adhesive layer with different compositions and properties. The first layer provides initial adhesion with lower liquid content, while the second layer provides softness and skin compatibility with higher liquid content, preventing cold flow while maintaining skin friendliness.
Solution Approach 2:
Different regions of the adhesive layer have different compositions - the first adhesive layer has different properties than the second adhesive layer. This local differentiation allows the patch to have firm adhesion in some areas while maintaining softness and preventing cold flow in others.
2Quantity of substance
If the adhesive layer is made thick to increase drug content and solubility, then the drug delivery capacity is improved, but cold flow tendency increases causing oozing and shape deformation
Solution Approach 1:
The thick adhesive layer is segmented into two distinct layers with different functions. The first layer provides structural stability and prevents cold flow, while the second layer contains the drug and provides therapeutic effect, allowing thick construction without shape deformation.
Solution Approach 2:
The adhesive layer uses a composite structure with two different adhesive materials having distinct properties. This composite approach allows the combination of shape-stabilizing characteristics with drug-containing soft adhesive properties, preventing cold flow while maintaining drug delivery capacity.
3Ease of operation
If the adhesive layer is made soft and velvety to enhance comfort, then the skin compatibility is improved, but the adhesive layer component oozes out during storage
Solution Approach 1:
The adhesive system is segmented into two layers where the first layer acts as a structural backbone preventing oozing, while the second layer provides the soft, velvety comfort feel. This segmentation allows comfort without compromising structural integrity during storage.
Solution Approach 2:
The physical and chemical parameters of the adhesive layers are optimized differently - the first layer has parameters optimized for shape stability and cold flow resistance, while the second layer has parameters optimized for softness and skin comfort, achieving both comfort and preventing oozing.
Data Source
AI summary
The invention is intended to provide an adhesive patch which contains a drug except bisoprolol and which effectively inhibits the occurrence of oozing out or sticking out of the adhesive layer components from the exposed area of the adhesive layer of the adhesive patch during storage as well as the occurrence of oozing out of the drug from the adhesive layer thereby preventing the reduction in drug content. The support, the release liner and the adhesive layer constituting the adhesive patch each are formed to have a rectangular planar shape and the entire adhesive patch are formed to have a rectangular planar shape, and a protrudent part is formed on the support-side surface of the adhesive patch at a corner thereof. In addition, the adhesive patch may be formed to have a middle part and a peripheral part, and the protrudent part may be formed at a corner of the rectangular middle part. Further, between the adjacent at least two protrudent parts, a connecting built-up part may be provided in which the thickness of the adhesive patch is smaller than the thickness of the adhesive patch in the protrudent part. In case where the release liner has a split part, the split part is made so as not to traverse the protrudent part.