Ketoprofen Adhesive Patch UV Stabilization
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Solution Overview
Problem
Patches containing nonsteroidal anti-inflammatory analgesic drugs and rubber-system macromolecules with double bonds in their adhesive base degrade upon UV exposure, leading to stickiness and stringiness issues due to radical formation from drug decomposition.
Innovation Solution
Incorporating UVA and/or UVB blockers into the adhesive base to stabilize the rubber-system macromolecules and prevent degradation, while selecting specific nonsteroidal anti-inflammatory drugs and blockers to maintain adhesive performance and skin penetrability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nonsteroidal anti-inflammatory analgesic drug and a rubber-system macromolecule having a double bond in a principal chain are used in an adhesive base, then the patch provides effective pain relief and adhesive performance, but the patch degrades upon UV exposure causing stickiness and stringiness
Solution Approach 1:
The patent introduces a UVA blocker and/or UVB blocker as an intermediary substance between the UV radiation and the rubber-system macromolecule. This mediator absorbs or blocks UV rays, preventing them from reaching and degrading the macromolecule, thus resolving the contradiction between maintaining adhesive performance and improving light stability.
Solution Approach 2:
The patent converts the harmful UV radiation into a beneficial effect by using the degradation products of the nonsteroidal anti-inflammatory drug as radical scavengers. These radicals, initially harmful to the macromolecule, are utilized to protect it from UV-induced degradation, turning a harmful mechanism into a protective one.
2Stability of the object's composition
If a UV blocker is added to the base to stabilize the rubber-system macromolecule, then light stability is improved, but the complexity of the formulation increases
Solution Approach 1:
The patent achieves multi-functionality by selecting UV blockers that simultaneously serve as stabilizers for the rubber-system macromolecule and as components that do not interfere with the analgesic effect of the drug. This approach adds light stability functionality without requiring separate additional components, thereby minimizing formulation complexity.
3Reliability
If the rubber-system macromolecule is exposed to UV rays, then the nonsteroidal anti-inflammatory drug decomposes and loses efficacy, but adding stabilizers increases the cost of production
Solution Approach 1:
The patent applies preliminary anti-action by incorporating UV blockers into the adhesive base formulation before the patch is exposed to UV radiation. These blockers proactively prevent the decomposition of the nonsteroidal anti-inflammatory drug by blocking UV rays in advance, thereby maintaining drug efficacy without requiring post-manufacturing interventions.
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 addition of UVA and/or UVB blockers effectively suppresses the degradation of rubber-system macromolecules, maintaining adhesive performance and preventing stickiness, while controlling drug skin penetrability and stability.
Implementation Method 1
adding a UVA blocker and/or a UVB blocker, which suppress decomposition of a nonsteroidal anti-inflammatory analgesic drug effectively
Implementation Method 2
the degradation of a rubber-system macromolecule having a double bond at least in a principal chain thereof, such as a styrene-isobutylene-styrene block copolymer, is also greatly accelerated by radicals formed as a result of decomposition of the drug due to the exposure to UV rays
Data Source
AI summary
An adhesive patch comprising a substrate and a pressure-sensitive adhesive base, wherein the pressure-sensitive adhesive base comprises a rubbery polymer having double bonds in the main chain and a nonsteroidal anti-inflammatory analgesic and contains a UVA screening agent and/or UVB screening agent as a stabilizer for the rubbery polymer. The adhesive patch is excellent in the stability of the pressure-sensitive adhesive base and in drug infiltration into the skin.