Transdermal Patch Using Local Anesthetic as Absorption Promoter
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Solution Overview
Problem
Existing transdermal adhesive patches face challenges in achieving high anti-inflammatory and analgesic effects while maintaining drug release without damaging physical properties or causing skin irritation, particularly when formulating basic anti-inflammatory analgesics with absorption promoters.
Innovation Solution
A transdermally absorbable adhesive patch containing a basic anti-inflammatory analgesic with a pKa of 7 or more, such as acetaminophen or valdecoxib, combined with a local anesthetic like lidocaine or oxybuprocaine, which serves as both an analgesic and absorption promoter, within specific weight percentages to ensure effective drug release and skin permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additives such as solubilizers or absorption promoters are formulated in adhesive patches to enhance transdermal absorption of basic drugs, then skin permeability of the basic drug is improved, but the physical properties of the adhesive patch are damaged and skin irritation increases
Solution Approach 1:
The patent uses an organic acid or organic salt as an intermediary substance to form stable ion pairs with the basic drug. This ion pair formation acts as a mediator that enhances skin permeability without requiring large amounts of traditional absorption promoters, thereby reducing skin irritation while maintaining improved drug absorption
Solution Approach 2:
The patent changes the chemical state of the basic drug by forming ion pairs with organic acids or salts. This parameter change (from neutral basic drug to ionized complex) allows the drug to penetrate skin more effectively without damaging patch physical properties or causing excessive irritation
2Reliability
If additives are formulated in adhesive patches to enhance transdermal absorption, then skin permeability of the basic drug is improved, but the physical properties of the adhesive patch are damaged
Solution Approach 1:
The patent changes the chemical form of the basic drug through ion pair formation with organic acids or salts. This parameter change enables effective transdermal delivery without requiring high concentrations of additives that would compromise the adhesive patch's physical integrity
Solution Approach 2:
The organic acid or salt serves as a chemical intermediary that facilitates drug permeation through ion pair formation. This approach allows for enhanced absorption with minimal additive concentrations, preserving the adhesive patch's physical properties
3Reliability
If a local anesthetic is formulated with an acidic anti-inflammatory analgesic, then transdermal absorption is enhanced, but few reports exist for basic anti-inflammatory analgesics with local anesthetics
Solution Approach 1:
The patent inverts the conventional approach by using a local anesthetic (typically cationic) as the absorption promoter for basic anti-inflammatory analgesics, rather than using organic acids with basic drugs or vice versa. This reverse strategy enables effective transdermal delivery of basic anti-inflammatory analgesics like acetaminophen, butorphanol, and buprenorphine
Solution Approach 2:
The patent applies the local anesthetic as a universal absorption promoter that works with basic anti-inflammatory analgesics through ion pair formation. This multi-functional approach allows the local anesthetic to serve both as an analgesic agent and as a permeation enhancer
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 high and sustained release of the basic anti-inflammatory analgesic with excellent analgesic activity of the local anesthetic, maintaining the physical properties of the patch and minimizing skin irritation, thereby providing effective transdermal absorption and clinical utility.
Implementation Method 1
the skin permeability of the basic drug has been enhanced by formation of a stable ion pair between the basic drug and the organic acid (salt) formulated
Implementation Method 2
transdermally absorbable adhesive patch which contains both a basic anti-inflammatory analgesic and a local anesthetic as an absorption promoter
Data Source
AI summary
A transdermally absorbable preparation in which a basic anti-inflammatory analgesic is formulated is provided to be an external adhesive patch, which has excellent drug releasing without damaging the physical properties of a plaster. The preparation can achieve high releasing of the basic anti-inflammatory analgesic without losing the releasing of the local anesthetic. Specifically provided is a transdermally absorbable adhesive patch, which contains both the basic anti-inflammatory analgesic and the local anesthetic as the absorption promoter for the basic anti-inflammatory analgesic. The basic anti-inflammatory analgesic has the acid dissociation constant (pKa) of 7 or more. The content of the basic anti-inflammatory analgesic is from 0.1% to 10% by weight to the total weight of the drug-containing plaster, and the content of the absorption promoter is from 0.01% to 20% by weight to the total weight of the drug-containing plaster in the transdermally absorbable adhesive patch.