Transdermal Preparation Using Acetic Acid-Sodium Acetate Complex
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Solution Overview
Problem
Transdermally absorbable preparations face challenges in maintaining stability and preventing drug crystallization, especially when high concentrations of poorly soluble drugs are used, due to the instability of silicate-based complexes and the volatility of organic acids during solvent removal, leading to reduced skin permeability and bioavailability.
Innovation Solution
A transdermally absorbable preparation comprising a complex of acetic acid and sodium acetate, with a particle diameter of 1-30 µm, and optionally including silicic anhydride, which forms a stable complex that suppresses drug crystallization and enhances skin permeability, characterized by specific X-ray diffraction peaks and a specific surface area of silicic anhydride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drug is blended in a high concentration to an adhesive base to improve transdermal absorbability, then transdermal absorbability is improved, but the drug crystallizes because it has low solubility to the base
Solution Approach 1:
The patent introduces silicic anhydride as an intermediary substance that mediates between the drug and the adhesive base. The silicic anhydride forms a complex with the organic acid, creating a stable intermediate structure that prevents direct crystallization of the drug from the base while maintaining high drug concentration for improved transdermal absorbability.
Solution Approach 2:
The patent creates a composite material system consisting of silicic anhydride, organic acid, and drug blended in the adhesive base. This composite structure allows the drug to be dispersed in a high concentration without crystallizing, as the silicic anhydride-organic acid complex provides a stable matrix that maintains drug solubility while enabling high drug loading for enhanced transdermal absorption.
2Stability of the object's composition
If silicic anhydride is used to suppress crystallization of a drug, then crystallization is suppressed initially, but crystallization gradually proceeds after preparing the preparation due to temperature/humidity effects
Solution Approach 1:
The organic acid acts as an intermediary that stabilizes the drug-silicic anhydride complex. The organic acid forms hydrogen bonds with both the silicic anhydride and the drug, creating a more robust intermediate structure that is less sensitive to temperature and humidity changes, thereby preventing gradual crystallization over time.
Solution Approach 2:
The patent creates a ternary composite system of silicic anhydride, organic acid, and drug that provides enhanced long-term stability. The synergistic interaction among these three components creates a stable matrix structure that resists crystallization under varying storage conditions, maintaining drug amorphous state and preventing gradual crystallization that occurs with silicic anhydride alone.
3Stability of the object's composition
If the amount of organic acid is decreased due to volatility during solvent removal, then the complex formation stability decreases, but the organic acid having a low boiling point volatilizes during the drying process
Solution Approach 1:
The silicic anhydride acts as a stable intermediary that forms a robust complex with the organic acid. This complex structure protects the organic acid from volatilization during solvent removal, as the strong interaction between silicic anhydride and organic acid reduces the free organic acid available for evaporation, maintaining complex formation stability even with low boiling point acids.
Solution Approach 2:
The patent modifies the physical-chemical parameters of the organic acid by forming a complex with silicic anhydride. This complexation changes the volatility parameter of the organic acid, effectively reducing its vapor pressure and preventing loss during the drying process, while maintaining the necessary amount of organic acid for stable complex formation with the drug.
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 preparation effectively suppresses drug crystallization, improves skin permeability, and maintains stability over time, allowing for high concentrations of poorly soluble drugs to be used without aggregation, thereby enhancing transdermal absorption and bioavailability.
Implementation Method 1
a transdermally absorbable preparation comprising a complex of acetic acid and sodium acetate... which forms a stable complex that suppresses drug crystallization
Implementation Method 2
Transdermally absorbable preparation... enhances skin permeability... enhancing transdermal absorption
Implementation Method 3
characterized by specific X-ray diffraction peaks... having peaks at one or more positions from 13.7 ± 0.2°, 22.5 ± 0.2°, 34.9 ± 0.2° (2θ)
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is a transdermally absorbable preparation in which the crystallization of a medicinal agent can be prevented even when the medicinal agent has poor solubility in a base material and is contained in the base material at a high concentration, and which exhibits excellent long-term stability and transdermal absorbability of the medicinal agent. By adding a complex of an organic acid and an organic acid salt and a medicinal agent to a base material, it becomes possible to produce a transdermally absorbable preparation in which the crystallization of the medicinal agent can be prevented and which has excellent preparation properties and transdermal absorbability. Also disclosed is use of a complex of an organic and an organic acid salt for preventing the crystallization of a medicinal agent in a transdermally absorbable preparation.