Biodegradable Microsphere Preparation Using Ternary Solvent System
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Solution Overview
Problem
Conventional methods for preparing biodegradable microspheres, such as solvent evaporation and spray-drying, face limitations in loading drugs insoluble in non-polar solvents and result in low uniformity of drug loading efficiency, especially for water-soluble drugs, due to phase separation issues and the presence of thickeners or surfactants within the microspheres.
Innovation Solution
A method utilizing a single-phase mixed solution of water, alcohol, and dichloromethane, where a drug and biodegradable polymer are dissolved, preventing phase separation, and the mixture is dispersed in an aqueous phase without a surfactant, allowing for uniform drug loading and stable microsphere formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a W/O/W double emulsion method is used to prepare biodegradable microspheres for water-soluble drugs, then the drugs can be loaded into the microspheres, but phase separation occurs during the preparation process resulting in low uniformity of drug loading efficiency
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system by introducing a specific ternary mixed solvent system (chloroform-methanol-water with optimized volume ratios) to prevent phase separation and achieve uniform drug loading throughout the preparation process
Solution Approach 2:
The patent uses a composite solvent system combining three different solvents (chloroform, methanol, and water) in specific proportions to create a stable single-phase mixed solution that maintains homogeneity during microsphere preparation
2Stability of the object's composition
If thickeners or surfactants are added to stabilize the emulsion during microsphere preparation, then phase separation is reduced, but the microspheres contain residual thickeners or surfactants that affect product purity
Solution Approach 1:
The patent removes (extracts) the need for thickeners and surfactants by using a specially designed ternary solvent system that inherently prevents phase separation through its unique phase behavior, eliminating harmful residues from the final product
Solution Approach 2:
The methanol component acts as an intermediary substance that facilitates the formation of a stable single-phase mixed solution, preventing phase separation without requiring additional thickeners or surfactants
3Ease of manufacture
If conventional solvent evaporation method is used with non-polar solvents, then the process is simple, but drugs insoluble in non-polar solvents cannot be loaded effectively
Solution Approach 1:
The patent creates a universal solvent system that can dissolve both water-soluble and non-polar drugs through its ternary composition, making the preparation method applicable to a wide range of drug types while maintaining process simplicity
Solution Approach 2:
The patent modifies the solvent polarity parameters by combining polar and non-polar solvents in specific ratios, creating a mixed solvent system with intermediate polarity that can accommodate drugs with varying solubility characteristics
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
This approach enables the preparation of biodegradable microspheres with consistent drug loading efficiency throughout the process, avoiding phase separation and the need for thickeners or surfactants, resulting in a stable and efficient sustained-release formulation.
Implementation Method 1
a single-phase mixed solution containing water, alcohol, and dichloromethane in a specific mixing ratio, the solvents surprisingly did not phase-separate
Implementation Method 2
the steps of evaporating an organic solvent used for preparing microspheres and hardening the microspheres
Data Source
AI summary
The present invention relates to a method for preparing biodegradable microspheres using a single-phase mixed solution containing water, alcohol, and dichloromethane. Provided is a method for preparing a biodegradable microsphere having a uniform drug loading efficiency by preparing and using a single-phase mixed solution in which no phase separation occurs without using a thickener and a surfactant. The preparation method of the present invention has the feature of keeping the content of a loaded drug uniform until a final biodegradable microsphere is prepared, by using a single-phase mixed solution in which no phase separation by a solvent occurs in the preparation process. Thus, the preparation method of the present invention is remarkably useful for the preparation of biodegradable microspheres.