SPG Membrane Emulsification for Biodegradable Microparticles
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Solution Overview
Problem
Existing methods for producing biodegradable polymer microparticles for tissue repair and drug delivery face challenges in achieving uniform size, spherical shape, and porosity, while also being suitable for industrial-scale production, which are necessary to avoid phagocytosis, foreign body reactions, and needle clogging, and to maintain volume over time.
Innovation Solution
A method involving the use of a Shirasu Porous Glass (SPG) membrane emulsification technique to form a dispersed phase of biodegradable polymers like poly(lactic acid) or poly(caprolactone) with a porogen, forming spherical microparticles with a diameter of 10 to 200 µm and porosity ratio of 10 to 50%, combined with biocompatible carriers for stable production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microparticle diameter is increased to avoid phagocytosis (≥20 μm), then immune system avoidance is improved, but injection needle passage capability deteriorates (>50 μm causes clogging)
Solution Approach 1:
The patent applies parameter changes by precisely controlling microparticle diameter within the 20-50 μm range, optimizing both immune avoidance and injectability. The SPG membrane emulsification method enables precise size control at this critical threshold range, where particles are large enough to avoid macrophage phagocytosis but small enough to pass through injection needles without clogging.
2Manufacturing precision
If microparticle size distribution is narrowed to improve uniformity, then product quality is improved, but mass production capability deteriorates
Solution Approach 1:
The patent replaces traditional mechanical homogenization methods with SPG membrane emulsification, which uses the membrane's porous structure to physically filter and size-select particles during formation. This substitution achieves narrow size distribution (high manufacturing precision) while maintaining high throughput (mass production capability) because the membrane process is inherently scalable and continuous.
Solution Approach 2:
The SPG membrane acts as an intermediary element that mediates between the emulsion formation process and the final particle size. The membrane's uniform pore structure (10-30 μm) serves as a physical template that guides droplet formation and size control, enabling both uniform particle size and high production efficiency simultaneously.
3Reliability
If microparticles are made porous to improve tissue integration, then biocompatibility is improved, but pore size uniformity deteriorates (pores >10 μm generated in large amount)
Solution Approach 1:
The patent utilizes porous materials by incorporating porogens (hydrophilic polymers or salts) into the emulsion before SPG membrane processing. These porogens create controlled porous structures within the microparticles during solvent removal, improving biocompatibility and tissue integration while the SPG membrane ensures uniform pore size distribution through its size-selective emulsification mechanism.
4Ease of manufacture
If homogenizer is used for simple production process, then manufacturing complexity is reduced, but particle size distribution broadens
Solution Approach 1:
The patent replaces the mechanical homogenization system with a membrane-based emulsification system. While the SPG membrane method requires additional equipment, it eliminates the need for complex multi-stage homogenization processes, actually simplifying the overall manufacturing流程 while achieving narrow particle size distribution through the membrane's inherent size-selective properties.
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 method produces biodegradable polymer microparticles with uniform size distribution, spherical shape, and controlled porosity, suitable for tissue repair and drug delivery, enabling efficient industrial-scale production and maintaining volume over time without foreign body reactions or needle clogging.
Implementation Method 1
applying pressure to the dispersed phase formed in step 1) to allow the dispersed phase to pass through the pore of SPG membrane (Shirasu Porous Glass membrane)
Implementation Method 2
form an emulsion in a continuous phase comprising a surfactant
Implementation Method 3
continuous phase comprising a surfactant
Implementation Method 4
removing the organic solvent from the emulsion formed in step 2) to form porous microparticles
Data Source
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AI summary
Provided are: a method for preparing biodegradable polymer microparticles and, particularly, porous microparticles of a biodegradable polymer; and biodegradable polymer microparticles prepared thereby, particularly, porous microparticles of a biodegradable polymer.