Polymeric Microsphere Production via Porous Membrane Solidification
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Solution Overview
Problem
Current methods for producing polymeric microspheres for controlled or sustained release of therapeutic agents face challenges such as sterilization difficulties due to protein susceptibility, size dispersion, low encapsulation efficiency, and burst release, which complicate the manufacturing process and reduce product quality.
Innovation Solution
A simplified process involving three unit operations: microsphere formation and solidification, identification and ejection of oversized particles, and surface smoothing, using a porous membrane and gentle solvent extraction to achieve uniform size and high encapsulation efficiency, minimizing exposure to hazardous conditions and reducing the number of unit operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sterilization methods (filtration, radiation, heating) are used, then sterilization is achieved, but protein denaturation and degradation occur
Solution Approach 1:
The invention performs sterilization by filtration at the very beginning of the process, before microsphere formation and protein encapsulation. This preliminary sterilization of the aqueous phase eliminates the need for post-formation sterilization that would expose proteins to denaturing conditions, thus resolving the contradiction between achieving sterilization and preventing protein degradation
Solution Approach 2:
The invention uses an intermediary approach by forming microspheres in a sterile aqueous environment through controlled solvent extraction, where the polymer matrix forms around already-sterilized proteins without requiring harsh sterilization of the final product. This intermediary process avoids direct exposure of proteins to sterilizing agents
2Stability of the object's composition
If stirring is used to prevent microsphere fusion, then fusion is reduced, but shear stress breaks microspheres and causes ingredient leakage
Solution Approach 1:
The invention applies gentle, minimal stirring just sufficient to prevent microsphere fusion during formation, rather than vigorous stirring. This partial action approach provides just enough mixing to maintain separation while avoiding the excessive shear stress that would break microspheres and cause ingredient leakage, thus resolving the contradiction
3Manufacturing precision
If sieving and powder-filling are used to remove undesired particles, then size uniformity is improved, but manufacturing complexity and exposure to ambience increase
Solution Approach 1:
The invention performs size selection during the microsphere formation process itself by controlling droplet generation at the porous membrane, rather than requiring post-formation sieving. This preliminary size control eliminates subsequent separation steps and avoids exposure to ambience, resolving the contradiction between achieving size uniformity and reducing manufacturing complexity
Solution Approach 2:
The invention merges the size control function with the microsphere formation process by using a porous membrane with controlled pore sizes that directly determines microsphere diameter. This consolidation of size selection into the formation step eliminates separate sieving operations, reducing manufacturing complexity while maintaining size uniformity
4Ease of manufacture
If microspheres are formed with diversified diameters, then production is simpler, but yield is reduced due to removal of undesired particles
Solution Approach 1:
The invention changes the key parameter of pore size in the porous membrane to directly control microsphere diameter. By selecting appropriate pore sizes, the process produces microspheres of desired uniform size without requiring post-formation size selection, thus maintaining production simplicity while maximizing yield by eliminating the need to remove undesired particles
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 process results in microspheres with 90%+ encapsulation efficiency, improved protein stability, and reduced burst release, enabling the production of uniform, designable particle sizes suitable for controlled release formulations with enhanced manufacturing efficiency and product quality.
Implementation Method 1
solidifying the detached embryonic microspheres by extracting the solvent that dissolves the microsphere-forming materials
Implementation Method 2
forcing the particle forming materials to pass through a porous wall and detach into a receiving/carrier medium as embryonic (soft) microspheres
Data Source
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AI summary
Disclosed a microsphere-producing process involving three integrated unit operations: 1) microspheres formation; 2) microspheres quality control; 3) post formation microspheres treatment. The first unit operation is integrated with four essential functions: forcing the particle forming materials to pass through a porous membrane to form embryonic microsphere; enforcing the embryonic microspheres to detach the porous membrane; solidifying the embryonic microspheres; collecting and outputting the solidified microspheres. The quality control unit operation consists of discrimination and ejection of oversized microspheres. The post treatment unit operation is integrated with two essential functions: smoothing the microsphere surfaces and reducing organic solvents trapped inside of microsphere matrix.