Membrane emulsification technology can be divided into direct membrane emulsification and fast membrane emulsification. Both membrane emulsification methods have their own advantages in the preparation of homogeneous emulsions with different particle size control ranges.
1. Direct Membrane Emulsification Technology
Direct membrane emulsification prepares microspheres by slowly passing through the membrane orifice by gas pressure of the dispersed phase in the storage tank. During the process, the droplets are subjected to the trapping force, droplet buoyancy, interfacial tension and membrane pressure at the outlet of the membrane orifice during continuous phase stirring, and under the action of these four forces, the emulsion grows from small to large on the membrane orifice and gradually forms homogeneous droplets.
2. Rapid Membrane Emulsification Technology
Rapid membrane emulsification is where larger droplets are deformed by pressure at the membrane orifice to produce small and uniform droplets. The higher the pressure applied, the more intense the squeeze on the emulsion and the smaller the size of the emulsion droplets formed. Therefore, selecting the right pressure allows the preparation of microspheres with target particle size and uniform size. In order to avoid as much as possible the errors caused by human operation factors and contamination by impurities and bacteria during the preparation process, the development of automated membrane emulsification equipment can also be carried out for use in the pilot and production of the company.
Advantages of Membrane Emulsification Technology for Making Microspheres
1. Green and environmental protection, reduce cost
The use of membrane emulsification technology to produce uniform particle size microspheres can significantly reduce the cost of raw and auxiliary materials, more in line with the needs of green chemicals. The whole process of preparing uniform particle size microspheres by membrane emulsification technology is gentle and mild, with less heat production and less loss of the active material embedded in the microspheres, which can save about 40% of raw and auxiliary materials and reduce the cost of raw and auxiliary materials. In terms of process, the microspheres prepared by membrane emulsification technology are of uniform particle size, which eliminates the need for sieving and subsequent screen cleaning and regeneration processes, simplifying the overall process flow and further reducing the process cost of homogeneous microsphere production.
2. Good batch-to-batch repeatability and scale up
The characteristics of uniform particle size and good batch-to-batch repeatability are the important guarantee of microsphere scale-up production. When the microsphere preparation is scaled up, the membrane emulsification technology has good controllability and repeatability for the preparation of homogeneous microspheres.
3. Facilitate the study of conformational relationships
As a drug carrier, the particle size of microspheres not only affects its release rate, but also influences its distribution and absorption in the body, thus affecting the final therapeutic effect.
Reference
1. Wang, L. Y., et al. (2005) Preparation of uniform sized chitosan microspheres by membrane emulsification technique and application as a carrier of protein drug. Journal of Controlled Release, 106(1-2), 62-75.
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