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08:06
Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications
Published on: June 2, 2017
Role of solvent/non-solvent ratio on microsphere formation using the solvent removal method
J Godbee1, E Scott, P Pattamunuch
1Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA.
Journal of Microencapsulation
|June 17, 2004
Summary
Microsphere formation during solvent removal depends critically on good solvent concentration in the non-solvent mixture. Higher polymer solution viscosity requires more good solvent to prevent rapid precipitation and ensure successful microsphere production.
Area of Science:
- Materials Science
- Chemical Engineering
- Biotechnology
Background:
- Microsphere formation via solvent removal is crucial for drug delivery and tissue engineering.
- Controlling polymer precipitation is key to achieving desired microsphere morphology and properties.
Purpose of the Study:
- To investigate the impact of good solvent concentration and non-solvent viscosity on microsphere formation.
- To determine the primary controlling parameters in the solvent removal process for microsphere fabrication.
Main Methods:
- Investigated the effect of varying good solvent concentrations in non-solvent mixtures.
- Evaluated the influence of polymer solution viscosity and non-solvent viscosity on microsphere formation.
- Utilized a model drug (fluorescein isothiocyanate conjugated-labelled bovine serum albumin) to assess its effect on polymer solution viscosity.
Main Results:
- Higher polymer solution viscosity necessitates a higher concentration of good solvent in the non-solvent mixture to prevent premature polymer precipitation.
- Non-solvent viscosity decreases with increasing good solvent concentration.
- Microsphere formation failed below critical good solvent concentrations (175 ml for poly-L-lactic acid, 150 ml for poly(D,L-lactide-co-glycolide)) or when ethyl acetate replaced methylene chloride, irrespective of achieved viscosity.
Conclusions:
- Good solvent concentration in the non-solvent mixture is a more critical factor in microsphere formation than non-solvent viscosity.
- Diffusion is the primary controlling parameter in the solvent removal process for microsphere fabrication.
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