PLGA microspheres with high drug loading and high encapsulation efficiency prepared by a novel solvent evaporation technique

J Microencapsul. 2006 Aug;23(5):471-9. doi: 10.1080/02652040600687613.


PLGA microspheres with high drug loading and high encapsulation efficiency were fabricated by a novel solvent evaporation process-in-situ S/O/W process. Insulin was dissolved in DMSO and dispersed into DCM to form fine particles due to an anti-solvent effect. The in-situ formed suspension was then added into an aqueous phase and emulsified. Microspheres were formed following the evaporation of organic solvents. The experimental results showed that the modified S/O/W process could encapsulate more than 90%(w/w) insulin in the microspheres with a drug loading of over 15% and the initial burst was much less than microspheres made by a W1/O/W2 process. Compared with a traditional water-in-oil-in-water (W1/O/W2) process, the in-situ S/O/W process does not require high solubility of the encapsulated drug in water and, because no special pre-treatment is needed to reduce the particle size of the drug, it is superior to an ordinary S/O/W process. The in-situ S/O/W process is particularly applicable to encapsulate peptides and low molecular weight proteins.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Biocompatible Materials / chemistry
  • Delayed-Action Preparations / chemistry
  • Dimethyl Sulfoxide / chemistry
  • Drug Compounding / methods
  • Insulin*
  • Lactic Acid / chemistry*
  • Microscopy, Electron, Scanning
  • Microspheres*
  • Particle Size
  • Polyglycolic Acid / chemistry*
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polymers / chemistry*
  • Solvents / chemistry
  • Surface Properties
  • Swine


  • Biocompatible Materials
  • Delayed-Action Preparations
  • Insulin
  • Polymers
  • Solvents
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyglycolic Acid
  • Lactic Acid
  • Dimethyl Sulfoxide