Development of new microencapsulation techniques useful for the preparation of PLGA microspheres

Hongkee Sah, Beom Jin Lee

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Intensive efforts were made to develop an efficient, novel microencapsulation system useful to encapsulate a model drug, risperidone, to PLGA microspheres. Methyl dichloroacetate was used as a dispersed solvent for the first time, since it possessed excellent solvency power on PLGA and readily underwent ammonolysis. A dispersed phase composed of methyl dichloroacetate, risperidone, and PLGA was emulsified in an aqueous phase to form an O/W emulsion. Adding ammonia solution into the emulsion rapidly converted methyl dichloroacetate into water-soluble dichloroacetamide and methanol. As a result, emulsion droplets were immediately transformed into hardened microspheres. The new microencapsulation system allowed us to make PLGA microspheres with a drug payload of > 40 wt.-% and attain almost complete encapsulation efficiencies. In summary, preparing an O/W emulsion and subjecting the emulsion to ammonolysis led to development of an efficient, novel microencapsulation system. It was anticipated that the new system could make it possible to load other bioactive materials into microspheres made of various types of hydrophobic polymers.

Original languageEnglish
Pages (from-to)1845-1851
Number of pages7
JournalMacromolecular Rapid Communications
Issue number21
StatePublished - 1 Nov 2006


  • Drug delivery systems
  • Microencapsulation
  • Microspheres
  • Polyesters


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